Solamargine Alleviated UVB-Induced Inflammation and Melanogenesis in Human Keratinocytes and Melanocytes via the p38 MAPK Signaling Pathway, a Promising Agent for Post-inflammatory Hyperpigmentation

Abstract

Post-inflammatory hyperpigmentation (PIH) is a common acquired pigmentary disorder occurring after skin inflammation or injury. Ultraviolet B irradiation could exaggerate PIH clinically due to its effect on promoting cutaneous inflammation and melanogenesis in keratinocytes and melanocytes, respectively. Solamargine (SM), a steroidal alkaloid glycoside extracted from Solanum undatum, significantly inhibits Ultraviolet B (UVB)-induced pro-inflammatory cytokines IL-1α, IL-1β, IL-8, and IFN-γ, as well as paracrine melanogenic factors ET-1, α-MSH, and bFGF in human keratinocytes. Additionally, SM significantly attenuated UVB-induced melanin synthesis in human epidermal melanocytes through down-regulation of tyrosinase activity and expression of MITF, TRP-1, TRP-2, and tyrosinase. SM exerted an anti-inflammatory effect in UVB-irradiated keratinocytes through the p38 MAPK/Nrf2/HO-1 signaling pathway. With its anti-inflammatory and whitening effect, SM may improve PIH through paracrine regulations of keratinocytes and direct action on melanocytes, making it a promising agent for PIH.

The Therapeutic Value of Solanum Steroidal (Glyco)Alkaloids: A 10-Year Comprehensive Review

“…Solamargine (SM, Solanum undatum ), a triglycoside derivative of solasodine, has shown promising anti-inflammatory properties, especially in UVB-induced inflammation models [ 82 ]. SM at doses of 1 µg/mL managed to reduce mRNA and protein expression of several pro-inflammatory markers in HaCaT cells, namely Il-1α, IL-1β, IFNγ and IL-8.…”

Keratinocyte-derived paracrine factors regulate stress response of melanocytes to UVB

“…Finally, melanogenesis (pigmentation) is a vital adaptive protective response against further DNA damage induced by UVR (Nguyen et al , 2019). Upon UVB exposure, KC-derived paracrine factors (e.g., α-MSH) can control melanogenesis and affect the survival and the differentiation of MC vi Mitf, which is regulated by MAPK signaling (Juemin et al , 2022). Our previous work also showed that KC exerted a paracrine protective effect on UVB-mediated DNA damage, apoptosis and inflammatory responses in association with MAPK pathways in MC (Jeayeng et al , 2017).…”