Anti-Photoaging and Anti-Melanogenic Effects of a Novel Lactiplantibacillus plantarum RKBP Isolated from Giant Centella asiatica

Ultraviolet B (UVB) irradiation is a major contributor to photoaging and hyperpigmentation, leading to collagen damage and excessive melanin accumulation.This study investigated the anti-photoaging and anti-melanogenic effects of heat-killed L. plantarum RKBP isolated from Giant Centella asiatica.L. plantarum RKBP was prepared by thermal inactivation and evaluated for anti-photoaging effects using human dermal fibroblasts and threedimensional (3D) human skin-equivalent tissues.The anti-melanogenic effects were assessed in α-melanocyte-stimulating hormone (α-MSH)-stimulated B16F10 melanoma cells, three-dimensional melanoma spheroids, and intrinsically pigmented 3D human skin-equivalent models.MAPK/AP-1 signaling, MMP-1 expression, collagen integrity, melanin content, and melanogenesis-related protein expression were analyzed.L. plantarum RKBP selectively suppressed UVB-induced ERK/JNK phosphorylation and AP-1-mediated MMP-1 expression, preserving collagen integrity in a 3D human skin-equivalent model.Treatment with L. plantarum RKBP reduced α-MSH-induced melanin production and decreased tyrosinase expression in B16F10 cells.L. plantarum RKBP also attenuated melanin accumulation in 3D melanoma spheroids and pigmented human skin-equivalent tissues.L. plantarum RKBP exerts anti-photoaging and anti-melanogenic effects across in vitro and 3D skin models.These findings support its potential as a postbiotic skin health ingredient.