Anti-trypanosomal Activity of Endophytic Streptomycete

This is the first report of anti-trypanosomal activity of endophytic streptomycetes isolated from plants in Malaysia. Eight endophytic streptomycetes were isolated from the stems and roots of Cinnamomum zeylanicum, Elettariopsis curtisii and Zingiber spectabile which were collected from a Northern Peninsula Malaysia Country Park based on their ethnobotanical properties. The endophytic actinomycetes isolated were subjected to molecular identification whereby DNA was extracted using Sarkosyl, followed by amplification of 16S rRNA using 27f and 765r primer, prior to gene sequencing, BLASTN search and construction of 16S rRNA phylogenetic tree using MEGA4. Simultaneously, secondary metabolites extracted from nutrient broth using ethyl acetate were tested for their anti-trypanosomal activity. The isolates were identified based on their 16S rRNA gene sequences and evaluated for anti-trypanosomal activities. Phylogenetic analyses showed that isolates SUK 17 and SUK 24 were closely related to Streptomyces niger strain and the remaining six isolates were closely related to Streptomyces sampsonii. Interestingly, although the 16S rRNA gene sequences of both isolates SUK 17 and SUK 24 were 100% identical, only isolate SUK 17 which was isolated from Cinnamomum zeylanicum has shown positive anti-trypanosomal activity with IC50 value of 4.48 μg mL-1 for Trypanosoma brucei brucei strain BS221 and 60.98 μg mL-1 for vero cells with the selectivity index of 13.61. The finding of this research could be a new breakthrough and the discovery of anti-trypanosomal secondary metabolites from isolate SUK 17 may be able contribute to the medical and pharmaceutical field.