Investigating of the Phytoconstituents, Anti‐ <i>α</i> ‐Glucosidase, Antilipase, Anti‐ <i>α</i> ‐Amylase, and DPPH Radical Scavenging Activities of Extracts From <i>Eriobotrya japonica</i>

Recent research reported inhibitory effects of <i>Eriobotrya japonica</i> leaf extracts on DPPH free radicals and <i>α</i>-amylase, <i>α</i>-glucosidase, and lipase enzymes. These enzymes were linked to the etiology of diabetes mellitus, obesity, and oxidative stress. The current study is aimed at determining the phytocontents of <i>E. japonica</i> aqueous extract leaves and exploring their potential antioxidant, anti-<i>α</i>-amylase, anti-<i>α</i>-glucosidase, and antilipase activity using reference phytochemical and biochemical assays. The phytochemical tests on the <i>E. japonica</i> aqueous extract confirmed the presence of alkaloids, glycosides, tannins, saponins, phytosteroids, carbohydrates, and phenols. The total phenol and tannin contents of the <i>E. japonica</i> aqueous extract were 21.64 ± 0.89 mg of GAE/g and 1.72 ± 1 mg of CAE/g, respectively. <i>E. japonica</i> aqueous extract had inhibitory effects on DPPH free radicals (IC₅₀ of 7.7 ± 3.11 <i>μ</i>g/mL) and <i>α</i>-amylase (IC₅₀ = 141 ± 0.35 <i>μ</i>g/mL) compared with Trolox and acarbose (6.3 ± 0.12 and 28.18 ± 1.22 <i>μ</i>g/mL, respectively). Moreover, <i>E. japonica</i> aqueous extract inhibited <i>α</i>-glucosidase (IC₅₀ = 39.81 ± 0.74 vs. 37.15 ± 0.33 <i>μ</i>g/mL inhibition by acarbose) and lipase (IC₅₀ = 316.2 ± 0.87 vs. 12.3 ± 0.33 <i>μ</i>g/mL inhibition by orlistat). In conclusion, the current results suggest that <i>E. japonica</i> aqueous extract possesses strong antioxidant, anti-<i>α</i>-glucosidase, anti-<i>α</i>-amylase, and antilipase activities with potential applications in the treatment and prevention of obesity, diabetes mellitus, and oxidative stress.