Multi target interactions of essential oil nanoemulsion of Cinnamomum travancoricum against diabetes mellitus via in vitro, in vivo and in silico approaches

Abstract

This study reports antidiabetic activity of leaf essential oil (EO) of Cinnamomum travancoricum from the Western Ghats, India via in vitro , in vivo and in silico methods. EO was characterized by GC-MS and GC-FID. Essential oil nanoemulsions (EN) were prepared and characterized. Antidiabetic potential was evaluated through in vitro assays namely, α-amylase and α-glucosidase inhibition, glucose uptake and insulin secretion assays. In vivo study was conducted on STZ-induced diabetic Wistar rats. Molecular docking was conducted to find the lead antidiabetic compounds. Of the 42 compounds identified in the EO, α-phellandrene (5.9%), β-phellandrene (12.6%), linalool (23.6%), safrole (6.8%) and shyobunol (5.1%) were major constituents. Of the two ENs formulated, 1:2 ratio (EO to surfactants) was better in zeta size (51.4 nm) and potential (−30.9). In vitro results were impressive. EN lowered elevated blood glucose level to normal (p < 0.01) and improved the insulin secretion (p < 0.01) in diabetic rats. Further, serum AST, ALT, ALP, triglyceride and pancreatic β-cell damage were seen reduced (p < 0.05). Molecular docking studies showed minor constituents of EO, namely, δ-cadinene, elemol, spathulenol and α-copaen-11-ol playing active role in antidiabetic activity through α-amylase, α-glucosidase, insulin receptor, and insulin secretion proteins.