Three new iridoid glycosides, named involucratosides A - C (1 - 3), were isolated from the H2 O subextract of crude MeOH extract prepared from the aerial parts of Asperula involucrata along with a known iridoid glycoside (adoxoside), three flavone glycosides (apigenin 7-O-β-glucopyranoside, luteolin 7-O-β-glucopyranoside, apigenin 7-O-rutinoside) as well as two phenolic acid derivatives (chlorogenic acid and ferulic acid 4-O-β-glucopyranoside). Their chemical structures were established by UV, IR, 1D- (1 H, 13 C and JMOD) and 2D- (COSY, HSQC, HMBC and NOESY) NMR experiments and HR-ESI-MS. In addition, the crude extract, subextracts and isolates were evaluated for their xanthine oxidase inhibitory and antioxidant activities in in vitro tests. This is the first report on the chemical composition and bioactivities of A. involucrata.
Keywords: Asperula involucrata; Antioxidant activities; Involucratosides A - C; Iridoid glycosides; Rubiaceae; Xanthine oxidase inhibitory activities.
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