Studies on the Chemical Constituents from Marine Bryozoan Cryptosula pallasiana

The aim of this study was to investigate the chemical constituents of marine bryozoan Cryptosula pallasiana inhabiting Huang Island of China. Three aromatic compounds, p-methylsulfonylmethyl-phenol (1), p-hydroxybenzaldehyde (4) and methylparaben (5), nine alkaloids, 7-bromoquinolin-4(1H)-one (2), 7-bromo-2,4(1H,3H)-quinazolinedione (3), benzamide (6), phenylacetamide (7), 4(3H)-quinazolinone (8), thymine (9), uracil (10), hypoxanthine (11) and tryptophan (12), together with two glycerol derivatives, glycerol (13) and monoheneicosanoin (14), were isolated for the first time from this marine bryozoan. Among the isolates, compounds 1 and 2 were new natural products, and their spectral traits were reported for the first time. The structures of the two compounds were elucidated by extensive spectroscopic analyses, including HR-ESI-MS, EI-MS, 1D- and 2D-NMR techniques. The isolated compounds 1–3 were evaluated for their cytotoxicity against HL-60 human myeloid leukemia cell line. The results showed that bromated alkaloid (3) appeared strong cytotoxicity against HL-60 cells with IC 50 value of 11.87 µg/mL, while compounds 1 and 2 were inactivity.