New sesquiterpenoids from the South China Sea soft corals Clavularia viridis and Lemnalia flava

Naturally Occurring Organohalogen Compounds-A Comprehensive Review

The present volume is the third in a trilogy that documents naturally occurring organohalogen compounds, bringing the total number-from fewer than 25 in 1968-to approximately 8000 compounds to date. Nearly all of these natural products contain chlorine or bromine, with a few containing iodine and, fewer still, fluorine. Produced by ubiquitous marine (algae, sponges, corals, bryozoa, nudibranchs, fungi, bacteria) and terrestrial organisms (plants, fungi, bacteria, insects, higher animals) and universal abiotic processes (volcanos, forest fires, geothermal events), organohalogens pervade the global ecosystem. Newly identified extraterrestrial sources are also documented. In addition to chemical structures, biological activity, biohalogenation, biodegradation, natural function, and future outlook are presented.

Chemistry and bioactivity of secondary metabolites from South China Sea marine fauna and flora: recent research advances and perspective

Marine organisms often produce a variety of metabolites with unique structures and diverse biological activities that enable them to survive and struggle in the extremely challenging environment. During the last two decades, our group devoted great effort to the discovery of pharmaceutically interesting lead compounds from South China Sea marine plants and invertebrates. We discovered numerous marine secondary metabolites spanning a wide range of structural classes, various biosynthetic origins and various aspects of biological activities. In a series of reviews, we have summarized the bioactive natural products isolated from Chinese marine flora and fauna found during 2000-2012. The present review provides an updated summary covering our latest research progress and development in the last decade (2012-2022) highlighting the discovery of over 400 novel marine secondary metabolites with promising bioactivities from South China Sea marine organisms.

Discovery of Niphimycin C from Streptomyces yongxingensis sp. nov. as a Promising Agrochemical Fungicide for Controlling Banana Fusarium Wilt by Destroying the Mitochondrial Structure and Function

Banana Fusarium wilt caused by Fusarium oxysporum f. sp. cubense (Foc) is the most destructive soil-borne fungal disease. Tropical race 4 (Foc TR4), one of the strains of Foc, can infect many commercial cultivars, which represents a threat to global banana production. Currently, there are hardly any effective chemical fungicides to control the disease. To search for natural product-based fungicides for controlling banana Fusarium wilt, we identified a novel strain Streptomyces yongxingensis sp. nov. (JCM 34965) from a marine soft coral, from which a bioactive compound, niphimycin C, was isolated using an activity-guided method. Niphimycin C exhibited a strong antifungal activity against Foc TR4 with a value of 1.20 μg/mL for EC₅₀ and obviously inhibited the mycelial growth and spore germination of Foc TR4. It caused the functional loss of mitochondria and the disorder of metabolism of Foc TR4 cells. Further study showed that niphimycin C reduced key enzyme activities of the tricarboxylic acid (TCA) cycle and the electron transport chain (ETC). It displayed broad-spectrum antifungal activities against the selected 12 phytopathogenic fungi. In pot experiments, niphimycin C reduced the disease indexes in banana plantlets and inhibited the infection of Foc TR4 in roots. Hence, niphimycin C could be a promising agrochemical fungicide for the management of fungal diseases.

Dolabellane Diterpenes and Elemane Alkaloids from the Soft Coral Clavularia inflata Collected in the South China Sea

Five new dolabellane diterpenes, clavularinlides A-E (1-5), and four new racemic elemane alkaloids, clavulacylides A-D (7-10), together with one known compound (6), were isolated from the soft coral Clavularia inflata collected in the South China Sea. Their structures were elucidated by 1D and 2D NMR, HRESIMS, calculated ECD, and DP4+ probability analyses. Compounds 1-7 showed anti-inflammatory activity in the zebrafish assay.

Arthriniumsteroids A-D, four new steroids from the soft coral-derived fungus Simplicillium lanosoniveum SCSIO41212

Four new steroids derivatives, namely arthriniumsteroids A - D (1-4), together with two known compounds, were isolated from the soft coral-derived fungus Simplicillium lanosoniveum SCSIO41212. Their structures were elucidated by spectroscopic analysis and by comparison with those reported in the literature. The absolute configuration of 2 was confirmed by single-crystal X-ray diffraction. In bioassay, all compounds showed weak inhibitory activities against lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW 264.7 cells.

Six New Diterpene Glycosides from the Soft Coral Lemnaliabournei

A chemical study on the extracts of soft coral Lemnalia bournei resulted in the isolation and identification of six new bicyclic diterpene glycosides including three new lemnaboursides E-G (1-3), and three new lemnadiolboursides A-C (4-6), along with three known lemnaboursides (7-9). Their structures were elucidated by detailed spectroscopic analysis, ECD analysis, chemical methods, and comparison with the literature data. Lemnadiolboursides A-C (4-6) contained a lemnal-1(10)-ene-7,12-diol moiety compared with the lemnaboursides. All these compounds were evaluated for antibacterial activity; cell growth inhibition of A549, Hela, HepG2, and CCRF-CEM cancer cell lines; and inhibition of LPS-induced NO production in RAW264.7 macrophages. The results indicated that compounds 1, 2, and 4-6 exhibited antibacterial activity against Staphylococcus aureus and Bacillus subtilis (MIC 4-16 μg/mL); compounds 1-9 displayed low cytotoxicity on the CCRF-CEM cell lines (IC₅₀ 10.44-27.40 µM); and compounds 1, 2, and 5 showed weak inhibition against LPS-induced NO production (IC₅₀ 21.56-28.06 μM).

Marine natural products

This review covers the literature published in 2019 for marine natural products (MNPs), with 719 citations (701 for the period January to December 2019) 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 (1490 in 440 papers for 2019), 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. Methods used to study marine fungi and their chemical diversity have also been discussed.