Isolation and comprehensive characterization of a bioactive compound from Garcinia nervosa: single-crystal X-ray diffraction, antioxidant, protein-binding, and chemosensing studies

Abstract

The study investigates the phytochemical composition and bioactive properties of Garcinia nervosa, with a focus on the structural elucidation of isolated compounds and their potential therapeutic applications. Three bioactive compounds, Gn-01, Gn-02, and Gn-03, were isolated from the leaves of G. nervosa. Gn-01, a known isoflavone named as bergenin, is reported for the first time from this plant, while Gn-03 is newly identified from this plant. These compounds were characterized using UV-Vis, FTIR, NMR, and MS. Single-crystal X-ray diffraction revealed compound Gn-01's orthorhombic space group P2₁2₁2₁, with Hirshfeld surface analysis showing significant O⋯H/H⋯O interactions that stabilize the crystal structure. Gn-01 demonstrated potent antioxidant activity with an IC₅₀ of 23.438 μg mL⁻¹, comparable to ascorbic acid, and strong non-intercalative binding to human serum albumin (HSA) with a Stern–Volmer constant (K_sv) of 168.3 × 10⁴ M⁻¹ and a binding constant (K_b) of 3.16 × 10⁴ M⁻¹, corroborated by molecular docking studies (binding affinity −7.364 kcal mol⁻¹). Notably, Gn-01 acted as a selective and sensitive Cu²⁺ chemosensor via a fluorescence turn-on (CHEF) mechanism, forming a 1 : 1 complex (K_b = 1.74 × 10⁴ M⁻¹; LOD ≈ 0.221 μM). The combination of first-time crystal structure determination, Hirshfeld surface analysis, antioxidant and HSA-binding activity, and Cu²⁺ chemosensing establishes Gn-01 as a novel bifunctional therapeutic agent with complementary antioxidant, protein-binding, and metal-sensing activities. Overall, these findings highlight Garcinia nervosa as a valuable source of the multifunctional bioactive molecule bergenin, supporting its chemotaxonomic and pharmacological significance and justifying further pharmacological exploration.