Photoprotective Properties of Two Antidiabetic Plants: An in Vitro Assessment of Sun Protection Factor

Abstract

Background: Ultraviolet (UV) radiation is an important environmental factor contributing to skin damage and photoaging. The search for naturally derived photoprotective agents has increased interest in medicinal plants as potential sources of UV-absorbing compounds. Salvia haematodes and Phlogacanthus thyrsiflorus are medicinal plants with established traditional and pharmacological importance, but their potential as sources of natural photoprotective agents requires further investigation. Aim: The present study aimed to evaluate the in vitro sun protection factor (SPF) of extracts and solvent fractions of Salvia haematodes root and Phlogacanthus thyrsiflorus flower and to identify fractions with promising photoprotective potential. Materials and Methods: Root material of S. haematodes and flower material of P. thyrsiflorus were extracted using methanol and subsequently subjected to solvent fractionation. The SPF of the prepared extracts and fractions was evaluated by UV-visible spectrophotometry at a concentration of 100 µg/mL. Absorbance was measured within the UVB wavelength range of 290–320 nm at 5-nm intervals. Methanol was used as the blank, and measurements were performed in triplicate. SPF values were calculated using the Mansur spectrophotometric equation with a correction factor of 10. Results: The tested extracts and fractions demonstrated varying degrees of UVB-absorbing activity. Among the preparations evaluated, the chloroform and ethyl acetate fractions of S. haematodes root showed the highest SPF values, 10.18 ± 0.12 and 9.63 ± 0.08, respectively, at 100 µg/mL. In comparison, the methanol and ethyl acetate extracts of P. thyrsiflorus flower showed SPF values of 5.82 ± 0.05 and 4.16 ± 0.04, respectively. The results indicate comparatively greater photoprotective potential for the tested S. haematodes root fractions. Conclusion: The findings demonstrate that selected solvent fractions of S. haematodes root possess appreciable in vitro SPF activity, with the chloroform and ethyl acetate fractions showing the highest values among the tested samples. These findings suggest that S. haematodes may serve as a promising botanical source of photoprotective constituents. Further phytochemical investigation and formulation-based studies are required to determine the suitability of these fractions for the development of plant-derived photoprotective preparations.