Lindenane disesquiterpenoids with anti-HIV-1 activity from Chloranthus japonicus.

Five new lindenane disesquiterpenoids, chlorajaponilides A-E (1-5), together with 11 known analogues were isolated from whole plants of Chloranthus japonicus. The structure and absolute configuration of 1 was confirmed by X-ray crystallography. Compounds 1 and 2 represent the first examples of lindenane disesquiterpenoids with a C-5 hydroxy group and a C-4-C-15 double bond. Compounds 8, 9, 11, and 12 showed anti-HIV-1 replication activities in both wild-type HIV-1 and two NNRTIs-resistant strains. Shizukaol B (8) exhibited the best activity against HIV(wt), HIV(RT-K103N), and HIV(RT-K103N) with EC₅₀ values of 0.22, 0.47, and 0.50 μM, respectively. Compounds 8, 9, 11, and 12 had significant cytotoxicities against C8166 cells with CC₅₀ values of 0.020, 0.089, 0.047, and 0.022, respectively, and exhibited inhibitory activities against HIV-1 with EC₅₀ values of 0.0014, 0.016, 0.0043, and 0.0033 μM, respectively.