Tribuloside Acts on the PDE/cAMP/PKA Pathway to Enhance Melanogenesis, Melanocyte Dendricity and Melanosome Transport

The study investigated the impact of tribuloside, a compound found in the plant Tribulus terrestris L., on pigmentation and the underlying mechanisms. The researchers found that tribuloside can increase melanin production in melanocytes, zebrafish, and human skin samples by inhibiting the expression of phosphodiesterase (PDE). This leads to an elevated concentration of cyclic adenosine monophosphate (cAMP) inside the cell, which activates cAMP-response element binding (CREB) through phosphorylation. Tribuloside can trigger the PDE/cAMP/protein kinase A (PKA) pathway to increase the levels of microphthalmia-associated transcription factor (MITF), tyrosinase, tyrosinase-related protein-1 (TRP-1), tyrosinase-related protein-2 (TRP-2), Rab27a, and cell division cycle protein 42 (Cdc42) expression, ultimately inducing melanogenesis, melanocyte dendricity, and melanin transport. This suggests that tribuloside could potentially be used to treat conditions related to skin pigmentation.