Herbal Extracts Encapsulated Nanoliposomes as Potential Glucose-lowering Agents: An in Vitro and in Vivo Approach Using Three Herbal Extracts

Abstract

Encapsulation of polyphenol-rich herbal extracts into nanoliposomes is a promising strategy for the development of novel therapeutic agents against type 2 diabetes mellitus. An attempt was made to encapsulate aqueous, ethanol, and aqueous ethanol (70% v/v) extracts of Senna auriculata (L.) Roxb., Murraya koenigii (L.) Spreng,. and Coccinia grandis (L.) Voigt into nanoliposomes and to screen acute bioactivities in vitro and in vivo. A wide spectrum of bioactivity was observed of which aqueous extracts encapsulated nanoliposomes of all three plants showed high bioactivity in terms of in vivo glucose-lowering activity in high-fat diet-fed streptozotocin induced Wistar rats, compared to respective free extracts. The particle size, polydispersity index, and zeta potential of the aforementioned nanoliposomes ranged from 179–494 nm, 0.362–0.483, and (–22) to (–17) mV, respectively. The atomic force microscopy (AFM) imaging reflected that the nanoparticles have desired morphological characteristics and Fourier-transform infrared (FTIR) spectroscopy analysis revealed successful encapsulation of plant extracts into nanoparticles. However, only the S. auriculata aqueous extract encapsulated nanoliposome, despite the slow release (9% by 30 hours), showed significant (p < 0.05) in vitro α-glucosidase inhibitory activity and in vivo glucose-lowering activity compared to free extract, proving worthy for future investigations.