Potential secondary metabolite from Indonesian Actinobacteria (InaCC A۷۵۸) against Mycobacterium tuberculosis

Objective(s): This study explored Indonesian Actinobacteria which were isolated from Curcuma zedoaria endophytic microbes and mangrove ecosystem for new antimycobacterial compounds. Materials and Methods: Antimycobacterial activity test was carried out against Mycobacterium tuberculosis H۳۷Rv. Chemical profiling of secondary metabolite using Gas Chromatography-Mass Spectroscopy (GC-MS) and High Resolution-Mass Spectroscopy (HR-MS) was done to the ethyl acetate extract of active strain InaCC A۷۵۸. Molecular taxonomy analysis based on ۱۶S rRNA gene and biosynthetic gene clusters analysis of polyketide synthase (PKS) and non-ribosomal peptide synthetase (NRPS) from InaCC A۷۵۸ have been carried out. Bioassay guided isolation of ethyl acetate extract was done, then structural elucidation of active compound was performed using UV-Vis, FT-IR, and NMR spectroscopy methods. Results: The chemical profiling using HR-MS revealed that InaCC A۷۵۸ has the potential to produce new antimycobacterial compounds. The ۱۶S rRNA gene sequencing showed that InaCC A۷۵۸ has the closest homology to Streptomyces parvus strain NBRC ۱۴۵۹۹ (۹۹.۶۴%). In addition, InaCC A۷۵۸ has NRPS gene and related to S. parvulus (۹۲% of similarity), and also PKS gene related to PKS-type borrelidin of S. rochei and S. parvulus (۷۴% of similarity). Two compounds with potential antimycobacterial were predicted as ۱) Compound ۱, similar to dimethenamid (C۱۲H۱۸ClNO۲S; MW ۲۷۵.۰۷۲۳), with MIC value of ۱۰۰ µg/ml, and ۲) Compound ۲, actinomycin D (C۶۲H۸۶N۱۲O۱۶; MW ۱۲۵۴.۶۲۸۵), with MIC value of ۰.۷۸ µg/ml. Conclusion: Actinomycin D has been reported to have antimycobacterial activity, however the compound has been predicted to resemble dimethenamid had not been reported to have similar activity.

Keywords:

Actinobacteria , Dactinomycin , Dimethenamid , Mass spectrometry , Mycobacterium tuberculosis , Peptide synthases RNA , Ribosomal , ۱۶S Streptomyces