Oleanane-type triterpenoid saponins from Camellia petelotii leaves and their hyaluronidase inhibitory activity

Seven previously unreported oleanane-type triterpenoid saponins (1-7), along with three known compounds (8-10), were isolated from the leaves of Camellia petelotii. Their structures, including the relative configurations of the aglycone moieties, were elucidated through comprehensive spectroscopic analysis, including extensive NMR and mass spectrometry. The absolute configurations of the sugar units attached to the saponins were determined by acid hydrolysis. All isolated compounds were screened for hyaluronidase inhibitory activity. As a result, compounds 2, 3, 4, 5, 8, 9, and 10 exhibited hyaluronidase inhibitory effects, with IC₅₀ values of 2.02 ± 0.16, 1.27 ± 0.20, 1.79 ± 0.25, 1.96 ± 0.19, 0.27 ± 0.07, 0.48 ± 0.04, and 0.86 ± 0.15 mM, respectively. Notably, compounds 8 and 9 showed inhibitory activity comparable to the positive control ascorbyl palmitate (IC₅₀ = 0.35 ± 0.02 mM), while compound 8 was even more potent.