Alpha-cadinol in Hinoki cypress induces hyaluronic acid production in dermal cells possibly through ERK signaling

In Japan, the essential oil from Hinoki cypress ( Chamaecyparis obtusa , EOHC) is registered as a flavoring agent for food additives, and previous studies reported it has antibacterial and insect-repellent activities, as well as a relaxation-inducing effect. We found EOHC promoted hyaluronic acid (HA) production in NB1RGB cells. EOHC increased HA levels in a concentration-dependent manner, and a hydrous ethanol extract of EOHC showed similar activity. Isolation using HPLC followed by LC-HRMS, cell assays, and NMR analyses identified α-cadinol as the factor promoting marked HA production, although it did not increase HA synthase 2 ( HAS2 ) gene expression. To investigate other mechanisms, we examined ERK phosphorylation, which reportedly activates HAS2, and found that α-cadinol enhanced ERK phosphorylation. Furthermore, the α-cadinol–induced increase in HA production was suppressed by an ERK inhibitor, suggesting that α-cadinol promotes HA production, possibly through ERK phosphorylation.