Two new phenolic compounds from Boerhavia erecta collected in Vietnam.

Boerhavia erecta is a tropical plant that is widely used in Asian folk medicine. Little is known about the alpha-glucosidase inhibition and antimicrobial properties of compounds from this plant. In the present study, the phytochemical study of the aerial parts of B. erecta collected in Vietnam was conducted using multiple chromatographic methods. The chemical structures of isolated compounds were identified by comprehensive spectroscopic methods. Two new compounds, berectone C (1) and (E)-tetracosyl 3-(3-hydroxy-4-methoxyphenyl)acrylate (4), together with the known compounds boeravinone C (2), liquiritigenin (3), bis(1H-indol-3-yl)methanone (5), and indole-3-carboxylic acid (6) were isolated and structural elucidated. Compounds 1 and 4 were evaluated for alpha-glucosidase inhibition and antimicrobial activity against antibiotic-resistant, pathogenic bacteria Enterococcus faecium, Staphylococcus aureus, and Acinetobacter baumannii. Compound 1 showed strong inhibition of the alpha-glucosidase enzyme (IC50 43 µg/mL). Only compound 1 exhibited antimicrobial property against A. baumannii, forming an inhibition zone of 11 mm.

Berectones A and B: Two new rotenoids from the aerial parts of Boerhavia erecta.

Two previously unreported rotenoids, berectones A and B (1 and 2), along with four known compounds, 3,3',4'-tri-O-methylellagic acid (3), kaempferol (4), 7,4'-dihydroxy-8-methoxyisoflavone (5), and trans-N-caffeoyltyramine (6) were isolated from the aerial parts of Boerhavia erecta. The structures of all isolated compounds were fully characterized using spectroscopic data, as well as comparison with the previous literature. Compound 6 exhibited the strongest inhibitory activity toward α-glucosidase with IC50 value of 4.74 µM.[Formula: see text].

A new diphenyl ether from Parmotrema indicum Hale growing in Vietnam.

Chemical investigation of the lichen Parmotrema indicum Hale led to the isolation of one new diphenyl ether, parmetherine D (1), along with eight known compounds (2-9). The structures were determined by analysis of MS and NMR data and by comparison with the literature. Compounds 1, 2, and 7 were evaluated for α-glucosidase inhibition. Only compound 1 exhibited significant inhibition.[Formula: see text].

29-Norlupane-1ß-hydroxy-3,20-dione, a new norlupane triterpenoid from the twigs and leaves of Phyllanthus acidus.

A new norlupane triterpenoid, 29-norlupane-1ß-hydroxy-3,20-dione (1), along with ten known compounds, 29-norlup-1-ene-3,20-dione (2), phyllanthol (3), phyllanthone (4), glochidone (5), lupeol (6), lupeone (7), 4-hydroxybenzoic acid (8), 4-hydroxybenzaldehyde (9), phyllane A (10) and methyl ß-orsellinate (11) were isolated the twigs and leaves of Phyllanthus acidus. The structure of 1 was identified by interpretation of their spectroscopic data and comparison with those reported in the literature. In addition, all isolated compounds 1-11 were evaluated for their antioxidant activity.