Copper ion-based chemical elicitation induces production of new benzofurans in Anthostomella brabeji, an endophytic fungus of Paepalanthus planifolius.

The present work reports the effects of chemical elicitors and epigenetic modifiers on the production and diversification of secondary metabolites produced by Anthostomella brabeji - an endophytic fungus isolated from Paepalanthus planifolius (Eriocaulaceae). The fungus was cultivated under four different small-scale culture conditions in potato dextrose broth (PDB): PDB (control), PDB + Mg+2, PDB + Cu+2 and PDB + 5-AZA (5-azacytidine). The incorporation of Cu+2 into PDB medium yielded the most promising results as the most significant differences in the metabolic profile of A. brabeji were observed under this condition. The chemical analysis of the PDB + Cu+2 extract resulted in the isolation of seven metabolites, including three new benzofuran derivatives (2, 4 and 6) and four known compounds (1, 3, 5 and 7). The metabolites were tested using the Gram-positive bacterium Staphylococcus aureus, Gram-negative bacteria Salmonella sp. and Escherichia coli, and six yeasts of Candida albicans and non-albicans. The EtOAc extract (PDB + Cu+2), and compounds 1, 2 and 7 exhibited relevant antifungal activity against Candida spp., with minimum inhibitory concentration ranging from 62.5 to 500.0 µg/mL.

New Isoquinoline Alkaloids from Paraphaeosphaeria sporulosa F03, a Fungal Endophyte Isolated from Paepalanthus planifolius.

As part of our continuing efforts to discover new bioactive compounds from endophytic fungal sources, we have investigated the extract of the Paraphaeosphaeria sporulosa F03 strain. The study led to the isolation of four new 3-methyl-isoquinoline alkaloids (1:  - 4: ) and four known polyketides (5:  - 8: ). The structures of compounds 1:  - 4: were elucidated by 1D and 2D NMR experiments and HRMS analysis. The absolute configuration of 4: was determined by comparison of its experimental electronic circular dichroism spectrum with calculated data. Compounds 1:  - 4: exhibited antifungal activity with minimal inhibitory concentration values ranging from 6.25 - 50 µg/mL against six Candida species but they did not present any cytotoxic activity against the human tumor cell lines A549 (lung), MCF-7 (breast), and HepG2 (hepatocellular). In addition, compound 4: exhibited antiplasmodial activity in the low micromolar range (IC50 = 4 µM).

Syngonanthus nitens (Bong.) Ruhland Derivatives Loaded into a Lipid Nanoemulsion for Enhanced Antifungal Activity Against Candida parapsilosis.

BACKGROUND: Vaginal infections caused by non-albicans species have become common in women of all age groups. The resistance of species such as Candida parapsilosis to the various antifungal agents is a risk factor attributed to these types of infections, which instigates the search for new sources of active compounds in vulvovaginal candidiasis (VCC) therapy. OBJECTIVE: This study evaluated the antifungal activity of Syngonanthus nitens Bong. (Ruhland) derivatives and employed a lipid nanoemulsion as a delivery system.' METHODS: In this study, a lipid nanoemulsion was employed as a delivery system composed of Cholesterol (10%), soybean phosphatidylcholine: Brij 58 (1: 2) and PBS (pH 7.4) with the addition of 0.5% of a chitosan dispersion (80%), and evaluated the antifungal activity of S. nitens Bong. (Ruhland) derivatives against planktonic cells and biofilms of Candida parapsilosis. By a biomonitoring fractionation, the crude extract (EXT) and one fraction (F2) were selected and incorporated into a lipid nanoemulsion (NL) composed of cholesterol (10%), a 1:2 mixture of soybean phosphatidylcholine:polyoxyethylene -20- cetyl ether (10%), and phosphate buffer solution (pH 7.4) with a 0.5% chitosan dispersion (80%). The NL presented a diameter size between 50-200 nm, pseudoplastic behavior, and positive charge. The EXT and five fractions were active against planktonic cells. RESULTS AND DISCUSSION: The incorporation of EXT and F2 into the NL increased antifungal activity and enhanced the anti-biofilm potential. This study classified the use of an NL as an important tool for the administration of S. nitens derivatives in cases of infections caused by this C. parapsisilosis. CONCLUSION: This work concluded that S. nitens derivatives were important sources of active molecules against C. parapsilosis and the use of a lipid nanoemulsion was an important tool to promote more effective F2 release and to improve the antifungal activity aiming the control of C. parapsilosis infections.

Spirocyclic lactams and curvulinic acid derivatives from the endophytic fungus Curvularia lunata and their antibacterial and antifungal activities.

Curvularia lunata, isolated from the capitula of Paepalanthus chiquitensis (Eriocaulaceae), was cultured in potato dextrose broth (PDB) medium. The ethyl acetate extract yielded two new spirocyclic γ-lactams (3 and 4), and five known compounds, namely: triticones E (1) and F (2), 5-O-methylcurvulinic acid (5), curvulinic acid (6) and curvulin (7). Their structures were elucidated by spectroscopic analysis and by the comparison with literature data. Besides, a computational study was used to elucidate the absolute configuration of the C - 3' in the compounds (3) and (4). The extract and the compounds (1 and 2), (6) and (7) were assayed against gram-positive and gram-negative bacteria and fluconazole-resistant yeast. The triticones (1) and (2) showed good antibacterial activity for Escherichia coli, with a minimum inhibitory concentration of 62.5 µg/mL.

New Benzaldehyde and Benzopyran Compounds from the Endophytic Fungus Paraphaeosphaeria sp. F03 and Their Antimicrobial and Cytotoxic Activities.

Three new benzaldehyde derivatives, sporulosaldeins A - C (1: -3: ), and 3 new benzopyran derivatives, sporulosaldeins D - F (4: -6: ), were discovered from an endophytic fungus, Paraphaeosphaeria sp. F03, which was isolated from Paepalanthus planifolius leaves. Compounds 1: -6: were elucidated by 1- and 2-dimensional nuclear magnetic resonance experiments and high-resolution mass spectrometry analysis. The absolute configuration of compound 5: was determined through the comparison of experimental and calculated electronic circular dichroism data. Compounds 1: -6: were found to exhibit antifungal activity with minimum inhibitory concentration (MIC) values of 7.8 - 250 µg/mL and racemic mixture of compound 6: exhibited weak cytotoxicity against MCF-7 and LM3 with IC50 values of 34.4 and 39.2 µM, respectively.

Estrogenic and chemopreventive activities of xanthones and flavones of Syngonanthus (Eriocaulaceae).

The possible benefits of some bioactive flavones and xanthones present in plants of the genus Syngonanthus prompted us to screen them for estrogenic activity. However, scientific research has shown that such substances may have undesirable properties, such as mutagenicity, carcinogenicity and toxicity, which restrict their use as therapeutic agents. Hence, the aim of this study was to assess the estrogenicity and mutagenic and antimutagenic properties. We used recombinant yeast assay (RYA), with the strain BY4741 of Saccharomyces cerevisiae, and Ames test, with strains TA100, TA98, TA97a and TA102 of Salmonella typhimirium, to evaluate estrogenicity, mutagenicity and antimutagenicity of methanolic extracts of Syngonanthus dealbatus (S.d.), Syngonanthus macrolepsis (S.m.), Syngonanthus nitens (S.n.) and Syngonanthus suberosus (S.s.), and of 9 compounds isolated from them (1=luteolin, 2=mix of A-1,3,6-trihydroxy-2-methoxyxanthone and B-1,3,6-trihydroxy-2,5-dimethoxyxanthone, 3=1,5,7-trihydroxy-3,6-dimethoxyxanthone, 4=1,3,6,8-tetrahydroxy-2,5-dimethoxyxanthone, 5=1,3,6,8-tetrahydroxy-5-methoxyxanthone, 6=7-methoxyluteolin-8-C-ß-glucopyranoside, 7=7-methoxyluteolin-6-C-ß-glucopyranoside, 8=7,3'-dimethoxyluteolin-6-C-ß-glucopyranoside and 9=6-hydroxyluteolin). The results indicated the estrogenic potential of the S. nitens methanol extract and four of its isolated xanthones, which exhibited, respectively, 14.74±1.63 nM; 19.54±6.61; 7.20±0.37; 6.71±1.02 e 10.01±4.26 nM of estradiol-equivalents (EEQ). None of the extracts or isolated compounds showed mutagenicity in any of the test strains and all of them showed antimutagenic potential, in particular preventing mutations caused by aflatoxin B1 (AFB1) and benzo[a]pyrene (B[a]P). The results show that the xanthones, only isolated from the methanol extract of S. nitens capitula, probably were the responsible for its estrogenic activity and could be useful as phytoestrogens, providing a new opportunity to develop hormonal agents. In addition, flavones and xanthones could also be used as a new antimutagenic agent. Since, the mutagens are involved in the initiation and promotion of several human diseases, including cancer, the significance of novel bioactive phytocompounds in counteracting these pro-mutagenic and carcinogenic effects is now gaining credence.

Correlation among antioxidant, antimicrobial, hemolytic, and antiproliferative properties of Leiothrix spiralis leaves extract.

The biological activities of a plant extract depend on a complex sum of individual properties including the antioxidant activity. Several biological activities protect against the harmful action of reactive oxygen species (ROS), and here we focused our attention on the relationship between the biological activities tested and the antioxidant properties. In this study, the total flavonoid content as well as the antioxidant, antimicrobial, hemolytic and cytotoxicity activities of the methanolic extract of Leitothrix spiralis leaves were evaluated. The extract showed a total flavonoid content of 19.26% and the chemical characterization by HPLC-PAD confirmed the presence of flavonoids as the major secondary metabolite compounds. Significant antioxidant activity (IC(50) = 1.743 µg/mL ± 0.063) was demonstrated and was effective against Gram-negative organisms and all Candida strains tested, and showed an ability to inhibit hyphal formation. Non-hemolytic and antiproliferative activity could be demonstrated.

Chemical constituents of the methanolic extract of leaves of Leiothrix spiralis Ruhland and their antimicrobial activity.

Chemical fractionation of the methanolic extract of leaves of Leiothrix spiralis Ruhland afforded the flavonoids luteolin-6-C-ß-D-glucopyranoside (1), 7-methoxyluteolin-6-C-ß-D-glucopyranoside (2), 7-methoxyluteolin-8-C-ß-D-glucopyranoside (3), 4'-methoxyluteolin-6-C-ß-D-glucopyranoside (4), and 6-hydroxy-7-methoxyluteolin (5), and the xanthones 8-carboxymethyl-1,5,6-trihydroxy-3-methoxyxanthone (6), 8-carboxy-methyl-1,3,5,6-tetrahydroxyxanthone (7). Methanolic extract, fractions, and isolated compounds of the leaves of L. spiralis were assayed against Gram-positive (Staphylococcus aureus, Bacillus subtilis and Enterococcus faecalis) and Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Salmonella setubal and Helicobacter pylori) and fungi (the yeasts Candida albicans, C. tropicalis, C. krusei and C. parapsilosis). We observed the best minimum inhibitory concentration values for the methanolic extract against Candida parapsilosis, for the fraction 5 + 6 against Gram-negative bacteria E. coli and P. aeruginosa, and compound 7 against all tested Candida strains. The methanolic extract contents suggest that this species may be a promising source of compounds to produce natural phytomedicines.