The Antibacterial Activities of Mikanolide and its Derivatives

Objective: The sesquiterpene, mikanolide, was found to possess antibacterial activity. As a result, a structure-activity relationship study was carried out on mikanolide and eleven of its derivatives. Methods: Mikanolide and two of its derivatives were isolated from organic extract of Mikania micrantha using chromatographic methods. Nine additional derivatives were synthesized and all were investigated for their antibacterial activity against the Gram positive pathogen Staphylococcus aureus and beta haemolytic Streptococcus group A (BHSA) as well as the Gram negative Escherichia coli using the disk diffusion assay. Results: The investigation revealed that only four of the derivatives displayed antibacterial activity and only pathogens Staphylococcus aureus and beta haemolytic Streptococcus group A were susceptible at a concentration of 100 μg per disk. However, there was an increase in activity for three of the derivatives in comparison to mikanolide. Conclusion: This study underscores the potential for phytochemicals from locally available plants to be further investigated and developed as antibacterial agents. Keywords: Antibacterial activity, M. micrantha, mikanolide, sesquiterpene "La Actividad Antibacteriana de la Mikanolida y sus Derivados" RESUMEN Objetivo: Se halló que el sesquiterpene – mikanolida – posee actividad antibacteriana. Como resultado, se llevó a cabo un estudio de la relación estructura-actividad de la mikanolida y once de sus derivados. Métodos: La mikanolida y dos de sus derivados fueron aislados a partir de un extracto orgánico de Mikania micrantha, mediante métodos cromatográficos. Se sintetizaron otros nueve derivados adicionales, y se investigó la actividad antibacteriana de todos sobre el patógeno Gram positivo Staphylococcus aureus y el Streptococcus beta hemolítico grupo A (BHSA) así como Escherichia coli Gram negativo, usando el ensayo de difusión en disco. Resultados: La investigación reveló que sólo cuatro de los derivados mostraban actividad antibacteriana y sólo los patógenos Staphylococcus aureus y Streptococcus beta hemolítico grupo A eran susceptibles a una concentración de 100 μg por disco. Sin embargo, se produjo un aumento en la actividad de tres de los derivados en comparación con la mikanolida. Conclusión: Este estudio subraya el potencial que poseen los fotoquímicos a partir de plantas localmente disponibles, para ser objeto de investigación ulterior y ser desarrollados como agentes antibacterianos. Palabras claves: Actividad antibacteriana, mikanolida, M. micrantha, sesquiterpen

Understanding the World with Geography: Junior Secondary

Electronic Textbook, 2014-15: Version 1.0: http://egeogbook.h

Understanding the World with Geography

Understanding the World with Geography, Version 1.0: http://egeogbook.hk/infopageThe Geography e-textbook (English version) entitled “Understanding the World with Geography” is developed for Junior Secondary 1-3. It is a web-based application that can be operated in a variety of platforms including Window, iOS and Android