ABSTRACT
INTRODUCCIÓN: reportes científicos han demostrado que la Morinda citrifolia L (noni) presenta actividad antimicrobiana frente a un gran número de bacterias y hongos patógenos, sin embargo estos estudios reportan estas propiedades para el fruto, existiendo poca información sobre las hojas, raíces y semillas de esta planta. OBJETIVOS: evaluar la actividad antimicrobiana in vitro de diferentes extractos de hojas secas y semillas de M. citrifolia L (noni), así como identificar mediante cromatografía de capa fina los principales metabolitos secundarios responsables de la actividad antimicrobiana. MÉTODOS: se evaluó la actividad antimicrobiana in vitro de los extractos alcohólicos, hexánicos, clorofórmicos y de acetato de etilo de las hojas y semillas de la M. citrifolia L. (noni) frente a cepas de E. coli, S. aureus y Candida sppor el método de Bauer-Kirby. Se identificaron mediante cromatografía de capa fina los metabolitos responsables de la actividad antimicrobiana en placas semi-preparativas de sílica gel, y se observaron los perfiles cromatográficos bajo la luz ultravioleta (l=365 nm). RESULTADOS: todos los extractos evaluados de las hojas y semillas de M. citrifolia L (noni) tuvieron actividad antimicrobiana frente a las cepas estudiadas. Los principales metabolitos secundarios detectados fueron, en los extractos de hojas, quinonas, coumarinas y flavonoides; en las semillas, coumarinas y flavonoides respectivamente. CONCLUSIONES: se demostró la actividad antimicrobiana de hojas y semillas del árbol de M. citrifolia L (noni), siendo los metabolitos secundarios quinonas y coumarinas los responsables de ésta.
INTRODUCTION: scientific studies have shown that Morinda citrifolia L. (noni) has antimicrobial activity against a large number of pathogenic bacteria and fungi. However, those studies report such activity in reference to the fruit, and there is little information about the leaves, roots and seeds of the plant. OBJECTIVES: evaluate the antimicrobial activity in vitro of various extracts from dry leaves and seeds of M. citrifoliaL. (noni) and identify by thin layer chromatography the main secondarymetabolites responsible for such antimicrobial activity. METHODS: an evaluation was conducted of the antimicrobial activity in vitro of alcoholic, hexanic, chloroformic and ethyl acetate extracts from leaves and seeds of M. citrifolia L. (noni) against E. coli, S. aureus and Candida sp. strains using the Bauer-Kirby method. Thin layer chromatography was used to identify the metabolites responsible for antimicrobial activity on semi-preparative silica gel plates. Chromatographic profiles were observed under ultraviolet light (l=365 nm). RESULTS: all the extracts evaluated of leaves and seeds of M. citrifolia L. (noni) had antimicrobial activity against the strains studied. The main secondary metabolites found were quinones, coumarins and flavonoids in the leaf extracts, and coumarins and flavonoids in the seed extracts. CONCLUSIONS: it was demonstrated that leaves and seeds of the M. citrifolia L. tree (noni) have antimicrobial activity, and that quinones and coumarins are the secondary metabolites responsible for such activity.