Identification of Substances Produced by Cercospora brachiata in Absence of Light and Evaluation of Antibacterial Activity

Abstract

Cercospora brachiata is a phytopathogenic fungus. To know more about the metabolites produced by this fungus, the objective of this work was to identify, isolate and characterize substances present in extracts of the growth broth and mycelium, using gas chromatography with mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR). It was also objective to evaluate the antibacterial activity of the extracts. Among the compounds identified, fatty acids, esters, and steroids can be highlighted. The main compounds identified are 9-hexadecenoic, hexadecenoic, oleic, octadecanoic, lauric, myristic, palmitic, doceno-13-enoic, stearic, linoleic, and nonadecanoic acids present in almost all extracts. For the antibacterial activity, the broth microdilution method was used. The ethyl acetate extract of the mycelium presented inhibitory concentrations (MICs) against the bacterium Actinomyces naeslundii (100 μg mL−1) and Streptococcus sanguinis (200 μg mL−1). Finally, two steroids were isolated and identified in the hexane extract of mycelium: ergosta-6,22-dien-3β,5α,8α-triol and brassicasterol.

Metabolites Profiling and In Vitro Biological Characterization of Different Fractions of Cliona sp. Marine Sponge from the Red Sea Egypt

“…37.43 min) exhibited a molecular ion peak at m / z 399 [M + H] + and m / z 381 [M + H-H 2 O] + , corresponding to C 28 H 46 O after the loss of one water molecule. In comparison with the literature [ 21 ], compound 23 was identified as brassicasterol.…”

“…Compounds 1 and 2 were obtained as a white amorphous mixture and were identified as coprostanol and brassicasterol based on a comparison of their spectroscopic analysis data, including EI-MS ( Figure S1 ), GC-MS ( Figures S2–S4 ), the ratio of coprostanol to brassicasterol (88.5% to 11.5%), 1 H-NMR, and 13 C-NMR ( Table S1 ), with the reported literature data [ 20 , 21 , 22 ].…”

“…Various spectral analyses such as EI-MS, GC-MS, 1 H-NMR, and 13 C-NMR were used for the structure elucidation of the isolated compounds in addition to the comparison with the available works of literature. They were characterized as coprostanol ( 1 ), brassicasterol ( 2 ) [ 20 , 21 , 22 ], stigmasterol ( 3 ) [ 23 ], and taurine ( 4 ) [ 24 , 25 ] ( Figure 1 ). To the best of our knowledge, this is the first report about the isolation of these compounds from Cliona sp.…”

Phytochemicals Screening and Antibacterial Activity of Teijsmaniadendron Holrungii from West Papua

“…The mechanism of steroid antibacterial activity through interactions with lipid membranes results in damage to liposomes, thereby inhibiting the entry of nutrients into bacterial cells (Nadaraia et al, 2019;Felisbino et al, 2021;Sharaf et al, 2022). Similarly, tannin compounds inhibit bacterial growth through interactions with cell membranes, causing changes in the structure of cell membranes and damaging membrane function in bacteria (Carvalho et al, 2018;Maisetta et al, 2019;Olchowik-Grabarek et al, 2022).…”

Identification of antifungal compound isolated from Cercospora sp. ME202 and evaluation of its inhibitory activity against Colletotrichum orbiculare

“…Therefore, Cercospora is considered an important control subject. In contrast, some Cercospora species have been found to produce secondary metabolites with antibacterial and antifungal activities (Felisbino et al 2021;Mookherjee et al 2020). We previously reported that Cercospora sp.…”