Hypoglycaemic activity of Smilax canellifolia Mill. rhizomes: a bioassay-guided isolation and identification of synergistic compounds

Background Smilax canellifolia Mill. is a native shrub used in commercial root tonics as an aphrodisiac, stimulant, and pain reliever. Traditional medicine incorporates the rhizomes of S. canellifolia for the treatment of anaemia, rheumatoid arthritis, and diabetes in Jamaica and its diaspora. In particular, the use of this plant in the management of diabetes has yet to receive any scientific evaluation. In this study, the hexane crude extract of S. canellifolia rhizomes (SCH) was investigated to determine its hypoglycaemic activity in normal Sprague-Dawley rats and to identify the compounds contributing to this activity. Methods The hypoglycaemic compounds were isolated using bioactivity-guided purification which involved hypoglycaemic screening using an Oral Glucose Tolerance Test (via intravenous administration of SCH and its fractions). Purification was performed using column chromatography, and the bioactive fractions were elucidated using spectroscopic techniques (IR; GC-MS; 1 H NMR and 13 C NMR). Results Administration of SCH at 50 mg/kg body weight (BW) to normal S-D rats produced a reduced glycaemic response, notably from the 90 to the 150-min intervals when compared with the control, dimethyl sulfoxide ( p