Partial Purification and Characterization of Albain 1, a Triterpene with Antimicrobial Activity, from the Wood Extract of Avicennia alba Blume

Secondary metabolites of plants are important resources for development of new drugs. Mangrove plants are very well known sources of wide variety of secondary metabolites. Many of these secondary metabolites from mangroves have been found to possess significant biological activities where human health is concerned. Avicennia alba Blume is one such mangrove plant with reports of having many such secondary metabolites of clinical and commercial interests.

Aim: To evaluate antimicrobial activity potential of A. alba wood extract and to isolate new bioactive constituent(s) responsible for such biological activity.

Methodology: Preliminary screenings of antimicrobial activities in different organic solvent extracts of A. alba wood tissue were done by TLC-bioautography method and phytochemical nature of the antimicrobial constituent(s) in the extracts have been studied. One compound exhibiting significant antimicrobial activity, named as Albain 1, has been isolated. MIC value has been determined for Albain 1. The purity and structure of Albain 1 have been determined by HPLC, 1H NMR, FTIR and HRMS etc. analysis.

Results: 1H NMR, FTIR and HRMS analysis have found out that the isolated compound Albain 1 is a triterpene and the molecular formula is C30H48O4. It has exhibited remarkable antimicrobial activity against Bacillus cereus, Bacillus polymyxa, Bacillus pumilas (MIC 125 μg / ml).

Conclusion: The observed antimicrobial activity of the isolated fraction of A. alba offer great potentials in pharmaceutical industries.