Development of an antidiabetic polyherbal formulation (ADPHF6) and assessment of its antioxidant activity against ROS-induced damage in pUC19 and human lymphocytes - an in vitro study.BACKGROUND
 Herbal-based combination therapy stages a vital role for the treatment of type 2 diabetes mellitus (T2DM) and associated complications.  The present study aims at developing an Ayurvedic-based polyherbal formulation (ADPHF6) and the assessing its antidiabetic and antioxidant property.


 ADPHF6 polyherbal formulation was measured for phytochemical components by qualitative methods.  The polyherbal formulation was quantitatively estimated for its phytochemical constituents, i.  total phenol and flavonoid content.  Further, the antioxidant property of ADPHF6 formulation was evaluated by 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) radical scavenging assay, hydrogen peroxide radical scavenging assay and metal chelating assay.  α-Amylase and α-glucosidase inhibitory activities of polyherbal formulation were also assessed.  ADPHF6 was further analysed for its protective antioxidant property against reactive oxygen species (ROS‾)-induced damage in human lymphocyte DNA and pUC19 plasmid.


 ADPHF6 polyherbal formulation revealed the presence of phytochemical constituents such as alkaloids, flavonoids, phenols, tannins, terpenoids, saponins and cardiac glycosides in significant levels.  Further, it also measured the higher levels of total phenols (473.3±3.05 mg/g) and flavonoid (664±5.29 mg/g) content.  Polyherbal formulation also exhibited IC50 values of 49.9±0.15, 65.1±0.10 and 60.1±0.05 mg/mL for 2,2- diphenyl-1-picryl-hydrazyl-hydrate (DPPH), hydrogen peroxide (H2O2) and Fe2+ radical scavenging activities, respectively.  ADPHF6 revealed an inhibitory activity (IC50) of 0.67±0.01 and 0.81±0.01 mg/mL for α-amylase and glucosidase, respectively.  Pre-treated human peripheral blood lymphocytes with ADPHF6 aqueous extract illustrated enhanced protection against ROS-mediated damage as compared with post-treated groups.  DNA nicking assay rendered protective activity against the OH¯ radical-induced DNA damage in supercoiled pUC19 plasmid.


 CONCLUSIONS
 Our present study demonstrates that ADPHF6 offers potent inhibitory activity against free radicals as well as digestive enzymes.  However, studies should be conducted using in vivo model to further elucidate the effect against free radicals and its anti-hyperglycaemic activity in the management of non-insulin-dependent diabetes.
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