Gymnema inodorum (GI) is a leafy green vegetable found in the northern region of Thailand. A GI leaf extract has been developed as a dietary supplement for metabolic diabetic control. However, the active compounds in the GI leaf extract are relatively nonpolar. This study aimed to develop phytosome formulations of the GI extract to improve the efficiencies of their phytonutrients in terms of anti-inflammatory and anti-insulin-resistant activities in macrophages and adipocytes, respectively. Our results showed that the phytosomes assisted the GI extract's dispersion in an aqueous solution. The GI phytocompounds were assembled into a phospholipid bilayer membrane as spherical nanoparticles about 160-180 nm in diameter. The structure of the phytosomes allowed phenolic acids, flavonoids and triterpene derivatives to be embedded in the phospholipid membrane. The existence of GI phytochemicals in phytosomes significantly changed the particle's surface charge from neutral to negative within the range of -35 mV to -45 mV. The phytosome delivery system significantly exhibited the anti-inflammatory activity of the GI extract, indicated by the lower production of nitric oxide from inflamed macrophages compared to the non-encapsulated extract. However, the phospholipid component of phytosomes slightly interfered with the anti-insulin-resistant effects of the GI extract by decreasing the glucose uptake activity and increasing the lipid degradation of adipocytes. Altogether, the nano-phytosome is a potent carrier for transporting GI phytochemicals to prevent an early stage of T2DM.
Keywords: Gymnema inodorum extract; adipocytes; anti-inflammation; anti-insulin resistance; macrophages; phytonutrient delivery; phytosome.