PROGRESS OF STUDIES ON THE NATURAL CEMBRANOIDS FROM THE SOFT CORAL SPECIES OF SARCOPHYTON GENUS - Medicinal Chemistry of Bioactive Natural Products - page 257

PROGRESS OF STUDIES ON THE
NATURAL CEMBRANOIDS FROM
THE SOFT CORAL SPECIES OF
SARCOPHYTON GENUS

Y ULIN L I ,L IZENG P ENG , AND T AO Z HANG
State Key Laboratory of Applied Organic Chemistry, Institute of Organic Chemistry,
Lanzhou University, Lanzhou, P. R. China

6.1 INTRODUCTION

Many cembrane-type diterpenoids have been isolated from terrestrial and especially
from marine sources in the past several decades. 1 The cembrane diterpenoids basic
skeleton 1 is an isoprenoid 14-membered carbocyclic ring, substituted with an iso-
propyl residue at C-1 and three symmetrically disposed methyl groups at positions
4, 8, and 12. It turns out that they constitute the most widely distributed of all diter-
pene families, even though the first representative, cembrene (2), was only discov-
ered in 1962 (Figure 6-1). 2,3 Many structural variants are now known from both the
plant and the animal kingdoms, and they display a wide range of biological activ-
ities. Most known cembranes have come from pine trees and tobacco plants, but
many others have come from marine sources. The soft corals have been a particu-
larly rich source of cembrane and cembranolide lactone natural products. In recent
years, there has been much interest in the metabolites of marine invertebrates such
as soft corals, sponges, and sea cucumbers, and the chemistry and biology of these
compounds in general have been reviewed. 4-8 Soft corals form a significant group of
marine organisms occurring widely in the coral reefs all over the world. Of those, the
corals of the genera Cespitularia, Clavularia, Gersemia, Lobophytum, Nephthea,