A new antifungal benzoic acid ester from Uvaria narum

Uvarmicranones A and B, two new benzoquinones and cytotoxic constituents from the stems of Uvaria micrantha (A. DC.) Hook. f. & Thomson

Two novel benzoquinones, uvarmicranones A (1) and B (2), along with 15 known compounds (3 - 17) were isolated from the stems of Uvaria micrantha (Annonaceae). Their structures were elucidated by analyses of NMR and high-resolution mass data. A plausible biosynthetic pathway of uvarmicranone A (1) via Diels-Alder cycloaddition reaction was also proposed. Some isolated compounds were evaluated for their cytotoxic activities. Compounds 1, 14, and 15 showed moderate cytotoxic effects against T-cell acute lymphoblastic cells (MOLT-3), with IC₅₀ values of 7.83 ± 0.83, 6.53 ± 1.01, and 4.20 ± 0.29 μM, respectively. Additionally, compound 15 exhibited moderate cytotoxicity against cervical carcinoma cells (HeLa) with an IC₅₀ value of 7.00 ± 3.15 μM.

Two new benzoic acid derivatives from endophytic fungus Aspergillus versicolor

Two new benzoic acid derivatives, named methyl(S)-3-hydroxy-4-(2- hydroxy -6-methylheptan-2-yl)benzoate (1) and 2-hydroxy-3-(6- hydroxy-6-methylhept-1-en-2-yl)benzoic acid (2), were isolated from the ethanol extract of an endophytic fungus Aspergillus versicolor derived from the medicinal plant Euphorbia royleana. The structures of compounds (1-2) were elucidated using NMR and MS methods.

Uvarialuridols A-C, three new polyoxygenated cyclohexenes from the twig and leaf extracts of Uvaria lurida

The first phytochemical investigation of Uvaria lurida resulted in the isolation and identification of three new polyoxygenated cyclohexenes, (+)-(1R,2S,3R,6S)-uvarialuridols A-C (1-3), together with 10 known compounds (4-13). All new structures were elucidated by spectroscopic methods and HRESIMS. The absolute configurations of compounds 1 and 5 were confirmed by X-ray diffraction analysis using Cu Kα radiation. The absolute configurations of compounds 2-4 were identified from comparisons of their specific rotations and ECD spectra with those of known compounds. Compound 11 showed α-glucosidase inhibitory activity with an IC₅₀ value of 30 μM which was better than the standard control, acarbose (74 μM) whereas, compound 10 exhibited nitric oxide (NO) production inhibitory activity with an IC₅₀ value of 37 μM.

Specialized metabolites contributing to colour and scent volatiles in Uvaria hamiltonii flowers

The present study focuses on the emitted and endogenous scent profiles of Uvaria hamiltonii flowers. Among the 34 compounds identified, sesquiterpenoids were found to dominate the floral volatiles composition. Profiles from endogenous scent volatiles showed higher number of compounds than the emitted ones. The anthocyanin pigment responsible for the flower colour was also explored. It was found that a single anthocyanin compound, cyanidin-3-O-glucoside, was principally responsible for petal colour. Total phenolic content was evaluated and antioxidant capacities were studied with the help of DPPH, FRAP and ABTS assays. The total phenolic content and the antioxidant capacity were higher in methanolic extract as compared to aqueous, petroleum ether and ethyl acetate extracts of U. hamiltonii flowers.