CC BY-NC-ND 4.0Poungcho, PattaraPattaraPoungchoTang, RachelRachelTangHairani, RitaRitaHairaniAbrahamian, CarlaCarlaAbrahamianNetcharoensirisuk, PonsawanPonsawanNetcharoensirisukChavasiri, WarinthornWarinthornChavasiriChaotham, ChatchaiChatchaiChaothamGrimm, ChristianChristianGrimmDe‑Eknamkul, WanchaiWanchaiDe‑Eknamkul2025-12-182025-12-182025https://publica.fraunhofer.de/handle/publica/502175https://doi.org/10.24406/publica-687210.1038/s41598-025-27629-y10.24406/publica-68722-s2.0-10502214475441254057Kaempferia parviflora, well-known as Thai ginseng (Krachaidum), has been used as a medicinal plant and food source for centuries. Its rhizome contains several flavonoids, particularly poly-O-methylated flavones (also known as polymethoxyflavones). We previously found that K. parviflora extract had a strong stimulatory effect on melanogenesis in B16F10 mouse melanoma cells. The aim of this study was to investigate the melanogenic stimulation exerted by various O-methylated flavonoids from K. parviflora in human melanoma cells and elucidate the mechanism of action of the most active compound. MNT-1 cells were used to screen for the most potent O-methylated flavonoid, and its effects on some key steps in melanin biosynthesis would subsequently be investigated. The poly-O-methylated flavone 3,5,7,3′,4′-pentamethoxyflavone (PMF) exhibited the strongest melanogenesis-stimulating activity among the 13 O-methylated flavones isolated from K. parviflora. It was shown to enhance tyrosinase (TYR) activity by upregulating the levels of TYR and TYR-related protein 1 (TRP-1) via its inhibitory effect on two-pore channel 2 (TPC2). In conclusion, poly-O-methylated flavones, especially PMF, were suggested as a potential group of flavonoids that could stimulate melanin production by inhibiting the activity of the TPC2 channel, leading to increased TYR and TRP-1 activities.entrue3,5,7,3′,4′-pentamethoxyflavoneKaempferia parvifloraMelanogenesisPoly-O-methylated flavonesTPC2 channelTyrosinasejournal article