A Polyherbal Formulation That Mitigates Cellular Damage in Narrowband UVB-Irradiated HaCaT Cells

Narrowband ultraviolet B (NB-UVB) phototherapy, used for treating skin diseases, can induce skin aging, cause inflammation, and reduce cell viability due to reactive oxygen species (ROS) generation. To mitigate these adverse effects, a multi-target polyherbal mixture for topical application was developed. This study investigated the effects of a polyherbal combination comprising Zingiber officinale (ZH), Garcinia mangostana (GE), and Centella asiatica (CAEw) extracts against NB-UVB-induced damage in HaCaT cells. Extracts were prepared to obtain high levels of specific biomarkers (compound D, α-mangostin, and asiaticoside). They were characterized for total phenolic and total flavonoid content, antioxidant properties, and anti-collagenase activity. The ability to enhance HaCaT cell viability after NB-UVB exposure was evaluated to determine the optimal polyherbal mixture ratios. Both the individual extracts and polyherbal formulations significantly improved irradiated HaCaT cell viability. Subsequent treatment with 100 µg/mL of the polyherbal mixture ZH:GE:CAEw (1:1:1) increased cell viability from 62.3% to 80.1% and decreased intracellular ROS (63.6%) without reducing cell apoptosis. It also downregulated the gene expression of cyclooxygenase-2, inducible nitric oxide synthase, matrix metalloproteinase-1 (MMP-1), and MMP-9, allowing their expression to reach the normal level of the non-irradiated cells. In conclusion, the polyherbal mixture effectively attenuated NB-UVB-induced damage and premature aging in HaCaT keratinocytes.