Actividad antituberculosa de plantas colombianas / Anti-tubercular activity of eleven aromatic and medicinal plants occurring in Colombia

ABSTRACT

Introduction. Human tuberculosis is a contagious-infectious disease mainly caused by Mycobacterium tuberculosis. Although regimens exist for treating tuberculosis, they are far from ideal. Development of effective strategies for treatment of human tuberculosis has posed a challenge, considering the increase in infections associated with the human immunodeficiency virus and immunocompromised patients. Essential oils -volatile, aromatic oil extracts from plants-have been used in traditional treatment of many diseases; however careful investigation of these oils has not been undertaken with respect to treatments of tuberculosis.Objective. The in vitro antitubercular activity of essential oils from 11 medicinal plants grown in Colombia were assessed for efficacy as new medications (phytomedicines) for treatment of M. tuberculosis H37Rv.Material and methods. Essential oil extraction and analysis were performed as described Stashenko et al. (2004). Minimal inhibitory concentrations were determined by a colorimetric macrodilution method, following the protocol described by Abate et al. (1998). Isoniazide and rifampin were used as control treatments. Bactericidal and bacteriostatic activity was measured using the method developed by the Clinical and Laboratory Standards Institute consigned in the M26-A protocol. Results. Essential oils from Achyrocline alata and Swinglea glutinosa were the most active with minimal inhibitory concentrations of 62.5 À0.1 and 100 À36 Ìg ml-1, respectively. Carvacrol, thymol, p-cymene, 1,8-cineole, limonene, and A-pinene were the major components, most often identified in the 11 plant extracts of essential oils. Time-kill curve assays demonstrated the bacteriostatic activity of these essential oils. Conclusions. The essential oils from A. alata and S. glutinosa plants, and the components identified therein, are candidates as potential phytotherapeutic agents for human tuberculosis control.

RESUMEN

Introducción. La tuberculosis es una enfermedad infecto contagiosa causada por Mycobacterium tuberculosis. Aunque existen protocolos para su tratamiento, no son ideales. Actualmente, el desarrollo de estrategias terapéuticas efectivas ha tomado nuevos rumbos, considerando el incremento de pacientes positivos para el virus de la inmunodeficiencia humana. Los medicamentos basados en plantas medicinales se usan ampliamente en la medicina tradicional para el tratamiento de diversas afecciones. Los aceites esenciales obtenidos de plantas medicinales presentan amplia actividad antimicrobiana, sin embargo, existen pocos estudios que reporten la actividad antituberculosa de los mismos. Objetivo. Evaluar la actividad antituberculosa in vitro de 11 aceites esenciales provenientes de plantas medicinales que crecen en Colombia, los cuales podrían ser candidatos para el desarrollo de futuros fitofármacos. Materiales y métodos. La extracción y el análisis de los aceites esenciales se realizó bajo la metodología desarrollada por Stashenko et al.. La obtención de la concentración inhibitoria mínima se llevó a cabo por un método colorímetrico de macrodilución en caldo descrito por Abate y et al.; la isoniacida y la rifampicina se usaron como medicamentos control. La actividad bactericida y bacteriostética se determinaron mediante el protocolo M26-A del Clinical and Laboratory Standards Institute. Resultados. Los aceites esenciales provenientes de las plantas Achyrocline alata y Swinglea glutinosa fueron los más activos con concentraciones inhibitorias mínimas de 62.5 À0.1 y 100À36 Ìg ml-1, respectivamente. Carvacrol, timol, p-cymene, 1,8-cineole, limoneno, y Â-pineno fueron los componentes mayoritarios identificados en los 11 aceites. Los ensayos de curva de letalidad evidenciaron que ambos aceites son bacteriostáticos. Conclusiones. Los aceites esenciales obtenidos de las plantas A. alata y S. glutinosa, así como sus componentes, son candidatos potenciales como fitoterapéuticos para el control de la tuberculosis.