LAUSR

The norbisabolane-type sesquiterpenoids bearing a spiroketal functionality have been found in Phyllanthus spp. and showed anti-HBV activities. As part of an ongoing effort to search for promising anti-HBV sesquiterpenes from Phyllanthus plants, we report four new norbisabolane-type sesquiterpenoids, phyacidusin A (1), phyacidusin B (2), phllanthacidoid A1 (3) and phllanthacidoid N1 (4), from stem of P. acidus collected in Xishuangbanna, Yunnan province, China. The absolute configuration of new compounds was established by coupling constants and ROESY correlations, as well as comparation of NMR data with those of known compounds. The absolute configuration of new compounds 1 and 2 was further confirmed by X-ray diffraction. Compound 2 showed effect to HBsAg with an IC50 value of 11.2 ± 0.01 μM, while compound 3 inhibited HBeAg secretion with an IC50 value of 57.1 ± 0.02 μM. The results enriched the diversity of anti-HBV norbisabolane sesquiterpenes.