Verticillane Derivatives from Natural Sources

New verticillane-diterpenoid as potent NF-κB inhibitor isolated from the gum resin of Boswellia sacra

Two new verticillane-diterpenoids (1 and 2) were isolated from the gum resin Boswellia sacra. Their structures were elucidated by physiochemical and spectroscopic analysis, as well as ECD calculation. In addition, the in vitro anti-inflammatory activities of the isolated compounds were evaluated by determining the inhibitory effects on lipopolysaccharide (LPS)-induced NO production in RAW 264.7 mouse monocyte-macrophages. The results showed that compound 1 exhibited significant inhibitory effect on NO generation with an IC₅₀ value of 23.3 ± 1.7 μM suggesting that it might be a candidate for an anti-inflammatory agent. Furthermore, 1 potently inhibited the release of inflammatory cytokines IL-6 and TNF-α induced by LPS in a dose-dependent manner. Using Western blot and Immunofluorescence methods, compound 1 was found to inhibit inflammation mainly by restraining the activation of NF-κB pathway. And in the MAPK signaling pathway, it was found to have inhibitory effects on the phosphorylation of JNK and ERK proteins and have no effect on the phosphorylation of p38 protein.

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

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.

The verticillenes. Pivotal intermediates in the biosynthesis of the taxanes and the phomactins

Recent enzymatic studies, quantum chemical calculations and biomimetic conversions consolidate the role of verticillenes in the biosynthesis of taxanes and phomactins.

New verticillane diterpenoids from Cespitularia taeniata

Chemical investigation of Cespitularia taeniata has led to the isolation of three new verticillanes, cespitulins E-G (1-3, resp.). The structures of these compounds were elucidated by spectroscopic analysis, especially HR-MS and 2D-NMR techniques. Compound 1 possesses a rare norverticillane skeleton with two adjacent OH groups at C(5) and C(6), while the seco-compound 2 with an aldehyde group at C(9) results from an unusual bond cleavage between C(9) and C(10). Pharmacological studies revealed that compound 3 exhibited significant activities on superoxide-anion generation and elastase release by human neutrophils in response to FMLP/CB. A plausible biogenetic pathway for compound 2 is also discussed.