Production of Bioactive Compounds with Broad Spectrum Bactericidal Action, Bio-Film Inhibition and Antilarval Potential by the Secondary Metabolites of the Endophytic Fungus Cochliobolus sp. APS1 Isolated from the Indian Medicinal Herb Andrographis paniculata

Abstract

Endophytes, being the co-evolution partners of green host plants, are factories of pharmaceutically valuable novel natural products. Cochliobolus sp. APS1, an endophyte of Andrographis paniculata (Green Chiretta), produces a plethora of natural bioactive compounds and the multipotent alkaloid Aziridine, 1-(2-aminoethyl)-, is the prime one among them. The isolate exhibited antibacterial, anti-biofilm, and antilarval potency. The MIC and MBC values of the ethyl-acetate culture extract ranged from 15.62 to 250 µg/mL against ten pathogenic microorganisms (including MRSA and VRSA). Killing kinetics data along with the leakage of macromolecules into the extracellular environment supports the cidal activity of the antibacterial principles. The broad spectrum antibacterial activity of Aziridine, 1-(2-aminoethyl)-, was optimized by a one-variable-at-a-time system coupled with response surface methodology, which led to a 45% enhancement of the antibacterial activity. The maximum response (22.81 ± 0.16 mm of zone of inhibition against MRSA) was marked in 250 mL Erlenmeyer flask containing 90 mL potato dextrose broth supplemented with (g%/L) glucose, 9.7; urea concentration, 0.74; with medium pH 6.48; after 8.76 days of incubation at 26 °C. APS1 strongly inhibited biofilm formation in the tested pathogenic microorganisms and acts as a larvicidal agent against the Dengue-vector Aedes aegypti. This is probably the first report of Aziridine, 1-(2-aminoethyl)-, from any endophytic source. Cochliobolus sp. APS1 possesses industrial importance for the production of bioactive alkaloids.

Broad-Spectrum Antimicrobial Action of Cell-Free Culture Extracts and Volatile Organic Compounds Produced by Endophytic Fungi Curvularia Eragrostidis

“…The necessary enzymes involved in central carbohydrate metabolism are also affected by the fungal metabolites, and there was a sharp inhibition of those enzymes involved in energy metabolism upon the increase of a treatment dose, i.e., MIC and MBC. A similar type of finding was made by Santra et al (2022) and Chatterjee et al (2019) where endophytic fungal metabolites inhibit the three main enzymes of potent bacterial pathogens involved in carbohydrate metabolism.…”

“…EA is selected as the most suitable extraction agent in comparison to other solvents (ethyl ether, petroleum ether, and n -hexane) as the EA fraction showed the highest antibacterial action. Non-proteinaceous nature and thermostability of antibacterial components obtained from endophytic fungi are also reported by Santra et al (2022) . Malhadas et al (2017) also reported the anti-bacterial action of the EA fraction of secondary metabolites of olive tree endophytes.…”

Cyclodepsipeptides: Isolation from Endophytic Fungi of Sarcophyton ehrenbergi and Verification of Their Larvicidal Activity via In-Vitro and In-Silico Studies

“…The misuse of these synthesized insecticides has led to environmental problems, in addition to the emergence of resistant variants [ 6 , 7 ]. To ensure the sustainability of the ecosystem, components with low or no toxicity to non-target organisms should be used [ 8 ]. Natural products derived from fungi or other biological sources are inexpensive, environmentally friendly, and play an important role in alleviating these types of problems [ 9 , 10 ].…”

Bioactivity study and metabolic profiling of Colletotrichum alatae LCS1, an endophyte of club moss Lycopodium clavatum L.

“…Antimicrobial resistance has become a serious global concern and it is high-time to adopt novel strategies to overcome this situation [ 51 ]. Bioactive compounds from endophytic communities have just opened a new sector in this respect [ 52 , 53 ].…”