Alkaloid-rich fraction of Anacardium occidentale L. nutshells ameliorates UV-B induced oxidative damage in human peripheral blood mononuclear cells

Humans suffer greatly from the ultraviolet (UV) radiation of the sun. A multitude of detrimental effects, such as sunburn, photoaging, hyperpigmentation, and skin cancer, are largely brought on by exposure to ultraviolet B (UV-B) radiation. These consequences can be avoided by using photoprotective agents. Recently, naturally derived products have become increasingly popular as skin photoprotective agents. Therefore, the objective of the current study was to evaluate in vitro UV-B protective activity of Anacardium occidentale L. nutshell fractions (AONFs) on human peripheral blood mononuclear cells (PBMCs). Four different AONFs, namely, aqueous, chloroform, organic, and ethyl acetate, each containing a unique combination of phytochemicals, were obtained by the Soxhlet extraction technique. The alkaloid-rich aqueous fraction displayed the highest Sun Protection Factor (SPF) and Boot Star rating, indicating its superior photoprotective efficacy. The IC₅₀ value of the aqueous fraction on PBMCs was discovered to be 20.199 µg/ml, depicting its moderate cytotoxicity. The UV-B-irradiated cells pre-treated with an aqueous fraction demonstrated its optimum UV-protective activity at 1.8 µg/ml concentration by exhibiting the highest cell viability. Nevertheless, this concentration was found to be far less than its IC₅₀ value. The specific activities of catalase, superoxide dismutase, and glutathione peroxidase were elevated in UV-B-irradiated cells, whereas the normal activity was documented in the irradiated cells, which are pre-treated with a 2 µg/ml fraction. Therefore, the results indicate that an alkaloid-rich aqueous fraction from cashew nut shells exhibits promising in vitro UV protective activity by displaying a wide therapeutic index and attenuating UV-induced oxidative damage.