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Potato common scab is a soil-borne bacterial disease caused by Streptomyces scabies , which is ubiquitous and difficult to control. In this study, the issue of developing antimicrobial agents derived from plant extracts against S. scabies was addressed. Three bioactive phenolic compounds, named gallic acid, 1-O-galloyl-β- d -glucose, and corilagin, were isolated and identified from Phyllanthus emblica pomace through bioassay-guided fractionation. The antibacterial effects of these compounds on S. scabies were evaluated with MIC values of 0.63, 0.31, and 1.25 mg/mL, respectively. Furthermore, Structure-activity relationship analyses of 17 gallic acid and its structural analogs revealed that the R 6 position of the benzene ring was a key factor to their antibacterial activity against S. scabies , among which pyrogallol had the best antibacterial effect. Scanning electron microscopy showed that when S. scabies was exposed to this gallic acid and its structural analogs, the cell membranes of which was damaged. The results will help promote the development and structural modification of plant-derived bacteriostatic agents. [Display omitted] • Three phenolic compounds were isolated and characterized from Phyllanthus emblica. • The phenolic compounds showed promising antibacterial activity against S. scabies. • SAR study showed carboxyl substituents of gallic acid affected bactericidal activity. • Gallic acid analog pyrogallol showed the strongest bactericidal activity. • Gallic acid and analogs damaged membrane integrity and permeability of S. scabies. [ABSTRACT FROM AUTHOR]

The traditional Chinese herb Anoectochilus roxburghii (A. roxburghii) is well-known for its medicinal value, but few studies have reported its ability to combat metabolic syndrome activities in vitro. In this study, the extraction of seven compounds from A. roxburghii using 70% ethanol, RP-C18, thin layer chromatography (TLC), Sephadex LH-20, high performance liquid chromatography (HPLC) and subsequent identification of their structures through nuclear magnetic resonance (NMR). Among these compounds, kaempferol-3- O -rutinoside and isorhamnetin-3- O - α - l -rhamnopyranoside-7- O - β - d -glucopyranoside were obtained from A. roxburghii for the first time. Results showed that those compounds inhibited key enzymes involved in metabolic syndrome in vitro. Molecular docking and binding free energy calculations were employed to elucidate the inhibition mechanism of these compounds, while SwissADME was used to assess their drug-like characteristics. Notably, 9-hydroxy-megastigma-4,7-dien-3-one-9- O - β - d -glucopyranoside has the potential as an α-amylase inhibitor for the first time. This research enriches the compound library of A. roxburghii and provides new ideas for medication research and the development of metabolic syndrome. Kaempferol-3- O -rutinoside and isorhamnetin-3- O - α - l -rhamnopyranosyl-7- O - β -D glucopyranoside were obtained from Anoectochilus roxburghii for the first time. 9-hydroxy-megastigma-4,7-dien-3-one-9- O - β - d -glucopyranoside was discovered to display potential α-amylase activity for the first time in vitro. [Display omitted] • Firstly, seven active compounds were identified from A. roxburghii. • Quercetin-7- O - β -D-glucoside has potent MetS-relevant enzyme inhibitory activity. • HMDO-Glu inhibited α-amylase activity in vitro. • Flavonoids from A. roxburghii could be a potential source of pharmaceutical use. [ABSTRACT FROM AUTHOR]

A known flavonoid triglycoside, apigenin 6-C-[ α - L -arabinopyranosyl-(1‴→2″)- β - D -glucopyranoside]-7-O- β - D - glucopyranoside (1), was isolated from the n -butanol extract of Styela plicata for the first time. The structure of 1 was established by spectroscopic methods and direct comparison with authentic samples on HPLC after acid hydrolysis as a new marine natural flavonoid. This work contributes to expand the knowledge about the chemical compositions of S. plicata and the chemotaxonomy of ascidians. Image 1 • A known flavone C-glycoside was isolated for the first time from Styela plicata. • The isolation of 1 enriches the chemical compositions of S. plicata. • The isolation of 1 contributed to the chemical diversity of marine flavonoids. [ABSTRACT FROM AUTHOR]