Garynthone A–I, PPAPs with diverse skeletons isolated from Garcinia yunnanensis and their immunosuppressive activity

Abstract

This study reports the isolation and structural characterization of 17 PPAPs from G. yunnanensis, including the novel Garynthone A (1) featuring an unprecedented 5-oxapentacyclo [7,3,1,1^4,7,1^6,11,0^1,6] pentadecane skeleton, along with eight previously undescribed PPAPs (2–9). NMR data analysis, coupling constants analysis, quantum calculations, modified mosher's method, X-ray single-crystal crystallography, ECD spectra, computer-assisted structure elucidation (CASE), and DP5/DP4 probability analyses were employed to characterize their structures and revise the structure of garcoblone E (10). Compounds (+)-2, 3, (+)-4, 5, (±)-6, (±)-7, 9, 14, 16, and 17 exhibited moderate inhibition of T-cell proliferation, with IC₅₀ values ranging from 2.02 to 19.41 μM.