A new dammarane saponin and other triterpenoids from Siolmatra brasiliensis and evaluation of the antidiabetic activity of its extract.
Context Siolmatra brasiliensis (Cogn.) Baill (Cucurbitaceae) is a climbing plant widely used for the treatment of diabetes mellitus symptoms. Objective This work evaluates the antidiabetic activity of an extract of S. brasiliensis in streptozotocin-diabetic rats and promotes the phytochemical investigation to isolate the major compounds of the same extract. Materials and methods Male Wistar rats were divided into normal (N) and diabetic rats (DC) treated with water; diabetic rats treated with 3U insulin (DI) or with 250 (DSb250) or 500 mg/kg (DSb500) of hydroalcoholic extract of the stalks of S. brasiliensis, via oral gavage, for 21 days. Physiological and biochemical parameters classically altered in diabetes were monitored. The triterpenoids were isolated from the ethyl acetate fraction under silica gel column chromatography and Sephadex-LH20 methods and their structures were determined by NMR, HR-ESI-MS and DC analysis. Results When compared with DC, DSb250 rats showed a reduction in the hyperglycemia (DC: 26.46 ± 0.69 versus DSb250: 19.67 ± 1.06 mmol/L) and glycosuria (DC: 43.02 ± 3.19 versus DSb250: 28.46 ± 2.14 mmol/24 h) and increase in hepatic glycogen (DC: 14.44 ± 1.26 versus DSb250: 22.08 ± 4.26 mg/g). Three known cucurbitacins were isolated from a hydroalcoholic extract of S. brasiliensis, i.e., cayaponosides A1, B4, D, and a new dammarane saponin 3-O-β-d-gentiobiosyl-26-O-β-d-glucopyranosyl-20-hydroxydammar-24-ene. The structures of these compounds were elucidated by spectral data analysis of the natural products and their acetyl derivatives. Discussion and conclusion The known cucurbitacins and/or the new identified saponin may be related with the antidiabetic activity of S. brasiliensis.
['Dos Santos|Carlos Henrique Corrêa|CH|', 'Borges|Izabeau Pontes|IP|', 'da Silva|Virgínia Claudia|VC|', 'de Sousa|Paulo Teixeira|PT|', 'Kawashita|Nair Honda|NH|', 'Baviera|Amanda Martins|AM|', 'Carvalho|Mario Geraldo de|MG|']
D000818:Animals D015415:Biomarkers D001786:Blood Glucose D066241:Carbon-13 Magnetic Resonance Spectroscopy D002942:Circular Dichroism D019662:Cucurbitaceae D003921:Diabetes Mellitus, Experimental D004305:Dose-Response Relationship, Drug D006003:Glycogen D006029:Glycosuria D007004:Hypoglycemic Agents D007328:Insulin D008099:Liver D008297:Male D015394:Molecular Structure D008517:Phytotherapy D010936:Plant Extracts D018547:Plant Stems D010946:Plants, Medicinal D066244:Proton Magnetic Resonance Spectroscopy D017208:Rats, Wistar D012503:Saponins D021241:Spectrometry, Mass, Electrospray Ionization D013311:Streptozocin D013997:Time Factors D014315:Triterpenes
Cucurbitaceae diabetes mellitus cucurbitacins Antihyperglycemic effect