Tannins and other phytochemical of the Samanaea saman pods and their antimicrobial activities

Abstract

Preliminary phytochemical screening of n-hexane extract of Samanea saman(Mimosaceae) pods revealed a moderate presence of the major secondary metabolites. Extraction and concentration of the S. saman pods with 70% aqueous acetone yielded the characteristic reddish brown solid tannins. Qualitative and quantitative analysis showed that the tannins were of condensed (catechol) type and about 7.9% (0.079 g). Characterization of the tannins by one dimensional paper chromatography using glacial acetic acid, n-butanol and distilled water (1:4:5) resulted in retardation factors (Rf) that indicated the components of the tannins as cyanidin, catechin, epicachin, anthocyanin monoglycones, delphinidin and malidin. Tannins in the ethyl acetate fraction (TEA) exhibited the highest activity against the tested pathogens, including the fungus (Candida albican). The observations could have resulted from variable synergistic interplay of the identified tannins constituents. These observations, besides supporting the use of S. saman plant parts in ethno-medicinal practice, probably highlight the overriding antimicrobial and fungistatic potentials of tannins in the ethyl acetate fraction (TEA) over the other tannins fractionates. On the whole, data from the present study suggest that ground pods ofS. saman could serve as a significant source of natural antimicrobials and antifungals (in the form of tannins) that could be harnessed in the formulation of a novel tannins/energy-rich nutraceutical tea. Based on the present results, the possible benefits and toxicological implications from such nutraceutical beverage are highlighted in the discussion. Key words: Phytochemical, antimicrobial, tannins, Samanea saman, toxicolgical, nutraceutical, fungistatic.