VOLUME 72 : 2024

Tuberculosis, the disease caused by Mycobacterium tuberculosis, has been a global health concern that has
plagued the Philippines and other developing countries. The need for continuous search for antitubercular
agents is a result of the emergence of drug resistant strains (multi drug- and extensively drug-resistant
strains) and other factors. Essential oils are multi-component mixtures that have been used since ancient
times for their medicinal properties. This study aimed to determine the in-vitro antitubercular activity of
the essential oils from 38 Philippine plants in two phases. Out of 38 species, only 21 yielded essential
oils which were assayed against M. tuberculosis H37Ra ATCC strain using the submerged disk method.
The bioactive essential oils were further assayed, using the agar dilution method, against resistant clinical
strains, including mono-, multi-, and poly-drug resistant strains. Those which inhibited the growth of
all the resistant strains (the 4 monoresistant strains – Str-, Pza-, Inh-, Rif-; 1 multidrug resistant strain
(MDR) – Inh-Rif-; 2 polydrug resistant (PolyDR) strains – Str-Inh-Rif-(SIR), Inh-Eth-Pza-(IEP)) at
all concentrations were from Citrus microcarpa Bunge (rind), Citrus maxima (Burm.) Osbeck (rind),
Cymbopogon citratus (DC.) Stapf (leaves, stalks) and Cymbopogon winterianus Jowitt ex Bor (leaves).