title: Ginsenosides Rb1 and Rg1 Stimulate Melanogenesis in Human Epidermal Melanocytes via PKA/CREB/MITF Signaling.
abstract: Reduced or defective melanin skin pigmentation may cause many hypopigmentation disorders and increase the risk of damage to the skin triggered by UV irradiation. Ginsenosides Rb1 and Rg1 have many molecular targets including the cAMP-response element-binding protein (CREB), which is involved in melanogenesis. This study aimed to investigate the effects of ginsenosides Rb1 and Rg1 on melanogenesis in human melanocytes and their related mechanisms. The effects of Rb1 and Rg1 on cell viability, tyrosinase activity, cellular melanin content and protein levels of tyrosinase, microphthalmia-associated transcription factor (MITF), and activation of CREB in melanocytes were assessed. Results showed that Rb1 or Rg1 significantly increased cellular melanin content and tyrosinase activity in a dose-dependent manner. By contrast, the cell viability of melanocytes remained unchanged. After exposure to Rb1 or Rg1, the protein levels of tyrosinase, MITF, and phosphorylated CREB were significantly increased. Furthermore, pretreatment with the selective PKA inhibitor H-89 significantly blocked the Rb1- or Rg1-induced increase of melanin content. These findings indicated that Rb1 and Rg1 increased melanogenesis and tyrosinase activity in human melanocytes, which was associated with activation of PKA/CREB/MITF signaling. The effects and mechanisms of Rb1 or Rg1 on skin pigmentation deserve further study.
authors.affiliation: Department of Dermatology, The Second Affiliated Hospital of Dalian Medical University, No. 467 Zhongshan Road, Dalian, Liaoning 116027, China ; College of Integrative Medicine, Dalian Medical University, Dalian 116027, China.
authors.forename: Mao
authors.identifier: 0000-0003-2446-5833
authors.initials: M
authors.lastname: Lin
authors.affiliation: Department of Dermatology, The Second Affiliated Hospital of Dalian Medical University, No. 467 Zhongshan Road, Dalian, Liaoning 116027, China.
authors.forename: Bao-Xiang
authors.initials: BX
authors.lastname: Zhang
authors.affiliation: Department of Dermatology, The Second Affiliated Hospital of Dalian Medical University, No. 467 Zhongshan Road, Dalian, Liaoning 116027, China.
authors.forename: Ci
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Department of Dermatology, The Second Affiliated Hospital of Dalian Medical University, No. 467 Zhongshan Road, Dalian, Liaoning 116027, China.
authors.forename: Nan
authors.initials: N
authors.lastname: Shen
authors.affiliation: Department of Dermatology, The Second Affiliated Hospital of Dalian Medical University, No. 467 Zhongshan Road, Dalian, Liaoning 116027, China.
authors.forename: Yun-Ying
authors.initials: YY
authors.lastname: Zhang
authors.affiliation: Department of Dermatology, The Second Affiliated Hospital of Dalian Medical University, No. 467 Zhongshan Road, Dalian, Liaoning 116027, China ; College of Integrative Medicine, Dalian Medical University, Dalian 116027, China.
authors.forename: Ao-Xue
authors.initials: AX
authors.lastname: Wang
authors.affiliation: Department of Dermatology, The Second Affiliated Hospital of Dalian Medical University, No. 467 Zhongshan Road, Dalian, Liaoning 116027, China ; College of Integrative Medicine, Dalian Medical University, Dalian 116027, China.
authors.forename: Cai-Xia
authors.initials: CX
authors.lastname: Tu