Anti-Diabetic Activity of Self-Microemulsifying Drug Delivery Systems from Bay Leaves (Eugenia polyantha Wight) with Virgin Coconut Oil as A Carrier

Insulin resistance is caused by the inability of target tissues to respond to insulin. Bay leaf (Eugenia polyantha Wight) extract has been used for the treatment of insulin-resistant type-2 diabetes mellitus (IRDM), but it has low solubility and bioavailability. To overcome these problems, chloroform extract of bay leaves was formulated into a self-microemulsifying drug delivery system (SMEDDS) using virgin coconut oil (VCO) as a carrier oil. This study aims to produce a micro-herbal medicine and to determine the effect of a micro-herbal preparation derived from bay leaves as an anti-IRDM agent. Homogeneous formulations were evaluated for extract loading, emulsification time, size, size distribution, and the polydispersion index of the droplet nanoemulsion, and their anti-IRDM activitieswereinvestigated on insulin-resistant rats using extracts, SMEDDS, metformin, negative control, and normal groups. Each group consisted of three randomly selected male Wistar rats. Blood cholesterol levels were checked at 0, 80, and 95days and analyzed using ANOVA. The results showed that the optimum SMEDDS formula was tween 80:PEG 400:virgin coconut oil (48%:32%:20%) in a total volume of 5 mL. It has an emulsification time ofless than 1 minute with an average of droplet size of 141.4µm and a polydispersion index value of 0.254. Morphological observation showed that the microemulsion particles were spherical and stable in varied pH media. The hypoglycemic effects of single- dose metformin, SMEDDS, and the combination of ahalf dose of SMEEDS with metformin were 28.3%, 15.6%, and 34.6%, respectively.