Marine Endophytic Fungus Research Articles

Evaluation of high-value bioproducts production by marine endophytic fungus Arthrinium sp. FAKSA 10 under solid state fermentation using agro-industrial wastes

BackgroundTo address public health challenges, there is increasing interest in bioactive metabolites from unconventional sources for targeted cancer and viral treatments with minimal side effects. Endophytic fungi are promising for these therapies. This study focused on maximizing bioactive agent yields from these fungi using a low-cost medium and optimized fermentation system. ResultsForty-three endophytic fungi isolated from Sinularia polydactyla were cultivated on wheat bran medium and evaluated for bioactive metabolites under solid-state fermentation. Strain FAKSA 10, identified as Arthrinium sp. FAKSA 10, exhibited the highest levels of pharmaceutical metabolites, including L-glutaminase, L-methioninase, L-arginase, L-asparaginase, L-tyrosinase, L-lysine α-oxidase, and ribonuclease, with a 79.12% hepatitis C virus knockdown rate. This strain produced 46 metabolites with anticancer, antioxidant, antiviral, and cytotoxic properties, including major compounds like hexadecanoic acid methyl ester; hexadecanoic acid ethyl ester; 9, 12-octadecadienoic acid (Z, Z), methyl ester; 9-octadecenoic acid (Z)-, methyl ester, and 11, 14-eicosadienoic acid, methyl ester. A cost effective strategy using 11 agro-industrial residues was applied, following by optimization of the solid-state fermentation system. This optimization increased enzyme yields and enhanced antiviral and antioxidant activities. The optimal conditions for solid-state fermentation were a 10 d incubation, 1 mm particle size, 60% initial moisture, 28°C temperature, and 2 × 107 CFU/mL inoculum size. ConclusionsThis study exploited Arthrinium sp. FAKSA 10 metabolites as natural pharmaceuticals against cancer and viral diseases, highlighting their significant antioxidant properties. Among various residues, oil cakes emerged as an effective and cost-efficient medium, capable of significantly enhancing the production of valuable bioactive metabolites.

Bioactivity and chemical screening of endophytic fungi associated with the seaweed Ulva sp. of the Bay of Bengal, Bangladesh

Abstract Several studies have shown that endophytic fungal metabolites possess vital biological activities; nevertheless, there is a lack of knowledge regarding the medicinally important marine endophytic fungi associated with the seaweeds mainly found in the Bay of Bengal, Bangladesh. In this study, six endophytic fungi, belonging to five genera and four classes, were isolated from the well-known chlorophyte, Ulva sp. and were most closely related to Chaetomium globosum, Nigrospora magnoliae, Curvularia sp., Curvularia moringae, Aspergillus terreus and Collariella sp. This is the first report of these fungi as endophytes associated with Ulva sp. from the Bay of Bengal, Bangladesh. A preliminary biological evaluation of the ethyl acetate extract of each endophytic fungal crude extract was the prime objective of this research, e.g., antimicrobial assay, 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity and brine shrimp lethality bioassay. Evaluation of test results revealed that each fungal crude extract possessed one or more relevant biological activities. Preliminary chemical screening using TLC and NMR spectroscopic analysis revealed the presence of several secondary metabolites in the crude fungal extracts. These findings suggest that the marine endophytic fungus may be a valuable source for investigating potentially bioactive chemicals or leads for novel drug candidates.

Improved Chrysin Production by a Combination of Fermentation Factors and Elicitation from Chaetomium globosum.

Flavonoids encompass a heterogeneous group of secondary metabolites with exceptional health benefits. Chrysin, a natural dihydroxyflavone, possesses numerous bioactive properties, such as anticancer, antioxidative, antidiabetic, anti-inflammatory, etc. However, using traditional sources of chrysin involves extracting honey from plants, which is non-scalable, unsustainable, and depends on several factors, including geography, climatic conditions, and the season, which limits its production at a larger scale. Recently, microbial production of desirable metabolites has garnered attention due to the cost-effectiveness, easy scale-up, sustainability, and low emission of waste. We previously reported for the first time the chrysin-producing marine endophytic fungus Chaetomium globosum, associated with a marine green alga. To extend our understanding of chrysin biosynthesis in C. globosum, in the present study, we have assessed the presence of flavonoid pathway intermediates in C. globosum extracts using LC-MS/MS. The presence of several key metabolites, such as dihydrokaempferol, chalcone, galangin, baicalein, chrysin, p-Coumaroyl-CoA, and p-Cinnamoyl-CoA, indicates the role of flavonoid biosynthesis machinery in the marine fungus. Further, we have aimed to enhance the production of chrysin with three different strategies: (1) optimizing the fermentation parameters, namely, growth medium, incubation time, pH, and temperature; (2) feeding key flavonoid pathway intermediates, i.e., phenylalanine and cinnamic acid; (3) elicitation with biotic elicitors, such as polysaccharide, yeast extract, and abiotic elicitors that include UV radiation, salinity, and metal stress. The combined effect of the optimized parameters resulted in a 97-fold increase in the chrysin yield, resulting in a fungal cell factory. This work reports the first approach for enhanced production of chrysin and can serve as a template for flavonoid production enhancement using marine endophytic fungi.

NATURAL BIOACTIVE PRODUCT OF ENDOPHYTIC FUNGI FROM VARIOUS MARINE SOURCES - A NOVELAPPROACH

Worldwide, ailments like cancer and infections are growing widespread, producing an urgent demand for new constructive compounds with different modes of action that may be used to combat these dreadful conditions. Endophytic fungi represent an source of great biodiversity for isolation of effective novel natural products for medical, agricultural, and industrial applications. Microorganisms associated with marine endophytic fungus by inter and intracellularly in marine source investigated (including algae, seagrass, driftwood, and mangrove plants), marine vertebrate (mainly sh), and marine invertebrate ( sponges and coral). The specialized techniques of interaction evolved from the evolution of bacteria and eukaryotes to a greater level of complexity, as a consequence of their co-evolution with one another. The organism produce compounds that have anticancer, antiviral, anti-neuro-degenerative, antimicrobial, antioxidant, and immuno-suppressive. Furthermore, fungal endophytes possess a wide range of biological capabilities used in environmental and agricultural sustainability, among other things. Novel lead compounds must be discovered to progress in the creation of new pharmaceuticals. The ability of endophytes to produce bioactive metabolites widely investigated over the past decade. The current level of research on endophytes from a range of situations from 2000 to 2022, emphasizing metabolites discovered in endophytic plants.Our research will help to accelerate the development of new treatments for a broad spectrum of human ailments for future research and development.

Culture medium from a marine endophytic fungus protects shrimp against acute hepatopancreatic necrosis disease (AHPND)

Because endophytic fungi are widely known for producing secondary metabolites and bioactive compounds, they are of interest to pharmaceutical and biotechnology industries. Many species are found in mangrove forests that are habitats for marine animals, especially in their early life stages. In this research, we screened 42 endophytic fungi originating from Thai mangrove forests for inhibitors of biofilm and planktonic cell growth of 7 Vibrio isolates. Some of these isolates were collected from shrimp ponds exhibiting early mortality syndrome (EMS) and diagnosed as outbreaks of acute hepatopancreatic necrosis disease (AHPND) that is caused by specific isolates of Vibrio parahaemolyticus (VPAHPND). Cell-free supernatants (CFS) of two fungal isolates (MCR433 and MCR 440) that inhibited biofilm growth for at least 5 out of the 7 Vibrio isolates were chosen for further study in shrimp feeding trials. One (MCR433) had strong biofilm inhibition and the other (MCR 440) weak biofilm inhibition for VPAHPND. Feed supplementation with CFS of MCR 433 protected shrimp against AHPND (72% mean survival) when compared to control shrimp given un-supplemented feed (20% mean survival) or given feed supplemented with CFS of MCR 440 (0% survival). Histological analysis of the hepatopancreas confirmed that shrimp given feed supplemented with MCR 433 showed little or no signs of AHPND pathology while shrimp in the other two groups showed histopathology typical AHPND. Using a multigene molecular typing approach, both MCR 433 and MCR 440 were identified as distinct members of the order Muyocopronales, class Dothideomycetes and phylum Ascomycota with differing biological activities. Further research is needed on the lead compounds generated by these strains. Those from MCR 433 have potential for use as feed additives against VPAHPND as an alternative to antibiotics.

Anti-Biofilm Action of Biological Silver Nanoparticles Produced by Aspergillus tubingensis and Antimicrobial Activity of Fabrics Carrying it

Biological silver nanoparticles (AgNPs) were synthesized using the marine endophytic fungus Aspergillus tubingensis and inhibited Bacillus subtilis biofilm formation at low concentrations. Cotton and polyester fabrics impregnated with AgNPs were analyzed by transmission electron microscopy (TEM), and the concentration of AgNPs in both fabrics was determined using inductively-coupled plasma atomic emission spectrometry (ICP-AES). The fabrics carrying the AgNPs inhibited the Staphylococcus aureus and Escherichia coli growth by 100%. Both fabrics impregnated one time with AgNPs inhibited yeasts' clinical species' growth, Candida albicans, Candida glabrata, and Candida parapsilosis, from 80.1% to approximately 98.0%. Besides the anti-biofilm effect, the AgNPs impregnation process on cotton and polyester fabrics was highly efficient, and both fabrics presented antimicrobial effects against clinically relevant bacteria and yeast species. The results evidence that functionalized textiles containing these biological AgNPs can play an essential role in combating pathogenic microorganisms. Thereby offering an alternative to design effective solutions, mainly for hospital garments and biomedical devices, to avoid microorganisms transmissions and hospital-acquired nosocomial infections.

Characterization of refined carrageenan from Kappaphycus alvarezii extracted using marine fungi

Carrageenan is a polysaccharide that widely used in food, pharmaceutical, cosmetic, textile and printing industries as a coagulate agent, stabilizer, and gelling agent. The extraction of carrageenan usually is carried out by alkali treatment, but it may have toxic effect for the environment. Therefore, another extraction method is required to reduce the toxic effect from carrageenan. Carrageenan can also be extracted by using a cellulolytic enzyme. A natural cellulolytic enzyme can be produced from endophytic fungi. The objective of this research was to extract carrageenan using endophytic fungal cellulase and to evaluate the effect of fungal cellulase concentration and extraction time on the quality of carrageenan. The materials used in this research were marine endophytic fungus (EN) and dried seaweed Kappaphycus alvarezii. This research was conducted in three steps. The first step was cultivating of endophytic fungus (EN) in cellulose basal medium. The second step was cellulase extraction from endophytic fungus EN. The last step was extraction of carrageenan by cellulase endophytic fungus. The highest yield was obtained by added 1% of EN cellulase enzyme and extraction period for 3 hours. Characteristics of carrageenan in generally met the standard, but the gel strength and whiteness was still below the standard.

Secondary metabolites from the marine‐derived fungus Paraconiothyrium sp. VK‐13

AbstractChemical investigation of a fermentation culture of the marine endophytic fungus Paraconiothyrium sp. VK‐13 resulted in the isolation of five compounds, including a new phenolic compound, 1‐(2,5‐dihydroxyphenyl)‐1‐oxobutan‐3‐yl acetate (1) and four known metabolites, 1‐(2,5‐dihydroxyphenyl)‐2‐buten‐1‐one (2), 3,7‐dimethyl‐1,8‐dihydroxy‐6‐methoxyisochroman (3), modiolides A (4) and B (5). Their chemical structures were identified based on 1D, 2D NMR, and MS spectroscopic analysis and comparison with the data reported previously in the literature. All the isolated compounds were reported for the first time from the genus Paraconiothyrium.

Macrolide and phenolic metabolites from the marine-derived fungus Paraconiothyrium sp. VK-13 with anti-inflammatory activity

Five new secondary metabolites, modiolides D-G (1-4) and 1-(2,5-dihydroxyphenyl)-3-methoxy-butan-1-one (8), one new natural product, 1-(2,5-dihydroxyphenyl)-3-hydroxybutan-1-one (7), along with three known compounds, modiolides A (5) and B (6), and 1-(2,5-dihydroxyphenyl)-2-buten-1-one (9) were isolated from a fermentation culture of the marine endophytic fungus Paraconiothyrium sp. VK-13. Their chemical structures were elucidated by the NMR and MS spectroscopic analysis as well as the modified Mosher's method. Compounds 7 and 9 inhibited the overproduction of proinflammatory mediators NO and PGE2 in LPS-stimulated RAW264.7 cells, with IC50 values ranging from 3.9 to 12.5 µM. The inhibitory effects of 7 and 9 on the release of NO and PGE2 were correlated with their significant suppression of iNOS and COX-2 protein expression, respectively. Furthermore, both compounds 7 and 9 inhibited the mRNA expression of proinflammatory cytokines, including TNF-α, IL-1β, IL-6, and IL-12, with IC50 values in a range of 2.4-12.5 µM.

Green synthesized silver nanoparticles by marine endophytic fungus Penicillium polonicum and its antibacterial efficacy against biofilm forming, multidrug-resistant Acinetobacter baumanii

Acinetobacter baumanii, a gram-negative, non-motile, encapsulated coccobacillus which causes infections worldwide. The objective of this study was to find a fungal strain that could be utilized to biosynthesize antibacterial silver nanoparticles (AgNPs) against Acinetobacter baumanii. The present investigation explains rapid and extracellular biosynthesis of silver nanoparticles by the algicolous endophytic fungus, Penicillium polonicum, isolated from the marine green alga Chetomorpha antennina. The obtained silver nanoparticles were characterized by UV-Vis spectroscopy, Raman spectroscopy, Fourier transformation infrared (FTIR), and Transmission electron microscopy (TEM). The SNPs showed a characteristic UV- visible peak at 430 nm with an average size of 10–15 nm. As evident from the FTIR and Raman spectra, possibly the protein components of fungal extract have caused the reduction of silver nitrate. Parametric optimization, including the concentration of AgNO3, ratio of cell filtrate and AgNO3, fungal biomass, reaction time, pH, and presence of light, was done for rapid AgNPs production. The antibacterial efficacy of AgNPs against multi-drug-resistant, biofilm-forming Acinetobacter baumanii, was evaluated by well diffusion assay. The Minimum inhibitory concentration (MIC) of AgNP was 15.62 μgml−1 and the minimum bactericidal concentration (MBC) was 31.24 μgml−1. Killing kinetic assay revealed complete killing of the bacterial cells within 6 h. Log reduction and percent survival of bacterial cells were analyzed from killing kinetic study. Bactericidal nature of synthesized nanoparticles was confirmed by fluorescent microscopical analysis. The effect of AgNPs on the ultrastructure of bacterial pathogen was evaluated by Transmission electron microscopy.

Optimizing production of asperolide A, a potential anti-tumor tetranorditerpenoid originally produced by the algal-derived endophytic fungus Aspergillus wentii EN-48

The marine algal-derived endophytic fungus Aspergillus wentii EN-48 produces the potential anti-tumor agent asperolide A, a tetranorlabdane diterpenoid active against lung cancer. However, the fermentation yield of asperolide A was very low and only produced in static cultures. Static fermentation conditions of A. wentii EN-48 were optimized employing response surface methodology to enhance the production of asperolide A. The optimized conditions resulted in a 13.9-fold yield enhancement, which matched the predicted value, and the optimized conditions were successfully used in scale-up fermentation for the production of asperolide A. Exogenous addition of plant hormones (especially 10 μmol/L methyl jasmonate) stimulated asperolide A production. To our knowledge, this is first optimized production of an asperolide by a marine-derived fungus. The optimization is Effective and valuable to supply material for further anti-tumor mechanism studies and preclinical evaluation of asperolide A and other norditerpenoids.

Structure and absolute configuration of 20β-Hydroxyprednisolone, a biotransformed product of predinisolone by the marine endophytic fungus Penicilium lapidosum.

The anti-inflammatory drug predinisolone (1) was reduced to 20β-hydroxyprednisolone (2) by the marine endophytic fungus Penicilium lapidosum isolated from an alga. The structural elucidation of 2 was achieved by 1D- and 2D-NMR, MS, IR data. Although, 2 is a known compound previously obtained through microbial transformation, the data provided failed to prove the C20 stereochemistry. To solve this issue, DFT and TD-DFT calculations have been carried out at the B3LYP/6–31+G (d,p) level of theory in gas and solvent phase. The absolute configuration of C20 was eventually assigned by combining experimental and calculated electronic circular dichroism spectra and 3JHH chemical coupling constants.

Safety of Malaysian marine endophytic fungal extract S2 from a brown seaweed Turbinaria conoides

Objective: To evaluate the in vivo acute toxicity and antioxidant activity of the marine endophytic fungus extract S2 isolated from Turbinaria conoides. Methods: Two doses (100 mg/kg and 400 mg/kg) of the S2 extract were administered to rats orally for acute toxicity and antioxidant test. The body weight, relative weight of six organs, haematological, biochemical and antioxidant properties were investigated on Day 14. Results: A single oral dose treatment did not cause any mortality or observable adverse effects in rats. No significant variations in the body and organ weights between the control and the treated groups were observed. Heamatological analysis and clinical blood chemistry also did not reveal any toxic effects of the extract. The total white blood cell count and haemoglobin levels were increased. The levels of total serum cholesterol in males treated with 100 and 400 mg/kg were significantly (P<0.05) decreased (1.28 and 1.34 mmol/L respectively) compared to control (1.55 mmol/L) rats. Pathologically, neither gross abnormalities nor histopathological changes were observed. This study showed strong evidence of the non-toxic effects of S2 extract. Furthermore the extract exhibited significant (P<0.05) antioxidant activity through increased levels of superoxide dismutase and glutathione peroxidase enzymes in serum, liver and kidney. Conclusions: The research findings from the present study showed the potential of marine natural products particularly in Malaysia as a source of bioactive compounds. Marine endophytic fungi as a potential source of anticancer drugs with great potential as they are potent yet safe, thus deserving further extensive investigation.

A new β-glucuronidase inhibiting butyrolactone from the marine endophytic fungus Aspergillus terreus

An endophytic fungus Aspergillus terreus, var. boedijnii (Blochwitz) was isolated from red marine alga Laurencia ceylanica, J. Agardh, cultured in large scale and extracted with EtOAc. The above-mentioned extract yielded a new butyrolactone, 3-hydroxy-4-(4-hydroxyphenyl)-5-methoxycarbonyl-5-(4-hydroxy-3-formylbenzyl)-2,5-dihydro-2-furanone (1), along with the previously reported nine compounds, butyrolactone-1 (2), 6-hydroxymellin (3), (3 R, 4 R)-6,7-dimethoxy-4-hydroxymellin (4), (+)-territonin (5), (+)-territonin-A (6), (+)-asterrelenin (7), (+)-terrein (8), oleic acid (9) and glucopyranosyl-β-sitosterol (10), on column and preparative thin-layer chromatography. Compounds 1–8 were subjected to β-glucuronidase inhibitory activity test, and 1 showed a remarkable activity, while 2 and 7 showed moderate activity.

Enhanced secondary metabolite production by microbial co-cultures

Microorganisms are a rich source of bioactive natural products beneficial in drug discovery. Competitive interactions are a prominent factor in secondary metabolite production. However, typical isolated cultivation techniques do not harness the complete chemical diversity found in their natural environment. Recently, microbial mixed fermentations have been employed to increase yields of previously described metabolites and induce production of novel secondary metabolites. Isolation of a marine endophytic fungus from a Xestospongia muta sponge has been shown to inhibit the growth of Aspergillus niger, a common foodstuff and laboratory mold contaminant. A co-culture technique of both fungi was utilized and lead to increased metabolite production from pure cultures. The research herein describes the methods and preliminary results from the co-cultures.

HLE-Inhibitory Alkaloids with a Polyketide Skeleton from the Marine-Derived Fungus Coniothyrium cereale

The marine endophytic fungus Coniothyrium cereale produces the structurally unusual polyketide-type alkaloids (-)-cereolactam (1) and (-)-cereoaldomine (3), incorporating a lactam and an imine functionality, respectively, as well as the related metabolite (-)-trypethelone (2). Compounds 1 and 3 showed selective inhibition of human leukocyte elastase with IC50 values of 9.28 and 3.01 μM, respectively. Compound 2 was found to be inhibitory toward Mycobacterium phlei, Staphylococcus aureus, and Escherichia coli and also cytotoxic against mouse fibroblast cells (IC50=7.5 μM).

Two New Derivatives of Griseofulvin from the Mangrove Endophytic FungusNigrosporasp. (Strain No. 1403) fromKandelia candel(L.) Druce

Two new compounds, methyl 3-chloro-6-hydroxy-2-(4-hydroxy-2-methoxy-6-methylphenoxy)-4-methoxybenzoate (1) and (2 S,5' R,E)-7-hydroxy-4,6-dimethoxy-2-(1-methoxy-3-oxo-5-methylhex-1-enyl)-benzofuran-3(2H)-one (2), together with four known compounds, griseofulvin (3), dechlorogriseofulvin (4), bostrycin (5), and deoxybostrycin (6), were isolated from the marine endophytic fungus NIGROSPORA sp. (No. 1403) collected from the South China Sea. The structures were elucidated by spectroscopic methods, 1D, 2D NMR, and HREIMS. Compounds 5 and 6 showed moderate antitumor and moderate antimicrobial activity.

A new anthraquinone derivative from the marine endophytic fungus Fusarium sp. (No. b77)

A new anthraquinone compound, 5-acetyl-2-methoxy-1,4,6-trihydroxy-anthraquinone (1), together with four known naphthoquinones (2–5), were isolated from the culture of the mangrove fungus (No. b77). All the isolated compounds (1–5) and the acetyl derivative (1a) were established by comprehensive analysis of the spectral data, especially 1D- and 2D-NMR (HMQC and HMBC) spectra. In the primary bioassays, compound 3 showed strong inhibitory effects on the growth of hepG2 and hep2 cells, with IC50 values of 1.0 and 2.5 µg mL−1, respectively.

Perylene Derivatives Produced by Alternaria alternata, an Endophytic Fungus Isolated from Laurencia Species

Two new perylene derivatives, 7-epi-8-hydroxyaltertoxin I (1) and 6-epi-stemphytriol (2), along with two known compounds stemphyperylenol (3) and altertoxin I (4) were isolated from Alternaria alternata, a marine endophytic fungus derived from an unidentified algal species of the genus Laurencia. Structures of compounds 1-4 were determined on the basis of detailed spectroscopic analysis, as well as by comparison with literature reports. The antimicrobial activities of compounds 1 and 3 against Staphylococcus aureus, Escherichia coli, and Aspergillus niger were evaluated; neither showed obvious activity.

3β-Hydroxyfriedelan-17β-carboxylic acid

The title compound, C30H50O3, which was isolated from a marine endophytic fungus, is a new friedelan derivative. The mol­ecule contains five six-membered rings, which exhibit boat (ring A), distorted boat (ring B) and chair (rings C–E) conformations. The crystal structure is stabilized by inter­molecular O—H⋯O hydrogen bonds, which link neighbouring mol­ecules into 12-membered rings.