(±) Cochlearoids N-P: three pairs of phenolic meroterpenoids from the fungus Ganoderma cochlear and their bioactivities

Insights into Ganoderma fungi meroterpenoids opening a new era of racemic natural products in mushrooms

Ganoderma meroterpenoids (GMs) containing 688 structures to date were discovered to have multiple remarkable biological activities. 65.6% of meroterpenoids featuring stereogenic centers from Ganoderma species are racemates. Further, GMs from different Ganoderma species seem to have their own characteristics. In this review, a comprehensive summarization of GMs since 2000 is presented, including GM structures, structure corrections, biological activities, physicochemical properties, total synthesis, and proposed biosynthetic pathways. Additionally, we especially discuss the racemic nature, species-related structural distribution, and structure-activity relationship of GMs, which will provide a likely in-house database and shed light on future studies on GMs.

Structural diversity, hypothetical biosynthesis, chemical synthesis, and biological activity of Ganoderma meroterpenoids

Covering: 2018 to 2022Meroterpenoids found in fungal species of the genus Ganoderma and known as Ganoderma meroterpenoids (GMs) are substances composed of a 1,2,4-trisubstituted benzene and a polyunsaturated side chain. These substances have attracted the attention of chemists and pharmacologists due to their diverse structures and significant bioactivity. In this review, we present the structures and possible biosynthesis of representative GMs newly found from 2018 to 2022, as well as chemical synthesis and biological activity of some interesting GMs. We propose for the first time a plausible biosynthetic pathway for GMs, which will certainly motivate further research on the biosynthetic pathway in Ganoderma species, as well as on chemical synthesis of GMs as important bioactive compounds for the purpose of drug development.

Natural sesquiterpene quinone/quinols: chemistry, biological activity, and synthesis

Covering: 2010 to 2021Sesquiterpene quinone/quinols (SQs) are characterized by a C15-sesquiterpenoid unit incorporating a C6-benzoquinone/quinol moiety. Numerous unprecedented carbon skeletons have been constructed with various connection patterns between the two parts. The potent anti-cancer, anti-inflammatory, anti-microbial, anti-viral, and fibrinolytic activities of SQs are associated with their diverse structures. The representative avarol has even entered the stage of clinical phase II research as an anti-HIV agent, and was developed as paramedic medicine against psoriasis. This review provides an overall summary of 558 new natural SQs discovered between 2010 and 2021, including seven groups and sixteen structure-type subgroups, which comprehensively recapitulates their chemical structures, spectral characteristics, source organisms, biological activities, synthesis, and biosynthesis, aiming to expand the application scope of this unique natural product resource.

Spiroganodermaines A-G from Ganoderma species and their activities against insulin resistance and renal fibrosis

Ganoderma mushrooms are a renowned Chinese medicine and functional food used worldwide. Seven undescribed spiro Ganoderma meroterpenoids spiroganodermaines A-G were isolated from Ganoderma species. Their structures were characterized by using spectroscopic, computational and X-ray diffraction methods. Biological studies showed that (+)-spiroganodermaine G significantly activates glucose uptake and IRS1 phosphorylation in insulin resistance C2C12 cells. Furthermore, (-)-spiroganodermaine G inhibits the expressions of fibronectin and α-SMA in TGF-β1 induced NRK-52E cells. These findings demonstrate the potential of Ganoderma meroterpenoids as medicines and dietary supplements.

Biological activities of meroterpenoids isolated from different sources

Meroterpenoids are natural products synthesized by unicellular organisms such as bacteria and multicellular organisms such as fungi, plants, and animals, including those of marine origin. Structurally, these compounds exhibit a wide diversity depending upon the origin and the biosynthetic pathway they emerge from. This diversity in structural features imparts a wide spectrum of biological activity to meroterpenoids. Based on the biosynthetic pathway of origin, these compounds are either polyketide-terpenoids or non-polyketide terpenoids. The recent surge of interest in meroterpenoids has led to a systematic screening of these compounds for many biological actions. Different meroterpenoids have been recorded for a broad range of operations, such as anti-cholinesterase, COX-2 inhibitory, anti-leishmanial, anti-diabetic, anti-oxidative, anti-inflammatory, anti-neoplastic, anti-bacterial, antimalarial, anti-viral, anti-obesity, and insecticidal activity. Meroterpenoids also possess inhibitory activity against the expression of nitric oxide, TNF- α, and other inflammatory mediators. These compounds also show renal protective, cardioprotective, and neuroprotective activities. The present review includes literature from 1999 to date and discusses 590 biologically active meroterpenoids, of which 231 are from fungal sources, 212 are from various species of plants, and 147 are from marine sources such as algae and sponges.

Natural Enantiomers: Occurrence, Biogenesis and Biological Properties

The knowledge that natural products (NPs) are potent and selective modulators of important biomacromolecules (e.g., DNA and proteins) has inspired some of the world's most successful pharmaceuticals and agrochemicals. Notwithstanding these successes and despite a growing number of reports on naturally occurring pairs of enantiomers, this area of NP science still remains largely unexplored, consistent with the adage "If you don't seek, you don't find". Statistically, a rapidly growing number of enantiomeric NPs have been reported in the last several years. The current review provides a comprehensive overview of recent records on natural enantiomers, with the aim of advancing awareness and providing a better understanding of the chemical diversity and biogenetic context, as well as the biological properties and therapeutic (drug discovery) potential, of enantiomeric NPs.

The chemistry and biology of fungal meroterpenoids (2009-2019)

Fungal meroterpenoids are secondary metabolites from mixed terpene-biosynthetic origins. Their intriguing chemical structural diversification and complexity, potential bioactivities, and pharmacological significance make them attractive targets in natural product chemistry, organic synthesis, and biosynthesis. This review provides a systematic overview of the isolation, chemical structural features, biological activities, and fungal biodiversity of 1585 novel meroterpenoids from 79 genera terrestrial and marine-derived fungi including macrofungi, Basidiomycetes, in 441 research papers in 2009-2019. Based on the nonterpenoid starting moiety in their biosynthesis pathway, meroterpenoids were classified into four categories (polyketide-terpenoid, indole-, shikimate-, and miscellaneous-) with polyketide-terpenoids (mainly tetraketide-) and shikimate-terpenoids as the primary source. Basidiomycota produced 37.5% of meroterpenoids, mostly shikimate-terpenoids. The genera of Ganoderma, Penicillium, Aspergillus, and Stachybotrys are the four dominant producers. Moreover, about 56% of meroterpenoids display various pronounced bioactivities, including cytotoxicity, enzyme inhibition, antibacterial, anti-inflammatory, antiviral, antifungal activities. It's exciting that several meroterpenoids including antroquinonol and 4-acetyl antroquinonol B were developed into phase II clinically used drugs. We assume that the chemical diversity and therapeutic potential of these fungal meroterpenoids will provide biologists and medicinal chemists with a large promising sustainable treasure-trove for drug discovery.

Meroterpenoids produced by fungi: Occurrence, structural diversity, biological activities, and their molecular targets

Meroterpenoids are partially derived from the terpenoids, distributing widely in the plants, animals and fungi. The complex structures and diverse bioactivities of meroterpenoids have attracted more attention for chemists and pharmacologists. Since the first review summarized by Geris in 2009, there are absent of systematic reviews reported about meroterpenoids from the higher and lower fungi up to now. In the past decades, myriads of meroterpenoids were discovered, and it is necessary to summarize these meroterpenoids about their unique structures and promising bioactivities. In this review, we use a new classification method based on the non-terpene precursors, and also highlight the structural features, bioactivity of natural meroterpenoids from the higher and lower fungi covering the period of September 2008 to February 2020. A total of 709 compounds were discussed and cited the 182 references. Meanwhile, we also primarily summarize their occurrence, structural diversity, biological activities, and molecular targets.