<b>Mechanistic Evaluation of the Antidiabetic Potential of <i>Newbouldia laevis</i>: Evidence from Phytochemical Profiling and Enzyme Inhibition Studies</b>

Abstract

Newbouldia laevis is widely utilized in traditional medicine for the management of metabolic and inflammatory disorders; however, its pharmacological properties require scientific validation. This study evaluated the phytochemical composition and in vitro antioxidant, anti-inflammatory, and antidiabetic activities of the crude aqueous leaf extract of Newbouldia laevis. Standard phytochemical screening methods and spectrophotometric assays, including DPPH, nitric oxide scavenging, ferric reducing antioxidant power (FRAP), protein denaturation, proteinase inhibition, α-amylase, and α-glucosidase inhibition assays, were employed, with IC₅₀ values determined. The extract contained alkaloids (12.52 mg/100 g) in moderate amounts and lower levels of flavonoids (8.62 mg/100 g), saponins (5.95 mg/100 g), tannins (3.42 mg/100 g), phenols, terpenoids, cardiac glycosides, and steroids. It exhibited notable antioxidant activity in DPPH (IC₅₀ = 6.33 µg/ml) and FRAP (IC₅₀ = 7.73 µg/ml) assays, indicating high radical scavenging and reducing capacity comparable to ascorbic acid/BHT under similar conditions, alongside moderate nitric oxide scavenging (IC₅₀ = 28.45 µg/ml), and anti-inflammatory activities. The extract also demonstrated notable α-amylase (IC₅₀ = 9.29 µg/ml) and α-glucosidase inhibition (IC₅₀ = 17.88 µg/ml); however, it exhibited lower potency than acarbose, with approximately 3-fold and 2.8-fold higher IC₅₀ values for α-amylase (9.29 vs. 3.17 µg/ml) and α-glucosidase (17.88 vs. 6.37 µg/ml), respectively. These findings suggest that the extract could possess multi-target bioactivity mediated by its phytochemical constituents. It may be concluded that Newbouldia laevis has significant therapeutic potential; therefore, further in vivo studies and isolation of active compounds are recommended, contributing novel evidence to its pharmacological validation