Phytochemistry and In Vitro Bioactivities of Elaeagnus angustifolia L. Leaves: Influence of Solvent Polarity, Antioxidant Properties, and α-Amylase Inhibition

This study investigated the effect of solvent polarity on extraction yield, phytochemical composition, antioxidant activity, and α-amylase inhibition of <i>Elaeagnus angustifolia</i> L. leaf extracts to evaluate their antidiabetic potential. Extraction yields varied with solvent polarity, with the hydroethanolic extract showing the highest (18.00%) and n-hexane the lowest (0.05%) yield. The n-butanol and ethyl acetate fractions contained the most phenolics (309.05 and 290.97 mg GAE/g), ethyl acetate was the richest in flavonoids (102.11 mg QE/g), and tannins were concentrated in dichloromethane (66.24 mg CE/g). HPLC revealed solvent-specific profiles: rutin and gallic acid dominated in n-butanol, quercetin in ethyl acetate, and 4-hydroxybenzoic and ferulic acids in dichloromethane, while chicoric acid appeared in hydroethanolic and n-hexane extracts. Antioxidant assays (DPPH, ABTS, and FRAP) showed strong activity in polar extracts, particularly hydroethanolic and ethyl acetate fractions. The n-hexane extract exhibited the highest α-amylase inhibition (IC₅₀ = 36.70 µg/mL), surpassing acarbose (IC₅₀ = 126.14 µg/mL), while other fractions were inactive (IC₅₀ > 400 µg/mL). Molecular docking highlighted rutin, chlorogenic acid, and chicoric acid as potential enzyme binders. These findings demonstrate the chemical diversity and significant bioactivities of <i>E. angustifolia</i> leaves, supporting their potential as natural antidiabetic agents.