Abstract
Hibiscus sabdariffa calyx is widely used in traditional medicine and as a food ingredient due to its antioxidant potential. This study investigated the toxicological and antioxidant effects of calyx extracts obtained after drying at four temperatures (- 58 °C, 30 °C, 40 °C, and 50 °C) in Wistar rats. Acute toxicity was assessed following the modified Lorke method (24-h observation), and chronic toxicity was evaluated over 28 days using doses of 250, 500, and 1000 mg/kg, in accordance with OECD guideline 407. Although no signs of acute toxicity or significant alterations in organ weights were observed, the antioxidant markers-GSH, CAT, and SOD-were dose-dependently enhanced, with the most potent activity recorded in extracts dried at 30 °C. These findings suggest that drying at 30 °C preserves key bioactive compounds, thereby maximizing the antioxidant potential of H. sabdariffa calyx. The study provides practical insights for optimizing processing conditions for medicinal and nutraceutical applications. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10068-025-01893-0.