Phytochemical Composition and In Vitro Anti-Pigmentation Activity of Persicaria senticosa Flower Absolute: Potential Dual Inhibition of Melanogenesis and Melanosome Transport

Background/Objectives: Persicaria senticosa (Meisn.) H.Gross (PS) has anti-photoaging, anti-inflammatory, and antioxidant activities, but the anti-pigmentation potential of the PS flower absolute (PSFAb) remains largely unexplored. This study aimed to examine the chemical composition and anti-melanogenic and melanosome transport-inhibitory effects of PSFAb using B16BL6 murine melanoma cells. Methods: PSFAb was extracted with hexane and analyzed by gas chromatography–mass spectrometry (GC-MS). The biological activities in B16BL6 murine melanoma cells were evaluated using water-soluble tetrazolium salt (WST) assays, 5-bromo-2′-deoxyuridine (BrdU) incorporation, enzyme-linked immunosorbent assays, and immunoblotting methods. Results: GC-MS analysis identified eight constituents in PSFAb. Cell viability was not significantly altered in B16BL6 cells at concentrations ≤ 100 μg/mL, which were used for additional tests. PSFAb inhibited serum-induced cell proliferation and suppressed α-melanocyte-stimulating hormone (α-MSH)-induced melanin synthesis and tyrosinase activity in B16BL6 cells. PSFAb also downregulated the α-MSH-induced expression of key melanogenic regulators, including microphthalmia-associated transcription factor (MITF), tyrosinase, tyrosinase-related protein-1 (TRP-1), and TRP-2. PSFAb decreased extracellular signal-regulated kinase 1/2 and p38 mitogen-activated protein kinase phosphorylation but enhanced JNK phosphorylation in α-MSH-stimulated B16BL6 cells. Furthermore, PSFAb reduced the α-MSH-induced expression of melanosome transport-related proteins (melanophilin and Rab27a) in B16BL6 cells. Conclusions: Overall, these results suggest that PSFAb has the potential to exert anti-pigmentation effects by suppressing melanogenesis and downregulating melanosome transport-related proteins. Therefore, PSFAb may be a promising candidate for the development of natural agents targeting hyperpigmentation and skin pigmentation regulation.