The Isolation And Elucidation Of The Hypoglycaemic Compounds From Eucalyptus Camaldulensis

Abstract

The folkloric use of medicinal plants has formed the backbone for the development of many current pharmaceuticals [1]. Diabetes mellitus is a global epidemic to over 366 million people between 20 – 79 age groups being affected [2]. This study aims to investigate the effect of Eucalyptus camaldulensis, on the blood glucose concentration and to subsequently determine the hypoglycaemic compound(s). An oral glucose tolerance test (OGTT) was done with the crude hexane, ethyl acetate and methanol extracts using an Accucheck Advantage (II) glucose kit in order to determine the effect on the blood glucose concentration. The crude hexane extract caused the most hypoglycaemic effect (4.71 ± 0.19 mmol/L vs. 6.32 ± 0.369 mmol/L dimethyl sulfoxide, control, at the 90 minutes interval) and as such further purification was carried out using chromatography. Bio-directed purification was carried out and yielded three (3) compounds: K1 (50 mg/kg body weight (BW), K2 (30 mg/kg BW) and K3 (30 mg/kg BW) which significantly reduce the glycaemic peak when compared with the control (5.26 ± 0.183 mmol/L, 5.44 ± 0.199 mmol/L and 5.05 ± 0.182 mmol/Lvs 6.32 ± 0.369 mmol/L at the 90 minutes interval respectively). The structures of the hypoglycaemic compounds were elucidated and compared with the commercially available compounds and a positive control, metformin. The hypoglycaemic compounds isolated from E. camaldulensis were identified as hexadecanoic and octadecanoic acids in a specific ratio (K2) and pure compounds (K1 and K3). Therefore, this research will contribute to an overall reduction in the healthcare cost for many countries.