Two new flavonol glycosides, myricetin 4'-O-α-L-rhamnopyranoside (1) and quercetin 3'-O-α-L-rhamnopyranoside (2), together with a novel biflavonol compound, speciin (3), as well as eleven phenolic metabolites, namely myricitrin (4), europetin 3-O-α-L-1C4-rhamnopyranoside (5), quercitrin (6),
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Two new flavonol glycosides, myricetin 4'-O
-α-L-rhamnopyranoside (1) and quercetin 3'-O
-α-L-rhamnopyranoside (2), together with a novel biflavonol compound, speciin (3), as well as eleven phenolic metabolites, namely myricitrin (4), europetin 3-O
-rhamnopyranoside (5), quercitrin (6), hyperin (7), rhamnetin 3-O
-β-galacto-pyranoside (8), caffeic acid (9), caffeic acid methyl ester (10), chlorogenic acid (11), chlorogenic acid methyl ester (12), gallic acid (13) and gallic acid methyl ester (14), were identified from the 80 % methanol extract of the aerial parts (leaves and stems) of Oenothera speciosa
Nutt. (Onagraceae). In addition myricetin (15), quercetin (16) and ellagic acid (17) were identified from the chloroform extract. The structures were established depending on their chemical and physical analyses (UV, HR-ESIMS, 1D and 2D NMR). It was found that 80 % aqueous methanol extract of O. speciosa
is non-toxic to mice up to 5 g kg-1
b.wt. The investigated extract exhibited significant antihyperglycaemic and anti-inflammatory activities in a dose dependant manner. Also, the 80 % methanol extract, myricitrin(4) and hyperin(7) showed potent antioxidant activity in vitro
using 1,1-diphenyl 2-picryl hydrazyl (DPPH) radical assay.