In-Vitro Antibacterial Activity of Endophytic Fungi from Peganum harmala (Laghouat, Algeria)

Abstract

Medicinal plants are an inexhaustible source of molecules. They are colonized by mycoendophytes, fungi living in their tissues without apparent symptoms. These fungi can provide secondary metabolites with biological activities. It is with this in mind that we are interested in a spontaneous plant from the dayas region (Laghouat, Algeria): Peganum harmala or Harmel, a toxic medicinal plant belonging to the family Zygophyllaceae. Our study consists in highlighting the antibacterial activity of four kinds of mycoendophytes: Cladosporium, Alternaria, Aspergillus and Penicillium isolated from the leaves of this plant. The antibacterial activity is evaluated by the technique of the double disk diffusion on agar with respect to some Gram-positive bacterial strains. We have adopted two protocols for this purpose. For the first, the mycelia of all the mushrooms are deposited in the same petri dish. For the second, a single disc of the mycelium of a single species is deposited per box. The results obtained show a difference in the sensitivity of the bacterial strains to the bioactive substances of the mycoendophytes studied. The Alternaria genus showed the most significant activity. ANOVA performed between the mean diameters of the mycoendophyte inhibition zones and the antibiotic test disc: Chloramphenicol showed a highly significant difference between these two measurements. The Newman-Keuls test revealed a difference in the susceptibility of bacterial strains to the secondary metabolites of fungus mycoendophytes of Peganum harmala according to the two protocols used. The antibacterial effect is related to interactions between endophytic fungi and their host plant.