Flavonoids and the Subchronic Toxicity, Antipeptic Ulcer, and Analgesic Effects of the Ethyl Acetate Soluble Fraction of the Ethanol Extract from Sanchezia nobilisHook. f Leaves

Seven known flavonoids were isolated from the ethyl acetate fraction of the 80% ethanol extract of Sanchezia nobilisHook. f leaves (EASN). The 7 known compounds as hispidulin (4′,5,7-trihydroxy-6-methoxyflavone) (1), hispidulin-7-O-α-galactopyranoside (2), hispidulin-4′-O-β-galactopyranoside (3), hispidulin-7-O-β-galacturonide methyl ester (4), apigenin-7-O-α-glucuronide (5), hispidulin-7-O-α-glucuronide (6), and hispidulin-7-O-β-glucuronide (7), all of which are first records for the Sancheziagenus. The structures of the compounds were confirmed using spectroscopic methods and by comparison with reported data. The antipeptic ulcer and analgesic effects of the extract were also tested in experimental animal models. At a 50 mg/kg/d dose, the ethyl acetate fraction significantly reduced mean ulcer score, gastric volume, and total acidity, and increased gastric pH, while also tending to reduce free acid in comparison with the model group. At a 100 mg/kg/d dose, the ethyl acetate fraction tended to have an analgesic effect. However, a dose of 300 mg/kg/d showed a significant elevation in pain. The extract was also continuously evaluated for subchronic toxicity for 28 days in rats but showed no effect at oral doses of 50 and 250 mg/kg/d. The results of this study have provided more scientific evidence for the chemical composition and use of SNF leaves to treat peptic ulcer disease in Vietnam.