Characterization, Antioxidant Capacity, and In Vitro Bioaccessibility of Ginger (Zingiber officinale Roscoe) in Different Pharmaceutical Formulations

Abstract

Ginger (Zingiber officinale Roscoe) has been widely recognized for its antioxidant properties, primarily attributed to its phenolic compounds such as gingerols and shogaols. However, limited data exist regarding how different pharmaceutical forms influence the bioaccessibility and antioxidant efficacy of these compounds. This study aimed to evaluate the antioxidant capacity and bioaccessibility of ginger in different pharmaceutical forms—capsules (20 mg, 40 mg, and 80 mg), a pure powdered extract, and a liquid formulation—standardized to ≥6% gingerols. The phenolic profile of each formulation was characterized using HPLC-DAD (High-Performance Liquid Chromatography with Diode Array Detection), followed by the evaluation of antioxidant capacity through DPPH (2,2-Diphenyl-1-picrylhydrazyl) and ORAC (Oxygen Radical Absorbance Capacity) assays, and the assessment of bioaccessibility via an in vitro digestion model. The results demonstrated that antioxidant activity was positively correlated with extract concentration and was highest in the liquid formulation (426.0 ± 0.05 µmol Trolox equivalents (TE) and 11,336.7 ± 0.20 µmol TE in the DPPH and ORAC assays, respectively). The bioaccessibility of 6-gingerol and 6-shogaol significantly increased in the liquid form, reaching 23.44% and 11.31%, respectively, compared to ≤4% in the pure extract. These findings highlight the influence of the formulation matrix on compound release and support the use of liquid preparations to enhance the functional efficacy of ginger-derived nutraceuticals. This standardized comparative approach, using formulations derived from the same extract, offers new insights into how the delivery matrix influences the functional performance of ginger compounds, providing guidance for the development of more effective nutraceutical strategies.