In vivo anti-diabetic agent from the “insulin plant” Costus igneus

Costus igneus Nak, belonging to the Costaceae family, is a perennial plant native to South and Central America, commonly known as “insulin plant” due to the use of its leaves in the traditional medicine for the treatment of diabetes [ 1 ]. Diabetes is a chronic metabolic disorder with a prevalence increasing worldwide, motivating the investigation of new active agents among natural sources with less side effects compared to synthetic drugs [ 2 ]. Several studies demonstrated the potential of C. igneus leaves in the treatment of diabetes [ 3 ] [ 4 ], but further studies are needed to elucidate the hypoglycaemic action of the plant and its components. The aim of this study was to isolate anti-diabetic compounds from C. igneus rhizome collected in Uyo (Nigeria). Dried and powdered rhizome was extracted with ethanol 99%, then dissolved in water and partitioned with dichloromethane, ethyl acetate, and n-butanol. All the extracts were assayed in alloxan-induced diabetic rats (dose 1000 mg/kg) showing significant reductions in blood glucose level being dichloromethane extract the most active during both the acute and prolonged studies. The dichloromethane extract was then subjected to chromatography to obtain five subfractions with fraction 4 showing the highest anti-diabetic activity. The fractionation of fraction 4 led to the isolation of a pure diosgenin triglycoside, identified by 1D and 2D NMR, and ESI-MS as aferoside A. Aferoside A at dose of 100 mg/kg showed significant reduction of blood glucose level (51.9% vs 64.8% of glibenclamide at 10 mg/kg), highlighting its potential in the use of management of diabetes. Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany