3,4-seco-24-homo-28-nor-Cycloartane and drimane-type sesquiterpenes and their lactams from the EtOAc-soluble fraction of a leaf extract of Cinnamosma fragrans and their biological activity

New sesquiterpenes from the soft coral Litophyton arboreum

Two new sesquiterpenes; 8α,11-dihydroxy-β-cyperon (2), and 5-epi-7α-hydroxy-( +)-oplopanone (3), were isolated from the soft coral Litophyton arboreum, together with nine known ones, including five sesquiterpenes; 11-hydroxy-8-oxo-β-cyperon (1), alismoxide (4), 5β,8β-epidioxy-11-hydroxy-6-eudesmene (5), chabrolidione B (6), 7-oxo-tri-nor-eudesm-5-en-4β-ol (7), two sterols; 7β-acetoxy-24-methyl-cholesta-5,24(28)-diene-3β,19-diol (8), nebrosteroid M (9), and two glycerol derivatives; chimyl alcohol (10) and batyl alcohol (11). The structures of the isolated compounds were characterized using spectroscopic techniques, predominately HR-ESI-MS, 1D, 2D-NMR, and ECD analyses. Compounds 1-11 were evaluated for their cytotoxic activity against three human cancer-cell lines (A549, MCF-7 and HepG2), and anti-leishmanial potential against the causal parasite, Leishmania major. Compounds 4, 8, and 9 exhibited potent cytotoxic activity against the A549 cell line (IC50 = 17.0 ± 2.5, 13.5 ± 2.1, and 16.5 ± 1.3 μg/ml, respectively) as compared with the standard antitumor agent etoposide (IC50 28.4 ± 4.5 μg/ml). In addition, compound 9 exhibited remarkable cytotoxic activity against MCF-7 cell line (IC50 = 24.7 ± 2.1 μg/ml: 22.2 ± 4.2 μg/mL for etoposide).

Drimane-Type Sesquiterpenoids Derived from the Tropical Basidiomycetes Perenniporia centrali-africana and Cerrena sp. nov

Five new drimane-type sesquiterpenoids were isolated from cultures of the tropical basidiomycetes, Perenniporia centrali-africana (originating from Kenya) and Cerrena sp. nov. (originating from Thailand). A new pereniporin A derivative (1), a new drimane-type sesquiterpene lactam (2), and the new 6,7-Dehydro-isodrimenediol (3) were isolated from P. centrali-africana. In parallel, the two new drimane-type sesquiterpene lactams 5 and 6 were isolated together with known isodrimenediol (4) from Cerrena sp. This is the first report of drimane-type sesquiterpene lactams from basidiomycetes. The structures were elucidated based on 1D and 2D nuclear magnetic resonance (NMR) spectroscopic data, in combination with high-resolution electrospray mass spectrometric (HR-ESIMS) data. The compounds were devoid of significant antimicrobial and cytotoxic activities.

Searching for constituents from plants in geographically characterized areas, Egypt, Madagascar, and Okinawa

Secondary metabolites may not be produced under some conditions, and in most cases, their function and significance in the producing organisms is unknown. Conversely, there are some that are produced for readily understood reasons, for example, toxic substances as defensive substances against invaders, or volatile substances that attract other species of organisms. These secondary metabolites also contribute to our health. However, there has not been sufficient research to evaluate them from a pharmacological perspective, and much progress is expected in this area in the future. About 90% of the existing plants have not been studied for their chemical components and biological activities (Kazuki Saito in Bunshun shinsho 1119, pp. 119-126. ISBN 978-4-16-661119-5, 2017). On this basis, we have been searching for the constituents of unknown plants, and whose constituents have not been studied extensively. In this paper, the authors have reviewed some of their previous searching for constituents from plants in geographically characterized areas, Egypt, Madagascar, and Okinawa.

Anticancer Activity of Natural and Semi-Synthetic Drimane and Coloratane Sesquiterpenoids

Drimane and coloratane sesquiterpenoids are present in several plants, microorganisms, and marine life. Because of their cytotoxic activity, these sesquiterpenoids have received increasing attention as a source for new anticancer drugs and pharmacophores. Natural drimanes and coloratanes, as well as their semi-synthetic derivatives, showed promising results against cancer cell lines with in vitro activities in the low micro- and nanomolar range. Despite their high potential as novel anticancer agents, the mode of action and structure–activity relationships of drimanes and coloratanes have not been completely enlightened nor systematically reviewed. Our review aims to give an overview of known structures and derivatizations of this class of sesquiterpenoids, as well as their activity against cancer cells and potential modes-of-action. The cytotoxic activities of about 40 natural and 25 semi-synthetic drimanes and coloratanes are discussed. In addition to that, we give a summary about the clinical significance of drimane and coloratane sesquiterpenoids.

Insecticidal and Antifeedant Activities of Malagasy Medicinal Plant (Cinnamosma sp.) Extracts and Drimane-Type Sesquiterpenes against Aedes aegypti Mosquitoes

The overuse of insecticides with limited modes of action has led to resistance in mosquito vectors. Thus, insecticides with novel modes of action are needed. Secondary metabolites in Madagascan plants of the genus Cinnamosma (Canellaceae) are commonly used in traditional remedies and known to elicit antifeedant and toxic effects in insect pests. Here we test the hypothesis that extracts of Cinnamosma sp. enriched in drimane sesquiterpenes are toxic and/or antifeedant to the yellow fever mosquito Aedes aegypti. We show that the bark and root extracts, which contain a higher abundance of drimane sesquiterpenes compared to leaves, were the most efficacious. Screening isolated compounds revealed cinnamodial to be the primary driver of adulticidal activity, whereas cinnamodial, polygodial, cinnafragrin A, and capsicodendrin contributed to the larvicidal activity. Moreover, an abundant lactone (cinnamosmolide) in the root extract synergized the larvicidal effects of cinnamodial. The antifeedant activity of the extracts was primarily contributed to cinnamodial, polygodial, and cinnamolide. Parallel experiments with warburganal isolated from Warburgia ugandensis (Canellaceae) revealed that aldehydes are critical for-and a hydroxyl modulates-insecticidal activity. Our results indicate that plant drimane sesquiterpenes provide valuable chemical platforms for developing insecticides and repellents to control mosquito vectors.

Triterpenoids

Covering 2014. Previous review: Nat. Prod. Rep., 2017, 34, 90-122 This review covers the isolation and structure determination of triterpenoids reported during 2014 including squalene derivatives, lanostanes, holostanes, cycloartanes, cucurbitanes, dammaranes, euphanes, tirucallanes, tetranortriterpenoids, quassinoids, lupanes, oleananes, friedelanes, ursanes, hopanes, serratanes, isomalabaricanes and saponins; 374 references are cited.

Biological activity of Entada phaseoloides and Entada rheedei

The aim of our study is to find functional compounds from natural resources. We focus on plants grown in tropical areas, especially Madagascar and Thailand, because they have unique flora and are expected to contain interesting compounds. We review the functional compounds of the seed kernels of Entada phaseoloides and E. rheedei and their biological activities such as anti-proliferation and melanogenesis inhibitory properties, etc.