Subergorgines A–E, five new suberosanone-purine hybrids from the South China Sea gorgonian Subergorgia suberosa

•Five new suberosanone-purine hybrids (1–5) were isolated from the South China Sea gorgonian Subergorgia suberosa.•Compounds 1–5 were rare purine alkaloids merged with the same suberosanone moiety different via different C (6)–N bridges.•Compound 4 showed considerable and selective cytotoxicity against HL-60 cell line (IC50 = 14.3 μM).•The likely biosynthetic origins of these new isolates were discussed.