Chromatographic and Spectrophotometric Determination of Some Phenolic Compounds in Tridax procumbens Linn Stem

Abstract

Phenolic compounds are copious secondary metabolites found in Tridax procumbens plant which is traditionally known for its antimicrobial activities. This research work is aimed at determining major phenolic compounds present in the stem of T. procumbens with their amounts. The phenolic compounds present in T. procumbens stem were separately extracted in methanol and ethanol. The total phenolic contents and the total flavonoid contents present were determined by UV–visible spectrophotometric analysis using Folin–Ciocalteu and Folin–Denin methods respectively. Gas chromatographic–mass spectrometric (GC–MS) analysis was used to identify and quantify some of the phenolic compounds present in the stem of T. procumbens. The total phenolic contents of methanolic and ethanolic extracts by spectrophotometric analysis were 52.8 mg gallic acid/g extract and 163.8 mg gallic acid/g extract respectively, while the total flavonoid contents were 19.9 mg rutin/g and 3.5 mg rutin/g respectively. The GC–MS analysis of the methanolic and ethanolic extracts showed the presence of four phenolic compounds with their respective concentrations, namely thymol (1.78 and 1.52 mg/g), eugenol (49.64 and 49.88 mg/g), gallic acid (0.34 and 0.52 mg/g) and isobutyl gallate (2.88 and 63.32 mg/g). The result obtained from the Folin-Ciocalteu and GC–MS revealed that the ethanolic extract (166.7 mg/g of gallic acid), has more phenolic content than the methanolic extract (54.64 mg/g of gallic acid). The ethanolic extracts showed greater ability of extraction for phenolic compounds from T. procumbens.