Antitumor and antibacterial activity of metabolites of endophytic Colletotrichum siamense isolated from coffee (Coffea arabica L. cv IAPAR-59).

Endophytic fungi produce a range of known metabolites and several others, not yet explored, which present important biological activities from the pharmaceutical and industrial perspective. Several studies have reported the diversity of endophytes in Coffea arabica plants, although few have been described in organic cultures. In the current paper, we describe the chemical profile of specialized metabolites in the ethyl acetate phase in a strain of the endophytic fungus Colletotrichum siamense associated with coffee (Coffea arabica L.) (Rubiaceae) and its potential against tumor cells and bacteria of medical and food importance. Cytotoxicity assays in tumor cells MCF-7 and HepG2/C3A were performed by MTT and microdilution in broth to evaluate the antibacterial action of metabolic extract. The antiproliferative assay showed promising results after 24 h of treatment, with 50% injunction concentrations for the two cell types. UHPLC-MS/MS analyses with an electrospray ionization source were used to analyze the extracts and identify compounds of species Colletotrichum siamense, which is still little explored as a source of active metabolites. Many of these compounds observed in the endophytic need to be chemically synthesized in industry, at high costs, while production by the fungus becomes a chemically and economically more viable alternative. Pyrocatechol, gentisyl alcohol, and alpha-linolenic acid, associated with different mechanisms of action against tumor cells, were detected among the main compounds. The extract of the endophytic fungus Colletotrichum siamense presented several compounds with pharmacological potential and antibacterial activity, corroborating its potential in biotechnological applications.

Influence of plant growth-promoting endophytes Colletotrichum siamense and Diaporthe masirevici on tomato plants (Lycopersicon esculentum Mill.).

The protective and growth-promoting activities of Colletrotrichum and Diaporthe endophytes on tomato plants (Lycopersicon esculentum Mill.) are underexplored. We screened 40 endophytic fungi associated with Mexican shrimp plant (Justicia brandegeana) using an in vitro dual culture assay for Fusarium oxysporum, one of the most important phytopathogens of tomato plants. The three best antagonists, Colletotrichum siamense (JB224.g1), C. siamense (JB252.g1), and Diaporthe masirevicii (JB270), were identified based on multilocus sequence analysis. They were assessed in vitro for their inhibition of F. oxysporum and phosphate solubilisation capacity, and for the production of indole acetic acid. Greenhouse experiments verified the growth-promoting effects of these endophytes and the suppression of F. oxysporum symptoms in tomato plants.   Under greenhouse conditions, the JB252.g1 and JB270 isolates showed positive results for seedling emergence speed. The radicular system depth of plants inoculated with JB270 was greater than that in uninoculated plants (27.21 vs 21.95 cm). The soil plant analysis development chlorophyll metre (SPAD) index showed statistically significant results, especially for the endophyte JB224.g1 (36.99) compared to the control plants (30.90) and plants infected solely with F. oxysporum (33.64).

Tibouchina granulosa (Vell.) Cogn (Melastomataceae) as source of endophytic fungi: isolation, identification, and antiprotozoal activity of metabolites from Phyllosticta capitalensis.

Endophytes are microorganisms that form symbiotic relationships with their own host. Included in this group are the species Phyllosticta capitalensis, a group of fungi that include saprobes that produce bioactive metabolites. The present study aimed to identify the cultivable endophytic fungal microbiota present in healthy leaves of Tibouchina granulosa (Desr.) Cogn. (Melastomataceae) and investigate secondary metabolites produced by a strain of P. capitalensis and their effects against both Leishmania species and Trypanossoma cruzi. Identification of the strains was accomplished through multilocus sequencing analysis (MLSA), followed by phylogenetic analysis. The frequency of colonization was 73.66% and identified fungi belonged to the genus Diaporthe, Colletotrichum, Phyllosticta, Xylaria, Hypoxylon, Fusarium, Nigrospora, and Cercospora. A total of 18 compounds were identified by high-resolution mass spectrum analysis (UHPLC-HRMS), including fatty acids based on linoleic acid and derivatives, from P. capitalensis. Crude extracts had activity against Leishmania amazonensis, L. infantum, and Trypanosoma cruzi, with inhibitory concentration (IC50) values of 17.2 µg/mL, 82.0 µg/mL, and 50.13 µg/mL, respectively. This is the first report of the production of these compounds by the endophytic P. capitalensis isolated from T. granulosa.

Antibacterial activity of papain and bromelain on Alicyclobacillus spp.

Alicyclobacillus spp. are spore forming bacteria that are often related to the deterioration of acidic products such as beverages and citrus juices. After the process of industrial pasteurization, the spore produced by the bacteria can germinate and the microorganism can grow, causing sensory abnormalities in the product. Alternative biopreservatives, such as the antimicrobial compounds, are of considerable importance to the food industry. Papain and bromelain are proteolytic enzymes derived frompapaya and pineapple, respectively. These enzymes are widely used in medicine and in the pharmaceutical and food industries, but while some studies have described their antibacterial action, no studies of the Alicyclobacillus spp. exist. The aimof this studywas to analyze the antibacterial effect of papain and bromelain on Alicyclobacillus spp. through 1) determining minimum inhibitory and bactericidal concentration (MIC and MBC); 2) determining the death time curve of the micro-organism in the presence and absence of enzymes; and 3) investigating the enzymatic mechanism on the microorganism. The antibacterial activity of enzymes in combination with nisin was also evaluated. The results showed that for the Alicyclobacillus acidoterrestris strain, the MIC of papain was 0.98 µg/mL and the MBC was 3.91 µg/mL, while theMIC of bromelain was 62.5 µg/mL and the MBCwas 250 µg/mL. The concentration of 4 ×MIC for both the enzymes was sufficient to eliminate 4 logs of the micro-organism after 24 h of incubation. Through the use of enzyme inhibitors specific for cysteine proteases, it was found that the antibacterial activity of papain and bromelain is not related to its proteolytic activity, butmay be related to other activities, such as amidse and esterase. The synergistic activity of the enzymes revealed a fractional inhibitory concentration (FIC) level of 0.16. Combination with nisin revealed an FIC of 0.25 for papain and 0.19 for bromelain, indicating synergism between both compounds. The application of enzymes in reconstituted orange juice contaminated with A. acidoterrestris was found to be effective, as after 48 h of incubation, at three different temperatures, the initial microbial population was eliminated. This study showed that the enzymes papain and bromelain have an antibacterial effect on A. acidoterrestris.