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Article

Biosynthesis of ZnO Nanoparticles Using Capsicum chinense Fruit Extract and Their In Vitro Cytotoxicity and Antioxidant Assay

by
Makiwa S. Mthana
1,2,
Doctor M. N. Mthiyane
1,2,
Damian C. Onwudiwe
3,4,* and
Moganavelli Singh
5
1
Department of Animal Science, School of Agricultural Sciences, Faculty of Natural and Agricultural Sciences, North-West University (Mahikeng Campus), Private Bag X2046, Mmabatho 2735, South Africa
2
Food Security and Safety Focus Area, Faculty of Natural and Agricultural Sciences, North-West University (Mahikeng Campus), Mmabatho 2735, South Africa
3
Material Science Innovation and Modelling (MaSIM) Research Focus Area, Faculty of Natural and Agricultural Sciences, North-West University (Mahikeng Campus), Private Bag X2046, Mmabatho 2735, South Africa
4
Department of Chemistry, School of Physical and Chemical Sciences, Faculty of Natural and Agricultural Sciences, North-West University (Mahikeng Campus), Private Bag X2046, Mmabatho 2735, South Africa
5
Nano-Gene and Drug Delivery Laboratory, Department of Biochemistry, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa
*
Author to whom correspondence should be addressed.
Appl. Sci. 2022, 12(9), 4451; https://doi.org/10.3390/app12094451
Submission received: 26 February 2022 / Revised: 13 April 2022 / Accepted: 20 April 2022 / Published: 28 April 2022
Browse Figures
Versions Notes

Abstract

:
Green synthesis of nanoparticles (NPs) has garnered wide research interest due to inherent properties such as eco-friendliness, compatibility with substrates, and cost-effectiveness. Here, zinc oxide nanoparticles (ZnO-NPs) were successfully synthesized for the first time using Capsicum chinense fruit extract. The optical property of the green and conventionally synthesized ZnO-NPs was characterized by UV-vis spectrophotometer, which exhibited absorption peaks at 302 and 481 nm, respectively, and the morphology of the NPs was analyzed by transmission and scanning electron microscopies (TEM and SEM). The X-ray diffraction (XRD) studies showed that the hexagonal wurtzite phase was obtained, with high crystalline nature, while the electron dispersion X-ray study (EDX) revealed the purity of ZnO-NPs. The cytotoxicity assay of the biosynthesized and conventionally synthesized ZnO-NPs was evaluated using human embryonic kidney (HEK 293) and cervical carcinoma (HeLa) cell lines treated with various concentrations of the ZnO-NPs and they exhibited reasonable activity. Antioxidant activity of the ZnO-NPs was measured using 1, 1-diphenyl-2-picrylhydrazyl (DPPH) assay and the green ZnO-NPs exhibited higher activity compared to conventional ZnO-NPs. These findings proved that aqueous extracts of C. chinense fruit are effective for the biosynthesis of ZnO-NPs with anticancer and antioxidant potential.

1. Introduction

Nanoparticles (NPs) contain uniquely increased surface area to volume ratio [1], varied shapes [2], and enhanced surface chemistry [3,4] in comparison to macro and microparticles. Their nanoscale size endows them with enhanced biological, chemical, magnetic, catalytic, optical, and electrical properties that render them highly reactive, versatile, and useful [5,6]. Consequently, they have found multitudinous applications in agriculture, food, cosmetics, medicine, and other sectors. In agriculture, they recently found applications even in niche areas such as mushroom production where administration of their small doses has been demonstrated to rapidly improve mushroom yields, biological and economic yields [7], nutritional composition [8,9], and substrate lignin biodegradation [8]. Conventionally, NPs have been synthesized using chemical methods that employ chemical substances as both stabilizing and capping agents [10,11]. However, such methods have recently been criticized for their use of costly, harmful, and toxic substances with the potential to harm human health and the environment [12].
Consequently, the field of nanomaterials science has witnessed a rapid surge in interest in green (bio) synthesis of nanoparticles that have been hailed as being biologically safe, environmentally friendly, highly stable, and easily characterizable [13,14]. Biosynthesis of NPs could be achieved by using biogenic materials such as microorganisms or plant extracts. However, the use of microorganisms entails some stringent procedures such as the high need for culture media, which might be expensive and time-consuming, pathogenicity, and non-feasibility of large-scale production [15]. Phyto-assisted synthesis of NPs and its utilization of plant extracts as sources of phytochemicals is an extremely practical and cheap method with enormous potential for expansion into the large-scale commercial generation of NPs [16]. Plant-derived biomolecules and metabolites contain functional groups that interact with metal ions, thus reducing their size into the nano range. In this connection, polyphenolic compounds including alkaloids, polysaccharides, amino acids, vitamins, and terpenoids have been reported to bio-reduce metal ions or metal oxides to zero valence metal NPs [17]. Specifically, flavonoids comprise numerous functional groups, particularly the hydroxyl (–OH) group, that mainly reduce metal ions in a single reaction into NPs and cap them, thus enhancing their stability and biocompatibility [18,19,20]. Furthermore, plant-assisted NPs synthesis kinetics is amply higher than in other biosynthetic approaches, and plants are preferred to microorganisms for green synthesis of NPs as they are non-pathogenic [11]. Numerous parts of plants including leaves [21,22], flowers [23], fruits [24,25,26], as well as seeds, stems, roots, and whole plants [11] have been used to biosynthesize ZnO-NPs and other metal NPs.
Orange Habanero pepper (C. chinense) is a perennial plant belonging to the Solanaceae family and native to Central America, Mexico [27], India, and most parts of Africa [28]. Its fruits are known for their extreme level of heat [27] and their abundant metabolites such as ascorbic acid, phenolic compounds, vitamin A, and carotenoids [29]. Since the fruits possess these desirable phytochemicals, it is therefore hypothesized that their extract can act as a stabilizing agent during the biosynthesis ZnO-NPs.
As part of attempts to investigate the utility and ensure the safety of NPs, it has become necessary to determine their deleterious effects on biological systems [30,31]. Many nanomaterials including ZnO-NPs have been shown to be cytotoxic due to their ion-shedding ability [32,33,34] and high solubility in acidic conditions [35,36]. ZnO-NPs intracellularly increase dissolved free zinc ions which disturbs metal ion homeostasis leading to mass production of reactive oxygen species (ROS) [26,37,38,39] that cause oxidative stress [27] and inflammation [40]. This property of ZnO-NPs might, however, be highly desirable in agricultural applications such as mushroom production where zinc ions appear to be necessary for the enhancement of mycelial growth and mushroom antioxidant capacity [41]. Notwithstanding, in addition to cytotoxicity, assessment of the ability of NPs to serve as antioxidants that quench free radicals and ROS in biological systems is of paramount importance. In this regard, previous studies have shown the antioxidant activity of ZnO-NPs synthesized using aqueous extracts of various parts of plants including leaves of neem (Azadirachta indica) [42], green tea (Camellia sinensis) [43], and hairy flowered (Himalayan) columbine (Aquilegia pubiflora) [44], fruits of dog rose (Rosa canina) [45] and flowers of red clover (Trifolium pretense) [46]. However, the cytotoxicity and antioxidant capacity of ZnO-NPs biosynthesized using extracts of C. chinense fruits have, thus far, not been explored. Therefore, the objective of this study was to biosynthesize, characterize, and evaluate for cytotoxicity and antioxidant capacity the C. chinense fruit extract-fabricated ZnO-NPs.

2. Materials and Methods

2.1. Materials

Zinc acetate dihydrate [Zn(CH3CO2)2·2H2O], sodium hydroxide (NaOH), and 1, 1-diphenyl-2-picrylhydrazyl (DPPH) were obtained from (Merck (Pty) Ltd., Merck, Darmstadt, Germany) Orange Habanero pepper (C. chinense Jacq) fruits were sourced from the Molelwane experimental farm of the North-West University. The farm is situated in Mahikeng Local Municipality, North-West Province, South Africa (coordinates: 25.8255° S, 25.6110° E).

2.2. Preparation of the Capsicum chinense Extract

After harvesting, the pedicels and sepals of the fruits were detached, and the fruits were cleaned thoroughly with distilled water. Then, 100 mL of distilled water was added to 50 g of fruits and then blended into pulp. The obtained pulp was sieved and filtered to attain a clean extract, which was stored in an airtight container and kept in a cooler (4 °C) for future use.

2.3. Synthesis of ZnO Nanoparticles

The Zn(CH3CO2)2·2H2O solution was prepared by dissolving 4.4 g of Zn(CH3CO2)2 2H2O into 20 mL of distilled water. About 20 mL of C. chinense extract was measured and its pH of 4.6 was increased to 12 by dropwise addition NaOH solution. To this solution, the prepared solution of Zn(CH3CO2)2·2H2O was added and stirred at 85 °C using a magnetic stirrer. After 2 h, the solution was centrifuged for 15 min at 5500 rpm and the product obtained was washed with water/ethanol solution to eradicate any impurities. The product was then transferred into a crucible and was calcinated at 350 °C for 2 h. The different stages of the biosynthesis of ZnO-NPs using C. chinense fruit extract is presented in Scheme 1. For comparison, ZnO-NPs was also prepared without the fruit extract through the conventional method.

2.4. Characterisation

The crystalline phase of the ZnO-NPs was analyzed using Bruker D8 Advanced X-ray diffraction (XRD) instrument (Karlsruhe, Germany)), with a nickel filtered CuKα radiation (k = 1.5418 Å) at room temperature, at a scanning rate of 0.0018° min−1. The external shape and structure of the NPs was studied using scanning electron microscopy (SEM) on a JEOL 6400F field-emission SEM, (Zeiss, Oberkochen Germany). While the internal shape and sizes of the NPs were studied using a TECNAI G2 (ACI) Transmission electron microscopy (TEM) (FEI, Bellaterra Spain). Elemental composition was determined using energy-dispersive X-ray (EDX). For optical examination, the UV-visible analysis of the samples was conducted using the Perkin Elmer Lambda 20UV–vis spectrophotometer.

2.5. Cytotoxicity Analysis

The cytotoxic assay was evaluated following a similar technique reported by Adeyemi et al. [47], however, with a few modifications. In this case, two cell line were used. The immortal human embryonic kidney (HEK 293) and cervical carcinoma (HeLa) cell lines were obtained from the ATCC, Manassas, VA, USA. The Dulbecco’s Modified Eagle’s Medium (DMEM) (Lonza BioWhittaker, Walkersville, MD, USA), with the presence of 10% fetal bovine serum, 100 μg/mL streptomycin, and 100 U mL−1 penicillin were used to culture the cells in a 25 cm2 tissue flasks. The MTT assay (3-(4,5-dimethylthiazol-2-yl)-2,6-diphenyltetrazolium bromide) was performed in a 96-well plate containing 2.5 × 102 cells/well in 100 μL DMEM. Prior inoculation, the cells were incubated overnight at 37 °C. Then different concentrations (10, 25, 50, and 100 μg/mL) of ZnO-NPs were applied to cells and were further incubated for 48 h at 37 °C, followed by the MTT assay. The standard used for comparison was 5-fluorouracil (5-FU). The medium in the assay was replaced by a fresh medium containing 10% MTT reagent and further incubated for 4 h at 37 °C. After incubation, the insoluble formazan crystals were dissolved in 100 μL of dimethyl sulfoxide (DMSO), then the absorbance was recorded at 570 nm with DMSO as a blank. These assays were replicated three times to obtain the average absorbance.

2.6. Antioxidant Activity Evaluation

The scavenging activity of ZnO-NPs was carried out using DPPH assay following methods adopted from Safawo et al. [48], however, with minor modification. The DPPH solution was prepared by dissolving 6.4 mg of DPPH in 25 mL of methanol to obtain 0.016 mM concentration of DPPH. The solution was placed in the dark for 30 min. After incubation, 1 mL of DPPH solution was added to ZnO solutions, which were prepared by dissolving different concentrations of ZnO-NPs (50, 25, 12.5, 6.25, 3.13, and 1.56 µg) in 1 mL of DMSO. The blank contained only DMSO and DPPH solution. The absorbance was recorded at 520 nm against 0.016 mM DPPH as a control, and the study was carried out three times. The inhibition of ZnO-NPs was estimated using the following equation:
% Inhibition = (Ac − As)/Ac × 100%
(Ac) represent the absorbance of the control, while (As) is the absorbance of the sample.

3. Results and Discussion

3.1. XRD Studies

Figure 1 shows the XRD patterns of ZnO-NPs, which were biosynthesized using C. chinense fruit extract. The diffractions identified at 2θ values of 31.70°, 34.37°, 36.23°, 47.50°, 56.60°, 62.98°, 66.26°, 67.93°, 69.10°, 72.62°, and 76.98° could be indexed to the (100), (002), (101), (102), (110), (103), (200), (112), (201), (204), and (202) planes, respectively, of the hexagonal wurtzite structure (JCP2 card no. 36-1451), which has lattice constants of a = b = 3.242 Å and c = 5.205 Å [49]. The narrow width and strong intensity of the diffraction peaks of the ZnO shows that they were highly crystalline in nature [50]. Furthermore, the absence of any impurity peaks approves the formation of pure phase ZnO. The Debye-Scherrer equation (Equation (2)) was employed to estimate the average crystallite size of the ZnO-NPs [51].
D = Kλ/βcosθ
where D = particles size (nm), K = Scherrer’s constant (0.90), λ = X-ray wavelength (1.5406 Å), β = full width at half the maximum (FWHM), and θ = Braggs’s angle of reflection. The average crystallite size of the synthesized ZnO-NPs was found to be 19.27.

3.2. SEM, TEM, and EDX Analysis

The morphological characteristics of ZnO-NPs biosynthesized using C. chinense fruit extract is shown in Figure 2. In the SEM micrograph, the lower magnification of the NPs showed that they are composed of a mixture of rice-shaped and spherical morphology (Figure 2a). However, a higher magnification micrograph (Figure 2b) presents a clearer image, showing that the spherical particles were agglomerates of the smaller sized rice shaped particles. This agglomeration might be ascribed to the effect of the high temperature of calcination, which increased the surface reactivity [52]. The TEM images of ZnO-NPs (Figure 2c) approve that the products were indeed spherical in shape and the particle length were observed to be 12.7 nm (Figure 2d). The EDX spectrograph of ZnO-NPs (Figure 2e) revealed zinc (Zn) and oxygen (O) peaks only, which confirmed the presence of zinc in the oxide form. Apart from Zn and O, there were no other elements found in the NPs sample. The EDX results, presented in Table 1, also showed the composition of each element. The weight percentage of Zn and O was found to be peaked at 77.51% and 22.49% with atomic weight percentage of 45.93% and 54.07%, respectively. The elemental mapping (Figure 3) showed that all component elements were uniformly distributed across the surface of the NPs. Furthermore, the ZnO-NPs were also synthesized conventionally without the use of fruit extract in order to evaluate the influence of C. chinense fruit extract on the particle size and morphology. The SEM micrograph (Figure 4a) showed that the ZnO-NPs were also spherical but at a higher degree of agglomeration. This was also confirmed by the TEM image of Figure 4b, which presents highly agglomerated pseudo spherical nanoparticles with a mean particle size of about 24.0 nm (Figure 4c). The increase in size and higher agglomeration in the sample prepared without plant extract, indicated that the extracts also play the role of size modulation.

3.3. UV-Visible Studies

The UV-visible absorption spectrum of the ZnO-NPs synthesized with and without C. chinense fruit extract is shown in Figure 5a and Figure 6a, respectively. The presence of peaks at around 302 nm and 481 confirmed the formation of ZnO-NPs synthesized with and without C. chinense fruit extract. According to Zak et al. [53], the peaks could be attributed to the intrinsic band-gap absorption of ZnO due to the electron transitions from the valence band to conduction band (O2p → Zn3d). The band gap energy was estimated using Tauc’s plot equation (Equation (3)) for ZnO-NPs.
[αhv = C(hv − Eg)]m
where α = absorbance coefficient, C = constant, h = Planck’s constant, ν = photon frequency, Eg = optical band gap, and m = 1/2 for direct band gap semiconductors. The calculated band gap energy for the ZnO-NPs synthesized with and without fruit extract was observed to be 3.76 eV (Figure 5b) and 3.49 eV (Figure 6b), respectively. These bandgap energies are higher than that of the bulk (3.4 eV), and higher than those reported in the literature [46,54,55,56]. The high band gap energy suggested that the ZnO-NPs synthesized using C. chinense extract have more energy required to excite an electron from the valence band to the conduction band [57]. According to Wang and Chang [58], this variation might be due to various factors such as grain size, surface roughness, and lattice strain.

3.4. Cytotoxic Analysis of ZnO-NPs

The extracts from most parts of the plant are known to contain substantial amounts of metabolites that are responsible for stabilizing, reducing, and capping efficacy [59]. It is with this regard that “green” or biosynthesized NPs are more stable with higher activity compared to conventionally synthesized NPs [60]. Here, the green and conventional ZnO-NPs were investigated for their ability to prevent the proliferation of cancer cells. The results of the assay are presented in Table 2, which showed that the cell viability of both HEK 293 and HeLa cells decreased with increasing concentrations of both studied ZnO-NPs (Figure 7). However, the standard used (5-Fluorouracil) showed higher anti-tumor activity compared to both ZnO-NPs on both cell lines. At higher concentration (25 to 100 µg/mL), the green ZnO-NPs lead to lower cell viability on both cell lines compared to the standard and conventional ZnO-NPs (Figure 7a,b). As a result, the green ZnO-NPs showed a lower concentration of the substance that led to half-maximal response (IC50) on both cell lines compared to conventional ZnO-NPs. These results suggest that the C. chinense mediated ZnO-NPs can effectively suppress the growth of studied cancer cells. Similar findings have been reported in literature [61,62,63], whereby green synthesized ZnO-NPs were proven to be effective in fighting cancer cells. Moreover, the study by Pandurangan et al. [63], observed the up-regulated apoptotic gene expression, which confirmed the occurrence of apoptosis. This suggests that the biosynthesized ZnO-NPs might induce the apoptosis of cancer cells through decreased intracellular ROS. Furthermore, ZnO-NPs has been reported to have the capacity to dissolve inside lysosome and donate Zn2+ ions [64]. These ions are involved in scavenging the ROS [65].

3.5. Antioxidant Activity Analysis of ZnO-NPs

DPPH assay was applied to measure the radical scavenging activity of ZnO-NPs. The DPPH is a free radical that has been extensively used to investigate the antioxidant potency of inorganic compounds and nanomaterials [46]. The prepared DPPH solution had a deep violet color, which changed to pale yellow upon the addition of ZnO-NPs, which generally indicates the antioxidant capacity of ZnO-NPs [44]. The results of the antioxidant assay in Table 3 show an increase in % inhibition with increasing concentrations of both ZnO-NPs synthesized with or without C. chinense fruit extract. The scavenging activity of ascorbic acid, which was used as reference/standard, was higher than that of both ZnO-NPs (Figure 8); thus, it indicates that the standard was more effective in capturing the DPPH’s free radicals compared to both ZnO-NPs. However, the green ZnO-NPs showed higher inhibition potency compared to the ZnO-NPs prepared by the conventional route. Since green ZnO-NPs was shown to have smaller particle size, they contain larger surface area to volume ratio than the conventional ZnO-NPs. Generally, large surface area to volume ratio of NPs results in high material performance due to domination of materials surface atoms [1,4]. The obtained IC50 values of 6.27 and 8.76 µg/mL for green and conventional ZnO-NPs, respectively, were higher than that of ascorbic acid (4.73 µg/mL). These results are in line with previous studies [66,67], which reported lower IC50 values of ascorbic acid than ZnO-NPs.

4. Conclusions

The current study is the first to explore the biosynthesis of ZnO-NPs using the extract of C. chinense fruits and their cytotoxicity and antioxidant activities. It demonstrated a successful biosynthesis of “green” ZnO-NPs using C. chinense fruit extract as a mediating agent and was characterized by different techniques. The XRD pattern confirmed a hexagonal wurtzite structure of ZnO-NPs of with average particle size of 19.27 nm. The external morphology showed a mixture of rice-shaped and spherical particles, with spherically shaped internal morphology. Furthermore, a UV-vis absorption peak at 302 and 481 nm confirmed the formation of ZnO-NPs with a band gap of 3.76 and 3.49 eV, respectively. The green synthesized ZnO-NPs displayed better and reasonable cytotoxic and antioxidant activities compared to conventionally synthesized ZnO-NPs. Thus, the results of these studies suggest that these NPs could be considered as a viable agent for various treatment purposes for the reduction of oxidative stress.

Author Contributions

Conceptualization, M.S.M., D.M.N.M. and D.C.O.; methodology M.S.M., D.M.N.M., D.C.O. and M.S.; software, D.C.O. and M.S.; validation, M.S.M., D.M.N.M. and D.C.O.; formal analysis, M.S.M., D.M.N.M., D.C.O. and M.S.; investigation, M.S.M., D.M.N.M., D.C.O. and M.S.; resources, D.C.O. and M.S.; data curation, M.S.M., D.C.O. and M.S.; writing—original draft preparation, M.S.M.; writing—review and editing, D.M.N.M. and D.C.O.; visualization, M.S.M. and D.C.O.; supervision, D.M.N.M. and D.C.O. All authors have read and agreed to the published version of the manuscript.

Funding

Authors gratefully acknowledge the National Research Foundation (NRF), South Africa and North-West University (NWU) for funding (141668 and 1K02799).

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Conflicts of Interest

There is no conflict of interest.

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Applsci 12 04451 sch001 550
Scheme 1. Schematic representation of the stages associated with the biosynthesis of ZnO-NPs using C. chinense fruit extract as a stabilizing agent.
Scheme 1. Schematic representation of the stages associated with the biosynthesis of ZnO-NPs using C. chinense fruit extract as a stabilizing agent.
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Figure 1. XRD analysis of ZnO-NPs biosynthesized using C. chinense fruit extract.
Figure 1. XRD analysis of ZnO-NPs biosynthesized using C. chinense fruit extract.
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Figure 2. SEM images at (a) low, (b) high magnification, (c) EDX spectrum, (d) TEM image, and (e) particles distribution histogram of ZnO-NPs biosynthesized using extract of C. chinense fruits.
Figure 2. SEM images at (a) low, (b) high magnification, (c) EDX spectrum, (d) TEM image, and (e) particles distribution histogram of ZnO-NPs biosynthesized using extract of C. chinense fruits.
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Figure 3. (a) Elemental mapping of ZnO, (b) Zn, and (c) O elements of ZnO-NPs biosynthesized using extract of C. chinense fruits.
Figure 3. (a) Elemental mapping of ZnO, (b) Zn, and (c) O elements of ZnO-NPs biosynthesized using extract of C. chinense fruits.
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Figure 4. (a) SEM, (b) TEM images, and (c) particle size distribution histogram inset of ZnO-NPs synthesized without C. chinense fruit extract.
Figure 4. (a) SEM, (b) TEM images, and (c) particle size distribution histogram inset of ZnO-NPs synthesized without C. chinense fruit extract.
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Figure 5. UV-visible absorption spectra (a), and Tauc plot (b) of biosynthesized ZnO-NPs using C. chinense fruits extract.
Figure 5. UV-visible absorption spectra (a), and Tauc plot (b) of biosynthesized ZnO-NPs using C. chinense fruits extract.
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Figure 6. UV-visible absorption spectra (a), and Tauc plot (b) of ZnO-NPs synthesized without C. chinense fruits extract.
Figure 6. UV-visible absorption spectra (a), and Tauc plot (b) of ZnO-NPs synthesized without C. chinense fruits extract.
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Figure 7. The percentage cell viability of: (a) HEK 293, and (b) HeLa cells treated with various concentrations of green and conventional ZnO-NPs.
Figure 7. The percentage cell viability of: (a) HEK 293, and (b) HeLa cells treated with various concentrations of green and conventional ZnO-NPs.
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Figure 8. Radical scavenging activity (%) of ZnO-NPs and ascorbic acid at various concentrations.
Figure 8. Radical scavenging activity (%) of ZnO-NPs and ascorbic acid at various concentrations.
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Table
Table 1. Elemental composition of Zn and O.
Table 1. Elemental composition of Zn and O.
ElementsWeight %Atomic %
Zinc77.5145.93
Oxygen22.4954.07
Total100100
Table
Table 2. Cytotoxic activities (%) of green and conventional ZnO-NPs.
Table 2. Cytotoxic activities (%) of green and conventional ZnO-NPs.
Cell LinesTest SamplesSample Concentrations (µg/mL)IC50 (µg/mL)
102550100
HEK 2935-FU (Fluorouracil)77.36 ± 0.04851.92 ± 0.00335.34 ± 0.01011.33 ± 0.0176.05
Green ZnO 86.34 ± 0.05458.22 ± 0.05750.64 ± 0.01337.06 ± 0.02249.35
Conventional ZnO 91.33 ± 0.04077.93 ± 0.01559.26 ± 0.04134.33 ± 0.01263.09
HeLa5-FU (Fluorouracil)78.40 ± 0.0358.89 ± 0.0450.47 ± 0.0237.99 ± 0.0217.48
Green ZnO87.10 ± 0.06357.64 ± 0.08038.92 ± 0.01427.76 ± 0.02337.30
Conventional ZnO74.61 ± 0.02165.65 ± 0.05652.34 ± 0.04342.78 ± 0.06762.34
Values are expressed as mean cell viability (%) ± Standard deviation (n = 3). Fluorouracil is a standard.
Table
Table 3. Antioxidant activity (%) of green and conventional ZnO-NPs.
Table 3. Antioxidant activity (%) of green and conventional ZnO-NPs.
Test SamplesSample Concentrations (µg /mL)IC50 (µg/mL)
1.563.136.2512.52550
Ascorbic acid4.73 ± 0.08412.26 ± 0.04035.95 ± 0.01140.04 ± 0.08052.21 ± 0.08265.20 ± 0.0644.73
Green ZnO3.31 ± 0.0697.46 ± 0.08315.43 ± 0.04827.40 ± 0.04537.59 ± 0.05149.83 ± 0.4476.27
Conventional ZnO1.31 ± 0.0684.37 ± 0.01012.72 ± 0.03421.29 ± 0.13326.09 ± 0.06431.51 ± 0.0178.76
Values are expressed as mean inhibition (%) ± Standard deviation (n = 3). Ascorbic acid is a standard.
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Mthana, M.S.; Mthiyane, D.M.N.; Onwudiwe, D.C.; Singh, M. Biosynthesis of ZnO Nanoparticles Using Capsicum chinense Fruit Extract and Their In Vitro Cytotoxicity and Antioxidant Assay. Appl. Sci. 2022, 12, 4451. https://doi.org/10.3390/app12094451

AMA Style

Mthana MS, Mthiyane DMN, Onwudiwe DC, Singh M. Biosynthesis of ZnO Nanoparticles Using Capsicum chinense Fruit Extract and Their In Vitro Cytotoxicity and Antioxidant Assay. Applied Sciences. 2022; 12(9):4451. https://doi.org/10.3390/app12094451

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Mthana, Makiwa S., Doctor M. N. Mthiyane, Damian C. Onwudiwe, and Moganavelli Singh. 2022. "Biosynthesis of ZnO Nanoparticles Using Capsicum chinense Fruit Extract and Their In Vitro Cytotoxicity and Antioxidant Assay" Applied Sciences 12, no. 9: 4451. https://doi.org/10.3390/app12094451

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