A new dammarane saponin and other triterpenoids from Siolmatra brasiliensis and evaluation of the antidiabetic activity of its extract

• Published in: Pharmaceutical biology Vol. 54; no. 9; pp. 1539 - 1547
• Main Authors: dos Santos, Carlos Henrique Corrêa, Borges, Izabeau Pontes, da Silva, Virgínia Claudia, de Sousa, Paulo Teixeira, Kawashita, Nair Honda, Baviera, Amanda Martins, Carvalho, Mario Geraldo de
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis 01-09-2016
• Subjects: Animals; Antihyperglycemic effect; Biomarkers - blood; Blood Glucose - drug effects; Blood Glucose - metabolism; Carbon-13 Magnetic Resonance Spectroscopy; Circular Dichroism; Cucurbitaceae; Cucurbitaceae - chemistry; cucurbitacins; Dammaranes; diabetes mellitus; Diabetes Mellitus, Experimental - blood; Diabetes Mellitus, Experimental - chemically induced; Diabetes Mellitus, Experimental - drug therapy; Dose-Response Relationship, Drug; Glycogen - metabolism; Glycosuria - chemically induced; Glycosuria - prevention & control; Hypoglycemic Agents - isolation & purification; Hypoglycemic Agents - pharmacology; Insulin - pharmacology; Liver - drug effects; Liver - metabolism; Male; Molecular Structure; Phytotherapy; Plant Extracts - isolation & purification; Plant Extracts - pharmacology; Plant Stems; Plants, Medicinal; Proton Magnetic Resonance Spectroscopy; Rats, Wistar; Saponins - isolation & purification; Saponins - pharmacology; Spectrometry, Mass, Electrospray Ionization; Streptozocin; Time Factors; Triterpenes - isolation & purification; Triterpenes - pharmacology; diabetes mellitus; Antihyperglycemic effect; cucurbitacins; Cucurbitaceae
• DOI: 10.3109/13880209.2015.1107108
• EISSN: 1744-5116
• ISSN: 1388-0209

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 (DSb
250
) or 500 mg/kg (DSb
500
) 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, DSb
250
rats showed a reduction in the hyperglycemia (DC: 26.46 ± 0.69 versus DSb
250
: 19.67 ± 1.06 mmol/L) and glycosuria (DC: 43.02 ± 3.19 versus DSb
250
: 28.46 ± 2.14 mmol/24 h) and increase in hepatic glycogen (DC: 14.44 ± 1.26 versus DSb
250
: 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.