Search Results (8)

Michael acceptors, such as chalcones and benzylidenes, are privileged scaffolds for the development of anticancer agents. Taking this into account, we developed a selective Claisen–Schmidt condensation of the dammarane-type triterpenoid hollongdione with pyridine-2-carbaldehyde, enabling controlled synthesis of mono- and bis-substituted triterpenes depending on the reaction conditions. The reaction demonstrated high temperature-dependent regioselectivity, providing C2-mono- 2 or 2,21-bis-substituted 3 triterpenes with yields up to 96% and 95%, respectively. The structures of the newly synthesized triterpene chalcones were elucidated by 1D and 2D NMR spectroscopy and unambiguously confirmed by a single-crystal X-ray diffraction, which established the E configuration of the exocyclic double bond. In biological studies, the bis-2-pyridylidene derivative 3 exhibited a pronounced and broad-spectrum antitumor activity in the NCI-60 panel, inducing cell death in 58 of 59 cancer cell lines. High selectivity toward melanoma, renal, and prostate cancer cell lines was observed, with selectivity indices (SI) of up to 18.82 for melanoma LOX IMVI. In MTT assays, compound 3 displayed a submicromolar cytotoxicity, particularly against the KRAS-mutant PANC-1 cell line (IC₅₀ = 0.22 µM). Anticancer activity was further confirmed in a zebrafish (Danio rerio) xenograft model of human HCT116 colon cancer, where tumor growth inhibition reached 72% without pronounced embryotoxicity (LC₅₀ = 1.4 µM). We have developed an efficient approach for the site-selective modification of hollongdione, providing access to potent anticancer dammarane-type chalcones. The bis-2-pyridylidene derivative 3 emerged as a promising lead compound, demonstrating submicromolar potency, high selectivity towards melanoma, and significant in vivo efficacy in a zebrafish xenograft model. Full article

Oleoresin of Dipterocarpus alatus Roxb. ex G. Don (DA) has been traditionally used for local medicinal applications. Several in vitro studies have indicated its pharmacological potential. However, the low water solubility hinders its use and development for pharmaceutical purposes. The study aimed to (1) formulate oil-in-water (o/w) Pickering emulsions of DA oleoresin and (2) demonstrate its activities in cancer cells. The Pickering emulsions were formulated using biocompatible carboxylated cellulose nanocrystal (cCNC) as an emulsifier. The optimized emulsion comprised 3% (F1) and 4% (v/v) (F2) of oleoresin in 1% cCNC and 0.1 M NaCl, which possessed homogeneity and physical stability compared with other formulations with uniform droplet size and low viscosity. The constituent analysis indicated the presence of the biomarker dipterocarpol in both F1 and F2. The pharmacological effects of the two emulsions were demonstrated in vitro against two cancer cell lines, HepG2 and HCT116. Both F1 and F2 suppressed cancer cell viability. The treated cells underwent apoptosis, as demonstrated by distinct nuclear morphological changes in DAPI-stained cells and Annexin V/PI-stained cells detected by flow cytometry. Our study highlights the prospect of Pickering emulsions for oleoresin, emphasizing enhanced stability and potential pharmacological advantages. Full article

Leaf litter is an essential functional aspect of forest ecosystems, acting as a source of organic matter, a protective layer in forest soils, and a nurturing habitat for micro- and macro-organisms. Through their successional occurrence, litter-inhabiting microfungi play a key role in litter decomposition and nutrient recycling. Despite their importance in terrestrial ecosystems and their abundance and diversity, information on the taxonomy, diversity, and host preference of these decomposer taxa is scarce. This study aims to clarify the taxonomy and phylogeny of four saprobic fungal taxa inhabiting Dipterocarpus alatus leaf litter. Leaf litter samples were collected from Doi Inthanon National Park in Chiang Mai, northern Thailand. Fungal isolates were characterized based on morphology and molecular phylogeny of the nuclear ribosomal DNA (ITS, LSU) and protein-coding genes (tub2, tef1-α, rpb2). One novel saprobic species, Ciliochorella dipterocarpi, and two new host records, Pestalotiopsis dracontomelon and Robillarda australiana, are introduced. The newly described taxa are compared with similar species, and comprehensive descriptions, micrographs, and phylogenetic trees are provided. Full article

Dipterocarpus alatus Roxb. ex G. Don is widely found in Southeast Asia. Its oleo-resin has reportedly been used in biodiesel production. Two different biodiesel production processes produce resinous byproducts, namely degumming (DG) and distillation (DT). Gas chromatography-mass spectrometry identified sesquiterpenes and triterpenes in oleo-resin, DG, and DT; and long-chain hydrocarbons in oleo-resin. High-performance liquid chromatography detected dipterocarpol as a marker compound, with the highest to lowest amounts detected in DG, DT, and oleo-resin, respectively. Oleo-resin, DG, and DT exerted more cytotoxicity than dipterocarpol, and melphalan, a chemotherapeutic drug. Oleo-resin, DG, and DT exerted cytotoxicity to a different degree in T cell leukemia (Jurkat), cervical adenocarcinoma (HeLa), and human hepatocellular carcinoma (HepG2) cells, while the highest selectivity was found in the Jurkat cells compared to the non-cancer Vero cells. Dipterocarpol exhibited the highest cytotoxicity in HepG2 cells and the lowest cytotoxicity in Jurkat cells. Oleo-resin, DG, and DT induced apoptosis in Jurkat cells. In oleo-resin, DG, and DT, dipterocarpol and other compounds may act in synergy leading to cytotoxicity and an apoptosis-inducing effect. Oleo-resin, DG, and DT could be potential sources for anticancer agents. Dipterocarpol could serve as a biomarker for follow ups on the anticancer activity of a sample from D. alatus. Full article

The loss of forests is a major environmental, social, and economic problem. The disappearance has been occurring to an extreme degree in many parts of Southeast Asia, including Thailand. Logging and clearing of forests for agriculture, cash crops, and food production has destroyed much of the tropical forests in Thailand. Floristic inventory could provide essential information for forest conservation but species identification as a part of inventory creating could be challenging in some cases. Barcode DNA coupled with High Resolution Melting analysis (Bar-HRM) was used here in aiding species identification of plant in Dipterocarpaceae (Dipterocarpus alatus, D. costatu, D. intricatus, D. obtusifolius, Hopea ferrea, H. odorata, Shorea guiso, S. obtuse, S. roxburghii, and S. siamensis) and Fagaceae (Castanopsis echinocarpa, C. inermis, Lithocarpus wallichianus, Quercus aliena and Q. oidocarpa) families. Two main experiments were conducted including: (1) a comparing method for primer design and (2) testing the robustness of the Bar-HRM by trying to identify tree samples that did not have sequences in the GenBank. In experiment 1, the manual design primer pair was found to be the best fit for the work. Of key importance is finding the primers which give the most nucleotide variations within the generated amplicon; this is a parameter that cannot be set in any web-based tools. Next, in experiment 2, Bar-HRM using primers of ITS1 and ITS2 regions were able to discriminate all 10 tested tree species without any problem, even when there were no sequences of the samples to be analysed before performing the HRM. Here, Bar-HRM poses potential to be a game-changer in tropical forest conservation, as it will be useful for species identification. Full article

Urban trees provide numerous ecosystem services in cities such as pollution absorption and reduced urban heat island intensity, energy use, and mental fatigue. Understanding urban tree species diversity can enhance tree planning and management in rapidly urbanizing areas. However, few studies have examined the effects of urbanization on urban tree diversity in Thailand. This study assessed the diversity of large trees in urban landscapes including 11 cities along the 372 km Chao Phraya River Rim in central Thailand. Species diversity, importance value, and distribution were evaluated in each city. Our survey documented 987 large trees belonging to 65 species, 48 genera, and 31 families. The dominant species of Dipterocarpus alatus and Hopea odorata had the highest importance and relative abundance. The highest abundance of large trees was seen in the rural city of Sing Buri, while large urban cities such as Ayutthaya and Bangkok exhibited the highest species diversity. Detrended correspondence analysis indicated that the diversity of unique species was high in large urban cities, while dominant and common species were ubiquitous in rural cities. These findings suggest that large trees are few in number but exhibit high species diversity in large rapidly urbanizing cities. Therefore, preserving good site conditions is critical for the survival of large trees in urban cities. Heritage tree registration may aid preservation efforts and enhance the benefits of these large trees in rapidly urbanizing areas. Full article

Treatment of the unpredictable chronic mild stress (UCMS) mice with the ethanol extract of Dipterocarpus alatus leaf attenuated anhedonia (increased sucrose preference) and behavioral despair (decreased immobility time in tail suspension test (TST) and forced swimming test (FST)). The extract not only decreased the elevation of serum corticosterone level and the index of over-activation of the hypothalamic-pituitary-adrenal (HPA) axis, caused by UCMS, but also ameliorated UCMS-induced up-regulation of serum- and glucocorticoid-inducible kinase 1 (SGK1) mRNA expression and down-regulation of cyclic AMP-responsive element binding (CREB) and brain-derived neurotrophic factor (BDNF) mRNAs in frontal cortex and hippocampus. In vitro monoamine oxidase (MAO) inhibition assays showed that the extract exhibited the partial selective inhibition on MAO-A. HPLC analysis of the extract showed the presence of flavonoids (luteolin-7-O-glucoside, kaempferol-3-glucoside, rutin) and phenolic acids (gallic acid, ferulic acid, and caffeic acid) as major constituents. Full article

Dipterocarpus alatus (Dipterocarpaceae) is a medicinal plant whose use is well known for the treatment of genito-urinary diseases. However, there is no report of its cytotoxic potential. In this study, the chemical composition, antioxidant and cytotoxic activities of extracts of the leaves, bark, twigs and oleo-resin from D. alatus are investigated. Cytotoxicity was measured by the neutral red (NR) assay against HCT116, SKLU1, SK-MEL2, SiHa and U937 cancer cell lines and antioxidant capacity was evaluated by DPPH, ABTS radical scavenging, and ferric reducing antioxidant power (FRAP) assays. The chemical composition was analyzed by gas chromatography–mass spectrometry (GC-MS). Leaf, bark and twig extracts exhibited stronger antioxidant activity than oleo-resin, with bark extract showing the highest antioxidant activity and the highest total phenolic content. All samples showed more cytotoxic activity against the U937 cell line than HCT116, SKLU1, SK-MEL2 and SiHa cells with oleo-resin being more cytotoxic than melphalan against U937 cells. Chemical composition analysis of oleo-resin by GC-MS showed that the major components were sesquiterpenes, namely α-gurjunene (30.31%), (-)-isoledene (13.69%), alloaromadendrene (3.28%), β-caryophyllene (3.14%), γ-gurjunene (3.14%) and spathulenol (1.11%). The cytotoxic activity of oleo-resin can be attributed to the sesquiterpene content, whereas the cytotoxic and antioxidant activities of leaf, bark and twig extracts correlated to total phenolic content. Full article