MD-1, a poly herbal formulation indicated in diabetes mellitus ameliorates glucose uptake and inhibits adipogenesis – an in vitro study

BACKGROUND: Type 2 Diabetes (T2D) is a polygenic disease requiring a multipronged therapeutic approach. In the current scenario, the use of polyherbals is increasing among the diabetics. MD-1, a poly herbal formulation is constituted as a mixture of six popular anti diabetic herbs, used in the management of Diabetes mellitus (DM). The physicochemical, biochemical and in vitro efficacy studies have been carried out to ascertain the possible mechanisms underlying the anti-diabetic action of MD-1. METHODS: MD-1 was evaluated for residual toxins as per Ayurvedic Pharmacoepia of India (API) procedures. The hydro alcoholic extract of the formulation (HAEF) was evaluated for anti oxidant activity against 2, 2-diphenyl-1-picrylhydrazil (DPPH) and nitric oxide radicals in vitro. The effect of HAEF on carbohydrate digestive enzymes α-glucosidase and α-amylase was studied using biochemical assays. HAEF was studied for its glucose lowering potential in L6 myotubes and 3T3L1 preadipocytes, using 2-deoxy-D-[1-³H] glucose (2-DG) uptake assay. Effect of MD-1 on adipogenesis was evaluated in 3T3L1 adipocytes using oil O red staining. The effect of HAEF on mRNA expression of peroxisome proliferator activated receptor gamma (PPARγ) and glucose transporter 4 (GLUT4) in 3T3L1 adiocytes was investigated by reverse transcriptase polymerase chain reaction (RT-PCR). Statistical analysis was performed by student t-test, ANOVA. RESULTS: Residual toxins present within the API limits and HAEF demonstrated strong antioxidant potential and significantly inhibited the α-glucosidase (IC₅₀ 63.6 ± 0.46 μg/mL) and α-amylase (IC₅₀ 242.81 ± 1.26 μg/mL) activity. HAEF significantly (p < 0.05) enhanced the insulin stimulated glucose uptake in both the cell lines studied. Unlike standard pioglitazone (PGZ), HAEF modulated the mRNA expression of PPARγ and GLUT4 (p < 0.0001) in 3T3L1 adipocytes, without inducing adipogenesis. CONCLUSION: Physicochemical parameters established in the study may serve as reference standards in regular quality control. Absence of residual toxins underpins the safety. The enhanced glucose uptake and favorable modulation of insulin sensitivity through a plausible weak PPARγ agonism is similar to the distinct PPARγ activation pattern of several reported natural compound agonists. The differential binding modes of such dynamic combinatorial ligands within the formulation unlike synthetic ligands like thiozolidinediones (TZD) can be linked to the safe mitigation of diabetic complications by MD-1.