Abstract

MORA-VILLA, A. et al. Evaluation of the antimicrobial activity of Leucaena esculenta and Leucaena leucocephala seed collected from Tlayacapan, Morelos (Mexico). Polibotánica [online]. 2021, n.52, pp.175-191.  Epub Oct 18, 2021. ISSN 1405-2768.  https://doi.org/10.18387/polibotanica.52.12.

Leucaena esculenta and Leucaena leucocephala (Fabaceae) are species known in Mexico as "guajes", both are used as food and medicinal resources to alleviate different infectious diseases. The objective of this study was to determine the antimicrobial activity of the methanolic, acetonic and hexanic extracts of the seeds of L. esculenta and L. leucocephala collected in the community of Tlayacapan Morelos. The extracts were obtained by the maceration technique with hexane, acetone and methanol from the same plant material and reduced by vacuum distillation using a rotary evaporator. The antimicrobial activity of the extracts was determined qualitatively and quantitatively in 20 bacterial strains, 3 yeast strains and 4 strains of filamentous fungi. In qualitative tests, antimicrobial activity was found in 6 bacterial strains (all of Staphylococcus aureus and Escherichia coli), 1 strain of yeast fungi and 4 of mycelial fungi. Using the broth microdilution technique, Escherichia coli CUSI showed MIC values ​​of 2000 and 3000 μg / mL for L. leucocephala and L. esculenta respectively and for Staphylococcus aureus CUSI, MIC = 4000 and 2000 μg / mL for methanolic extracts of L. leucocephala and L. esculenta respectively. The MBC values ​​for the kinetics of death (6000 μg / mL for L. leucocephala and 4000 μg / mL for L. esculenta) had a significant effect in the first 10 hours of treatment. Meanwhile, Candida glabrata was susceptible to methanolic extracts with MFC values ​​of 4000 μg / mL (L. leucocephala) and 6000 μg / mL (L. esculenta). In radial growth inhibition technique, it was reported that the lowest values ​​of CF50 correspond to the acetonic extracts of seeds (L. lecucocephala = 2.28 mg / mL and L. esculenta = 2.72 mg / mL) having a significant effect against strains Trichophyton mentagrophytes and Aspergillus niger, respectively. In qualitative tests for the determination of secondary metabolites, the presence of alkaloids, triterpenes, monoterpenes, steroids, saponins and phenolic compounds were found, which report antimicrobial potential. The methanolic and acetonic extracts from the seeds of both guajes showed significant biological activity on different strains of bacteria and fungi, thus validating the medicinal use of this resource by the Tlayacapan community.

Keywords : Antimicrobial activity; Leucaena leucocephala; Leucanea esculenta; medicinal plants; Tlayacapan.

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