Concoctions containing extract from Cocos nucifera husk fiber are used in Nigeria by traditional medicine practitioners for management of diabetes and its associated complications. Preliminary antidiabetic study was designed to validate the folkloric usage of the plant extract. Dried coconut husk fiber was pulverized and extracted with methanol, followed by partitioning of the methanolic extract in ethyl acetate. Phenolic content, radical scavenging activity and antioxidant capacity as well as inhibitory effects of C. nucifera methanolic (CN‐M) extract and its ethyl acetate (CN‐E) fraction on pancreatic α‐amylase and lipid peroxidation were determined. Total phenolic content and antioxidant capacity of CN‐E fraction were significantly higher than that of CN‐M extract, whereas there was no significant difference in their ability to scavenge free radicals. The CN‐E fraction also exhibited higher in vitro and in vivo inhibitory effects on α‐amylase activity and lipid peroxidation; reducing blood glucose level within 5 days following intraperitoneal administration of the C. nucifera extract to alloxan‐induced hyperglycemic rats. The phenolic‐rich extracts from coconut husk can be further explored as nutraceutical supplement in food formulation for diabetic patients.

The antidiabetic potentials of Heliotropium indicum L. leaf aqueous (HILA) extract used for the management of diabetes by Traditional Medicinal Practitioners (TMPs) in Nigeria was assessed. Alloxan (ALX)-induced hyperglycaemic rats were orally administered with known folkloric dosage of 30 and 75 mg/kg b. wt. of HILA extract, once a day, for 14 days. Fasting blood glucose (FBG) levels were monitored and pancreatic histology was examined. Net hepatic glycogen (GLY) concentration and lipid profiles were also determined. Prior to treatment, ALX-induced hyperglycaemia (>250 mg/dL) was established in rats. Oral administration of 30 and 75 mg/kg b. wt. HILA extract to diabetic rats for 14 days caused significant reduction in FBG to baseline values observed in non-diabetic conditions. Treatment with HILA extract also showed improvement in lipid abnormalities observed in hyperglycaemic condition, levels of triglyceride, total cholesterol and LDL-cholesterol were significantly reduced and HDL-cholesterol increased resulting in improved artherogenic index. Hepatic GLY concentration was significantly increased in diabetic rat treated with the extract. Histological examinations showed degenerated and sparse pancreatic islets β-cells in non-treated diabetic rat, whereas microscopy of treated rats showed mild to normal architecture with enriched β-cells. Preliminary phytochemical profiling of the extract revealed the presence of alkaloids (2.54 mg/g), saponins (0.28 mg/g), phenols (0.04 mg/g) and anthraquinones (0.01 mg/g). Results from this study revealed that the aqueous leaf extract of H. indicum possesses not only antihyperglycaemic, but also antidyslipidemic activities, that may prove to be of clinical importance in the management of diabetes and associated secondary complications.

Extraction of phytoceuticals from medicinal plants need to be optimized to produce standardized, dose-dependent and reliable extracts to meet food or drug administration regulations for translation into approved nutraceutical or pharmaceutical products. Effect of selected limiting extraction variables on yield and antiradical activity of curcumin-rich extract from Curcuma longa rhizomes was investigated. Assay-guided response (free radical scavenging activity) was used to determine the optimized set of extraction parameters. Curcumin-rich extract was produced using solvent boiling process at 65 oC with absolute methanol of weight ratio 1:50 (w/v) within 1 h. Relative radical scavenging activity of the extract derived using the optimized set of parameters recorded an IC50 of 497 μg/ml and its total antiradical capacity determined within 6 h (76 - 85 % at a concentration of 400 – 600 μg/ml) was not significantly different from that of commercially available natural curcumin used as reference. Time-dependent kinetic analysis revealed an initial fast burst in rate of activity (2.27 – 7.77 min-1) followed by a slow reaction rate in a steady second phase (0.12 – 0.54 min-1). Conclusively, appreciable amount of curcumin-rich extract of enhanced antiradical activity was extracted from the rhizome of C. longa using assay-guided procedure.