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Four compounds, luteolin (1), 6-γ,γ-dimethylallylquercetin 7-O-β-D-glucopyranoside (2), 6-γ,γ-dimethylallylkaempferol 7-O-β-D-glucopyranoside (3), and 6-γ,γ-dimethylallyldihydrokaempferol 7-O-β-D-glucoside (4), were isolated for the first time from AcOEt extract of the O. integerrima flower. We then evaluated the antioxidant effects of AcOEt, butanol, and MeOH extracts and their effects on H

A new xanthone derivative, aspidxanthone A (1), and three known compounds ((2S)-1-(β-D-galactopyranosyloxy)-3-(hexadecanoyloxy)propan-2-yl (9Z,12Z)-octadeca-9,12-dienoate (2), (25S)-spirostane-1β,3α,5β-triol (3), and asparenyldiol (4)) were isolated from the whole of the endemic species Aspidistra letreae in Vietnam. Their structures were elucidated by means of extensive spectroscopic analyses and comparison with published data. In this study, we report the isolation and structure elucidation of a new compound aspidxanthone A, antioxidant activities of the extract and isolates 1-4, and in silico molecular docking of aspidxanthone A. The ethyl acetate extract had good antioxidant activity with an IC50 value of 26.3 μg mL-1 . Among the isolates, aspidxanthone A exhibited DPPH reduction activity with an IC50 value of 11.2 μM, which is in the same range as that of the positive control, ascorbic acid. The mechanism of action of aspidxanthone A on the tyrosinase and xanthine oxidase proteins have been clarified by in silico studies.

A new decenoic acid derivative, gelliodesinic acid, and a naturally new alkaloid, together with three known furanoterpenoids and two known indole alkaloids, were isolated from the MeOH extract of the marine sponge Gelliodes sp. collected in Vietnam. The chemical structures of the isolated compounds were determined by analyses of 1D- and 2D-NMR and MS data and by comparisons of the data with those reported in the literature. The cytotoxicity assay against HeLa, MCF-7, and A549 cancer cell lines revealed that the three known furanoterpenes exhibited cytotoxic activities with IC50 values ranging from 23.6 to 75.5 μM against the three cell lines, and that 1H-indole-3-carboxylic acid showed cytotoxicity with an IC50 value of 89.2 μM against A549 cancer cell lines.

A new tribromoiododiphenyl ether (1) and eight known brominated diphenyl ethers (2-9) were isolated from the MeOH extract of the sponge Arenosclera sp. collected in Vietnam, using repeated open column chromatography and preparative thin layer chromatography. The chemical structure of the new compound 1 was determined by analyses of spectroscopic (1D- and 2D-NMR, and MS) data and by comparison of our data with those reported in the literature. Compounds 1, 3, and 8 exhibited strong antibacterial activities against the Gram-positive bacteria Bacillus subtilis and Staphylococcus aureus and the Gram-negative bacterium Klebsiella pneumoniae with MIC values ranging from 0.8 to 6.3 μm, while compounds 5 and 7 only displayed activities against Gram-positive bacteria with MIC values from 0.5 to 3.1 μm. Compound 2 showed activities against the four tested bacteria with MIC values ranging from 0.5 to 6.3 μm.