Novel Compounds with new Anti-Ulcergenic Activity from Convolvulus pilosellifolius Using Bio-Guided Fractionation

Oral administration of the total alcohol extract of Convolvulus pilosellifolius Desr. (250 and 500 md/kg) showed potent anti-ulcerogenic activity in absolute ethanol-induced ulcer model in rats; it showed percent protection of control ulcer by 69.2 and 84.6%, respectively, while standard ranitidine (100 mg/kg) exhibited 46.2%. Bio-guided work leads to isolation of two novel compounds (1 and 2), which were identified through ¹ H, ¹³ C NMR, HMPC, HMQC and DEPT as: methyl 2-(hydroxymethyl) octanoate, named as amanitate, and 16-amino-9,13-dimethyl-17-(prop-1-en-2-yl)-hexadecahydro-1H-cyclopenta[a] phenanthren-3-ol, named as asmatol. Both compounds (50 mg/kg) possessed anti-ulcerogenic activity with 95.4% and 55.84% protection, respectively. Two known compounds (3 and 4) were also isolated and identified through comparison with authentic samples and confirmed through different NMR techniques as kampeferol and quercetin. These compounds also showed anti-ulcerogenic activity with 78.38% and 5.38% protection, respectively. The cytoprotective mechanism explains the potent anti-ulcerogenic activity of the total alcohol extract and the isolated compounds. The extract was highly safe as the LD₅₀ was more than 5000 mg/kg. These results were well supported by the sub-chronic toxicity study, as the extract (500 mg/kg) administrated orally to rats for 35 consecutive days showed no alteration in the liver and kidney functions. Copyright © 2016 John Wiley & Sons, Ltd.