Introduction: Leucas zeylanica (L.) W.T.Aiton is a plant used in traditional medicine as a remedy against several dermatological conditions. The high UV-filtering potential observed for the aqueous methanolic extract of this plant suggests its suitability to develop herbal skin care agents. Therefore, this study was undertaken to develop herbal skin care formulations from the aqueous methanolic (hydro-alcoholic) extract of the whole plants of L. zeylanica and evaluate the photoprotective efficacy.

Methodology: Three formulations were prepared by incorporating different concentrations (25%, 50%, and 75%) of the extract into an aqueous cream base. Thereafter, the UV filtering potential and sun protection factor (SPF) were determined.

Results: The formulation comprised of 75% of the extract displayed the highest UV absorbance as well as the highest SPF value (26.76±3.82). All formulations in general exhibited good photostability profiles. The anti-tyrosinase assay revealed very mild tyrosinase inhibitory potential of the aqueous methanolic extract of L. zeylanica. Therefore our formulations do not interfere with the biosynthesis of melanin, the natural photoprotectant molecule in the skin, unlike most commercial sunscreens.

Conclusion: The strong and broad-range UV-filtering potential, high SPF and photostability profiles observed for the sunscreen formulation comprised of 75% of the extract suggest the potential utility of L. zeylanica extract for the development of herbal skin care formulations in a commercial scale.

Keywords
Herbal , Leucas zeylanica , photoprotective , skin care , sunscreens