Endophytic Fusarium solani: A rich source of cytotoxic and antimicrobial napthaquinone and aza-anthraquinone derivatives

Endophytic fungi: A future prospect for breast cancer therapeutics and drug development

Globally, breast cancer is a primary contributor to cancer-related fatalities and illnesses among women. Consequently, there is a pressing need for safe and effective treatments for breast cancer. Bioactive compounds from endophytic fungi that live in symbiosis with medicinal plants have garnered significant interest in pharmaceutical research due to their extensive chemical composition and prospective medicinal attributes. This review underscores the potentiality of fungal endophytes as a promising resource for the development of innovative anticancer agents specifically tailored for breast cancer therapy. The diversity of endophytic fungi residing in medicinal plants, success stories of key endophytic bioactive metabolites tested against breast cancer and the current progress with regards to in vivo studies and clinical trials on endophytic fungal metabolites in breast cancer research forms the underlying theme of this article. A thorough compilation of putative anticancer compounds sourced from endophytic fungi that have demonstrated therapeutic potential against breast cancer, spanning the period from 1990 to 2022, has been presented. This review article also outlines the latest trends in endophyte-based drug discovery, including the use of artificial intelligence, machine learning, multi-omics approaches, and high-throughput strategies. The challenges and future prospects associated with fungal endophytes as substitutive sources for developing anticancer drugs targeting breast cancer are also being highlighted.

New insights into the anti-inflammatory and anti-melanoma mechanisms of action of azelaic acid and other Fusarium solani metabolites via in vitro and in silico studies

Metabolites exploration of the ethyl acetate extract of Fusarium solani culture broth that was isolated from Euphorbia tirucalli root afforded five compounds; 4-hydroxybenzaldehyde (1), 4-hydroxybenzoic acid (2), tyrosol (3), azelaic acid (4), malic acid (5), and fusaric acid (6). Fungal extract as well as its metabolites were evaluated for their anti-inflammatory and anti-hyperpigmentation potential via in vitro cyclooxygenases and tyrosinase inhibition assays, respectively. Azelaic acid (4) exhibited powerful and selective COX-2 inhibition followed by fusaric acid (6) with IC50 values (2.21 ± 0.06 and 4.81 ± 0.14 μM, respectively). As well, azelaic acid (4) had the most impressive tyrosinase inhibitory effect with IC50 value of 8.75 ± 0.18 μM compared to kojic acid (IC50 = 9.27 ± 0.19 μM). Exclusive computational studies of azelaic acid and fusaric acid with COX-2 were in good accord with the in vitro results. Interestingly, this is the first time to investigate and report the potential of compounds 3-6 to inhibit cyclooxygenase enzymes. One of the most invasive forms of skin cancer is melanoma, a molecular docking study using a set of enzymes related to melanoma suggested pirin to be therapeutic target for azelaic acid and fusaric acid as a plausible mechanism for their anti-melanoma activity.

Utilization of Fusarium Solani lipase for enrichment of polyunsaturated Omega-3 fatty acids

Omega-3 fatty acids, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), offer numerous health benefits. Enriching these fatty acids in fish oil using cost-effective methods, like lipase application, has been studied extensively. This research aimed to investigate F. solani as a potential lipase producer and compare its efficacy in enhancing polyunsaturated omega-3 fatty acids with commercial lipases. Submerged fermentation with coconut oil yielded Lipase F2, showing remarkable activity (215.68 U/mL). Lipase F2 remained stable at pH 8.0 (activity: 93.84 U/mL) and active between 35 and 70 °C, with optimal stability at 35 °C. It exhibited resistance to various surfactants and ions, showing no cytotoxic activity in vitro, crucial for its application in the food and pharmaceutical industries. Lipase F2 efficiently enriched EPA and DHA in fish oil, reaching 22.1 mol% DHA and 23.8 mol% EPA. These results underscore the economic viability and efficacy of Lipase F2, a partially purified enzyme obtained using low-cost techniques, demonstrating remarkable stability and resistance to diverse conditions. Its performance was comparable to highly pure commercially available enzymes in omega-3 production. These findings highlight the potential of F. solani as a promising lipase source, offering opportunities for economically producing omega-3 and advancing biotechnological applications in the food and supplements industry.

Tapping into Tapajos: antibacterial potential of fungal strains isolated from decaying wood in the Brazilian Amazon

The emergence of bacterial resistance to antimicrobials poses a significant health threat. To address this issue, exploring the fungal diversity in freshwater environments in the Amazon Forest has potential in the search for new antimicrobials. This study aimed to investigate the production of antibacterial metabolites by aquatic fungi from Amazon lakes, specifically Lake Juá and Lake Maicá (Brazil-PA). The fungal isolates were obtained from wood fragments submerged in these lakes, and the ethyl acetate extracts were evaluated for antibacterial activity against Staphylococcus aureus ATCC 25923, S. aureus (MRSA), ATCC 43300, Escherichia coli ATCC 25922, and E. coli (ESBL) NCTC 13353. Additionally, toxicity of the extracts (EtOAc with antimicrobial activity) against human fibroblasts MRC-5 was investigated. The study identified 40 fungal strains with antimicrobial screening, and the ethyl acetate extracts of Fluviatispora C34, Helicascus C18, Monodictys C15, and Fusarium solani LM6281 exhibited antibacterial activity. F. solani LM6281 showed the lowest minimum inhibitory concentration (MIC) of 50 µg/mL against S. aureus strains and MIC of 100 µg/mL against E. coli strains including ESBL. The cytotoxicity (IC50) of the extract (EtOAc) of F. solani LM6281 was 34.5 µg/mL. Preliminary studies of the TLC culture and RNM-H from the extract (EtOAc) of F. solani suggested the presence of substances from the class of terpenes, quinones, phenolics, and flavonoids. This study highlights the potential of submerged wood fungi in the Amazon region to produce antibacterial substances, thus identifying them as sources of novel bioactive compounds with potential use in the pharmaceutical industry and regional bioeconomy.

A Review of the Chemistry and Biological Activities of Natural Colorants, Dyes, and Pigments: Challenges, and Opportunities for Food, Cosmetics, and Pharmaceutical Application

Natural pigments are important sources for the screening of bioactive lead compounds. This article reviewed the chemistry and therapeutic potentials of over 570 colored molecules from plants, fungi, bacteria, insects, algae, and marine sources. Moreover, related biological activities, advanced extraction, and identification approaches were reviewed. A variety of biological activities, including cytotoxicity against cancer cells, antioxidant, anti-inflammatory, wound healing, anti-microbial, antiviral, and anti-protozoal activities, have been reported for different pigments. Considering their structural backbone, they were classified as naphthoquinones, carotenoids, flavonoids, xanthones, anthocyanins, benzotropolones, alkaloids, terpenoids, isoprenoids, and non-isoprenoids. Alkaloid pigments were mostly isolated from bacteria and marine sources, while flavonoids were mostly found in plants and mushrooms. Colored quinones and xanthones were mostly extracted from plants and fungi, while colored polyketides and terpenoids are often found in marine sources and fungi. Carotenoids are mostly distributed among bacteria, followed by fungi and plants. The pigments isolated from insects have different structures, but among them, carotenoids and quinone/xanthone are the most important. Considering good manufacturing practices, the current permitted natural colorants are: Carotenoids (canthaxanthin, β-carotene, β-apo-8'-carotenal, annatto, astaxanthin) and their sources, lycopene, anthocyanins, betanin, chlorophyllins, spirulina extract, carmine and cochineal extract, henna, riboflavin, pyrogallol, logwood extract, guaiazulene, turmeric, and soy leghemoglobin.

Fusarium-Derived Secondary Metabolites with Antimicrobial Effects

Fungal microbes are important in the creation of new drugs, given their unique genetic and metabolic diversity. As one of the most commonly found fungi in nature, Fusarium spp. has been well regarded as a prolific source of secondary metabolites (SMs) with diverse chemical structures and a broad spectrum of biological properties. However, little information is available concerning their derived SMs with antimicrobial effects. By extensive literature search and data analysis, as many as 185 antimicrobial natural products as SMs had been discovered from Fusarium strains by the end of 2022. This review first provides a comprehensive analysis of these substances in terms of various antimicrobial effects, including antibacterial, antifungal, antiviral, and antiparasitic. Future prospects for the efficient discovery of new bioactive SMs from Fusarium strains are also proposed.

Exploring the biomedical competency of gamma-radiation aided hydroxyapatite and its composite fabricated with nano-cellulose and chitosan

The well-known biomaterial Ca-hydroxyapatite (Hap) in its pristine form holds the top ranking position in the field of biomedical research and extensive investigation is continuing across the globe to enhance its competency. Hence, having the intention to introduce superior physiognomies (e.g. cytotoxicity, haemocompatibility, and bioactivity coupled with antimicrobial and antioxidant activity) in Hap, in this research work, we exposed Hap to 200 kGy γ-radiation. As a result, γ-radiated Hap exhibited extreme antimicrobial (more than 98%) and moderate (∼34%) antioxidant properties. On the other hand, cytotoxicity and haemocompatibility of γ-radiated Hap were in good agreement with the ISO 10993-5 and ISO 10993-4 standards respectively. Since, bone and joint infections as well as degenerative disorders e.g. osteoarthritis, osteomyelitis, bone injury, and spinal problems have emerged as serious issues and urge a remedial way out, application of γ-radiated Hap could be a promising solution in this regard.

Anti-multidrug-resistant Staphylococcus aureus and anti-dermatophyte activities of secondary metabolites of the endophytic fungus Penicillium brevicompactum ANT13 associated with the Algerian endemic plant Abies numidica

This study aims to identify and assess the antimicrobial activity of endophytic fungi found in the endemic plant Abies numidica. Among all isolates, the ANT13 isolate demonstrated significant antimicrobial activity in the preliminary screening, particularly Staphylococcus aureus ATCC 25923 and Candida albicans ATCC 1024, with inhibition zones of 22 and 21.5 mm, respectively. Based on its morphological and molecular features, this isolate was identified as Penicillium brevicompactum. The maximum activity was observed in the ethyl acetate extract, followed by the dichloromethane extract; however, the n-hexane extract exhibited no activity. The ethyl acetate extract demonstrated very significant activity against the five strains of multidrug-resistant Staphylococcus aureus used, with average zones of inhibition ranging from 21 to 26 mm, in contrast to more resistant Enterococcus faecalis ATCC 49452 and Bacillus cereus ATCC 10876. The ethyl acetate extract was also very active against dermatophytes, where the zones of inhibition for Candida albicans, Microsporum canis, Trichophyton mentagrophytes, Trichophyton rubrum, and Epidermophyton floccosum were 23.5, 31, 43, 47, and 53.5 mm, respectively. The MIC values for dermatophytes ranged between 100 and 3200 µg/mL. The wild isolate of Penicillium brevicompactum ANT13 discovered as an endophyte in Abies numidica may be a distinctive source of novel compounds and drug discovery to trait dermatophytes and multidrug-resistant Staphylococcus aureus infections.

Chemical Profile and Biological Activities of Fungal Strains Isolated from Piper nigrum Roots: Experimental and Computational Approaches

The current report describes the chemical investigation and biological activity of extracts produced by three fungal strains Fusarium oxysporum, Penicillium simplicissimum, and Fusarium proliferatum isolated from the roots of Piper nigrum L. growing in Vietnam. These fungi were namely determined by morphological and DNA analyses. GC/MS identification revealed that the EtOAc extracts of these fungi were associated with the presence of saturated and unsaturated fatty acids. These EtOAc extracts showed cytotoxicity towards cancer cell lines HepG2, inhibited various microbacterial organisms, especially fungus Aspergillus niger and yeast Candida albicans (the MIC values of 50-100 μg/mL). In α-glucosidase inhibitory assay, they induced the IC₅₀ values of 1.00-2.53 μg/mL were better than positive control acarbose (169.80 μg/mL). The EtOAc extract of F. oxysporum also showed strong anti-inflammatory activity against NO production and PGE-2 level. Four major compounds linoleic acid (37.346 %), oleic acid (27.520 %), palmitic acid (25.547 %), and stearic acid (7.030 %) from the EtOAc extract of F. oxysporum were selective in molecular docking study, by which linoleic and oleic acids showed higher binding affinity towards α-glucosidase than palmitic and stearic acids. In subsequent docking assay with inducible nitric oxide synthase (iNOS), palmitic acid, oleic acid and linoleic acid could be moderate inhibitors.

The endophytic Fusarium strains: a treasure trove of natural products

The complexity and structural diversity of the secondary metabolites produced by endophytes make them an attractive source of natural products with novel structures that can help in treating life-changing diseases. The genus Fusarium is one of the most abundant endophytic fungal genera, comprising about 70 species characterized by extraordinary discrepancy in terms of genetics and ability to grow on a wide range of substrates, affecting not only their biology and interaction with their surrounding organisms, but also their secondary metabolism. Members of the genus Fusarium are a source of secondary metabolites with structural and chemical diversity and reported to exhibit diverse pharmacological activities. This comprehensive review focuses on the secondary metabolites isolated from different endophytic Fusarium species along with their various biological activities, reported in the period from April 1999 to April 2022.

Overview of Bioactive Fungal Secondary Metabolites: Cytotoxic and Antimicrobial Compounds

Microorganisms are known as important sources of natural compounds that have been studied and applied for different purposes in distinct areas. Specifically, in the pharmaceutical area, fungi have been explored mainly as sources of antibiotics, antiviral, anti-inflammatory, enzyme inhibitors, hypercholesteremic, antineoplastic/antitumor, immunomodulators, and immunosuppressants agents. However, historically, the high demand for new antimicrobial and antitumor agents has not been sufficiently attended by the drug discovery process, highlighting the relevance of intensifying studies to reach sustainable employment of the huge world biodiversity, including the microorganisms. Therefore, this review describes the main approaches and tools applied in the search for bioactive secondary metabolites, as well as presents several examples of compounds produced by different fungi species with proven pharmacological effects and additional examples of fungal cytotoxic and antimicrobial molecules. The review does not cover all fungal secondary metabolites already described; however, it presents some reports that can be useful at any phase of the drug discovery process, mainly for pharmaceutical applications.

Culturable endophytic fungal assemblages from Styrax sumatrana and Stryax benzoin and their potential as antifungal, antioxidant, and alpha-glucosidase inhibitory resources

Benzoin resin, produced by the native Indonesian trees Styrax sumatrana and Styrax benzoin, has been incorporated into medical practices to treat wounds, erythema, and many other conditions for centuries. Endophytic fungi that reside within medicinal plants have antimicrobial, antioxidant, and α-glucosidase inhibitory capacities, contributing to plant health and derivative products. In this study, we determined the antifungal, antioxidant, and α-glucosidase inhibitory capacities of endophytic fungal isolates from three different tissues (leaves, bark, and stems) of S. sumatrana and S. benzoin trees. The genera of fungal isolates were determined by phylogenetic analysis of internal transcribed spacer sequences. A total of 58 fungal isolates were classified into 15 different fungal genera from eight taxonomic orders—Hypocreales, Botryosphaeriales, Glomerellales, Diaphortales, Pleosporales, Eurotiales, Xylariales, and Mucorales—with a pattern of host species specificity. Among these isolates, Trichoderma sp. 6407 consistently exhibited high inhibition of the growth of plant pathogens Fusarium sp., Trichoderma viride, and Aspergillus niger. With respect to antioxidant activity, Phyllosticta sp. 6454 consistently showed 2,2-diphenyl-1-picrylhydrazyl inhibition (37.59 ± 0.05%), 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid)-based antioxidant activity (25.04 ± 0.27 mgTE/g), and α-glucosidase inhibitory activity (52.15 ± 10.08%). Neopestalotiopsis sp. 6431 was notably potent in 2,2-diphenyl-1-picrylhydrazyl inhibition (49.65 ± 0.80%), ferric reducing antioxidant power-based antioxidant activity (197.49 ± 8.65 mgTE/g), and α-glucosidase inhibitory activity (52.88 ± 4.93%). This study revealed that Trichoderma sp. 6407, Phyllosticta sp. 6454, and Neopestalotiopsis sp. 6431 exhibited antifungal, antioxidant, and α-glucosidase inhibitory activities.

Isolation and Identification of Endophytic Fungi from Syzygium cumini Linn and Investigation of Their Pharmacological Activities

This study was conducted to isolate and identify the endophytic fungi from the bark and leaves of the Syzygum cumini plant and investigate the pharmacological activities of endophytic fungi along with plant parts. After isolation, endophytic fungi were identified based on morphological characteristics and molecular identification. Antimicrobial, antioxidant, and cytotoxic activities were studied by a disc diffusion method, free radical scavenging DPPH assay, and brine shrimp lethality bioassay, respectively. A total of eight endophytic fungi were isolated and identified up to the genus level based on morphological characteristics and confirmed by molecular identification techniques. Among the eight isolates, three isolates were identified as Colletotrichum sp. (SCBE-2, SCBE-7, and SCLE-9), while the rest of the isolates belonged to Diaporthe sp. (SCBE-1), Pestalotiopsis sp. (SCBE-3), Penicillium sp. (SCBE-4), Phyllosistica sp. (SCLE-7), and Fusarium sp. (SCLE-8). The presence of flavonoids, anthraquinones, coumarins, and isocoumarins was assumed by the preliminary screening of the fungal and plant extracts by a thin-layer chromatographic technique under UV light. Fungal extracts of Pestalotiopsis sp. Penicillium sp. were found sensitive to all test bacteria, but only extracts from the leaf and bark showed significant antifungal activity along with their antimicrobial activity. Penicillium sp. The fungal extract showed the highest free radical scavenging activity (2.43 μg/mL) near that of ascorbic acid (2.42 μg/mL). Some fungal extracts showed cytotoxic activity that, in general, suggests their probable abundance of biological metabolites. This is the first approach to investigate the endophytic fungi of Syzygium cumini Linn. in Bangladesh, to find the pharmacological potential of endophytes, and to explore novel compounds from those endophytes.

Metabolites of medicine food homology-derived endophytic fungi and their activities

Medicine food homology (MFH) substances not only provide essential nutrients as food but also have corresponding factors that can prevent and help treat nutritional imbalances, chronic disease, and other related issues. Endophytic fungi associated with plants have potential for use in drug discovery and food therapy. However, the endophytic fungal metabolites from MFH plants and their effects have been overlooked. Therefore, this review focuses on the various biological activities of 108 new metabolites isolated from 53 MFH-derived endophytic fungi. The paper explores the potential nutritional and medicinal value of metabolites of MFH-derived endophytic fungi for food and medical applications. This research is important for the future development of effective, safe, and nontoxic therapeutic nutraceuticals for the prevention and treatment of human diseases.

Synthesis and biological activity, and molecular modelling studies of potent cytotoxic podophyllotoxin-naphthoquinone compounds

A new approach for the synthesis of podophyllotoxin-naphthoquinone compounds using microwave-assisted three-component reactions is reported in this study. Novel podophyllotoxin-naphthoquinone derivatives with modification on ring E were synthesized. All the synthetic compounds were assessed in terms of their cytotoxicity profile against four cancer cell lines (KB, HepG2, A549, and MCF7), and noncancerous Hek-293 cell lines. Notably, treatment of SK-LU-1 cells with compounds 5a and 5b resulted in G2/M phase arrest of the cell cycle, caspase-3/7 activation, and apoptosis. Additionally, molecular docking studies were performed and showed important interaction of two compounds against residues in the colchicine-binding-site of tubulin as well. Taken together, compounds 5a and 5b were identified as potent anticancer agents.

A new approach for the synthesis of podophyllotoxin-naphthoquinone compounds using microwave-assisted three-component reactions is reported in this study.

Endophytic fungi and their bioactive secondary metabolites in medicinal leguminosae plants: Nearly untapped medical resources

There are many species of Chinese traditional leguminosae family plants that are well known for their medicinal applications, such as Astragalus membranaceus, Catsia tora, Glycyrrhiza uralensis, Sophora flavescens and Albacia acacia. Their unique bioactive composition and internal phenological environment contribute to the formation of specific and unique endophytic fungal communities, which are important resources for new compounds used in a variety of pharmacological activities. Nonetheless, they have not been systematically studied. In the last decade, nearly 64 genera and thousands of species of endophytic fungi have been discovered from leguminosae plants, as well as 138 secondary metabolites (with 34 new compounds) including flavonoid, alkaloids, phenol, anthraquinone, macrolide, terpenoid, phytohormone and many more. They were shown to have diverse applications and benefits, such as antibacterial, antitumor, antioxidative, immunoregulatory and neuroprotective properties. Here, we provide a summarized overview with the aim of raising awareness of endophytic fungi from medicinal leguminosae plants and providing a comprehensive review of the discoveries of new natural products that may be of medicinal and pharmaceutical importance.

Production of a Polyketide Pigment by Fusarium chlamydosporum

The present study was focused to study the production of secondary metabolite by the fungus, F. chlamydosporum on a non-defined medium with less concentration of nitrogen; the organic nitrogen source being peptone and beef extract. In this context, we have been successful in extracting a polyketide pigment from the fungus by using the homogenization technique. The pigments thus extracted were subjected to various purification techniques via thin layer chromatography, column chromatography, UV-visible spectrophotometry, fourier-transform infrared spectroscopy and finally molecular determination by liquid chromatography coupled to tandem quadrupole mass spectrometry (LC-MS-MS). The polyketide red pigment was finally characterized and identified to be fusarubin following which its cytotoxicity was evaluated in vitro by using normal lung fibroblast cell lines (MRC-5). In the verge of researchers identifying novel compounds for various applications, the production of fusarubin by the fungus can be a major breakthrough as fusarubin has been investigated to exhibit many pharmacological activities. Though fusarubin is reported to be produced by other Fusarium species, this is the foremost study on the production of fusarubin by F. chlamydosporum; the composition of the culture medium is also unique. The production of this polyketide probably correlates in the pathogenesis of F. chlamydosporum as studies comment on this fungus as an opportunistic pathogen.

Endophytism of Fusarium Solani in Meristems of Delonix Regia (Bojer ex Hook.) Raf

A bright yellow pigment-producing endophytic fungus strain GMRS1 was isolated from the meristems of Delonix regia (Bojer ex Hook.) Raf. The fungus was identified as Fusarium solani on grounds of morphological and molecular analysis. The chemical composition of the crude pigments was partially analyzed by Quadrupole Time-of-flight Liquid chromatography/Mass spectrometry/Mass spectrometry and the major compounds were reported. The crude pigments were proved toxic and unsafe by acute oral toxicity study on Wistar rats. The total cholesterol and glucose levels of the rats ingested with crude pigments were significantly elevated than the control rats. The treatment rats were further observed with damaged liver and kidney tissues. The LD₅₀ value of the crude pigments was higher than 1000 mg/kg of body weight.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s12088-021-00968-w.

Physicochemical, Pharmacokinetic and Cytotoxicity of the Compounds Isolated from an Endophyte Fusarium oxysporum: In Vitro and In Silico Approaches

The present study was intended to characterize the secondary metabolites of the endophyte Fusarium oxysporum isolated from the plant Aglaonema hookerianum Schott. And to investigate the cytotoxic and other pharmacological properties of the isolated compounds as part of the drug discovery and development process. Different chromatographic techniques were adopted to isolate the bioactive compounds that were identified by spectroscopic techniques. The cytotoxic properties of the compounds were assessed in the Vero cell line via the trypan blue method. Moreover, physicochemical, pharmacokinetic, bioactivity and toxicity profiles of the compounds were also investigated through in silico approaches. After careful spectral analysis, the isolated compounds were identified as 3β,5α-dihydroxy-ergosta-7,22-dien-6-one (1), 3β,5α,9α-trihydroxy-ergosta-7,22-dien-6-one (2), p-hydroxybenzaldehyde (3), 3-(R)-7-butyl-6,8-dihydroxy-3-pent-11-enylisochroman-1-one (4) and beauvericin (5). An in vitro study in the Vero cell line revealed that the presence of the compounds reduced the number of cells, as well as the percentage of viable cells, in most cases. An in silico cytotoxic analysis revealed that compounds 1, 2 and 5 might be explored as cytotoxic agents. Moreover, compounds 3 and 4 were found to be highly mutagenic. The present study suggested that further thorough investigations are necessary to use these molecules as leads for the cytotoxic drug development process.

Endophytic Fungi: An Effective Alternative Source of Plant-Derived Bioactive Compounds for Pharmacological Studies

Plant-associated fungi (endophytic fungi) are a biodiversity-rich group of microorganisms that are normally found asymptomatically within plant tissues or in the intercellular spaces. Endophytic fungi promote the growth of host plants by directly producing secondary metabolites, which enhances the plant's resistance to biotic and abiotic stresses. Additionally, they are capable of biosynthesizing medically important "phytochemicals" that were initially thought to be produced only by the host plant. In this review, we summarized some compounds from endophyte fungi with novel structures and diverse biological activities published between 2011 and 2021, with a focus on the origin of endophytic fungi, the structural and biological activity of the compounds they produce, and special attention paid to the exploration of pharmacological activities and mechanisms of action of certain compounds. This review revealed that endophytic fungi had high potential to be harnessed as an alternative source of secondary metabolites for pharmacological studies.

Putative Anticancer Compounds from Plant-Derived Endophytic Fungi: A Review

Endophytic fungi are microorganisms that exist almost ubiquitously inside the various tissues of living plants where they act as an important reservoir of diverse bioactive compounds. Recently, endophytic fungi have drawn tremendous attention from researchers; their isolation, culture, purification, and characterization have revealed the presence of around 200 important and diverse compounds including anticancer agents, antibiotics, antifungals, antivirals, immunosuppressants, and antimycotics. Many of these anticancer compounds, such as paclitaxel, camptothecin, vinblastine, vincristine, podophyllotoxin, and their derivatives, are currently being used clinically for the treatment of various cancers (e.g., ovarian, breast, prostate, lung cancers, and leukemias). By increasing the yield of specific compounds with genetic engineering and other biotechnologies, endophytic fungi could be a promising, prolific source of anticancer drugs. In the future, compounds derived from endophytic fungi could increase treatment availability and cost effectiveness. This comprehensive review includes the putative anticancer compounds from plant-derived endophytic fungi discovered from 1990 to 2020 with their source endophytic fungi and host plants as well as their antitumor activity against various cell lines.

Functional characterization of culturable fungi from microbiomes of the "conical cobs" Mexican maize (Zea mays L.) landrace

Mexican maize landraces, produced for local consumption, are adapted to different environmental conditions, and their yield is affected by abiotic and biotic factors, including the use of agrochemicals. The search for sustainable alternatives to agrochemicals includes the study of the culturable microbial communities. In this study, the fungal communities associated with 2 Mexican maize landraces reddish and bluish "conical cobs" were found to be comprised of Ascomycota fungi, represented by 89 strains within 6 orders (Pleosporales, Hypocreales, Onygenales, Capnodiales, Helotiales, and Eurotiales) and 16 genera. Cellulases and metallophores production were the primary enzymatic products and plant growth-promoting activities were detected among the isolates. Penicillium, Didymella, and Fusarium strains had the most active enzymatic and plant growth promoting activities, however, Aspergillus sp. HES2-2.2, Talaromyces sp. RS1-7, and Penicillium sp. HFS3-3 showed antagonistic activity against the four phytopathogenic Fusarium strains Fusarium oxysporum, Fusarium sambucinum, Fusarium fujikuroi and Fusarium incarnatum-equiseti and also a high and diverse production of enzymatic and plant growth promoting activities; here we identified fungal strains as candidates to promote maize growth.

Production and Selectivity of Key Fusarubins from Fusarium solani due to Media Composition

Natural products display a large structural variation and different uses within a broad spectrum of industries. In this study, we investigate the influence of carbohydrates and nitrogen sources on the production and selectivity of production of four different polyketides produced by Fusarium solani, fusarubin, javanicin, bostrycoidin and anhydrofusarubin. We introduce four different carbohydrates and two types of nitrogen sources. Hereafter, a full factorial design was applied using combinations of three levels of sucrose and three levels of the two types of nitrogen. Each combination displayed different selectivity and production yields for all the compounds of interest. Response surface design was utilized to investigate possible maximum yields for the surrounding combinations of media. It was also shown that the maximum yields were not always the ones illustrating high selectivity, which is an important factor for making purification steps easier. We visualized the production over time for one of the media types, illustrating high yields and selectivity.

Fusarium solani G6, a novel vitexin-producing endophytic fungus: characterization, yield improvement and osteoblastic proliferation activity

The study aimed to characterize a novel vitexin-producing endophytic fungus Fusarium solani G6 from Cajanus cajan, improve its capability for producing vitexin and evaluate its osteoblastic proliferation activity. A total of 153 endophytic fungi, classified into 6 genera, were isolated from C. cajan. Among them, only one strain, endophyte G6 identified as Fusarium solani, was found to produce vitexin. After the optimization of fermentation conditions, the highest vitexin yield (18.72 mg/L) for the strain was observed in PDB liquid medium containing 20.54 g/L of glucose and 8.90 g/L of ammonium sulfate, at an initial medium pH of 5.1 and at 28 °C for 6 days of cultivation. Moreover, the fungal vitexin exhibited notable osteoblastic proliferation stimulating activity. A novel vitexin-producing endophytic fungus F. solani G6 was characterized from C. cajan for the first time. The findings highlighted its potential use for large-scale production of vitexin and might have a promising use as therapeutic agent for osteoporosis.

Bioprospecting of endophytic microorganisms for bioactive compounds of therapeutic importance

Presently, several drug discovery investigations on therapeutic management of human health are aimed at bioprospecting for microorganisms, especially endophytic microbes of biotechnological importance. This review investigates the benefits of endophytes, especially in producing bioactive compounds useful in modern medicine by systematically reviewing published data from 12 databases. Only experimental studies investigating either or both bacterial and fungal endophytes and within the scope of this review were selected. The published data from the last 2 decades (2000-2019) revealed diverse endophytes associated with different plants produce a broad spectrum of bioactive compounds with therapeutic benefits. Notably, antibacterial, followed by anticancer and antifungal activities, were mostly reported. Only three studies investigated the anti-plasmodial activity. The variation observed in the synthesis of bioactive compounds amongst endophytes varied with host type, endophyte species, and cultivation medium. Fungal endophytes were more investigated than bacterial endophytes, with both endophytes having species diversity amongst literature. The endophytes were predominantly from medicinal plants and belonged to either Ascomycota (fungi) or Proteobacteria and Firmicutes (bacteria). This review presents excellent prospects of harnessing endophytes and their unique bioactive compounds in developing novel and effective compounds of medicinal importance.

UV-assisted synthesis of hydroxyapatite from eggshells at ambient temperature: cytotoxicity, drug delivery and bioactivity

Hydroxyapatite [Ca10(PO4)6(OH)2], an important biomaterial, retains a chemical structure that is similar to the mineral phase of bone. Consequently, the ability of hydroxyapatite (Hap) to augment bone growth within bone tissue has made it a potential candidate for use as a hard tissue-implant material. In this work, adopting a UV-mediated solid-state method for the first time, hydroxyapatite was synthesized from eggshells and no thermal treatment was used but ambient temperature was maintained. This simple synthesis process involved a combination of ball milling of the starting materials followed by UV-irradiation. UV-excitation of the Ca and P precursors resulted in the desired Hap and X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) and Raman spectroscopic techniques were used for characterization. The potency of UV-Hap as a biomaterial was examined via the bioactivity, cytotoxicity and the drug (ciprofloxacin) loading-releasing response, which was encouraging. The results of the cell viability assays complied an insignificant cytotoxicity and the simulated body fluid immersion test indicated the bioactivity was within the acceptable range. On the other hand, to better understanding the drug ejection and associated transport phenomenon, two kinetic models (Higuchi and Ritger-Peppas models) were used and a diffusion controlled ciprofloxacin release mechanism was observed using the Higuchi model. However, the experimental outcomes of a drug delivery response exposed UV-Hap as a favorable vehicle for drug loading and release. Hence, this research highlights the prospects of a UV-assisted synthesis method as a green route for the synthesis of Hap to be applied in biomedical fields.

Cytotoxic metabolites from Thysanolaena maxima Roxb. available in Bangladesh

Background

Thysanolaena maxima (Roxb.) Kuntze, a perennial grass plant, is usually distributed in hilly regions of the Indian Subcontinent. Different parts of T. maxima have been used as herbal medicine by traditional healers of this region. In this present study, T. maxima plant extract has been screened for examination of its secondary metabolite content with their probable cytotoxic activity.

Methods

Secondary metabolites of the crude T. maxima plant extract were isolated by different chromatographic methods. The structures were elucidated by spectroscopic data (1H NMR, 13C NMR) as well as comparison with available literature sources. Antiradical activity by DPPH radical scavenging assay and antimicrobial activity by disc diffusion method of the fractions and cytotoxic activity by trypan blue exclusion method of the isolated compounds were also evaluated.

Results

Three phenolic compounds 4-hydroxybenzaldehyde (1), 4-hydroxycinnamic acid (2), 4-hydroxybenzoic acid (3) and two steroids stigmast-4-en-3-one (4) and β-stigmasterol (5) were isolated from the aerial part of T. maxima. Among the compounds 4-hydroxycinnamic acid, 4-hydroxybenzoic acid and stigmast-4-en-3-one exhibited notable cytotoxic activity against African Green Monkey Kidney Cell line (Vero cell).

Conclusion

Bioassay investigation of the isolated compounds and fractions suggested that T. maxima could be a potential source of bioactive secondary metabolites.

Graphical abstract

Fungal Bioactive Anthraquinones and Analogues

This review, covering the literature from 1966 to the present (2020), describes naturally occurring fungal bioactive anthraquinones and analogues biosynthesized by the acetate route and concerning several different functionalized carbon skeletons. Hydrocarbons, lipids, sterols, esters, fatty acids, derivatives of amino acids, and aromatic compounds are metabolites belonging to other different classes of natural compounds and are generated by the same biosynthetic route. All of them are produced by plant, microorganisms, and marine organisms. The biological activities of anthraquinones and analogues comprise phytotoxic, antibacterial, antiviral, anticancer, antitumor, algicide, antifungal, enzyme inhibiting, immunostimulant, antiplatelet aggregation, cytotoxic, and antiplasmodium activities. The review also covers some practical industrial applications of anthraquinones.

Soil Saprobic Fungi Differ in Their Response to Gradually and Abruptly Delivered Copper

The overwhelming majority of studies examining environmental change deliver treatments abruptly, although, in fact, many important changes are gradual. One example of a gradually increasing environmental stressor is heavy metal contamination. Essential heavy metals, such as copper, play an important role within cells of living organisms but are toxic at higher concentrations. In our study, we focus on the effects of copper pollution on filamentous soil fungi, key players in terrestrial ecosystem functioning. We hypothesize that fungi exposed to gradually increasing copper concentrations have higher chances for physiological acclimation and will maintain biomass production and accumulate less copper, compared to fungi abruptly exposed to the highest copper concentration. To test this hypothesis, we conducted an experiment with 17 fungal isolates exposed to gradual and abrupt copper addition. Contrary to our hypothesis, we find diverse idiosyncratic responses, such that for many fungi gradually increasing copper concentrations have more severe effects (stronger growth inhibition and higher copper accumulation) than an abrupt increase. While a number of environmental change studies have accumulated evidence based on the magnitude of changes, the results of our study imply that the rate of change can be an important factor to consider in future studies in ecology, environmental science, and environmental management.

Pigment production by Fusarium solani BRM054066 and determination of antioxidant and anti-inflammatory properties

The fungal kingdom has been widely studied as a source of bioactive compounds of interest to the pharmaceutical and food industry. This paper studies the production of natural red pigments by Fusarium solani BRM054066 in the submerged fermentation system, using Doehlert experimental design to determine optimal cultivation conditions. The chemical composition of the red pigment was determined by Nuclear Magnetic Resonance spectroscopy (NMR) and Ultra-Performance Liquid Chromatography coupled to Mass Spectrometry (UPLC-MS). Antioxidant activity was assessed by the ability to sequester of free radical DPPH. In the analysis of anti-inflammatory activity, murine peritoneal macrophages activated by LPS were used, and the gene expression of TNF-α, IL-1β, IL-6, IL-10 and IL-17 was determined using qPCR. As a result, it was found that agitation at 200 rpm and glucose concentration ≥ 20 g/L promote the best results in the production of red pigment. The chemical compounds identified were two naphthoquinones, fusarubin and dihydrofusarubin, and an anthraquinone, a bostrycoidin, being fusarubin the majority compound. The red pigment showed antioxidant activity by scavenge 50% of the DPPH radical, in a concentration of 24 µg/mL. The pigment also showed an effective anti-inflammatory capacity by reducing the overexpression of the pro-inflammatory cytokines TNF-α, IL-1β and IL-6 and promoting the production of anti-inflammatory IL-10 and IL-17, in murine macrophages activated by LPS (p < 0.05). According to the results, the fungus F. solani BRM054066, under optimized conditions of cultivation, proved to be a promising source of biologically active natural pigments with wide industrial applicability.

Neuroprotective γ-Pyrones from Fusarium Solani JS-0169: Cell-Based Identification of Active Compounds and an Informatics Approach to Predict the Mechanism of Action

Glutamate toxicity has been implicated in neuronal cell death in both acute CNS injury and in chronic diseases. In our search for neuroprotective agents obtained from natural sources that inhibit glutamate toxicity, an endophytic fungus, Fusarium solani JS-0169 isolated from the leaves of Morus alba, was found to show potent inhibitory activity. Chemical investigation of the cultures of the fungus JS-0169 afforded isolation of six compounds, including one new γ-pyrone (1), a known γ-pyrone, fusarester D (2), and four known naphthoquinones: karuquinone B (3), javanicin (4), solaniol (5), and fusarubin (6). To identify the protective effects of the isolated compounds (1–6), we assessed their inhibitory effect against glutamate-induced cytotoxicity in HT22 cells. Among the isolates, compound 6 showed significant neuroprotective activity on glutamate-mediated HT22 cell death. In addition, the informatics approach using in silico systems pharmacology identified that compound 6 may exert its neuroprotective effect by controlling the amount of ubiquinone. The results suggest that the metabolites produced by the endophyte Fusarium solani JS-0169 might be related to the neuroprotective activity of its host plant, M. alba.

Bioprospecting endophytic fungi from Fusarium genus as sources of bioactive metabolites

Endophytic fungi became an attractive source for the discovery of new leads, because of the complexity and the structural diversity of their secondary metabolites. The genus Fusarium comprising about 70 species is extremely variable in terms of genetics, biology, ecology, and consequently, secondary metabolism and have been isolated from countless plants genera from diverse habitats. These endophytic microbes may provide protection and survival strategies in their host plants with production of a repertoire of chemically diverse and structurally unprecedented secondary metabolites reported to exhibit an incredible array of biological activities including antimicrobial, anticancer, antiviral, antioxidants, antiparasitics, immunosuppressants, immunomodulatory, antithrombotic, and biocontrol ability against plants pathogens and nematodes. This review comprehensively highlights over the period 1981-2019, the bioactive potential of metabolites produced by endophytes from Fusarium genus. Abbreviations: AIDS: Acquired immune deficiency syndrome; BAPT: C-13 phenylpropanoid side chain-CoA acyltransferase; CaBr2: Calcium bromide; DBAT: 10-deacetylbaccatin III-10-O-acetyl transferase; DNA: Deoxyribonucleic acid; EI-MS: Electron ionization mass spectrometer; EN: Enniatin; ERK: Extracellular regulated protein kinase; EtOAc: Ethyl acetate; FDA: Food and Drug Administration; GAE/g: Gallic acid equivalent per gram; GC-MS: Gas chromatography-mass spectrometry; HA: Hyperactivation; HCV: Hepatitis C Virus; HCVPR: Hepatitis C Virus protease; HeLa: Human cervical cancer cell line; HIV: Human immunodeficiency viruses; HPLC: High Performance Liquid Chromatography; IAA: Indole-3-acetic acid; IARC: International Agency for Research on Cancer; IC50: Half maximal inhibitory concentration; LC50: Concentration of the compound that is lethal for 50% of exposed population; LC-MS: Liquid chromatography-mass spectrometry; MCF-7: Human breast cancer cell line; MDR: Multidrug-resistant; MDRSA: Multidrug-resistant S. aureus; MFC: Minimum fungicidal concentration; MIC: Minimum inhibitory concentration; MRSA: Multidrug-resistant S. aureus; MTCC: Microbial type culture collection; PBMCs: Peripheral blood mononuclear cells; PCR: Polymerase chain reaction; TB: Tuberculosis; TLC: Thin layer chromatography; TNF: Tumor necrosis factor; WHO: World Health Organization http://www.zoobank.org/urn:lsid:zoobank.org:pub:D0A7B2D8-5952-436D-85C8-C79EAAD1013C.

Fusaproliferin, a Fungal Mycotoxin, Shows Cytotoxicity against Pancreatic Cancer Cell Lines

As a part of our ongoing research on endophytic fungi, we have isolated a sesterterpene mycotoxin, fusaproliferin (FUS), from a Fusarium solani strain, which is associated with the plant Aglaonema hookerianum Schott. FUS showed rapid and sub-micromolar IC₅₀ against pancreatic cancer cell lines. Time-dependent survival analysis and microscopy imaging showed rapid morphological changes in cancer cell lines 4 h after incubation with FUS. This provides a new chemical scaffold that can be further developed to obtain more potent synthetic agents against pancreatic cancer.