Antidiabetic polyherbal formulations (APH) are used in management of diabetes mellitus (DM). High glucose levels in DM are related to oxidative stress leading to its associated complications. Therefore, assessing antioxidant activity of various APH might unveil an antioxidant-rich formulation for management of DM and its associated complications. Subsequently selecting an antioxidant assessment method is a challenging aspect, considering various in vitro assays working with diverse mechanism of action. Therefore, present study aims to validate the sensitivity/capacity of different antioxidant assay, thereby assessing the antioxidant potential of 9-APH. Obtained results revealed the ABTS·+ values were higher compared to DPPH+ assay. I-9-HAE (DPPH+: IC50 53.31µg/ml), NK-HAE (ABTS·+: IC50 2.71µg/ml), and MN-HAE (FRAP and TAC) exhibited highest antioxidant capacity. A significant correlation was obtained between TPC-DPPH+ (r2: 0.8187****). Furthermore, three APH with better antiradical potential was chosen for various in vitro and in silico method, for validating scientific antidiabetic propensities. Among the tested extracts, I-9-HAE (α-amylase inhibition: IC50 831.84µg/ml) and MN-HAE (α-glucosidase inhibition: IC50 558.64µg/ml and antiglycation: IC50 883.74µg/ml) have showed highest antihyperglycemic and antiglycation properties. Finally, the secondary-metabolites of selected APH were screened through literature search, Lipinski rule, ADMET, and ProTox-II. Subsequently, in molecular docking for the selected 9 secondary metabolites, highest binding affinity was observed in apigenin-7-glucuronide for DPPiv (- 9.6), GLP-1 (- 8.8), NADPH (- 8.7), and HSA (- 9.4). Thus, obtained result proposes synergistic interaction with high antioxidant potential of the selected 3-APH and can be considered an alternative for management of DM, where multiple secondary metabolites exert holistic biological effects. Furthermore, our study also provides data on sensitivity/capacity of different in vitro antioxidant assays.