Phytochemicals, Cytotoxicity, Inhibitory Effect on Nitric Oxide Production and Alpha-Glucosidase Activity, and DPPH Scavenging Activity of Leaf Extract from Gymnema inodorum (Lour.) Decne

Abstract

Investigation of phytochemicals, cyto-toxicity, inhibitory effect on nitric oxide (NO) production and α-glucosidase activity, and DPPH scavenging activity of leaf extract from Gymnema inodorum (Lour.) Decne (LEGI) revealed that GC-MS analysis demonstrated the presence of 83 phytochemicals with 5 main compounds i.e. Phytol (18.14 %), n-Hexadecanoic acid (12.45 %), 9,12-Octadecadienoic acid (Z,Z)-(3.92 %), 9,12,15-Octadecatrienoic acid, (Z,Z,Z)-(10.39 %) and Betulin (8.56 %), and 78 trace compounds in LEGI. MTT assay to investigate cytotoxicity showed that LEGI exhibited low cytotoxicity to the RAW 264.7 macrophages with IC50 of 128.77±2.82 µg/mL. Treatment with the LEGI significantly inhibited nitric oxide (NO) production, an inflammatory mediator, in the LPS-stimulated RAW 264.7 cells. At the concentration of 50 mg/mL, LEGI inhibited NO production by 16.73±1.52 % which was less than Diclofenac did (27.07±1.81 %). The α-glucosidase inhibitory activity to determine the antidiabetic activity showed that LEGI exhibited the inhibition on α-glucosidase activity with IC50 of 0.34 mg/mL, which was less potent than Acarbose (IC50 of 0.20 mg/mL). Assay of 2,2-diphenyl-2-picrylhydrazyl-hydrate (DPPH) radical scavenging to examine antioxidant activity revealed that LEGI demonstrated less potent DPPH scavenging activity compared to Butylated hydroxytoluene, BHT with IC50 of 0.43 vs 0.36 mg/mL, respectively. These results indicate that the leaf extract from G. inodorum possesses anti-inflamatory, antidiabetic and antioxidant activities that can be developed and used as natural agents for the tréamatent of diseases related to these activities.