A Novel Approach for Oral Delivery of Insulin via Desmodium gangeticum Aqueous Root Extract

Many challenges are associated with the oral delivery of insulin, relating to the physical and chemical stability of the hormone, and its absorption and metabolism in the human body. The present study aims to demonstrate the oral delivery of insulin in both normal and steptozotocin (STZ)-induced diabetic rats with the help of the aqueous extract of Desmodium gangeticum (DG) root. Human insulin was mixed with the aqueous extract of DG root (0.1 mg/ml) with human insulin (40 IU/ml) in ratio 1:1(v/v), to prepare oral insulin drug. Decreased plasma glucose level and increased plasma insulin in normal and STZ-induced diabetic rat suggested the probable absorption of insulin through GI tract when insulin was administered by mixing with DG extract. Indeed, insulin mixed DG potentially stimulates the release of insulin in STZ-induced diabetic rat rather than in normal animal. In vivo insulin secretaguage action of oral insulin drug was determined by isolated rat heart model and the results showed a significant cardio protection in STZ rat. The finding of this study suggests that insulin mixed with DG extract can be a promising vehicle for oral delivery of insulin. However, further studies are required to explore the exact compound(s) responsible for the protective delivery of insulin orally. Increased plasma insulin level by insulin mixed DG extract administration in STZ-treated diabetic rat indicates not only insulin secretaguage action of the mixture but also a probable altered insulin release mechanism in diabetic condition.