Moreover, the non-sulphated congeners of lamellarin A (1) displayed no inhibitory activity against the HIV-1 integrase enzyme at concentration 1.6 mM compared to the mono-and di-sulphated analogues [lamellarin A 20-sulfate and 13,20-disulfate], they showed robust integrase enzyme inhibitory activity with IC50 values 22 and 49 mM respectively. This might implies the central role of the sulphate group as a pharmacophoric key for the antiviral activity . Furthermore, Kamiyama et al., comprehensively established formal total syntheses, structure-activity relationships (SARs) for numerous natural and synthetic fused and non-fused ring opened lamellarin A 20-sulphate analogues alongside their mechanism of action as anti-HIV-1 inhibitors.