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Article

Chemical Composition, Antioxidant and Antimicrobial Activity of Pericarpium Citri Reticulatae Essential Oil

1
College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
2
Sericulture & Agro-Food Processing Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou 510610, China
*
Authors to whom correspondence should be addressed.
Molecules 2011, 16(5), 4082-4096; https://doi.org/10.3390/molecules16054082
Submission received: 21 February 2011 / Revised: 29 April 2011 / Accepted: 3 May 2011 / Published: 18 May 2011

Abstract

:
The chemical composition, antioxidant and antimicrobial activity of Pericarpium Citri Reticulatae (PCR) essential oil obtained using an improved Clevenger type apparatus were studied. Among the five different PCRs examined the highest yield of essential oil was found in Chachi 2004 (harvested and stored in 2004) and the lowest in Chachi 2008 (harvested and stored in 2008). Fifty three different volatile compounds were determined, including terpenic hydrocarbons, alcohols, aldehydes, ketones and esters. D-limonene, one of terpenes, was the major constituent in PCR. The antioxidant capacity of PCR essential oil varied considerably with the duration of storage time, and the oil from Chachi 1994 has the strongest ferric-reducing antioxidant power. In addition, the essential oil possessed varying degrees of antimicrobial activity against Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis, Bacillus cereus), except Streptococcus faecalis, while had no effect on Gram-negative bacteria (Escherichia coli, Enterobacter cloacae).

1. Introduction

Pericarpium Citri Reticulatae (PCR), the dried ripe peel of mandarin (Citrus reticulata Blanco) and its cultivars, is acknowledged in the People’s Republic of China Pharmacopoeia, and has been used in traditional Chinese herbal medicine for a long time [1,2]. PCR “Chachi”, as the most popular type, has been used in foods and drugs due to its effectiveness as an antioxidant, in regulating qi (energy), normalizing the function of spleen and stomach, resolving phlegm, and so on [3,4,5]. The essential oil of PCR “Chachi”, as one of major bioactive compositions, perhaps accounts for the use of PCR as a Chinese herbal medicine.
At present, some studies on the fresh peel oils of different mandarins have been reported. The major monoterpenes of Turkish mandarin peel oil were found to be D-limonene (90.7%), γ-terpinene (3.9%), myrcene (2.1%), α-pinene (0.5%), sabinene (0.3%) [6]. The result is agreement with other literature. In Ponkan peel oil, where the monoterpene fraction accounts for more than 89.6% of the components, D-limonene was the most abundant component (80.3%), followed by γ-terpinene (4.7%), myrcene (2.1%) and α-pinene (1.2%) [7]. The major sesquiterpene component was (E)-β-farnesene (0.1%). The major oxygenated components found in the oil were octanal (0.2%), decanal (0.1%), linalool (0.4%), α-terpineol (0.1%), geranyl acetate (0.2%) and neryl acetate (0.1%) [6].
In addition, the essential oil of PCR has also been studied. The literature shows that the major components of PCR essential oil are D-limonene (75.28%), 1-methyl-4-(1-methylethyl)-1,4-cyclo- hexadiene (7.7%), β-myrcene (2.98%), α,α-4-trimethyl-3-cyclohexene-1-methanol (0.94%), 2-methoxy-4-vinylphenol (0.87%) and α-pinene (0.53%) [8]. Among the components, terpenes as the major components of the essential oil have effective antifungal and antioxidant activity [9,10,11]. Thus, the essential oil can partially replace chemical and synthetic agents with antioxidant and antimicrobial activity to avoid the toxicities and carcinogenic effects of chemical and synthetic agents [12,13,14]. However, there are few reports on the variation of essential oil of PCR after different storage times in relation to the function of PCRs. In traditional Chinese medicine, the quality of PCR “Chachi” is regarded to increase with the storage time, however, the reason for this remains unknown. Therefore, we focused our study on the chemical compositions, antioxidant and antimicrobial activity of the essential oil in PCR “Chachi” to try to find the truth.

2. Results and Discussion

2.1. Yields Rates of the Essential Oil

At present, many researchers used Clevenger apparatus to extract essential oil from samples [15,16,17]. The yield of essential oil by an improved microwave Clevenger apparatus in 30 min was equivalent to that obtained after 3 h with a regular Clevenger apparatus, as reported by Ferhat et al. [18]. The high temperature processing of hydro-distilled extraction methods, such as Clevenger apparatus can result in degradation of thermally labile compounds [19]. In our work the essential oil of PCRs was extracted with a modified Clevenger-type apparatus with a water-cooled oil receiver to reduce formation of artifacts due to overheating during hydro-distillation; the yield rates were listed in Table 1. The results showed that the highest essential oil yield was found in Chachi 2004 and the lowest in Chachi 2008. The essential oil yield variation first went up and then down with the duration of storage time. Since all the five types of PCRs were harvested from the same cultivar in the same plantation, it was inferred that the variation on yield rate of essential oil could not be caused by the difference of harvested material for PCRs. Therefore, the increase of the essential oil from Chachi 2008 to Chachi 2004 may be attributed to the transformation of some metabolites to the essential oil by way of secondary metabolism. The decrease in yield rate of essential oil with storage time from Chachi 2004 to Chachi 1994 probably happened because of high consumption of essential oil due to evaporation with the duration of storage time.

2.2. Linearity and Recovery of Standards

A standard mixture of seven compounds found in PCR oil was used to test linearity and recovery. Five levels of each analyte were prepared for plotting standard calibration curves. The concentration ranges, regression equations, R2 values, recoveries are shown in Table 2. The results showed a good linear behavior in the concentration ranges. Furfural showed the best linearity (R2 = 0.9983) and the least linearity was obtained for α-pinene (R2 = 0.9588). Recoveries were performed to test the accuracy of the method. As shown in Table 2, the average recoveries of standard compounds ranged from 84.9% to 113.7%. The results demonstrated that the method was applicable for the analysis of PCR oil because of good linearity and recoveries. It was agreement with the report by Mirhosseini et al. [20], while the report by Ibáñez et al. showed that the recoveries of 3-methylbutanol and ethyl-hexanoate ranged from 10 to 45%, and the recovery of hydrocarbons ranged from 4 to 25% [21].

2.3. Sample Analysis

PCR oil with five different storage times was analyzed to determine the composition of volatile compounds (Table 1 and Figure 1). Fifty three volatile compounds from the PCR oil were detected by GC-MS. The volatiles detected included terpenic hydrocarbons, alcohols, aldehydes, ketones and esters. A total of 61 and 59 compounds in the essential oil of Pericarpium Citri Reticulatae Viride (PCRV) and PCR determined were previously reported by Wang et al. [22]. There were 53, 48, 46, 47 and 45 volatile compounds identified in Chachi 2008, Chachi 2004, Chachi 2001, Chachi 1998 and Chachi 1994 respectively. Among these volatile compounds, seven compounds were identified by using chemical standards and the others were identified tentatively. The terpenes in volatile compounds were major components, and the composition and concentration of the terpenes were observed to differ with storage time (Table 1). Among the samples of five different storage times, the terpenes content of Chachi 2008 was highest. D-limonene was the predominant compound in the PCRs. It was in agreement with olfaction tests. D-limonene was also identified as the major component, accounting for 65.61-83.14% in PCRVs and PCRs reported by Wang et al. [22]. In addition, the concentrations of several volatile compounds such as β-myrcene, γ-terpinene, terpinolene and β-pinene in PCRs were detected to be relatively high.

2.4. Antioxidant Activity

Antioxidation is a complex process usually occurring through several mechanisms. The evaluation of the antioxidant activity for pure compounds or extracts should be carried out by more than one test method [39]. For the scavenging of DPPH radicals, the IC50 values (defined as the concentration of sample at which the inhibition percentage reached 50%) of essential oil were different (Table 3). The IC50 value of Vc was 3.14 ± 0.21 μg/mL. DPPH scavenging activity of those samples followed the order: Chachi 2008 > Chachi 2001 > Chachi 1998 > Chachi 2004 > Chachi 1994. The scavenging activity of Chachi 2008 was significantly (P < 0.05) stronger than that of the others. For the reducing power, Table 3 shows great differences in total antioxidant activity measured by the FRAP method. Chachi 1994 had the highest value of 26.89 ± 1.11 μmol TE/g, while Chachi 2008 had the lowest value of 11.36 ± 1.50 μmol TE/g. The rank order was Chachi 1994 > Chachi 1998 > Chachi 2001 > Chachi 2004 > Chachi 2008. The results showed that the reducing power of PCR essential oil from different storage times increased with the duration of PCR storage time. It is probably related to the increment of some components such as α-pinene and β-pinene during storage time. For the scavenging ABTS·+ radicals, the results showed that the inhibitory potentials followed the order: Chachi 2001 > Chachi 1998 > Chachi 2004 > Chachi 2008 > Chachi 1994. Thus the scavenging ABTS·+ radicals of PCR essential oil differed with the storage time. Although there were few literatures about the antioxidant activity of PCR essential oil, the antioxidant activity of PCR extract has been reported. According to Su et al. [40], the reducing power of PCR extracts increased with concentration (0-0.3 mg/mL) and the EC50 is 0.25 ± 0.02. However, the correlation between EC50 values of reducing power and total phenolic contents of PCR tested was low and not significant. Thus the reducing power of PCR extract might not attribute to the main phenolic components. Meanwhile, PCR extract had lower hydrogen peroxide-scavenging effect.
In general, the antioxidant capacities of PCR essential oil varied considerably with the storage time while Chachi 1994 has best antioxidant by FRAP. It may partially demonstrate PCR as a genuine medicinal herb why the pharmacologic activity is better with the duration of storage time.

2.5. Antimicrobial Activity

In Table 4, the PCR essential oil of different storage times were tested for antimicrobial activity by using 11 strains of microbes, viz. Salmonella lignieres (S. lignieres), Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), Bacillus subtilis (B. subtilis), Pseudomonas aeruginosa (P. aeruginosa), Bacillus cereus (B. cereus), Enterobacter cloacae (E. cloacae), Streptococcus faecalis (S. faecalis), Aspergillus flavus (A. flavus), Aspergillus niger (A. niger), Debaryomyces hansenii (D. hansenii). The results showed that the essential oil possessed effective antimicrobial activity against Gram-positive bacteria (S. aureus, B. subtilis, B. cereus) in varying degrees except S. faecalis. The essential oil had no effect on Gram-negative bacteria (E. coli, E. cloacae). Those results were confirmed by literatures. It has been reported that the essential oil from citrus peel shows inhibition against all Gram-positive bacteria, yeast and mold [41,42,43]. B. subtili, B. cereus, A. flavus and D. hansenii were the most sensitive microorganisms to the PCR essential oil (diameter of inhibition zone ranging from 8.1 to 16.9 mm; MIC values ranging from 0.03 to 0.06 mg/mL). Gram-positive bacteria are more sensitive to essential oil than Gram-negative bacteria due to their outer membrane barriers [44]. Gram-positive bacteria are more susceptible since have only an outer peptidoglycan layer which is not an effective permeability barrier while Gram-negative bacteria have outer phospholipids membranes [45]. Some reports showed terpenes, which constitute the major part of citrus peel oil, have a strong antifungal and antioxidant activities [9,46]. α-Pinene (monoterpene hydrocarbon) had slight activity against a panel of microorganisms [47]. Despite slight activity, pinene-type monoterpenes could be responsible for the total activity spectrum. At present, the mechanism of terpenes action is not fully understood but is speculated to involve membrane disruption by the lipophilic compounds [48].

3. Experimental

3.1. Materials and Chemicals

Five types of PCRs (named as “Chachi + harvested time”) were purchased from “Xin Baotang Chen Pi” Co. Ltd., which was one of the biggest traders of PCR in Xinhui County, China. All five types of PCRs were harvested from the same “Chachi” cultivar (Citrus reticulata Blanco) in the same plantation. These samples were authenticated by Professor Jiang Yueming at South China Botanical Garden, Chinese Academy of Sciences. A voucher specimen of each type is deposited at the Sericulture & Agro-Food Processing Research Institute, Guangdong Academy of Agricultural Sciences. These samples were dried in the oven at 50 °C to constant weight and ground and stored in refrigerator at 4 °C before use.
1,1-Diphenyl-2-picrylhydrazyl (DPPH) was purchased from Wako Co. Ltd. 2,4,6-Tri-pyridyl-s-triazine (TPTZ) was purchased from Tokyo Kasei Kogyo Co. Ltd. ABTS was purchased from Amresco Co. Ltd. 6-Hydroxy-2,5,7,8-tetramethyl-2-chromanecarboxylic acid (Trolox), cyclohexanone and a mixture of aliphatic hydrocarbons (C6-C22) were obtained from Sigma Chemical Co. (Shanghai, China). The standard chemicals used for identification, such as D-limonene was obtained from Aladdin Chemistry Co. Ltd. (Shanghai, China). The aroma standards furfural, α-pinene, β-myrcene, terpinolene, decanal and β-caryophyllene were provided without charge from Gld-boton Essential Company (Shenzhen, China). All other chemicals, analytical grade, i.e. anhydrous sodium carbonate, trichloroacetic acid (TCA), potassium dihydrogen phosphate, potassium hydrogen phosphate, potassium persulfate, dimethyl sulfoxide (DMSO), and methanol used in this study were purchased from Guangzhou Chemical Reagant Plant (Guangzhou, China). All culture media were purchased from Huankai Microbial Sci. & Tech. Co. Ltd. (Guangzhou, China).

3.2. Extraction of Essential Oil

PCRs were subjected to hydro-distillation for 2 h, in a modified Clevenger-type apparatus, with a water-cooled oil receiver to reduce formation of artifacts due to overheating during hydro-distillation. The essential oils were collected over water, separated and dried over anhydrous sodium sulfate. They were stored at 4 °C prior to studies.

3.3. Gas Chromatography/Mass Spectrograph (GC/MS)

Desorption and analysis of volatile components were carried out on an Agilent 6890 GC system coupled with an Agilent MSD 5975 quadrupole mass spectrometer. The separation was achieved on two fused silica capillary columns: (1) DB-WAX (30 m × 25 mm i.d. × 25 μm film); (2) DB-5MS (30 m × 25 mm i.d. × 25 μm film). The carrier gas was helium with flow rate of 1.0 mL/min. A sample of 1.0 μL was injected, using split mode (split ratio, 1: 20). The injector temperature was set at 250 °C. The GC oven temperature was increased from 40 °C to 70 °C at a rate of 10 °C /min, then programmed at 3 °C/min to 190 °C, then at 10 °C/min to 250 °C. The temperature of mass spectrometer was 230 °C. The ionizing energy was 70 eV. All data were obtained by collecting the full-scan mass spectra within the scan range 40-500 amu.

3.4. Qualitative and Quantitative Analysis

Identification of compounds detected by GC/MS analysis was done by comparing mass spectra and retention indices (RI) with the authentic standards and published data, as well as by comparing their mass spectra with the National Institute of standards and Technology (NIST) MS spectral database [49]. RI was calculated using a mixture of n-alkanes as standards. Some volatile compounds’ regression equations were made and their concentrations were obtained from these equations. For the other volatile compounds, quantitative determinations were obtained by using cyclohexanone as an internal standard. Volatile compounds’ content was calculated from the GC-peak areas relating to the GC-peak area of the internal standard. Some results were expressed as follows: Molecules 16 04082 i001

3.5. Scavenging of DPPH Radical

The effect of PCR on DPPH free radical was measured using the modified method of Shimada, Fujikawa, Yahara, and Nakamura [50]. A methanolic solution of DPPH (2.5 mL, 1 × 10-4 mol/L) was mixed with aliquots (0.5 mL) of different concentrations of sample in a tube. The reaction mixture was shaken well and incubated for 30 min at room temperature. Controls containing methanol instead of the antioxidant solution and blanks containing methanol instead of DPPH solution were also made. Vc was regarded as positive probe. The absorbance of the resulting solution was read at 517 nm against blank. The DPPH radical-scavenging activity was calculated as follows:
Scavenging activity (%) = [1 − (Asample − Ablank)]/Acontrol × 100
where Asample is the absorbance of DPPH added to sample at 517 nm, Ablank is the absorbance of methanol added to sample at 517 nm, Acontrol is the absorbance of DPPH added to methanol (without sample) at 517 nm.

3.6. Ferric-Reducing Antioxidant Power (FRAP) Assay

For FRAP assay, the procedure followed the method of Benzie and Strain with some modifications [51]. The FRAP reagent included acetate buffer (pH 3.6), 10 mM TPTZ solution in 40 mM HCl, and 20 mM Trolox solution. The FRAP reagent was prepared and warmed to 37 °C in a water bath prior to use. FRAP reagent (900 μL) was mixed with H2O (90 μL) and test sample (30 μL), and the final dilution of the test sample in the reaction mixture was 1/34. The solution was used to perform the calibration curves. Results were expressed as μmol TE/g PCR.

3.7. ABTS·+ Assay

The antioxidant capacity of PCR was estimated according to the measurement described by Siddhuraju and Manian with some modifications [52]. ABTS was dissolved in water to a 7 mM concentration. ABTS radical cation (ABTS·+) was produced by the reaction of ABTS stock solution and 2.45 mM potassium persulfate (final concentration). Then the mixture was placed in the dark at room temperature for 12-16 h before use. Oxidation of the ABTS commenced immediately, but the absorbance was not maximal and stable until more than 6 h had elapsed. The radical was stable in this form for more than two days when stored in the dark at room temperature. Prior to assay, the solution was diluted in methanol, to an absorbance of 0.70 ± 0.02 at 734 nm and equilibrated at 30 °C. After addition of diluted ABTS·+ solution (1.0 mL) to test sample or Trolox standard (50 μL), the reaction mixture was incubated for 30 min at 30 °C. All the measurements were performed in triplicate and results were averaged. The unit was defined as the concentration of Trolox having the equivalent antioxidant activity expressed as μmol TE/g PCR.

3.8. Microbial Strains

The antimicriobial activity of the essential oil were individually tested against a panel of microorganisms, including Gram-positive bacteria: Staphylococcus aureus (S. aureus) (GIM 1. 142), Bacillus cereus (B. cereus) (CMCC 63302), Bacillus subtilis (B. subtilis) (ATCC 9372), Streptococcus faecalis (S. faecalis) (ATCC 29212); Gram-negative bacteria: Escherichia coli (E. coli) (ATCC 25922), Salmonella lignieres (S. lignieres) (CMCC 50115), Pseudomonas aeruginosa (P. aeruginosa) (ATCC 9027), Enterobacter cloacae (E. cloacae) (CMCC 4350); fungi: Aspergillus flavus (A. flavus) (AS3. 3950), Aspergullus niger (A. niger) (ATCC 16404), Debaryomyces. hansenii (D. hansenii). All these microorganisms were purchased from Microbial Culture Collection Centre of Guangdong, China. Bacterial strains were cultured overnight at 37 °C in Nutrient agar (NA) while fungal strains were cultured overnight at 30 °C using Potato dextrose agar (PDA).

3.9. Disc Diffusion Assay

Determination of antimicrobial activity of essential oil of PCR was accomplished by agar disc diffusion method [53]. Briefly, suspension of tested microorganisms (100 µL), containing about 106 colony-forming units (cfu)/mL of bacteria cells and 104 cfu/mL spores of fungal strains spread on NA and PDA medium, respectively. The discs (6 mm in diameter) impregnated with the essential oil and placed on the inoculated agar. Disc soaked with amoxycillin (0.85 mg/mL) and flumequine (0.85 mg/mL) were served as a positive growth control for bacteria and fungi, respectively, while without samples were used as a negative control. The inoculated plates were incubated for 24 h at 37 °C for bacterial strains and 48 h at 30 °C for fungal strains. The diameters of inhibition zones were used as a measure of antimicrobial activity and each assay was conducted in triplicate.

3.10. Determinations of Minimum Inhibitory Concentration (MIC)

A broth microdilution method was used to determine the MIC [54]. Bacterial strains were cultured overnight at 37 °C in NB and the fungi were cultured overnight at 30 °C in SDB, and adjusted to a final density of 106 cfu/mL. Dilutions series were prepared from 6 to 40 mg/mL of the essential oil in a 96-well microtitre plate, 160 µL of NB and SDB for bacteria and fungi, respectively, were added onto microplates and tested solution (20 µL). Then, 5 × 105 cfu/mL of standard microorganism suspension (20 µL) were inoculated onto microplates. The inoculated plates were incubated for 24 h at 37 °C for bacterial strains and 48 h at 30 °C for fungal strains. The same test was performed simultaneously for the growth control (NB + DMSO) and sterility control (NB + DMSO + test oil). Amoxycillin was used as a reference compound for antibacterial and flumequine for antifungal activities. The growth was indicated by the presence of a white ‘‘pellet” on the well bottom.

3.11. Statistical Analysis

All experiments were performed in triplicates and the experimental results represent treatment groups expressed as means ± SD. One-way analysis of variance (ANOVA) was used to compare the means, and the least significant difference (LSD) test showed the values statistically different at P < 0.05. Analysis was performed using SPSS 11.5 for windows.

4. Conclusions

PCR Chachi 2004 exhibited the highest yield rate of essential oil, while Chachi 2008 was the lowest. In the PCRs, 53 volatile compounds were identified, including terpenic hydrocarbons, alcohols, aldehydes, ketones and esters. D-limonene was the major constituent in PCR. The antioxidant capacity of PCR essential oil varied considerably with the duration of storage time and the essential oil possessed effective antimicrobial activity against Gram-positive bacteria (S. aureus, B. subtilis, B. cereus) in varying degrees, except S. faecalis, while had no effect on Gram-negative bacteria (E. coli, E. cloacae).

Acknowledgements

We are grateful to Jiang Yueming for the contribution and the identification of plants. This work was funded by the financial support from Science and Technology Planning Project of Guangdong Province, China (Grant No. 2007A020901004).

References

  1. Shen, Y.J. Pharmacology of Traditional Chinese Medicine; Shanghai Publishing House of Science and Technology: Shanghai, China, 2002; pp. 108–111. [Google Scholar]
  2. Xia, J.; Kotani, A.; Hakamata, H.; Kusu, F. Determination of hesperidin in Pericarpium Citri Reticulatae by semi-micro HPLC with electrochemical detection. J. Pharm. Biomed. Anal. 2006, 41, 1401–1405. [Google Scholar] [CrossRef] [PubMed]
  3. Balakrishnan, A.; Menon, V.P. Antioxidant properties of hesperidin in nicotine-induced lung toxicity. Fund. Clin. Pharmacol. 2007, 21, 535–546. [Google Scholar] [CrossRef] [PubMed]
  4. Kalpana, K.B.; Srinivasan, M.; Menon, V.P. Evaluation of antioxidant activity of hesperidin and its protective effect on H2O2 induced oxidative damage on pBR322 DNA and RBC cellular membrane. Mol. Cell. Biochem. 2009, 323, 21–29. [Google Scholar] [CrossRef] [PubMed]
  5. Zheng, G.D.; Yang, D.P.; Wang, D.M.; Zhou, F.; Yang, X.; Jiang, L. Simultaneous Determination of Five Bioactive Flavonoids in Pericarpium Citri Reticulatae from China by High-Performance Liquid Chromatography with Dual Wavelength Detection. J. Agric. Food Chem. 2009, 57, 6552–6557. [Google Scholar] [CrossRef] [PubMed]
  6. Kirbaşlar, F.G.; Tavman, A.; Dülger, B.; Türker, G. Antimicrobial activity of Turkish Citrus peel oils. Pak. J. Bot. 2009, 41, 3207–3212. [Google Scholar]
  7. Sawamura, M.; Minh Tu, N.T.; Onishi, Y.; Ogawa, E.; Choi, H.S. Characteristic odor components of Citrus reticulate Blanco (Ponkan) cold-pressed oil. Biosci. Biotechnol. Biochem. 2004, 68, 1690–1697. [Google Scholar] [CrossRef] [PubMed]
  8. Yu, L.; Li, X.; Liu, S.; Xu, G.; Liang, Y. Comparative analysis of volatile constituents in Citrus Reticulata Blanco using GC-MS and alternative moving window factor analysis. J. Sep. Sci. 2009, 32, 3457–3465. [Google Scholar] [CrossRef] [PubMed]
  9. Rehman, Z. Citrus peel extract-A natural source of antioxidant. Food Chem. 2006, 99, 450–454. [Google Scholar] [CrossRef]
  10. Pernice, R.; Boriello, G.; Ferracane, R.; Borrelli, R.C.; Cennamo, F. Bergamot: A source of natural antioxidant for functionalized fruit juices. Food Chem. 2009, 112, 545–550. [Google Scholar] [CrossRef]
  11. Viuda-Matros, M.; Ruiz-Navajas, Y.; Fernández-López, J.; Pérez-Álvarez, J. Antifungal activity of lemon (Citrus lemon L.), mandarin (Citrus reticulata L.), grapefruit (Citrus paradisi L.) and orange (Citrus sinensis L.) essential oils. Food Control 2008, 19, 1130–1138. [Google Scholar] [CrossRef]
  12. Adams, R.P. Systematics of multi-seeded eastern hemisphere Juniperus based on leaf essential oils and RAPD DNA fingerprinting. Biochem. Syst. Ecol. 1999, 27, 709–725. [Google Scholar] [CrossRef]
  13. Bektas, T.; Dimitra, D.; Atalay, S.; Munevver, S.; Moschos, P. Antimicrobial and antioxidant activities of the essential oil and various extracts of Salvia tomentosa Miller (Lamiaceae). Food Chem. 2005, 90, 333–340. [Google Scholar]
  14. Ahn, G.N.; Kim, K.N.; Cha, S.H.; Song, C.B.; Lee, J.; Heo, M.S. Antioxidant activities of phlorotannins purified from Ecklonia cava on free radical scavenging using ESR and H2O2-mediated DNA damage. Eur. Food Res. Technol. 2007, 226, 71–79. [Google Scholar] [CrossRef]
  15. Mothana, R.A.; AI-Rehaily, A.J.; Schultze, W. Chemical analysis and biological activity of the essential oils of two endemic soqotri Commiphora species. Molecules 2010, 15, 689–698. [Google Scholar] [CrossRef] [PubMed]
  16. Ben Marzoug, H.N.; Romdhane, M.; Lebrihi, A.; Mathieu, F.; Couderc, F.; Abderraba, M.; Khouja, M.L.; Bouajila, J. Eucalyptus oleosa essential oils: Chemical composition and antimicrobial and antioxidant activities of the oils from different plant parts (stems, leaves, flowers and fruits). Molecules 2011, 16, 1695–1709. [Google Scholar] [CrossRef] [PubMed]
  17. Wang, P.; Kong, C.H.; Zhang, C.X. Chemical composition and antimicrobial activity of the essential oil from Ambrosia trifida L. Molecules 2006, 11, 549–555. [Google Scholar] [CrossRef] [PubMed]
  18. Ferhat, M.A.; Meklati, B.Y.; Smadja, J.; Chemat, F. An improved microwave Clevenger apparatus for distillation of essential oils from orange peel. J. Chromatogr. A 2006, 1112, 121–126. [Google Scholar] [CrossRef] [PubMed]
  19. Houghton, P.J.; Raman, A. Laboratory handbook for fractionation of natural extracts; Chapman and Hall: London, UK, 1998; p. 199. [Google Scholar]
  20. Mirhosseini, H.; Salmah, Y.; Nazimah, S.A.H.; Tan, C.P. Solid-phase microextraction for headspace analysis of key volatile compounds in orange beverage emulsion. Food Chem. 2007, 105, 1659–1670. [Google Scholar] [CrossRef]
  21. Ibáñez, E.; López-Sebastián, S.; Ramos, E.; Tabera, J.; Reglero, G. Analysis of volatile fruit components by headspace solid-phase microextraction. Food Chem. 1998, 63, 281–286. [Google Scholar] [CrossRef]
  22. Wang, Y.; Yi, L.Z.; Liang, Y.Z.; Li, H.D.; Yuan, D.L.; Gao, H.Y.; Zeng, M.M. Comparative analysis of essential oil components in Pericarpium Citri Reticulatae Viride and Pericarpium Citri Reticulatae by GC-MS combined with chemometric resolution method. J. Pharm. Biomed. Anal. 2007, 46, 66–74. [Google Scholar] [CrossRef] [PubMed]
  23. Insausti, K.; Goñi, V.; Petri, E.; Gorraiz, C.; Beriain, M.J. Effect of weight at slaughter on the volatile compounds of cooked beef from Spanish cattle breeds. Meat Sci. 2005, 70, 83–90. [Google Scholar] [CrossRef] [PubMed]
  24. Leffingwell, J.C.; Alford, E.D. Volatile constituents of Perique tobacco. J. Environ. Agric. Food Chem. 2005, 4, 899–915. [Google Scholar]
  25. Isidorov, V.; Jdanova, M. Volatile organic compounds from leaves litter. Chemosphere 2002, 48, 975–979. [Google Scholar] [CrossRef]
  26. Boulanger, R.; Crouzet, J. Free and bound flavour components of Amazonian fruits: 2. cupuacu volatile compounds. Flavour Fragr. J. 2000, 15, 251–257. [Google Scholar] [CrossRef]
  27. Helmig, D.; Pollock, W.; Greenberg, J.; Zimmerman, P. Gas chromatography mass spectrometry analysis of volatile organic trace gases at Mauna Loa Observatory, Hawaii. J. Geophys. Res. 1996, 101, 14697–14710. [Google Scholar] [CrossRef]
  28. Angioni, A.; Barra, A.; Coroneo, V.; Dessi, S.; Cabras, P. Chemical composition, seasonal variability, and antifungal activity of Lavandula stoechas L. ssp. stoechas essential oils from stem/leaves and flowers. J. Agric. Food Chem. 2006, 54, 4364–4370. [Google Scholar] [CrossRef] [PubMed]
  29. Pino, J.A.; Mesa, J.; Muñoz, Y.; Martí, M.P.; Marbot, R. Volatile components from mango (Mangifera indica L.) cultivars. J. Agric. Food Chem. 2005, 53, 2213–2223. [Google Scholar] [CrossRef] [PubMed]
  30. Kim, T.H.; Lee, S.M.; Kim, Y.S.; Kim, H.; Oh, S.; Lee, H.J. Aroma dilution method using GC injector split ratio for volatile compounds extracted by headspace solid phase microextraction. Food Chem. 2003, 83, 151–158. [Google Scholar]
  31. Congiu, R.; Falconieri, D.; Marongiu, B.; Piras, A.; Porcedda, S. Extraction and isolation of Pistacia lentiscus L. essential oil by supercritical CO2. Flavour Fragr. J. 2002, 17, 239–244. [Google Scholar] [CrossRef]
  32. Högnadóttir, Á.; Rouseff, R.L. Identification of aroma active compounds in organce essence oil using gas chromatography-olfactometry and gas chromatography-mass spectrometry. J. Chromatogr. A 2003, 998, 201–211. [Google Scholar] [CrossRef]
  33. Skaltsa, H.D.; Mavrommati, A.; Constantinidis, T. A chemotaxonomic investigation of volatile constituents in Stachys subsect. Swainsonianeae (Labiatae). Phytochemistry 2001, 57, 235–244. [Google Scholar] [CrossRef]
  34. Flamini, G.; Cioni, P.L.; Morelli, I.; Ceccarini, L.; Andolfi, L.; Macchia, M. Composition of the essential oil of Medicago marina L. from the coastal dunes of Tuscany, Italy. Flavour Fragr. J. 2003, 18, 460–462. [Google Scholar] [CrossRef]
  35. Singh, G.; Maurya, S.; Catalan, C.; de Lampasona, M.P. Studies on essential oils, Part 42: Chemical, antifungal, antioxidant and sprout suppressant studies on ginger essential oil and its oleoresin. Flavour Fragr. J. 2005, 20, 1–6. [Google Scholar] [CrossRef]
  36. Amparo, B.M.; Pérez, I.; Boira, H. Essential oil analysis of Teucrium libanitis and T. turredanum by GC and GC-MS. Flavour Fragr. J. 2003, 18, 497–501. [Google Scholar]
  37. Ames, B.N.; Profet, M.; Gold, L.S. Dietary pesticides (99.99% all natural). Proc. Natl. Acad. Sci. U.S.A. 1990, 87, 7777–7781. [Google Scholar] [CrossRef] [PubMed]
  38. Srivastava, S.; Mallavarapu, G.R.; Rai, S.K.; Singh, D.; Mishra, R.; Pandey-Rai, S.; Kumar, S. Composition of the essential oils of the leaves and flowers of Rhus mysurensis Heyne ex Wight & Arn growing in the Aravalli mountain range at New Delhi. Flavour Fragr. J. 2006, 21, 228–229. [Google Scholar]
  39. Aruoma, O. Methodological considerations for characterizing potential antioxidant actions of bioactive components in plant foods. Mutat. Res./Fundam. Mol. Mech. Mutagen. 2003, 523–524, 9–20. [Google Scholar] [CrossRef]
  40. Su, M.S.; Shyu, Y.T.; Chien, P.J. Antioxidant activities of citrus herbal product extracts. Food Chem. 2008, 111, 892–896. [Google Scholar] [CrossRef]
  41. Chanthaphon, S.; Chanthachum, S.; Hongpattarakere, T. Antimicrobial activities of essential oils and crude extracts from tropical Citrus spp. against food-related microorganisms. Songklanakarin J. Sci. Technol. 2008, 30 S1, 125–131. [Google Scholar]
  42. Caccioni, D.R.L.; Guizzardi, M.; Biondi, D.M.; Renda, A.; Ruberto, G. Relationship between volatile components of citrus fruit essential oils and antimicrobial action on Penicillium digitatum and Penicillium italicum. Int. J. Food Microbiol. 1998, 43, 73–79. [Google Scholar] [CrossRef]
  43. Dabbah, R.; Edwards, M.V.; Moats, A.W. Antimicrobial action of some citrus fruit oils on selected food borne bacteria. J. Appl. Microbiol. 1970, 19, 27–31. [Google Scholar]
  44. Burt, S. Essential oils: Their antibacterial properties and potential applications in foods: A review. Int. J. Food Microbiol. 2004, 94, 223–253. [Google Scholar] [CrossRef] [PubMed]
  45. Arias, M.E.; Gomez, J.D.; Cudmani, N.M.; Vattuone, M.A.; Isla, M.I. Antibacterial activity of ethanolic and aqueous extracts of Acacia aroma Gill. ex Hook et Arn. Life Sci. 2004, 75, 191–202. [Google Scholar] [CrossRef] [PubMed]
  46. Pernice, R.; Boriello, G.; Ferracane, R.; Borrelli, R.C.; Cennamo, F. Bergamot: A source of natural antioxidant for functionalized fruit juices. Food Chem. 2009, 112, 545–550. [Google Scholar] [CrossRef]
  47. Dorman, H.J.D.; Deans, S.G. Antimicrobial agents from plants: antibacterial activity of plant volatile oils. J. Appl. Microbiol. 2000, 88, 308–316. [Google Scholar] [CrossRef] [PubMed]
  48. Cowan, M.M. Plant products as antimicrobial agents. Clin. Microbiol. Rev. 1999, 12, 564–582. [Google Scholar] [PubMed]
  49. Zhang, Y.; Gao, B.; Zhang, M.W.; Shi, J.; Xu, Y.J. Headspace solid-phase microextraction-gas chromatography-mass spectrometry analysis of the volatile components of longan (Dimocarpus longan Lour.). Eur. Food Res. Technol. 2009, 229, 457–465. [Google Scholar] [CrossRef]
  50. Shimada, K.; Fujikawa, K.; Yahara, K.; Nakamura, T. Antioxidantive properties of xanthan on the anti-oxidation of soybean oil in cyclodextrin emulsion. J. Agri. Food Chem. 1992, 40, 945–948. [Google Scholar] [CrossRef]
  51. Benzie, I.F.F.; Strain, J.J. The ferric reducing ability of plasma (FRAP) as a measure of “antioxidant power”: the FRAP assay. Anal. Biochem. 1996, 239, 70–76. [Google Scholar] [CrossRef] [PubMed]
  52. Siddhuraju, P.; Manian, S. The antioxidant activity and free radical-scavenging capacity of dietary phenolic extracts from horse gram (Macrotyloma uniflorum (Lam.) Verdc.) seeds. Food Chem. 2007, 105, 950–958. [Google Scholar] [CrossRef]
  53. NCCLS (National Committee for Clinical Laboratory Standards). Performance Standards for Antimicrobial Disc Susceptibility Testing, 6th ed.; Wayne, PA, USA, 1997; p. M2-A6. [Google Scholar]
  54. NCCLS (National Committee for Clinical Laboratory Standards). Performance Standards for Antimicrobial Susceptibility Testing; 9th International Supplement; Wayne, PA, USA, 1999; p. M100-S9. [Google Scholar]
Sample Availability: Samples of the compounds are available from the authors.
Figure 1. GC chromatogram of PCR essential oil at different storage time a: Chachi 2008, b: Chachi 2004, c: Chachi 2001, d: Chachi 1998, e: Chachi 1994. Component numbers in the chromatogram come from Table 1.
Figure 1. GC chromatogram of PCR essential oil at different storage time a: Chachi 2008, b: Chachi 2004, c: Chachi 2001, d: Chachi 1998, e: Chachi 1994. Component numbers in the chromatogram come from Table 1.
Molecules 16 04082 g001
Table 1. Yield rates and chemical composition of PCR essential oil at different storage times.
Table 1. Yield rates and chemical composition of PCR essential oil at different storage times.
No.CompoundsKIɑConcentration (g/L)ID
DB-5MSDB-WAXChachi
2008
Chachi
2004
Chachi
2001
Chachi
1998
Chachi
1994
Yields rates of the essential oil (%)0.96 ± 0.005.41 ± 0.094.29 ± 0.204.19 ± 0.052.13 ± 0.20
1.Acetone [23,24]c8110.013 ± 0.0210.011 ± 0.0010.012 ± 0.0020.012 ± 0.0010.008 ± 0.000 d,e,f
2.3-Buten-2-ol, 2-methyl- [24]c61110390.281 ± 0.0210.031 ± 0.0050.350 ± 0.0830.215 ± 0.0040.195 ± 0.006 d,e,f
3.Butanal, 3-methyl- [23,24,25]c6520.032 ± 0.0080.008 ± 0.0020.021 ± 0.0220.007 ± 0.0000.015 ± 0.002 d,e,f
4.Butanal, 2-methyl- [24]c6620.010 ± 0.0010.042 ± 0.0060.003 ± 0.0010.004 ± 0.0000.003 ± 0.001 d,e,f
5.2-Buten-1-ol, 3-methyl- [24,26]c7710.051 ± 0.0140.084 ± 0.0080.041 ± 0.0090.018 ± 0.0020.017 ± 0.001 d,e,f
6.Furfural [24,25,26]b8280.711 ± 0.1380.184 ± 0.0230.117 ± 0.0120.093 ± 0.0020.085 ± 0.008 d,e,f
7.2-Hexenal [25,27]c8490.014 ± 0.0010.005 ± 0.0010.010 ± 0.0000.010± 0.0010.012 ± 0.005 d,e,f
8.Nonanec9000.014 ± 0.0020.004 ± 0.0010.011 ± 0.0010.005 ± 0.0010.006 ± 0.001 d,e
9.Thujene [28]c92410231.669 ± 0.2266.172 ± 0.8286.310 ± 0.7416.037 ± 0.5905.870 ± 0.302 d,e,f
10.α-Pinene [23,24,25]b93210192.825 ± 0.70613.132 ± 1.70215.053 ± 0.04116.413 ± 1.17617.945 ± 0.977d,e,f
11.Camphene [28]c9480.093 ± 0.0110.188 ± 0.0150.333 ± 0.0090.338 ± 0.0350.334 ± 0.055 d,e,f
12.Furfural, 5-methyl- [29]c9560.031 ± 0.006ND0.0129 ± 0.0020.021 ± 0.0010.016 ± 0.004 d,e,f
13.β-Phellandrene [28]c97112050.901 ± 0.1381.322 ± 0.1841.329 ± 0.2320.678 ± 0.1520.561 ± 0.033 d,e,f
14.β-Pinene [25,28,29]c97711044.278 ± 0.36711.317 ± 1.35112.629 ± 0.07812.953 ± 1.44713.814 ± 0.902 d,e,f
15.β-Myrcene [24,25,26,29]b989115761.112 ± 21.89241.534 ± 10.12442.647 ± 6.93432.631 ± 3.89320.443 ± 4.400 d,e,f
16.α-Phellandrene [25,29]c1007 1.066 ± 0.0681.069 ± 0.1481.118 ± 0.06251.061 ± 0.0211.044 ± 0.040 d,e,f
17.2-Carene [29]c10170.938 ± 0.0712.618 ± 0.2891.983± 0.9152.192 ± 0.1232.013 ± 0.192 d,e,f
18.Benzene, 1-methyl- 2-(1- methylethyl)- [28]c102412661.343 ± 0.1254.430 ± 0.7199.730 ± 6.3508.606 ± 1.45910.246 ± 1.640 d,e,f
19.D-Limonene [30]b10331199454.708 ± 32.664393.136 ± 35.731385.490 ± 63.149386.604 ± 17.763378.721 ± 44.626 d,e,f
20.Ocimene [31]c104912481.753 ± 0.3151.535 ± 0.1461.247 ± 0.3721.380 ± 0.0940.908 ± 0.020 d,e,f
21.γ-Terpinene [24,28,29]c1063124235.164 ± 2.48263.063 ± 5.31664.038 ± 7.30357.366 ± 6.66450.083± 11.938 d,e,f
22.Terpinolene [24,28]b108612811.687 ± 0.27111.933 ± 1.5809.325 ± 1.9779.159 ± 0.3088.397 ± 1.386 d,e,f
23.Benzene, 1-methyl- 4-(1- methylethenyl)- 10910.131 ± 0.0260.606 ± 0.0460.761 ± 0.2100.672 ± 0.0770.507 ± 0.107 d,e,f
[26,28,30]c
24.Linalool [28,29]c110015460.751 ± 0.0731.712 ± 0.1681.435 ± 0.1080.662 ± 0.071ND d,e,f
25.Nonanal [23,26,29]c11050.103 ± 0.0160.582 ± 0.0290.532 ± 0.0300.457 ± 0.0060.447 ± 0.018 d,e,f
26.β-Terpinol [32]c11480.192 ± 0.0220.469 ± 0.0350.541 ± 0.1530.531 ± 0.0520.531 ± 0.006 d,e,f
27.Citronellal [32]c11510.116 ± 0.0150.300 ± 0.0430.288 ± 0.0100.185 ± 0.032ND d,e,f
28.L-4-Terpineol [33]c11801.200 ± 0.2211.614 ± 0.0921.741 ± 0.0311.984 ± 0.3972.135 ± 0.001 d,e,f
29.p-Menth-1-en-8-ol [26,29,32]c11951.486 ± 0.0781.982 ± 0.1132.300 ± 0.0782.698 ± 0.5372.846 ± 0.079 d,e,f
30.Decanal [27,29,32]b120614921.391 ± 0.2051.324 ± 0.1361.181 ± 0.1410.670 ± 0.0930.603 ± 0.187 d,e,f
31.Acetic acid, octyl ester [29]c12100.125 ± 0.0200.101 ± 0.010NDNDNDd,e,f
32.cis-Carveol [29,32]c12180.628 ± 0.1320.391 ± 0.0480.235 ± 0.0050.679 ± 0.0190.698 ± 0.063 d,e,f
33.trans-Carveol [29,32]c12320.065 ± 0.0030.149 ± 0.0060.259 ± 00720.318 ± 0.0120.339 ± 0.044 d,e,f
34.Carvone [32]c12440.101 ± 0.0250.273 ± 0.0090.214 ± 0.0200.311 ± 0.0060.337 ± 0.067 d,e,f
35.Geraniol [26,29,32]c12500.131 ± 0.012NDNDNDNDd,e,f
36.Perillaldehyde [32]c127617660.071 ± 0.0110.426 ± 0.0200.374 ± 0.0720.074 ± 0.0140.097 ± 0.026 d,e,f
37.Carvacrol [29]c12920.246 ± 0.0340.677 ± 0.058NDNDNDd,e,f
38.Vinylguaiacol [34]c13100.951 ± 0.0690.254 ± 0.0250.330 ± 0.0730.308 ± 0.0420.306 ± 0.018 d,e,f
39.δ-Elemene [35]c13361.424 ± 0.135NDNDNDNDd,e,f
40.α-Cubebene [36]c13470.115 ± 0.0200.196 ± 0.0140.030 ± 0.0010.030 ± 0.0050.035 ± 0.004 d,e,f
41.Nerol acetate [29,32]c13591.307 ± 0.1770.050 ± 0.0060.0630 ± 0.0110.098 ± 0.0160.110 ± 0.009 d,e,f
42.β-Elemene [29,35]c13882.880 ± 0.1720.044 ± 0.002ND0. 087 ± 0.0180.109 ± 0.020 d,e,f
43.β-Caryophyllene [28,29,32]b14160.725 ± 0.0710.710 ± 0.0940.672 ± 0.2070.933 ± 0.1901.092 ± 0.036 d,e,f
44.α-Caryophyllene [28,29]c14520.981 ± 0.0890.087 ± 0.0080.091 ± 0.0070.112 ± 0.0260.136 ± 0.018 d,e,f
45.Germacrene-D [28,29,36]c14783.265 ± 0.2030.096 ± 0.0000.085 ± 0.0150.062 ± 0.0250.055 ± 0.015 d,e,f
46.Valencene [28,29,32]c14890.735 ± 0.0490.031 ± 0.0050.032 ± 0.0030.040 ± 0.0030.039 ± 0.001 d,e,f
47.Bicyclogermacrene [28]c14920.798 ± 0.0630.281 ± 0.0370.270 ± 0.0670.269 ± 0.0460.310 ± 0.035 d,e,f
48.α-Muurolene [24]c14950.258 ± 0.0320.023 ± 0.0020.032 ± 0.0080.033 ± 0.0030.048 ± 0.020 d,e,f
49.α-Bulnesene [29]c14980.334 ± 0.035NDNDNDNDd,e,f
50.α-Farnesene [37]c150317416.116 ± 0.3812.021 ± 0.1992.013 ± 0.3171.439 ± 0.1671.287 ± 0.256 d,e,f
51.δ-Cadinene [29,36,37]c15151.841 ± 0.2410.227 ± 0.0080.246 ± 0.0230.322 ± 0.0570.422 ± 0.114 d,e,f
52.Cadinadiene-1,4 [38]c15290.038 ± 0.003NDNDNDNDd,e,f
53.Elemol [37]c15450.139 ± 0.0170.020 ± 0.0010.019 ± 0.0010.053 ± 0.0120.066 ± 0.011 d,e,f
ND: not detected.
a KI: Kovats indices obtained using series of n-alkanes on DB-5MS and DB-WAX column.
b Concentration are obtained from these regression equations on DB-5MS column.
c Concentration are obtained on DB-5MS column, (Peak area/IS area) × IS concentration (n = 3).
ID: identification by d mass spectrum, e KI and f references.
Table 2. The concentration range, regression equations, R2, recovery for the standard compounds.
Table 2. The concentration range, regression equations, R2, recovery for the standard compounds.
CompoundsRetention timeConcentration
range (g/L)
Regression
equation
R2Recovery
range (%)
Furfural5.4090.023-2.320Y = 1E + 07X + 6729480.998389.3
α-Pinene7.8271.718-17.182Y = 2E + 07X + 2E + 080.9588104.2
β-Myrcene9.44315.820-791.000Y = 3E + 06X + 4E + 080.994788.5
D-Limonene11.05084.020-840.200Y = 9E + 06X + 2E + 090.997590.3
Terpinolene12.7750.861-86.100Y = 1E + 07X + 8E + 070.976984.9
Decanal17.6400.415-8.300Y = 2E + 07X − 7010440.9976113.7
β-Caryophyllene26.5570.450-8.995Y = 2E + 07X + 7E + 060.9977106.4
Y: the volatile compound peak area; X: the volatile compound concentration.
Table 3. The antioxidant activities of PCR essential oil at different storage time.
Table 3. The antioxidant activities of PCR essential oil at different storage time.
Antioxidant activitiesChachi 2008Chachi 2004Chachi 2001Chachi 1998Chachi 1994
DPPH IC50 (mg/mL)6.30 ± 0.50a13.33 ± 0.56c8.45 ± 0.51b9.24 ± 0.59b13.40 ± 0.46c
FRAP (μmol TE/g PCR)11.36 ± 1.50a15.79 ± 1.62b17.50 ± 1.48b21.61 ± 3.80c26.89 ± 1.11d
ABTS (μmol TE/g PCR)21.23 ± 1.09b21.59 ± 1.08b26.48 ± 1.36d24.22 ± 0.74c16.71 ± 1.40a
Values are means ± standard deviation of three separate experiments. Different letters (a, b, c) in a row indicate significant differences (p < 0.05).
Table 4. The antimicrobial activity of PCR essential oil at different storage time.
Table 4. The antimicrobial activity of PCR essential oil at different storage time.
Tested organismEssential oilsAmoxicillinFlumequine
Chachi
2008
Chachi
2004
Chachi
2001
Chachi
1998
Chachi
1994
Diameter of inhibition zone (mm)A
S. lignieres7.8 ± 0.4a8.4 ± 0.8a9.3 ± 0.8a8.7 ± 0.7a8.2 ± 0.8a18.0 ± 1.5b
E. coli6.0 ± 0.0a6.0 ± 0.0a6.0 ± 0.0a6.0 ± 0.0a6.0 ± 0.0a11.4 ± 0.3b
S. aureus8.9 ± 1.3a11.3 ± 1.4a 16.9 ± 2.7b9.4 ± 1.0a10.4 ± 0.7a44.8 ± 3.0c
B. subtilis9.8 ± 1.6a13.7 ± 2.8ab22.7 ± 2.4c12.2 ± 1.8a17.1 ± 3.9b56.2 ± 1.9d
P. aeruginosa7.8 ± 0.4a7.4 ± 0.2a7.7 ± 0.3a8.6 ± 1.0ab7.4 ± 0.2a9.3 ± 0.6b
B. cereus9.3 ± 1.2a8.4 ± 0.5a8.7 ± 1.2a8.1 ± 0.6a9.0 ± 0.9a15.3 ± 1.2b
E. cloacae6.0 ± 0.0a6.0 ± 0.0a6.0 ± 0.0a6.0 ± 0.0a6.0 ± 0.0a6.0 ± 0.0a
S. faecalis6.0 ± 0.0a6.0 ± 0.0a6.0 ± 0.0a6.0 ± 0.0a6.0 ± 0.0a33.1 ± 1.7b
A. flavus13.6 ± 0.8a13.9 ± 1.3a14.1 ± 0.9a14.6 ± 1.2a11.4 ± 2.6a 18.1 ± 2.9b
A. niger6.0 ± 0.0a6.0 ± 0.0a6.0 ± 0.0a6.0 ± 0.0a6.0 ± 0.0a 6.0 ± 0.0a
D. hansenii10.5 ± 0.5a10.8 ± 0.9a10.9 ± 1.2a10.7 ± 0.8a10.4 ± 0.6a 10.6 ± 0.4a
Minimum inhibitory concentration (mg/mL)
S. lignieres0.12 ± 0.02b0.12 ±0.02b0.12 ± 0.02b0.12 ± 0.02b0.1 ± 0.01b0.03 ± 0.0a
E. coliNTNTNTNTNTNT
S. aureus0.12 ± 0.02b0.12 ± 0.02b0.12 ± 0.02b0.12 ± 0.02b0.12 ± 0.02b0.0±0.0a
B. subtilis0.03 ± 0.00b0.03 ± 0.0b0.03 ± 0.0b0.03 ± 0.0b0.03 ± 0.0b0.0 ± 0.0a
P. aeruginosaNTNTNTNTNTNT
B. cereus0.06 ± 0.00a0.06 ± 0.00a0.06 ± 0.0a0.06 ±0.0a0.06 ± 0.0a0.05 ± 0.0a
E. cloacaeNTNTNTNTNTNT
S. faecalisNTNTNTNTNT0.02 ±0.0
A. flavus0.06 ± 0.00b0.06 ±0.0b0.06 ± 0.0b0.06 ± 0.0b0.06 ± 0.0b 0.0 ± 0.0a
A. nigerNTNTNTNTNT 0.02 ± 0.0
D. hansenii0.03 ± 0.00a0.03 ± 0.0a0.03 ± 0.0a0.03 ± 0.0a0.03 ± 0.0a 0.02 ± 0.0a
NT: not tested. Values are means ± standard deviation of three separate experiments. Different letters in a row indicate significant differences. A diameter of inhibition zone (mm) including disc diameter of 6 mm.

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Gao, B.; Chen, Y.; Zhang, M.; Xu, Y.; Pan, S. Chemical Composition, Antioxidant and Antimicrobial Activity of Pericarpium Citri Reticulatae Essential Oil. Molecules 2011, 16, 4082-4096. https://doi.org/10.3390/molecules16054082

AMA Style

Gao B, Chen Y, Zhang M, Xu Y, Pan S. Chemical Composition, Antioxidant and Antimicrobial Activity of Pericarpium Citri Reticulatae Essential Oil. Molecules. 2011; 16(5):4082-4096. https://doi.org/10.3390/molecules16054082

Chicago/Turabian Style

Gao, Bei, Yulong Chen, Mingwei Zhang, Yujuan Xu, and Siyi Pan. 2011. "Chemical Composition, Antioxidant and Antimicrobial Activity of Pericarpium Citri Reticulatae Essential Oil" Molecules 16, no. 5: 4082-4096. https://doi.org/10.3390/molecules16054082

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