Evaluation of Pharmacological Potential of Miliusa nilagirica Bedd. Leaves Using In Vitro Antidiabetic and Antioxidant Assays.

Miliusa nilagirica, a rare tree species of Western Ghats, belongs to the Annonaceae family, a family with potential antioxidant and antidiabetic properties. This study is designed vividly to establish the relationship between the constituent phytochemicals and their hyperglycemic effects through the antioxidant traits of M. nilagirica in vitro. Phytochemical tests were conducted on dry powdered leaves and extracts of various methods to determine the existence of various constituents. The antidiabetic potential of leaf extracts was estimated by using the α-amylase inhibitory model and the antioxidant potential was estimated with various assays. The quantitative phytochemical screening of leaf parts shows the presence of carbohydrates (88.74 ± 0.65 mg GE/g sample), proteins (82.17 ± 2.52 mg BSAE/g sample), phenolics (40.44 ± 0.43 GAE/100 g), and flavonoids (66.05 ± 0.48 mg RE/g extract). Methanol extract of Soxhlet of M. nilagirica registered the strongest antioxidant activity in all assays, 75.66% inhibition (DPPH assay), 795.01 µmol/g (ABTS˙ radical scavenging), 994.33 µmol/g (FRAP assay), 362.02 mg AAE/g extract (TAC assay), 47% inhibition (NO scavenging assay). In vitro α-amylase inhibition showed a highly noticeable reduction in ethyl acetate extract from Soxhlet (75.19%). HPLC and FTIR analyses on the extracts added strengths to the obtained results on the potentiality of M. nilagirica. From the results, it is evident that phytochemicals from M. nilagirica can be studied further, isolated, and incorporated as an alternative to synthetic supplements for hyperglycemia.