Polyhydroxylated bergamotane-type sesquiterpenoids from cultures of Paraconiothyrium sporulosum YK-03 and their absolute configurations

Two new bergamotane-type sesquiterpeniods from the plant endophytic fungus Paraconiothyrium brasiliense

One new bergamotane-type sesquiterpeniod lactam brasilactam A (1) and one new bergamotane-type sesquiterpeniod spiroketal lactone brasiketalolide A (2), along with two known compounds ampullicin (3) and isoampullicin (4) were isolated from the crude extract of the plant endophytic fungus Paraconiothynium brasiliense Verkley. The structures of the new compounds were elucidated on the basis of extensive 2D NMR techniques. The absolute configurations of 1 and 2 were assigned by 13C NMR and electronic circular dichroism (ECD) calculations. Furthermore, compounds 1 - 4 were tested for their cytotoxicity against four human cancer cell lines.

Bergamotenes: A comprehensive compile of their natural occurrence, biosynthesis, toxicity, therapeutic merits and agricultural applications

Sesquiterpenoids constitute the largest subgroup of terpenoids that have numerous applications in pharmaceutical, flavor, and fragrance industries as well as biofuels. Bergamotenes, a type of bicyclic sesquiterpenes, are found in plants, insects, and fungi with α-trans-bergamotene as the most abundant compound. Bergamotenes and their related structures (Bergamotane sesquiterpenoids) have been shown to possess diverse biological activities such as antioxidant, anti-inflammatory, immunosuppressive, cytotoxic, antimicrobial, antidiabetic, and insecticidal effects. However, studies on their biotechnological potential are still limited. This review compiles the characteristics of bergamotenes and their related structures in terms of occurrence, biosynthesis pathways, and biological activities. It further discusses their functionalities and potential applications in pharmaceutical, nutraceuticals, cosmeceuticals, and pest management sectors. This review also opens novel perspectives in identifying and harnessing bergamotenes for pharmaceutical and agricultural purposes.

New meroterpenoids and polyketides from the endophytic fungus Paraphaeosphaeria sp. C-XB-J-1 and their anti-inflammatory and SARS-CoV-2 Mpro inhibitory activities

Seven new meroterpenoids, paraphaeones A-G (1-7), and two new polyketides, paraphaeones H-I (8-9), along with eight known compounds (10-17), were isolated from the endophytic fungus Paraphaeosphaeria sp. C-XB-J-1. The structures of 1-9 were identified through the analysis of 1H, 13C, and 2D NMR spectra, assisted by HR-ESI-MS data. Compounds 1 and 7 exhibited a dose-dependent decrease in lactate dehydrogenase levels, with IC50 values of 1.78 μM and 1.54 μM, respectively. Moreover, they inhibited the secretion of IL-1β and CASP-1, resulting in a reduction in the activity levels of NLRP3 inflammasomes. Fluorescence microscopy results indicated that compound 7 concentration-dependently attenuated cell pyroptosis. Additionally, compounds 4 and 7 showed potential inhibitory effects on the severe acute respiratory syndrome coronavirus-2 main protease (SARS-CoV-2 Mpro), with IC50 values of 10.8 ± 0.9 μM and 12.9 ± 0.7 μM, respectively.

Marine natural products

Covering: January to the end of December 2022This review covers the literature published in 2022 for marine natural products (MNPs), with 645 citations (633 for the period January to December 2022) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, the submerged parts of mangroves and other intertidal plants. The emphasis is on new compounds (1417 in 384 papers for 2022), 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 NP structure class diversity in relation to biota source and biome is discussed.

Bergamotane-type sesquiterpenes from the leaves and twigs of Illicium oligandrum and their anti-inflammatory activities

Eight undescribed β-bergamotene-type sesquiterpene oliganins A-H (1-8) and one known α-bergamotene-type sesquiterpene (9) were isolated from the leaves and twigs of Illicium oligandrum Merr. & Chun. The structures of compounds 1-8 were elucidated by extensive spectroscopic data, and the absolute configurations were determined by using a modified Mosher's method and electronic circular dichroism calculations. The isolates were further evaluated in terms of their anti-inflammatory potential on nitric oxide (NO) generation in lipopolysaccharide-stimulated RAW264.7 and BV2 cells. Compounds 2 and 8 exhibited potent inhibitory effects on the production of NO with IC₅₀ values ranging from 21.65 to 49.28 μM, which were greater than or comparable to those of dexamethasone (positive control).

Santalane-type sesquiterpenoids and isobenzofuranones from cultures of Paraconiothyrium sporulosum YK-03

Three undescribed santalane-type sesquiterpenoids (parasantalenoic acids A-C) and two undescribed epimeric isobenzofuranones (paraphthalides A and B) were isolated from cultures of the marine mud-associated fungus Paraconiothyrium sporulosum YK-03. Their structures were elucidated by analysis of the extensive spectroscopic and crystal X-ray diffraction data, combined with ECD calculations and comparison. Santalane-type sesquiterpenoids have been firstly found in the Paraconiothyrium species. Parasantalenoic acids A-C represent three rare polyhydroxylated santalane-type sesquiterpenoid carboxylic acids, and parasantalenoic acid A represents the first example of 2-chlorinated santalane-type sesquiterpenoid. A plausible biosynthetic pathway for parasantalenoic acids A-C was proposed. Additionally, the anti-neuroinflammatory activities of parasantalenoic acids A-C were investigated by evaluating their inhibitory effects on nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated BV-2 microglia cells. Among them, parasantalenoic acid C showed significant anti-neuroinflammatory activity with an inhibition of 86.45 ± 2.45% at 10 μM.

Fungal Bergamotane Sesquiterpenoids-Potential Metabolites: Sources, Bioactivities, and Biosynthesis

The marine environment represents the largest ecosystem on the Earth's surface. Marine-derived fungi are of remarkable importance as they are a promising pool of diverse classes of bioactive metabolites. Bergamotane sesquiterpenoids are an uncommon class of terpenoids. They possess diverse biological properties, such as plant growth regulation, phototoxic, antimicrobial, anti-HIV, cytotoxic, pancreatic lipase inhibition, antidiabetic, anti-inflammatory, and immunosuppressive traits. The current work compiles the reported bergamotane sesquiterpenoids from fungal sources in the period ranging from 1958 to June 2022. A total of 97 compounds from various fungal species were included. Among these metabolites, 38 compounds were derived from fungi isolated from different marine sources. Furthermore, the biological activities, structural characterization, and biosynthesis of the compounds are also discussed. The summary in this work provides a detailed overview of the reported knowledge of fungal bergamotane sesquiterpenoids. Moreover, this in-depth and complete review could provide new insights for developing and discovering new valuable pharmaceutical agents from these natural metabolites.

Characteristic guaiane sesquiterpenes from Daphne penicillata and ECD/NMR-based assignment of C-1 configuration

40 compounds including the first C17 homo-guaiane sesquiterpene (1) were isolated from Daphne penicillata and an efficient method using ECD/NMR strategy to access the C-1 configuration of characteristic guaiane sesquiterpenes has been developed.