Novel triterpenoids from Ganoderma resinaceum attenuate UV-induced photoaging via modulating Nrf2 and MAPK signaling pathways

As a dual-purpose medicinal and edible mushroom, Ganoderma species have garnered significant interest in both the food, cosmetics and pharmaceutical industries. To further substantiate its traditional and functional uses, we conducted a systematic phytochemical study of Ganoderma resinaceum fruiting bodies, isolating 43 lanostane-type triterpenoids. Among these, 16 were identified as new compounds (1-11, 15, 31, 35, 37, and 42). Compound 1 represents the first reported C₂₉ lanostane triterpenoid featuring a 21,24-cyclo five membered carbon ring fraction. The spectroscopic (1D/2D NMR, ESIMS) and X-ray crystallographic analyses confirmed their structures. Among these, compounds 2-4, 13, 17, 35, 36, and 42 exhibited potent antioxidant activity by suppressing UV-induced ROS in skin keratinocytes. The most active compound, 42, reduced ROS and malondialdehyde (MDA) levels, enhanced antioxidant defenses (superoxide dismutase, SOD; hydroxyproline), and suppressed matrix metalloproteinases (MMPs) through activating Nrf2 pathway and suppressing MAPK signaling. These results position G. resinaceum triterpenoids, particularly compound 42, as multifunctional natural antioxidants with applications in functional foods for oxidative stress management or skin-protective formulations.