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.

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.

One new Lignan derivative from the fruiting bodies of Ganoderma lipsiense

One new lignan derivative 2,3-dimethyl-4-(4'-hydroxy-3',5'-dimethoxyphenyl)-6-hydroxy-7-methoxy-naphthalene (1), together with four known analogues (2-5), were isolated from acetone extract of the fruiting bodies of Ganoderma lipsiense collected in the Hainan Province, China. Their structures were elucidated by the detailed analysis of comprehensive spectroscopic data. Compound 1 showed insecticidal activity against newly hatched karvae of Helicoverpa armigera Hubner. Compounds 1-5 showed moderate antibacterial activity against Staphylococcus aureus with the same MIC value of 1.25 μg/mL.

Cytotoxic and N-Acetyltransferase Inhibitory Meroterpenoids from Ganoderma cochlear

Seven compounds, including two pairs of new meroterpenoids, (+)- and (−)-gancochlearol C (1), (+)- and (−)-cochlearoid Q (3), and a new meroterpenoid gancochlearol D (2), together with four known meroterpenoids were isolated from the aqueous EtOH extract of the fruiting bodies of Ganoderma cochlear. Their structures were determined by spectroscopic data. The isolated compounds were evaluated for their cytotoxic activity against three human lung cancer cells (H1975, PC9, A549) and N-acetyltransferase inhibitory property. The results show that (+)-gancochlearol C could inhibit N-acetyltransferase with an IC₅₀ value of 5.29 μM. In addition, ganomycin F was found to show moderate activity against the H1975 human lung cancer cell line, with an IC₅₀ value of 19.47 μM.

(±)-Applanatumines B–D: novel dimeric meroterpenoids from Ganoderma applanatum as inhibitors of JAK3

Applanatumines B–D (1–3), three pairs of dimeric meroterpenoid enantiomers featuring the presence of a 6-oxo-4,4a,5,5a,6,8,8a,8b-octahydrofuro[3′,4′:4,5]cyclopenta[1,2-b]pyran-3-carbaldehyde structure core, were isolated from the fruiting bodies of Ganoderma applanatum.