Evaluación de la función antibacteriana de las β-carbolinas extraídas de banisteriopsis caapi (ayahuasca) contra bacterias gram-positivas y negativas

Abstract

Globally, there is growing concern about the increase in antibiotic resistance by bacteria; consequently, several strains of bacteria resistant to various types of antibiotics have appeared and spread to such an extent that some of these are now obsolete. For this reason, organizations, such as the WHO, promote the continuous search for new active principles that allow us to combat these microorganisms. In that sense, Ecuador is a privileged country in terms of flora and fauna, so the search for these new active principles should be promoted. These active principles could positively impact the Public Health System, and the country could receive an economic benefit. For this reason, the present work analyzes the antibacterial capacity of extracts of Banisteriopsis caapi, a typical plant of the Amazon region of Ecuador, which contains β-carbolines as its active principle. These have been shown to have antibacterial, antitumor, and antiparasitic effects and could be a good alternative in fighting antibiotic resistance. The extracts were analyzed by HPLC, quantifying harmine in all of them. The antimicrobial efficacy was verified against several Gram-positive and Gram-negative bacteria such as (S. aureus, K. pneumoniae, E. faecalis, E. coli, and P. aeruginosa) which are often a problem due to nosocomial infections of resistant microorganisms. Extracts 3, 8, and 9 showed harmine in their composition. On the other hand, extract 7 did not show any harmine. The broth microdilution method was used, which allowed, from the % of inhibition, to establish the IC50 to compare potencies and efficiencies of the different extracts and these with the antibiotics used as positive control. The Gram-positive bacteria Enterococcus faecalis was identified as the most sensitive. Furthermore, extract 3 was identified as the most effective, with results comparable to positive controls. In addition, extract 9 showed the highest potency with the lowest IC50 values. Our results conclude that B. caapi extracts are effective in inhibiting the growth of the bacteria analyzed with potency and efficacy comparable to those of commercial antibiotics.