Optimization of Ultrasound‑Assisted Extraction of L‑Ascorbic Acid from Adansonia digitata (Linn.) and Evaluation of its Antityrosinase Activity

Objectives: The aim of this study was to optimize the extraction of AA from the fruit pulp of A. digitata by ultrasound‑assisted extraction and to evaluate the antityrosinase activity of the extract. Materials and Methods: A rotatable central composite design was used to investigate the effect of process variables by surface response methodology. The effect of key parameters of extraction temperature (30°C–40°C), extraction time (12–28 min), and ratio solvent to material (7–13 mL/g) was investigated on AA content. Then, mushroom tyrosinase was used to evaluate the antityrosinase activity of the extract. Results: The optimal conditions were obtained with a temperature of 43.4°C, in 23.5 min with a ratio solvent to material of 15.04 mL/g. Under these conditions, AA content from A. digitata (167.4 ± 5.724 mg AA per 100 g dry weight) was determined. Antityrosinase activity of A. digitata extract containing AA was 31.36% ± 1.65%. After degradation of AA, tyrosinase activity decreases to 24.21% ± 1.43%. Conclusion: AA contained in A. digitata extract show to increases significantly the inhibition of enzymatic tyrosinase activity. This extract may have a potential impact on skin depigmentation for the treatment of hyperpigmentation disorders.