Chemical Constituents from the Formosan Octocoral Nephthea columnaris

In the studies on the chemical constituents of octocoral Nephthea columnaris, collected off the coast of Southern Taiwan, had led to the isolation of 11 metabolites, including ten sterols, columnaristerols A-C (1-3), litosterol (4), 24-methylene-cholesterol (5), 24-methylene-cholest-5-ene-3β,7α-diol (6), 5α,8α-epidioxy-24-methylcholesta-6,24(28)-dien-3β-ol (7), 4α-methylergosta-22(E),24(28)-dien-3β-ol (8), 24-methylcholesta-5,24(28)-diene-3β,19-diol-7-one (9), 5,6-epoxylitosterol (10), and one cembranoid, 2β-hydroxy-11α,12β-epoxynephthenol (11). Among these natural products, columnaristerols A-C (1-3) are new sterols and sterol 8 (4α-methylergosta-22(E),24(28)-dien-3β-ol) was first being reported from a natural source. The structures of above metabolites were determined by spectroscopic methods. Columnaristerol A (1) was proven to be a rare natural 19-norsterol possessing a 10β-hydroxy group and this compound was found to exhibit cytotoxic effects toward MOLT-4 and SUP-T1 cells.

Fig. 1