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Abstract: Eubacterium limosum ZL-II is an anaerobic bacterium with demethylated activity, which was isolated from human intestinal bacteria in our previous work. In this study, the flavonolignan constituents of Silybi Fructus were biotransformed by E. limosum 1 [1] Eubacterium limosum. ZL-II, producing four new transformation products — demethylisosilybin B (T1), demethylisosilybin A (T2), demethylsilybin B (T3) and demethylsilybin A (T4), among which T1 and T2 were new compounds. Their chemical structures were identified by ESI-TOF/MS, 1H NMR, 13C NMR, HMBC and CD spectroscopic data. The bioassay results showed that the transformation products T1–T4 exhibited significant inhibitory activities on Alzheimer's amyloid-? 42 (A?42 2 [2] Amyloid-?. ) aggregation with IC50 values at 7.49?M–10.46?M, which were comparable with that of the positive control (epigallocatechin gallate, EGCG 3 , [3] Epigallocatechin gallate. at 9.01?M) and much lower than those of their parent compounds (at not less than 145.10?M). The method of biotransformation by E. limosum ZL-II explored a way to develop the new and active lead compounds in Alzheimer's disease from Silybi Fructus. However, the transformation products T1–T4 exhibited decreased inhibitory activities against human tumor cell lines comparing with their parent compounds. [Copyright &y& Elsevier]

Abstract: One alkyl glycoside, saussurostelloside A (1), two phenolic glycosides, saussurostellosides B1 (2) and B2 (3), and 27 known compounds, including eleven flavonoids, seven phenolics, six lignans, one neolignan, one phenethyl glucoside and one fatty acid, were isolated from an ethanol extract of Saussurea stella (Asteraceae). Their structures were elucidated by NMR, MS, UV, and IR spectroscopic analysis. Of the known compounds, (+)-medioresinol-di-O-β-d-glucoside (7), picraquassioside C (10), and diosmetin-3′-O-β-d-glucoside (27) were isolated from the Asteraceae family for the first time, while (+)-pinoresinol-di-O-β-d-glucoside (6), di-O-methylcrenatin (11), protocatechuic acid (14), 1,5-di-O-caffeoylquinic acid (17), formononetin (28), and phenethyl glucoside (29) were isolated from the Saussurea genus for the first time. The anti-inflammatory activities of three new compounds (1–3), five lignans ((−)-arctiin (4), (+)-pinoresinol-4-O-β-d-glucoside (5), (+)-pinoresinol-di-O-β-d-glucoside (6), (+)-medioresinol-di-O-β-d-glucoside (7) and (+)-syringaresinol-4-O-β-d-glucoside (8)), one neolignan (picraquassioside C (10)), and one phenolic glycoside (di-O-methylcrenatin (11)) were evaluated by testing their inhibition of the release of β-glucuronidase from PAF-stimulated neutrophils. Only compound 5 showed moderate inhibition of the release of β-glucuronidase, with an inhibition ratio of 39.1%. [Copyright &y& Elsevier]