Promising Endophytic Alternaria alternata from Leaves of Ziziphus spina-christi: Phytochemical Analyses, Antimicrobial and Antioxidant Activities

Sesquiterpenoid isolated from Colletotrichum truncatum derived from Gynura japonica: isolation, structure elucidation, and biological activity

The aim of this research was isolation, structure elucidation, and biological activities of terpenoids from endophytic fungus obtained from G. japonica. An endophytic fungus, Colletotrichum truncatum, was isolated from the roots of G. japonica. C. truncatum was cultivated and extracted to give the crude extract. The crude extract was fractionated using vacuum liquid chromatography followed by separation and purification with column chromatography to obtain a terpenoid derivative (12.8 mg). The compound was characterised for its structure using FT-IR and NMR spectra. Based on spectral analysis, the isolated compound was identified as sydonic acid. The isolated sydonic acid was active against three tested bacterial strains and also demonstrated antioxidant activity with an IC50 value of 76.5 ± 0.93 μg/mL. Interestingly, chemical research on the terpenoid derivative from the fungus C. truncatum associated with G. japonica is first reported herein.

In Vitro Antioxidant and Antibacterial Activities of Ethyl Acetate Extracts of Ziziphus lotus Leaves and Five Associated Endophytic Fungi

The exploration of new pharmacological compounds from endophytic fungi offers infinite possibilities. The aim of this study was to evaluate the antibacterial and antioxidant activities of extracts from the leaves of Ziziphus lotus and five of its endophytic fungi and investigate the chemical diversity of the secondary metabolites produced. Isolated, purified, and molecularly identified endophytes and plant leaves were subjected to ethyl acetate extraction. The antibacterial potential of the extracts was assessed by the disc diffusion method against five bacterial strains: Staphylococcus aureus ATCC 25923; Staphylococcus aureus MU50; Enterococcus faecalis WDCM00009; Escherichia coli ATCC 25922; and Pseudomonas aeruginosa ATCC 27853. DPPH and reducing power tests were performed to assess antioxidant potential. GC-MS analysis was used to identify volatile compounds in extracts. Fungal endophytes were identified as Aspergillus cavernicola, Aspergillus persii, Alternaria alternata, Cladosporium asperlatum, and Fusarium incarnatum-equiseti complex, with respective accession numbers DTO 412-G6, DTO 412-I5, DTO 413-E7, DTO 412-G4, and DTO 414-I2. GC-MS analysis revealed a large number of bioactive compounds. All extracts showed antibacterial activity against at least two of the bacteria tested, and most showed antioxidant activity. The Aspergillus cavernicola extract stood out for its higher phenolic content and higher antioxidant and antibacterial activities in all tests.

Revealing culturable fungal microbiome communities from the Arabian Peninsula desert representing a unique source of biochemicals for drug discovery and biotechnology

Background

Microbes living at extremes evolve unique survival strategies to adapt to challenging environmental conditions. Among these strategies is their distinctive metabolic potential and ability to produce specialized metabolites enabling them to compete for limited resources and defend against predators. These metabolites have significant potential in pharmaceutical and industrial applications, particularly in the development of drugs and biochemicals.

Objectives

This study aimed to investigate the culturable fungal communities associated with four desert plants and their surrounding soils in the Arabian Peninsula desert to identify their bioactive properties.

Methods

A total of 12 distinct fungal species were isolated from the plants and soils. Each plant hosted a unique set of fungi, demonstrating the diversity of desert-adapted fungal communities. Biological activities of the fungal extracts were evaluated through various assays, including antimicrobial, antifungal, anticancer, and antioxidant properties.

Results

Panicum turgidum harbors the most diverse fungal community, dominated by genera such as Mucor, Aspergillus, Colletotrichum, Alternaria, and Chaetomium. Aspergillus species comprise 33% of the total isolates, followed by Fusarium at 16%. All extracts exhibit diverse activities, with Aspergillus species demonstrating the highest antioxidant activities and total phenolic and flavonoid content. Fungi from P. turgidum, particularly Mucor sp., Aspergillus sp., and Curvularia sp., display potent activity against Staphylococcus aureus, while Mucor sp., Chaetomium sp., and Curvularia sp. exhibit moderate inhibition against Pseudomonas aeruginosa.

Conclusion

This study highlights the importance of exploring extremophilic microorganisms, such as those found in desert ecosystems, as they offer a wealth of compounds that could address current challenges in drug discovery and biotechnology.

Antibacterial and anticancer potential of bioactive compounds and secondary metabolites of endophytic fungi isolated from Anethum graveolens

Fungal endophytes are known to produce bioactive chemicals and secondary metabolites that are often identical to those produced by their host plants. The main objective of the current study was to isolate and identify endophytic fungi associated with the medicinal plant Anethum graveolens, and to investigate their potential antibacterial and anticancer properties. The ethyl acetate extracts from the isolated endophytic fungi, as well as the host plant A. graveolens, were subjected to bioactivity assays to evaluate their antibacterial and anticancer potential against multi-drug resistant bacterial strains and the human hepatocellular carcinoma cell line HepG2. The endophytic fungi isolated and identified from the A. graveolens samples included Diaporthe, Auxarthron, Arthrinium, Aspergillus, Microsporum, Dothiorella, Trichophyton, Lophiostoma, Penicillium, and Trichoderma species. The minimum inhibitory concentration (MIC) assay revealed that the A. graveolens extract exhibited the strongest antibacterial activity, with an MIC value of 4 μg/ml, followed by the Trichoderma sp. (5 μg/ml) and Penicillium sp. (6 μg/ml) extracts. Additionally, the crude extracts of Trichoderma sp., Penicillium sp., and Fusarium sp. demonstrated high anticancer activity against HepG2 cells, with inhibition rates ranging from 89 to 92% at a concentration of 50 μg/ml. Interestingly, the A. graveolens extract showed the most potent anticancer activity, with a 95% inhibition rate against HepG2 cells at the same concentration. These findings highlight the significant potential of endophytic fungi associated with A. graveolens, as a source of bioactive compounds with promising antibacterial and anticancer properties. The results reinforce the hypothesis that medicinal plants and their endophytic fungi can serve as an attractive alternative for the development of novel therapeutic agents, potentially offering a more sustainable and less harmful approach to disease management compared to traditional chemical-based methods.

Purification of ursolic acid and β-sitosterol from endophytic Alternaria alternata for their alpha-amylase inhibitory activity

Fungal endophytes are a known warehouse of bioactive compounds with multifarious applications. In the present investigation two compounds, β-Sitosterol (1) and ursolic acid (2), were isolated from Alternaria alternata, an endophytic fungus associated with Morus alba Linn for the first time. The structure of the compounds was elucidated on the basis of comprehensive spectral analysis (UV, IR, 1 H-, 13 C- and 2D-NMR, as well as HRESI-MS). In the in vitro alpha amylase inhibitory assay both compounds (1) and (2) show potent antidiabetic activity. In support, Docking studies indicate significant binding affinity of the isolated compounds. Hence from the present study, it can be concluded that endophytic fungi in Morus alba Linn can find use in antidiabetic drug development in the medicinal industry.Communicated by Ramaswamy H. Sarma.

Anti-inflammatory potential of aconitine produced by endophytic fungus Acremonium alternatum

Argemone mexicana belonging to family Papaveraceae is a traditional medicinal plant widely utilized by tribal people in India for treating various ailments like skin infections, wounds and inflammation. This plant is very rich in alkaloidal content, which has a great potential in the treatment of anti-inflammatory disorders. Therapeutically promising bioactive molecules are often produced by endophytic fungi associated with medicinal plants. In this investigation, endophytic fungi were isolated from various parts of A. mexicana and screened for alkaloidal content. Among these, one of the fungal isolate, Acremonium alternatum AMEF-5 producing maximum alkaloids showed significant anti-inflammatory activity. Fractionation of this crude fungal extract through column chromatography yielded eight fractions, which were further screened for anti-inflammatory activities. Fraction 3 exhibited significant anti-inflammatory activity by the inhibition of lipoxygenase enzyme (IC50 15.2 ± 0.09 µg/ml), scavenging of the nitric oxide radicals (IC50 11.38 ± 0.35 µg/ml), protein denaturation (IC50 14.93 ± 0.4 µg/ml), trypsin inhibition (IC50 12.06 ± 0.64 µg/ml) and HRBC stabilization (IC50 11.9 ± 0.22 µg/ml). The bioactive alkaloid in fraction 3 was identified as aconitine which was confirmed by UV, FTIR, HPLC, HRMS, 1H NMR, and 13C NMR analysis. This study demonstrates that endophytic fungi serve a potential source for sustainable production of therapeutically important alkaloids.

Antimicrobial secondary metabolites and antioxidant activities of fungal endophytes associated with Ziziphus spina-christi (L.) Desf. (Nabq) leaves

A total of 20 endophytic fungi were isolated (ZSEFL1-ZSEFL20) from Ziziphus spina-christi (L.) Desf. (Nabq) leaves. Four isolates A2/ZSEFL2, Alternaria alternata, D/ZSEFL14, Aspergillus niger, E/ZSEFL15, Epicoccum nigrum, and S/ZSEFL19, Penicillium crustosum were found to show the most promising antimicrobial activities either in plug or disc diffusion screening assays against Gram-positive, Gram-negative bacteria and pathogenic fungi. Antimicrobial activity was tested against Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 29213, Serratia marcescens ATCC 14764, Klebsiella pneumoniae ATCC 700603, Candida albicans ATCC 10231, and Fusarium oxysporum ATCC417. In vitro antioxidant activity assay was conducted using the ABTS [2,2'-Azino-bis (3-Ethylbenzthiazoline-6-Sulfonic Acid)] free radical scavenging method. EtOAc extracts of all isolated endophytic fungi showed antioxidant activities. This study would be one of the first reports to measure the antioxidant activity of Z. spina-christi (L.) Desf. endophytic fungi. Therefore, these isolated endophytic fungi can provide additional information for medicinal sources of natural antioxidants and antimicrobial agents.

Profile and in silico analysis of metabolite compounds of the endophytic fungus Alternaria alternata K-10 from Drymoglossum piloselloides as antioxidants and antibacterials

Endophytic fungi are known for producing secondary metabolites with valuable biological activities, including antiviral, anticancer, antibacterial, and antioxidant properties. This study aims to evaluate an endophytic fungus from Dragon Scales leaves (Drymoglossum piloselloides) and analyze its metabolites as antioxidants and antibacterials. In this study, an endophytic fungus was isolated from the leaves of Dragon Scales (D. piloselloides) and identified using molecular analysis of the Internal Transcribed Spacer (ITS) ribosomal RNA locus. The fungus was authenticated as Alternaria alternata strain K-10. Crude extracts were obtained using n-hexane and ethyl acetate and analyzed via GC-MS Shimadzu-QP 2010 Ultra with NIST spectral library. Antibacterial activity was observed against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa using the paper disc method, showing inhibition zones of 8.7-9.3 mm and 8.8-9.4 mm for ethyl acetate and n-hexane extracts, respectively. Ethyl acetate and n-hexane extracts exhibited strong antioxidant potential against 2,2-diphenyl-1-picrylhydrazil (DPPH) radical (IC50 values of 50.99 μg mL-1 and 74.44 μg mL-1, respectively). GC-MS analysis revealed 40 compounds in both extracts, some of which, including 2-ethylhexyl ester benzoic acid, benzo-b-dihydropyran-6-hydroxy-4-4-5-7-8-pentamethyl, diethyl phthalate, and octadecanoic acid, were identified through in silico analysis and found to possess antioxidant properties. These findings hold implications for potential applications of the plant and its biological constituent to be developed as lead compounds in the medical sector.

Endophytic fungus from Gynura japonica: phytochemical screening, biological activities, and characterisation of its bioactive compound

The research aims to identify the chemical constituents of endophytic fungi associated with Gynura japonica and their biological activities. Two endophytic fungi, labelled as GS-1 and GS-2, have been isolated from the leaves of G. japonica. They were cultivated on white rice media for their optimum cultivation time. Cultivated fungi were extracted with ethyl acetate and concentrated to give a crude extract. All crude extracts were evaluated for their phytochemical screening and assayed for their antibacterial and antioxidant activities. Based on the results, fungal GS-1 was the most potential fungus to produce bioactive secondary metabolites and identified as Dimorphiseta acuta. A bioactive compound was isolated from crude extract of fungal D. acuta and identified as emodin. To the best of our knowledge, the study of secondary metabolite and its biological activity of endophytic fungus colonised with the leaves of G. japonica is reported here for the first time.

Investigation the biological activities and the metabolite profiles of endophytic fungi isolated from Gundelia tournefortii L

Endophytic fungi are microorganisms that are considered as a potential source of natural compounds, and can be applied in various industries. The aims of this research were molecular identification of endophytic fungi isolated from the Gundelia tournefortii stems, and investigation their biological activities as well as phenolic and fatty acid profile. Surface sterilized stems of G. tournefortii were placed on potato dextrose agar (PDA) to isolate the fungal endophytes. Genomic DNA was extracted by CTAB method, and PCR amplification was performed by ITS 1 and ITS 4 as primers. The enzyme production of endophytic fungi was determined based on the formation of a clear zone that appeared around the colonies of fungus. The anti-oxidant activity was evaluated by measuring the amount of free radicals DPPH. Also, the total phenol and flavonoid contents were measured obtained by Folin-Ciocalteu and aluminum chloride colorimetric methods, respectively. Moreover, the separation and identification of phenolic acids and fatty acids were done by HPLC and GC, respectively. Phylogenetic analysis was done based on the Internal Transcribed Spacer (ITS) region, and five isolates were identified as following: Aspergillus niger, Penicillium glabrum, Alternaria alternata, A. tenuissima, and Mucor circinelloides. Evaluation of the enzymatic properties showed that P. gabrum (31 ± 1.9 mm), and A. niger (23 ± 1.7) had more ability for producing pectinase and cellulase. The anti-oxidant activity of isolates showed that A. alternata extract (IC50 = 471 ± 29 µg/mL) had the highest anti-oxidant properties, followed by A. tenuissima extract (IC50 = 512 ± 19 µg/mL). Also, the extract of A. alternata had the greatest amount of total phenols and flavonoids contents (8.2 ± 0.4 mg GAL/g and 2.3 ± 0.3 mg QE/g, respectively). The quantification analysis of phenolic acid showed that rosmarinic acid, para-coumaric acid, and meta-coumaric acid (42.02 ± 1.31, 7.53 ± 0.19, 5.41 ± 0.21 mg/g, respectively) were the main phenolic acids in the studied fungi. The analysis of fatty acids confirmed that, in all fungi, the main fatty acids were stearic acid (27.9-35.2%), oleic acid (11.3-17.3%), palmitic acid (16.9-23.2%), linoleic acid (5.8-11.6%), and caprylic acid (6.3-10.9%). Our finding showed that endophytic fungi are a source of bioactive compounds, which could be used in various industries. This is the first report of endophytic fungi associated with G. tournefortii, which provides knowledge on their future use on biotechnological processes.

Characterization and antimicrobial activity of endophytic fungi from medicinal plant Agave americana

Endophytic microorganisms associated with medicinal plants are of particular interest as they are a potential source of new bioactive chemicals effective against novel emerging and drug-resistant pathogens. Agave americana is a tropical medicinal plant with antibacterial, antifungal, and anticancer properties. We studied the biodiversity of fungal endophytes of A. americana and their antimicrobial production potential. Isolated endophytic fungi were classified into 32 morphotypes (15 from stem and 17 from leaf) based on their cultural and morphological characteristics. Among the fungal crude extracts tested, 82% of isolates from the leaves and 80% of the isolates from the stem showed antibacterial activity against the bacterial strains (Escherichia coli ATTC 25902, Staphylococcus aureus ATTC 14775, and Bacillus subtilis NRRL 5109) tested. Extracts from four fungal isolates from leaves showed antifungal activity against at least one of the fungal strains (Candida albicans ATTC 10231 and Aspergillus fumigatus NRRL 5109) tested. Crude extracts of seven fungal isolates showed a zone of inhibition of more than 11 mm at 10 mgml-1 against both Gram-positive and Gram-negative bacteria tested. Penicillium, Colletotrichum, Curvularia, Pleosporales, Dothideomycetes, and Pleurotus are the main endophytes responsible for bioactive potential. These results indicate that A. americana harbors endophytes capable of producing antimicrobial metabolites.

Phytochemical Analysis and Antioxidant Activity of Endophytic Fungi Isolated from Dillenia indica Linn

Endophytic fungi live symbiotically inside plants and are hidden source of natural bioactive molecules. The present study was carried out to investigate the phytochemical analysis and antioxidant activity of endophytic fungi isolated from the ethnomedicinal plant Dillenia indica L. The ethyl acetate crude extracts of the endophytic fungal strains were preliminarily evaluated for their phytochemical analysis, and the results showed the presence of alkaloids, flavonoids, phenolics, terpene, and saponins. The crude extracts of more than 60% of the isolates showed 50-90% antioxidant activity by DPPH and H2O2 assay. The inhibition percentage of ethyl acetate extracts ranges from 34.05 to 91.5%, whereas IC50 values vary from 72.2 to 691.14%. Among all the strains, Fomitopsis meliae crude extract showed a maximum inhibition percentage, i.e., 91.5%, with an IC50 value of 88.27 µg/mL. Chaetomium globosum showed significant activity having an inhibition percentage of 89.88% and an IC50 value of 74.44 µg/mL. The total phenolic and flavonoid content in the crude extract of Chaetomium globosum was 37.4 mg gallic acid equivalent (GAE)/g DW and 31.0 mg quercetin equivalent (GAE)/g DW. GC-MS analysis of crude extract of C. globosum revealed different compounds, such as squalene; butanoic acid, 2-methyl-; hexadecanoic acid; 2-propanone, 1-phenyl-; 5-oxo-pyrrolidine-2-carboxylic acid methyl ester; 9,12-octadecadienoic acid (z)- etc. Many of these belong to phenolics, which are natural antioxidant compounds. The findings suggested that endophytic fungi associated with Dillenia indica L. can be a potential source of novel antioxidant compounds.

Antimicrobial, antioxidant, and cytotoxic properties of endophytic fungi isolated from Thysanolaena maxima Roxb., Dracaena spicata Roxb. and Aglaonema hookerianum Schott

BACKGROUND

Endophytic fungi have recently been recognized as an impressive source of natural biomolecules. The primary objective of the research was to isolate fungal endophytes from Thysanolaena maxima Roxb., Dracaena spicata Roxb. and Aglaonema hookerianum Schott. of Bangladesh and assess their pharmacological potentialities focusing on antimicrobial, antioxidant, and cytotoxic properties.

METHODS

The fungal isolates were identified up to the genus level by analyzing their macroscopic and microscopic characteristics. Ethyl acetate extracts of all the fungal isolates were screened for different bioactivities, including antimicrobial (disc diffusion method), antioxidant (DPPH scavenging assay), and cytotoxic (brine shrimp lethality bioassay) activities.

RESULTS

Among the thirteen isolates, Fusarium sp. was the most recognized genus, while the others belonged to Colletotrichum sp. and Pestalotia sp. Comparing the bioactivity of all the extracts, Fusarium sp. was shown to be the most effective endophyte, followed by Colletotrichum sp. and Pestalotia sp. In the antimicrobial study, two isolates of Fusarium sp. (internal strain nos. DSLE-1 and AHPE-4) showed inhibitory activity against all the tested bacteria and the highest zone of inhibition (15.5 ± 0.4 mm) was exerted by AHPE-4 against Bacillus subtillis. All the fungal isolates produced mild to moderate free radical scavenging activity, where the highest antioxidant activity was revealed by one isolate of Fusarium sp. (internal strain no. AHPE-3) with an IC50 value of 84.94 ± 0.41 µg/mL. The majority of Fusarium sp. isolates exhibited notable cytotoxic activity, where AHPE-4 exhibited the highest cytotoxicity, having the LC50 value of 14.33 ± 4.5 µg/mL.

CONCLUSION

The findings of the study endorsed that the fungal endophytes isolated from T. maxima, D. spicata, and A. hookerianum hold potential as valuable origins of bioactive substances. Nevertheless, more comprehensive research is warranted, which could develop novel natural compounds from these endophytes to treat various infectious and cancerous diseases.

Bacterial Endophytes from Moringa oleifera Leaves as a Promising Source for Bioactive Compounds

Bacterial endophytes reside within the tissues of living plant species without causing any harm or disease to their hosts. Bacterial endophytes have produced a variety of bioactive compounds that can be used for different biomedical applications. In the current study, two bacterial endophytes were isolated from healthy Moringa oleifera leaves, and identified genetically as Stenotrophomonas maltophilia and Alcaligenes faecalis. Phytochemical results illustrated that A. faecalis produced phenolics at 547.2 mg/g, tannins at 156.7 µg/g, flavonoids at 32.8 µg/g, and alkaloids at 111.2 µg/g compared to S. maltophilia, which produced phenolics at 299.5 mg/g, tannins at 78.2 µg/g, flavonoids at 12.4 µg/g, and alkaloids at 29.4 µg/g. GC-MS analysis indicated that A. faecalis extract has 24 bioactive compounds, including 9 major compounds, namely octadecanoic acid, hexadecanoic acid, linoleic acid ethyl ester, octadecenoic acid, methyl ester, methyl stearate, nonacosane, indolizine, palmitoleic acid, and heptacosane. On the other hand, S. maltophilia extract has 11 bioactive compounds, including 8 major compounds, namely oleic acid, octadecanoic acid, hexadecanoic acid, cis-2-phenyl-1, 3-dioxolane-4-methyl, ergotamine, diisooctyl phthalate, diethyl phthalate, and pentadecanoic acid. To check the safety of these extracts, the cytotoxicity of Ethyl acetate (EA) extracts of S. maltophilia and A. faecalis were evaluated against the Vero normal cell line, and the results confirmed that these extracts are safe to use. Moreover, results revealed that EA extracts of S. maltophilia and A. faecalis exhibited anticancer activity against the cancerous MCF7 cell line, where IC50 was 202.4 and 119.7 µg/mL, respectively. Furthermore, EA extracts of S. maltophilia had antibacterial and antifungal activity against Gram-positive and Gram-negative bacteria, and unicellular fungi. Likewise, the EA extract of A. faecalis exhibited antibacterial and antifungal activity against Gram-positive bacteria, as well as unicellular fungi, but did not show any activity against Gram-negative bacteria. Also, EA extracts of S. maltophilia and A. faecalis exhibited moderate antioxidant activity where IC50 were 146.2 and 147.6 µg/mL, respectively. In conclusion, the two isolated endophytic bacteria S. maltophilia and A. faecalis have promising bioactive compounds that have antibacterial, antioxidant, and anticancer activities.

Antimicrobial, antiproliferative activities and molecular docking of metabolites from Alternaria alternata

Endophytic fungi allied to plants have sparked substantial promise in discovering new bioactive compounds. In this study, propagation of the endophytic fungus Alternaria alternata HE11 obtained from Colocasia esculanta leaves led to the isolation of Ergosterol (1), β-Sitosterol (2), Ergosterol peroxide (3), in addition to three dimeric naphtho-γ-pyrones, namely Fonsecinone A (4), Asperpyrone C (5), and Asperpyrone B (6), which were isolated from genus Alternaria for the first time. Structures of the isolated compounds were established on the basis of extensive 1D and 2D NMR and, MS measurements. The ethyl acetate extract, as well as compounds 1, 3, 4 and 6 were evaluated for their antimicrobial activity using agar well-diffusion and broth microdilution assays. Molecular docking study was carried out to explore the pharmacophoric moieties that governed the binding orientation of antibacterial active compounds to multidrug efflux transporter AcrB and the ATP binding site to E. coli DNA gyrase using MOE software. Results revealed that the most active antibacterial compounds 4 and 6 bind with high affinity in the phenylalanine-rich cage and are surrounded with other hydrophobic residues. The antiproliferative activity of all isolated compounds was in vitro evaluated using the human prostatic adenocarcinoma cell lines DU-145, PC-3, PC-3 M, 22Rv1 and CWR-R1ca adopting MTT assay. Compound 4 was the most active against almost all tested cell lines, with IC₅₀ values 28.6, 21.6, 17.1 and 13.3 against PC-3, PC-3 M, 22Rv1 and CWR-R1ca cell lines, respectively.

Bioactive compounds and biomedical applications of endophytic fungi: a recent review

Human life has been significantly impacted by the creation and spread of novel species of antibiotic-resistant bacteria and virus strains that are difficult to manage. Scientists and researchers have recently been motivated to seek out alternatives and other sources of safe and ecologically friendly active chemicals that have a powerful and effective effect against a wide variety of pathogenic bacteria as a result of all these hazards and problems. In this review, endophytic fungi and their bioactive compounds and biomedical applications were discussed. Endophytes, a new category of microbial source that can produce a variety of biological components, have major values for study and broad prospects for development. Recently, endophytic fungi have received much attention as a source for new bioactive compounds. In addition, the variety of natural active compounds generated by endophytes is due to the close biological relationship between endophytes and their host plants. The bioactive compounds separated from endophytes are usually classified as steroids, xanthones, terpenoids, isocoumarins, phenols, tetralones, benzopyranones and enniatines. Moreover, this review discusses enhancement methods of secondary metabolites production by fungal endophytes which include optimization methods, co-culture method, chemical epigenetic modification and molecular-based approaches. Furthermore, this review deals with different medical applications of bioactive compounds such as antimicrobial, antiviral, antioxidant and anticancer activities in the last 3 years.

Isolation and identification of novel selective antitumor constituents, sidrin and sidroside, from Zizyphus spina-christi

Background

The leaves of Zizyphus spina-christi (L.) Willd contain several compounds exhibiting different pharmacologic activities. However, studies on the cytotoxic activity of these compounds are limited.

Objectives

We aimed to investigate and isolate cytotoxic compounds with selective antitumor effects from the leaves of Z. spina-christi using bioassay-guided fractionation of methanol extract.

Methods

Powdered, dried leaves were subjected to methanol extraction and fractionated using n-hexane, chloroform, ethyl acetate, and n-butanol. Fractions with positive cytotoxicity against HeLa and THP-1 cell lines were further fractionated and eluted using various concentrations of organic solvents. Active compounds were isolated using different chromatographic methods and their chemical structures were determined using extensive spectroscopic methods, such as 1D NMR (¹H NMR, ¹³C NMR, and DEPT), 2D NMR (COSY, HMBC, and HMQC), HRFAB-MS, and IR. Furthermore, the cytotoxic effects of the isolated compounds were evaluated against 62 tumor cell lines (including HeLa and THP-1) in addition to normal bone marrow cells.

Results

The chloroform and aqueous methanol fractions of the leaves showed cytotoxic activity. Two compounds were successfully isolated and named "sidrin" (13-β-hydroxy-lup-20(30)-ene-2,3-β-epoxy-28-carboxylate) and "sidroside" (3-O-β-D-glucopyranosyl-(1-3)-α-L-arabinopyranosyl-jujubogenin-20-O-α-L-rhamnopyranoside). Sidrin exhibited cytotoxic activity against the human leukemia (Hl-60, RPMI-8226), lung cancer (A549, EKVX), breast cancer (BT-549, MDA-MB-231/ATCC), colon cancer (KM12), melanoma (M14, SK-MEL-5), and central nervous system (CNS) cancer (SF-295) cell lines, and selectivity was observed against the Hl-60, EKVX, BT-549, KM12, and SF-295 cell lines. In addition, sidrin was more active than sidroside and doxorubicin against the Hl-60 and EKVX cell lines. In contrast, sidrin had a similar effect to doxorubicin against the BT-549 and renal cancer (UO-31) cell lines. Sidroside was more selective against the leukemia (CCRF-CEM, MOLT-4), lung cancer (HOP-92, NCI-H322M), breast cancer (MDA-MB-468), melanoma (LOX IMVI), CNS cancer (SNB-19), ovarian cancer (OVCAR-8), renal cancer (UO-31, RXF 393), and prostate cancer (PC-3) cell lines. Both compounds exhibited similar activity against the breast cancer (MDA-MB-231, T-47D), colon cancer (HCC-2998, HCT-116), ovarian cancer (OVCAR-3), renal cancer (UO-31, 786-0, and SN 12C) cell lines. Normal bone marrow cells were unaffected at the same concentrations of sidrin and sidroside applied to tumor cells.

Conclusions

These results suggest tumor-selective cytotoxicity of sidrin and sidroside.

Secondary metabolites produced by endophytic fungi, Alternaria alternata, as potential inhibitors of the human immunodeficiency virus

Antiretroviral treatment has significantly reduced human immunodeficiency virus infection and mortality. However, the current treatment regimen is limited by adverse side effects, the emergence of drug resistance, and the inability to eliminate viral reservoirs. Here, fifteen endophytic fungi were isolated from Sclerocarya birrea and Hypoxis plants. Crude extracts of Alternaria alternata (strain ID PO4PR1, PO4PR2, and PO2PL1) of the fifteen isolate's crude extracts showed anti-HIV-1 activity in TZM-bl cell line at inhibitory concentration (IC₅₀) values ranging from 0.017 to 1.170 μg/ml. The three crude extracts also maintained the virus replication inhibition profile on PBMCs and CD4⁺ T cells at concentrations ranging from 0.3 to 50.2 ng/ml. Partial purification using the solid phase extraction and analysis with Gas Chromatography-Mass spectrophotometry showed a diverse profile. The bioactive compounds were identified based on peak area, retention time, similarity index. The major compounds from GC-MS analysis of A. Alternata revealed the existence of cyclotrisiloxane octamethyl (22.92%); Propaninitrile (16,67%); Pyrrolol[1,2-a]pyrazine-1,4-dione, hexahydro-3-(2-methyl propyl) (10.42%); Silane, diethylethoxy(2-ethoxyethyloxy) (4.17%); Coumarin, 3,4-dihydro-4,5,7-trimethyl- 4,5,7-Trimethyl-2-chromanone (13.7%) and 1,2-Cyclobutanedicarbonitrile (2.08%) with previously reported biological activities such as antimicrobial, anti-inflammatory and antioxidant properties. Therefore, these bioactive compounds from A. alternata fungal endophytes could be repurposed as potential anti-HIV agents. This study showed the potential of endophytic fungi, Alternaria alternata from S. birrea, and Hypoxis species as producers of anti-HIV compounds.

Biostimulation of tomato growth and biocontrol of Fusarium wilt disease using certain endophytic fungi

BACKGROUND

Tomato plant (Solanum lycopersicum L.) suffers from numerous fungal pathogens that cause damage to yeild production qualitatively and quantitatively. One of the most destructive disease of tomato is Fusarium wilt that caused by soil borne fungus called F. oxysporum.

METHODS

In this study, the anti-Fusarium capabilities of the foliar application of fungal endophytes extracts have been investigated on tomato under Fusarium challenges. Antifungal assay, inhibition of conidial germination, disease severity, photosynthetic pigments, osmolytes, secondary metabolites, oxidative stress, peroxidase (POD) and polyphenol oxidases (PPO) isozymes were tested for potential resistance of tomato growing under Fusarium infection.

RESULTS

Ethyl acetate extracts of A. flavus MZ045563, A. fumigatus MZ045562 and A. nidulans MZ045561 exhibited antifungal activity toward F. oxysporum where inhibition zone diameters were 15, 12 and 20 mm, respectively. Moreover, extracts of all fungal isolates at concentration 7.5 mg/mL reduced conidia germination from 94.4 to 100%. Fusarium infection caused a destructive effects on tomato plant, high severity desiese index 84.37%, reduction in growth parameters, photosynthetic pigments, and soluble protein. However, contents of proline, total phenol, malondialdehyde (MDA), hydrogen peroxide (H₂O₂) and antioxidant enzymes activity were increased in tomato plants grown under Fusarium wilt. Treatment of healthy or infected tomato plants by ethyl acetate fungal extracts showed improvements in morphological traits, photosynthetic pigments, osmolytes, total phenol and antioxidant enzymes activity. Besides, the harmful impacts of Fusarium wilt disease on tomato plants have also been reduced by lowering MDA and H₂O₂ levels. Also, treated tomato plants showed different responses in number and density of POD and PPO isozymes.

CONCLUSION

It could be suggested that application of ethyl acetate extracts of tested fungal endophytes especially combination of A. flavus, A. nidulans and A. fumigatus could be commercially used as safe biostimulation of tomato plants as well as biofungicide against tomato Fusarium wilt disease.

Cultivable endophytic fungal community associated with the karst endemic plant Nervilia fordii and their antimicrobial activity

Endophytic fungi from medicinal plants with specific pharmacological functions attract much attention to provide the possibility of discovering valuable natural drugs with novel structures and biological activities. Nervilia fordii is a rare and endangered karst endemic plant that is used as medicine and food homology in Guangxi, China. These plants have been reported to have antimicrobial, antitumor, antiviral, and anti-inflammatory activities. However, few studies have focused on the diversity and antibacterial activity of endophytic fungi from N. fordii. In the present study, 184 endophytic fungi were isolated from the healthy tissues of N. fordii, and their molecular diversity and antimicrobial activities were analyzed for the first time. These fungi were categorized into 85 different morphotypes based on the morphological characteristics and the similarity between the target sequence and the reference sequence in the GenBank database. With the exception of 18 unidentified fungi, the fungal isolates belonged to at least 2 phyla, 4 classes, 15 orders, 45 known genera, and 45 different species, which showed high abundance, rich diversity, and obvious tissue specificity. All isolates were employed to screen for their antimicrobial activities via the agar diffusion method against Escherichia coli, Staphylococcus aureus, and Candida tropicalis. Among these endophytes, eight strains (9.41%) displayed inhibitory activity against E. coli, 11 strains (12.94%) against S. aureus, and two strains (2.35%) against C. tropicalis, to some extent. In particular, our study showed for the first time that the fungal agar plugs of Penicillium macrosclerotiorum 1151# exhibited promising antibacterial activity against E. coli and S. aureus. Moreover, the ethyl acetate (EA) extract of P. macrosclerotiorum 1151# had antibacterial effects against E. coli and S. aureus with a minimum inhibitory concentration (MIC) of 0.5 mg ml-1. Further research also confirmed that one of the antimicrobial compounds of P. macrosclerotiorum 1151# was methyl chloroacetate and exhibited excellent antibacterial activity against E. coli and S. aureus up to 1.71-fold and 1.13-fold compared with tetracycline (TET) (5 mg ml-1), respectively. Taken together, the present data suggest that various endophytic fungi of N. fordii could be exploited as sources of novel natural antimicrobial agents.

The effects of Ziziphus Spina leaves’ Hydro-Alcoholic Extract Vaginal Cream and Clotrimazole on Candida albicans in Wistar Rats

Background:

In vitro, Ziziphus Spina-Christi (ZSC) leaves have been shown to have antimicrobial and antifungal effects. This study aimed to examine the effects of Ziziphus Spina leaves hydro-alcoholic extracts with Clotrimazole against Candida albicans in female rats.

Methods:

Four groups of rats were infected vaginally with C. Albicans, and 1 group not infected was considered negative control. The infected groups received the following treatments: 2 groups were treated with vaginal 5%, or 10%, of Ziziphus Spina extract creams. One group received 1% clotrimazole, and 1 group did not receive any treatment considered a positive control.

Results:

The mean number of colony-forming units (CFUs) before the intervention was 195.83 ± 395.126 in the 5% ZSC group, 346.33 ± 396.719 in the 10% ZSC group, 345.17 ± 507.431 in the clotrimazole group, 212.20 ± 148.304 in the positive control group (P = .604), and 0 in the negative control group (P = .003). After 1 week, the average number of CFUs considerably dropped to 65.14 ± 36.03 in the 5% ZSC group, 1.43 ± 3.60 in the 10% ZSC group, and 0.43 ± 1.13 in the clotrimazole group. The number in the positive control group remained unchanged (212.20 ± 148.304) (P = .005). After 2 weeks, the average number of CFUs was 0 in the 10% ZSC group, Clotrimazole and negative control groups and was 4.57 ± 23.99 in the 5% ZSC group (P < .001).

Conclusions:

Our findings indicated that the effectiveness of Vaginal creams containing 10% Ziziphus Spina is similar to Clotrimazole in eliminating C. Albicans.