Terpenoids from the South China Sea soft coral Sinularia multiflora

Discovery of uncommon terpenoids from the South China Sea soft coral Sinularia scabra

Sinulatones A and B, presented as the unusual carbon skeleton with bicyclo[4.5.0] system, two undescribed sesquiterpenoids, namely sinulalides A and B, along with eight known terpenoids, were isolated from the South China Sea soft coral Sinularia scabra. The structures and stereochemistry of these compounds were determined based on extensive spectroscopic data analyses, and computer-assisted methods, including the quantum mechanical-nuclear magnetic resonance (QM-NMR) and TDDFT-ECD calculations. In bioassay, sinulatones A and B showed inhibitory activity against osteoclast precursor cells, with IC₅₀ values of 16.8 and 5.8 μM, respectively.

Marine natural products

Covering: January to December 2021This review covers the literature published in 2021 for marine natural products (MNPs), with 736 citations (724 for the period January to December 2021) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1425 in 416 papers for 2021), together with the relevant biological activities, source organisms and country of origin. Pertinent reviews, biosynthetic studies, first syntheses, and syntheses that led to the revision of structures or stereochemistries, have been included. An analysis of the number of authors, their affiliations, domestic and international collection locations, focus of MNP studies, citation metrics and journal choices is discussed.

Mitochondrial Pro-Apoptotic Properties of Sinularia compressa from Persian Gulf against Breast Cancer Cells and Its Chemical Composition

Locals in the Persian Gulf islands traditionally use Sinularia compressa to treat cancer. Therefore, this study deals with the cytotoxic activity of the soft coral Sinularia compressa chloroform extract (SCE), its pro-apoptotic activity, and the determination of its secondary metabolites. Cytotoxicity was done against MCF-7 and MDA-MB-231 and MCF‑10A cells. Apoptosis induction was checked by flow cytometry. The DCFDA and JC-1 probes were used to assess the production of reactive oxygen species (ROS) and the mitochondrial transmembrane potential. Caspase-9, Bax, and Bcl-2 proteins were determined with ELISA Kit, and by western blot analysis. SCE exhibited cytotoxic activity with an IC₅₀ value of 32.51 ± 0.70 μg/ml against MCF-7, and 8.53 ± 0.97 μg/ml against MDA-MB-231 cancer cells. The induction of the intrinsic apoptosis pathway was found by ROS generation, attenuation of Bcl-2 and induction of Bax proteins. It was supported by activation of caspase-9, increased apoptotic cells, as well as decrease of ΔΨm. In the acute toxicity, there was no detectable sign of hepatic or renal toxicity in the SCE 100 mg/kg. GC mass and NMR identified bioactive compounds as one monoterpene, one sesquiterpene, five fatty acids, one phthalate, and two steroidal compounds.

Recent updates on Sinularia soft coral

Marine organisms are recognized as a rich source of bioactive secondary metabolites. The remarkable abundance and diversity of bioactive small molecules isolated from soft corals displayed their essential role in drug discovery for human diseases. Sterols and terpenes, particularly cembranolides, 14-membered cyclic diterpene, demonstrated numerous biological activities, such as antitumor, antimicrobial, antiviral, antidiabetic, anti-osteoporosis and anti-inflammatory. Accordingly, continuous investigation of marine soft corals will be the way for the discovery of a plentiful number of chemical diverse natural products with various biological potentials for prospective pharmaceutical industrial applications. Such review affords plenary inspection of the total secondary metabolites isolated from the Sinularia, from 2008 until 2020, besides their natural sources as well as bioactivities whenever possible.

Hot off the press

A personal selection of 32 recent papers is presented covering various aspects of current developments in bioorganic chemistry and novel natural products such as pyrasplorine A from Aspergillus versicolor.

Chemical Diversity and Biological Activity of Secondary Metabolites from Soft Coral Genus Sinularia since 2013

Sinularia is one of the conspicuous soft coral species widely distributed in the world’s oceans at a depth of about 12 m. Secondary metabolites from the genus Sinularia show great chemical diversity. More than 700 secondary metabolites have been reported to date, including terpenoids, norterpenoids, steroids/steroidal glycosides, and other types. They showed a broad range of potent biological activities. There were detailed reviews on the terpenoids from Sinularia in 2013, and now, it still plays a vital role in the innovation of lead compounds for drug development. The structures, names, and pharmacological activities of compounds isolated from the genus Sinularia from 2013 to March 2021 are summarized in this review.

Marine natural products as antifouling molecules - a mini-review (2014-2020)

In the present review, 182 antifouling (AF) natural products from marine microorganisms, algae and marine invertebrates reported from August 2014 to May 2020 are presented. Amongst these compounds, over half were isolated from marine-derived microorganisms, including 70 compounds from fungi and 31 compounds from bacteria. The structure-relationship of some of these compounds is also briefly discussed. Based on the work reported, a general workflow was drafted to refine the procedures for the commercialization of any novel AF compounds. Finally, butenolide, which is considered a potential environmentally friendly antifoulant, is used as a case study to show the procedures involved in AF compound work from the aspect of discovery, structure optimization, toxicity, stability, AF mechanism and coating incorporation, which highlight the current challenges and future perspectives in AF compound research.

Diving into the world of marine 2,11-cyclized cembranoids: a summary of new compounds and their biological activities

This review summarises new marine 2,11-cyclized cembranoids from the past decade in a structured presentation according to their hypothetical biosynthesis.