Trichodermanins C-E, New Diterpenes with a Fused 6-5-6-6 Ring System Produced by a Marine Sponge-Derived Fungus

Diterpenoids with Antibacterial Activities from the Fungus Trichoderma harzianum

A new fusicoccane diterpenoid, harziaderma A (1), two novel harziane diterpenoids, harzianones G and H (2 and 3), one revised harziane diterpenoid (4), and two known diterpenoids (5 and 6) were isolated from the fungus Trichoderma harzianum and established via NMR, HRESIMS, Mo2(OAc)4-induced circular dichroism (ICD) and electronic circular dichroism (ECD) calculations. It is worth noting that compound 1 represents the first instance of a fusicoccane-type diterpenoid derived from T. harzianum. The structure of furanharzianone B was revised to 4 via careful spectroscopic analyses. Additionally, compounds 2 and 5 could suppress the overall growth of the foodborne bacterial pathogen Bacillus cereus. Compound 4 showed a moderate suppressive impact on NO generation in lipopolysaccharide (LPS)-treated RAW 264.7 cells. The discoveries from the current study not only expanded the structural variety of diterpenoids isolated from T. harzianum but also laid a robust foundation for the development of harziane diterpenoids as anti-foodborne pathogen agents.

Chemistry and biology of marine-derived Trichoderma metabolites

Marine-derived fungi of the genus Trichoderma have been surveyed for pharmaceuticals and agrochemicals since 1993, with various new secondary metabolites being characterized from the strains of marine animal, plant, sediment, and water origin. Chemical structures and biological activities of these metabolites are comprehensively reviewed herein up to the end of 2022 (covering 30 years). More than 70 strains that belong to at least 18 known Trichoderma species have been chemically investigated during this period. As a result, 445 new metabolites, including terpenes, steroids, polyketides, peptides, alkaloids, and others, have been identified, with over a half possessing antimicroalgal, zooplankton-toxic, antibacterial, antifungal, cytotoxic, anti-inflammatory, and other activities. The research is highlighted by the molecular diversity and antimicroalgal potency of terpenes and steroids. In addition, metabolic relevance along with co-culture induction in the production of new compounds is also concluded. Trichoderma strains of marine origin can transform and degrade heterogeneous molecules, but these functions need further exploration.

Enantioselective Syntheses of Wickerols A and B

The evolution of a successful strategy for the synthesis of the strained, cage-like antiviral diterpenoids wickerols A and B is described. Initial attempts to access the carbocyclic core were surprisingly challenging and in retrospect, presaged the many detours needed to ultimately arrive at the fully adorned wickerol architecture. In most cases, conditions to trigger desired outcomes with respect to both reactivity and stereochemistry were hard-won. The successful synthesis ultimately leveraged alkenes in virtually all productive bond-forming events. A series of conjugate addition reactions generated the fused tricyclic core, a Claisen rearrangement was used to install an otherwise unmanageable methyl-bearing stereogenic center, and a Prins cyclization closed the strained bridging ring. This final reaction proved enormously interesting because the strain of the ring system permitted diversion of the presumed initial Prins product into several different scaffolds.

A Review of Diterpenes from Marine-Derived Fungi: 2009-2021

Marine-derived fungi are important sources of novel compounds and pharmacologically active metabolites. As an important class of natural products, diterpenes show various biological activities, such as antiviral, antibacterial, anti-inflammatory, antimalarial, and cytotoxic activities. Developments of equipment for the deep-sea sample collection allow discoveries of more marine-derived fungi with increasing diversity, and much progress has been made in the identification of diterpenes with novel structures and bioactivities from marine fungi in the past decade. The present review article summarized the chemical structures, producing organisms and biological activities of 237 diterpenes which were isolated from various marine-derived fungi over the period from 2009 to 2021. This review is beneficial for the exploration of marine-derived fungi as promising sources of bioactive diterpenes.

Structures and Biological Activities of Secondary Metabolites from Trichoderma harzianum

The biocontrol fungus Trichoderma harzianum, from both marine and terrestrial environments, has attracted considerable attention. T. harzianum has a tremendous potential to produce a variety of bioactive secondary metabolites (SMs), which are an important source of new herbicides and antibiotics. This review prioritizes the SMs of T. harzianum from 1988 to June 2022, and their relevant biological activities. Marine-derived SMs, especially terpenoids, polyketides, and macrolides compounds, occupy a significant proportion of natural products from T. harzianum, deserving more of our attention.

Trichoderma species from plant and soil: An excellent resource for biosynthesis of terpenoids with versatile bioactivities

BACKGROUND

Trichoderma species are rich source of bioactive secondary metabolites. In the past decades, a series of secondary metabolites were reported from different Trichoderma fungi, among which terpenoids possessing versatile structural diversities and extensive pharmacological activities are one of the particularly important categories.

AIM OF REVIEW

The review aims to summarize the terpenoids isolated from Trichoderma species regarding their structural diversities, biological activities, and promising biosynthetic potentials.

KEY SCIENTIFIC CONCEPTS OF REVIEW

So far, a total of 253 terpenoids, including 202 sesquiterpenes, 48 diterpenes, 2 monoterpenes and 1 meroterpenoid, were isolated and identified from Trichoderma species between 1948 and 2022. Pharmacological investigations of Trichoderma terpenoids mainly focused on their antibacterial activities, antifungal activities, inhibitory activities on marine plankton species and cytotoxic activities, indicating that Trichoderma species are important microbial agents for drug discovery and environmentally friendly agrochemicals development. Intriguing chemistry and enzymology involved in the biosynthesis of Trichoderma terpenoids were also presented to facilitate further precise genome mining-guided novel structure discovery. Taken together, the abundance of novel skeletons, bioactivities and biosynthetic potentials presents new opportunities for drug and agrochemicals discovery, genome mining and enzymology exploration from Trichoderma species. The work will provide references for the profound study of terpenoids derived from Trichoderma, and facilitate further studies on Trichoderma species in the areas of chemistry, medicine, agriculture and microbiology.

Enantiomeric composition of natural pericosine A derived from Periconia byssoides and α-glycosidase inhibitory activity of (-)-enantiomer

Chiral high-performance liquid chromatography (HPLC) analysis of natural pericosine A, which appeared in literature first in 1977, from Periconia byssoides was conducted using a column CHIRALPAK® AD-H to determine the enantiomeric composition of the original mixture which was found to be 68: 32 mixtures of (+)- and (-)-enantiomer, respectively. Furthermore, two independently isolated samples of pericosine A from the same fungus were also analyzed to show the two peaks in the HPLC charts at approximate 1:1 ratio. These results concluded that pericosine A derived from Periconia byssoides was indeed an enantiomeric mixture. Synthesized enantiomers were subjected to evaluation of antitumor activity against three kinds of tumor cells (p388, L1210, HL-60), indicating moderate cytotoxicity against all three kinds of tumor cell lines, but significant difference in potency between the enantiomers was not observed. In contrast, when both the enantiomers of pericosine A were evaluated against five kinds of glycosidases-inhibitory activities (α- and β-glucosidases, α- and β-galactosidases, and α-mannosidase), an apparent difference on anti-glycosidase assay was found between the enantiomers: (-)-pericosine A inhibited α-glucosidase at IC₅₀ : 2.25 mM, and β-galactosidase at IC₅₀ : 5.38 mM, albeit the (+)-enantiomer showed inactivity against these five enzymes.

Diterpenes Specially Produced by Fungi: Structures, Biological Activities, and Biosynthesis (2010–2020)

Fungi have traditionally been a very rewarding source of biologically active natural products, while diterpenoids from fungi, such as the cyathane-type diterpenoids from Cyathus and Hericium sp., the fusicoccane-type diterpenoids from Fusicoccum and Alternaria sp., the guanacastane-type diterpenoids from Coprinus and Cercospora sp., and the harziene-type diterpenoids from Trichoderma sp., often represent unique carbon skeletons as well as diverse biological functions. The abundances of novel skeletons, biological activities, and biosynthetic pathways present new opportunities for drug discovery, genome mining, and enzymology. In addition, diterpenoids peculiar to fungi also reveal the possibility of differing biological evolution, although they have similar biosynthetic pathways. In this review, we provide an overview about the structures, biological activities, evolution, organic synthesis, and biosynthesis of diterpenoids that have been specially produced by fungi from 2010 to 2020. We hope this review provides timely illumination and beneficial guidance for future research works of scholars who are interested in this area.

α-Pyrone and decalin derivatives from the marine-derived fungus Trichoderma harzianum PSU-MF79

Two new compounds, one α-pyrone (trichoharzianone) and one decalin (trichoharzianin), along with eight known compounds including three decalins, two δ-lactones, two carboxylic acids and one isochroman were isolated from the marine-derived fungus Trichoderma harzianum PSU-MF79. The structures were determined by spectroscopic methods. The relative configuration of trichoharzianin was assigned based on NOEDIFF data and coupling constants whereas the absolute configurations were established by comparison of electronic circular dichroism data with those of the co-metabolites. Known (-)-massoia lactone exhibited mild antifungal activity against Cryptococcus neoformans ATCC90113 flucytosine-resistant, Candida albicans ATCC90028 and C. albicans NCPF3153 with MIC values of 128, 200 and 200 µg/mL, respectively, and weak cytotoxic activity against HCT-116 and MCF-7 cell lines with the respective IC₅₀ values of 17 and 32 µM. In addition, it was noncytotoxic against noncancerous Vero cells with an IC₅₀ value of >100 µM.

Marine Sponge-Associated Fungi as Potential Novel Bioactive Natural Product Sources for Drug Discovery: A Review

Marine sponge-associated fungi are promising sources of structurally interesting and bioactive secondary metabolites. Great plenty of natural products have been discovered from spongeassociated fungi in recent years. Here reviewed are 571 new compounds isolated from marine fungi associated with sponges in 2010-2018. These molecules comprised eight different structural classes, including alkaloids, polyketides, terpenoids, meroterpenoids, etc. Moreover, most of these compounds demonstrated profoundly biological activities, such as antimicrobial, antiviral, cytotoxic, etc. This review systematically summarized the structural diversity, biological function, and future potential of these novel bioactive natural products for drug discovery.

Naphthalene derivatives and halogenate quinoline from the coral-derived fungus Trichoderma harzianum (XS-20090075) through OSMAC approach

OSMAC approach was performed on the soft coral-derived fungus Trichoderma harzianum (XS-20090075) leading to the significant changes of its secondary metabolites by using two different cultures. A new naphthalene derivative, trichoharzin B (1) and a new natural product, methyl-trichoharzin (2) were isolated by using rice medium. Whereas, a new natural product, ethyl 2-bromo-4-chloroquinoline-3-carboxylate (9) was obtained by using Czapek's medium. Their structures were established by extensive spectroscopic investigation. The absolute configuration of 5 was determined by single-crystal X-ray diffraction. Compound 9 was the first halogenate quinoline derivative isolated from the genus of Trichoderma.

A Review of Terpenes from Marine-Derived Fungi: 2015-2019

Marine-derived fungi are a significant source of pharmacologically active metabolites with interesting structural properties, especially terpenoids with biological and chemical diversity. In the past five years, there has been a tremendous increase in the rate of new terpenoids from marine-derived fungi being discovered. In this updated review, we examine the chemical structures and bioactive properties of new terpenes from marine-derived fungi, and the biodiversity of these fungi from 2015 to 2019. A total of 140 research papers describing 471 new terpenoids of six groups (monoterpenes, sesquiterpenes, diterpenes, sesterterpenes, triterpenes, and meroterpenes) from 133 marine fungal strains belonging to 34 genera were included. Among them, sesquiterpenes, meroterpenes, and diterpenes comprise the largest proportions of terpenes, and the fungi genera of Penicillium, Aspergillus, and Trichoderma are the dominant producers of terpenoids. The majority of the marine-derived fungi are isolated from live marine matter: marine animals and aquatic plants (including mangrove plants and algae). Moreover, many terpenoids display various bioactivities, including cytotoxicity, antibacterial activity, lethal toxicity, anti-inflammatory activity, enzyme inhibitor activity, etc. In our opinion, the chemical diversity and biological activities of these novel terpenoids will provide medical and chemical researchers with a plenty variety of promising lead compounds for the development of marine drugs.

Biological and Chemical Diversity of Marine Sponge-Derived Microorganisms over the Last Two Decades from 1998 to 2017

Marine sponges are well known as rich sources of biologically natural products. Growing evidence indicates that sponges harbor a wealth of microorganisms in their bodies, which are likely to be the true producers of bioactive secondary metabolites. In order to promote the study of natural product chemistry and explore the relationship between microorganisms and their sponge hosts, in this review, we give a comprehensive overview of the structures, sources, and activities of the 774 new marine natural products from sponge-derived microorganisms described over the last two decades from 1998 to 2017.

New Diterpenes with a Fused 6-5-6-6 Ring System Isolated from the Marine Sponge-Derived Fungus Trichoderma harzianum

New diterpenes, namely, trichodermanins F–H, with a fused 6-5-6-6 ring system were isolated from the fungus Trichoderma harzianum OUPS-111D-4 separated from a marine sponge Halichondria okadai. These chemical structures were elucidated by 1D and 2D NMR as well as high-resolution fast atom bombardment mass spectrometry (HRFABMS) spectral analyses. We established their absolute stereostructures by application of the modified Mosher’s method or circular dichroism (CD) spectroscopy. In addition, their cytotoxicities were assessed using several cancer cell lines, with 1 and 2 exhibiting modest activities.

Trichosordarin A, a norditerpene glycoside from the marine-derived fungus Trichoderma harzianum R5

A new sordarin derivative, trichosordarin A (1), with a unique norditerpene aglycone was isolated from the culture of a marine-sediment-derived fungal strain, Trichoderma harzianum R5. Its structure and relative configuration were unequivocally identified by a combination of 1D/2D NMR, IR, and mass spectrometric methods. Compound 1 was assayed to be toxic to the marine zooplankton Artemia salina.

Marine natural products

Covering: January to December 2017This review covers the literature published in 2017 for marine natural products (MNPs), with 740 citations (723 for the period January to December 2017) 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 477 papers for 2017), together with the relevant biological activities, source organisms and country of origin. Reviews, biosynthetic studies, first syntheses, and syntheses that led to the revision of structures or stereochemistries, have been included. Geographic distributions of MNPs at a phylogenetic level are reported.

Diterpenes and Sesquiterpenes from the Marine Algicolous Fungus Trichoderma harzianum X-5

Six new terpenes, including one harziane diterpene, 3 R-hydroxy-9 R,10 R-dihydroharzianone (1), one proharziane diterpene, 11 R-methoxy-5,9,13-proharzitrien-3-ol (2), three cyclonerane sesquiterpenes, 11-methoxy-9-cycloneren-3,7-diol (3), 10-cycloneren-3,5,7-triol (4), and methyl 3,7-dihydroxy-15-cycloneranate (5), and one acorane sesquiterpene, 8-acoren-3,11-diol (6), were isolated from the culture of Trichoderma harzianum X-5, an endophytic fungus obtained from the marine brown alga Laminaria japonica. Their structures and relative configurations were established by analysis of 1D/2D NMR, HREIMS, and IR data, and the absolute configurations were assigned on the basis of ECD curves or biogenetic considerations. These terpenes possess four different carbon skeletons, and compound 2, with a rarely occurring bicyclic framework, represents a possible precursor of tetracyclic harzianes. Compounds 1-6 exhibited growth inhibition of some marine phytoplankton species.

Four New C9 Metabolites from the Sponge-Associated Fungus Gliomastix sp. ZSDS1-F7-2

Four new structurally related metabolites, one γ-lactone named gliomasolide F (1), one δ-lactone named gliomasolide G (2), and two medium-chain fatty acids named gliomacids A–B (3–4), each containing nine carbons in total, were identified from the sponge-associated fungus Gliomastix sp. ZSDS1-F7-2. The planar chemical structures of these novel C9 metabolites were elucidated by nuclear magnetic resonance (NMR) spectroscopic methods, in connection with the analysis of high-resolution mass spectrometry (HRMS) and infrared (IR) data. The absolute configuration of 1, was determined by comparisons of experimental circular dichroism (CD) and optical rotation (OR) value with corresponding ones computed by quantum chemistry. The relative configuration of 2 was determined by the Nuclear Overhauser effect spectroscopy (NOESY) spectrum, while its absolute configuration was tentatively determined in view of the biogenetic and biosynthetic relationships between 1 and 2. Compounds 3–4, originally as an inseparable mixture, were successfully isolated after chemical modifications. The stereo-chemistries of compounds 3–4 were assumed by comparison of ¹³C NMR with those of the similar moiety reported in literature, in addition to the biogenetic and biosynthetic relationships with 1. The plausible biosynthetic relationships among these four C9 metabolites were supposed. Biologically, compounds 1–4 showed no cytotoxic effect against HeLa cell line at concentrations up to 25 μg/mL, while 1 exhibited moderate antifouling activity against the settlement of Balanus amphitrite larvae with IC₅₀ being 12.8 μg/mL and LC₅₀ > 25 μg/mL. The co-occurrence of macrolides gliomasolides A—E and four C9 metabolites in the same fermentation culture made us assume that these C9 metabolites might be biosynthetic building blocks toward the construction of more complex macrolides such as gliomasolides A—E or other unidentified polyketides.

Elucidation of the Relationship between CD Cotton Effects and the Absolute Configuration of Sixteen Stereoisomers of Spiroheterocyclic-Lactams

As part of research to search for antitumor agents in fungi originating from marine organisms, cephalimysins E–L were isolated from a culture broth of Aspergillus fumigatus that was separated from the marine fish Mugil cephalus. One- and two-dimensional nuclear magnetic resonance spectra revealed their planar structures, which are diastereomers of each other. Their absolute stereostructures were established by epimerization at C-8 with acidic methanol, nuclear Overhauser effect spectroscopy (NOESY), and circular dichroism (CD) spectroscopy. These demonstrated the detailed relationships between absolute configuration and CD Cotton effects. Additionally, in the growth inhibition assay against P388, HL-60, L1210, and KB cell lines, some of the fungal metabolites or reaction products exhibited moderate activities.

Sterepinic Acids A⁻C, New Carboxylic Acids Produced by a Marine Alga-Derived Fungus

Sterepinic acids A⁻C (1⁻3), new carboxylic acids with two primary alcohols, have been isolated from a fungal strain of Stereum sp. OUPS-124D-1 attached to the marine alga Undaria pinnatifida. Dihydro-1,5-secovibralactone (4), a new vibralactone derivative, was isolated from the same fungal metabolites together with known vibralactone A (5), and 1,5-secovibralactone (6). The planar structures of these compounds have been elucidated by spectroscopic analyses using IR, HRFABMS, and NMR spectra. To determine the absolute configuration of the compounds, we used the phenylglycine methyl ester (PGME) method. These compounds exhibited less activity in the cytotoxicity assay against cancer cell lines.

Strepchazolins A and B: Two New Alkaloids from a Marine Streptomyces chartreusis NA02069

Two new alkaloids, strepchazolins A (1) and B (2), together with a previously reported compound, streptazolin (3), were isolated from a marine actinomycete, Streptomyces chartreusis NA02069, collected in the Coast of Hainan Island, China. The structures of new compounds were determined by extensive NMR, mass spectroscopic and X-ray crystallographic analysis, as well as modified Mosher’s method. Compound 1 showed weak anti-Bacillus subtilis activity with the MIC value of 64.0 μM, and weak inhibitory activity against acetylcholinesterase (AChE) in vitro with IC₅₀ value of 50.6 μM, while its diastereoisomer, Compound 2, is almost inactive.