Bioactivity-guided isolation of compounds from Sophora flavescens with antibacterial activity against Acinetobacter baumannii.

Bioactivity-guided fraction of an extract of Sophora flavescens to identify antibacterial compounds against Acinetobacter baumannii, led to the isolation of two new compounds, (2″R)-5-methoxy-7-hydroxy-8-lavandulylchromone (13) and (2S,ßS)-(-)-sophobiflavonoid CE (19), and 18 known flavonoids, (6aR,11aR)-(-)-maackiain (1), (2S)-(-)-8-prenylnaringenin (2), (2S)-(-)-exiguaflavanone K (3), (2S)-(-)-sophoraflavanone G (4), (2S)-(-)-leachianone A (5), (2S)-(-)-kushenol E (6), (2S)-(-)-leachianone G (7), (±)-kushenol F (8), (2S)-(-)-kurarinone (9), (2S)-(-)-kurarinol (10), (2 R,3R)- (+)-3,7,4'-trihydroxy-5-methoxy-8-prenylflavanone (11), (2S)-(-)-isoxanthohumol (12), (2S)-(-)-2'-methoxykurarinone (14), (2 R,3R)-(+)-kushenol I (15), calycosin (16), kuraridin (17), (2S)-(-)-kushenol A (18), and trifolirhizin (20). Their structures were elucidated based on NMR, MS, and CD spectroscopic analysis. Among them, 1, 2, 5, and 15 exerted modest antibacterial activity against A. baumannii, with MIC95 of 128-256 µg/mL for 2 and 256-512 µg/mL for 1, 5 and 15.

Catecholic alkaloid sulfonates and aromatic nitro compounds from Portulaca oleracea and screening of their anti-inflammatory and anti-microbial activities.

Acidic compounds were enriched from a water decoction of Portulaca oleracea using 717 anion exchange resin column chromatography. A total of 22 compounds including 9 catecholamine derivatives, of which six were rare sulfonic acid derivatives, and 9 nitro derivatives, were further isolated through various column chromatographic methods, and their structures were elucidated by interpreting their spectroscopic data and ECD calculations. Among them, 16 compounds were isolated from P. oleracea for the first time, 8 of which were undescribed compounds and four compounds were natural products. Pharmacological screening indicated that cis-3-(3-nitro-4-hydroxyphenyl)-methyl acrylate exhibited anti-inflammatory activity, measured as inhibition of nitric oxide production in LPS-stimulated RAW264.7 macrophage cells, with an EC50 value of 18.0 µM, The compounds showed only weak anti-microbial activity with (2R)-(+)-2-chloro-3-(3-nitro-4-hydroxyphenyl)-propionic acid methyl ester inhibiting Candida albicans with a MIC of 256 µg/mL, and 3-methoxy-4,5-dinitrophenol inhibiting Shigella sonnei with a MIC of 512 µg/mL.