Assessment of different biological capacities of Alpinia speciosa (Pers.) B.L. Burtt and R.M. Sm

Objective: The present study was undertaken to evaluate antioxidant, depigmenting and photoprotective activities of the hydroalcoholic extract of Alpinia speciosa leaves. Methods: In vitro spectrophotometric methods were used to determine the total phenolic and flavonoids contents and the above mentioned biological capacities. Results: The antioxidant activity for the hydroalcoholic extract of A. speciosa showed a very good result (IC50=7.13 μg mL-1, statistically different from the ascorbic acid reference standard at p<0.05), which can be elucidated by their content of phenolic compounds, such as flavonoids. As for the depigmenting activity, the tyrosinase inhibitory ability demonstrated that the A. speciosa presented IA% lower than 50%, but it also presented a better stability than kojic acid standard. The extract also presented a significant photoprotection for a single UV-filter substance (SPF, UVAPF, Critical Wavelength and UVA/UVB Ratio), and it can be considered a broad-spectrum filter. Conclusion: These data altogether indicate that A. speciosa can have application in cosmeceuticals for aesthetics or degenerative diseases.