Hybrid Herbal-Synthetic Sunscreen Formulations: Boosting SPF With Hippophae Rhamnoides and Sapindus Mukorossi...

Ultraviolet (UV) radiation accelerates skin aging and carcinogenesis, driving the demand for safer sunscreens. This study evaluated the SPF-enhancing potential of Hippophae rhamnoides (Elaeagnaceae) and Sapindus mukorossi (Sapindaceae) extracts in octocrylene-based oil-in-water emulsions. Formulations with 5% octocrylene ± 5% herbal extracts were assessed for in vitro SPF, antioxidant activity, and stability. The Hippophae rhamnoides and octocrylene combination achieved the highest SPF (15.42 ± 0.60), a 2.4-fold increase over octocrylene alone (6.47 ± 0.74), while Sapindus mukorossi yielded 9.03 ± 0.65. Antioxidant assays showed superior radical scavenging for Hippophae rhamnoides formulations (IC₅₀: 18.4 µg/mL) compared with Sapindus mukorossi (29.6 µg/mL). All formulations remained physically and chemically stable over 8 weeks. These results demonstrate that Hippophae rhamnoides can markedly enhance photoprotection and reduce synthetic filter load, supporting the development of hybrid herbal-synthetic sunscreens. In vivo validation and photostability testing are recommended.