Bioactive Diterpenes, Norditerpenes, and Sesquiterpenes from a Formosan Soft Coral Cespitularia sp.

You-Cheng Lin,Yi-Chia Chu,Chung-Wei Fu,Jyh-Horng Sheu,Chi-Chien Lin

doi:10.3390/ph14121252

Abstract

Chemical investigation of the soft coral Cespitularia sp. led to the discovery of twelve new verticillane-type diterpenes and norditerpenes: cespitulins H–O (1–8), one cyclic diterpenoidal amide cespitulactam L (9), norditerpenes cespitulin P (10), cespitulins Q and R (11 and 12), four new sesquiterpenes: cespilins A–C (13–15) and cespitulolide (16), along with twelve known metabolites. The structures of these metabolites were established by extensive spectroscopic analyses, including 2D NMR experiments. Anti-inflammatory effects of the isolated compounds were studied by evaluating the suppression of pro-inflammatory protein tumor necrosis factor-α (TNF-α) and nitric oxide (NO) overproduction, and the inhibition of the gene expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), in lipopolysaccharide-induced dendritic cells. A number of these metabolites were found to exhibit promising anti-inflammatory activities.

Highlights

In the inflammatory stimuli, the inflammatory mediators such as tumor necrosis factor-α (TNF-α), prostaglandin E2 (PGE2), and nitric oxide (NO) are known to be secreted through lipopolysaccharide (LPS)-induced activation of macrophages [1,2,3] and dendritic cells [4,5,6,7]
It has been well known that natural products have a great potential in drug discovery, the anti-inflammatory activity screening by evaluating the suppression of TNF-α and NO overproduction, and the inhibition of inducible nitric oxide synthase (iNOS)
Of verticillane-type diterpene were supported by analysis of the 13 C and 1 H NMR signals along with heteronuclear single quantum coherence (HSQC) spectrum (Tables 1 and 2)

Summary

Introduction

The inflammatory mediators such as tumor necrosis factor-α (TNF-α), prostaglandin E2 (PGE2), and nitric oxide (NO) are known to be secreted through lipopolysaccharide (LPS)-induced activation of macrophages [1,2,3] and dendritic cells [4,5,6,7]. It has been well known that natural products have a great potential in drug discovery, the anti-inflammatory activity screening by evaluating the suppression of TNF-α and NO overproduction, and the inhibition of iNOS and COX-2 protein and gene expression, in LPS-induced macrophages or dendritic cells (DCs) is one of the important methods for searching for anti-inflammatory agents from natural compounds [8,9,10,11,12,13,14]. With the aim of discovering bioactive compounds from marine invertebrates for further biomedical studies, we carried out the chemical investigation of the EtOAc extract of a Formosan soft coral Cespitularia sp. to search the bioactive principles, as preliminary bioassay showed that

Results

Discussion

Conclusion