Fractionation and assessment of antioxidant activities of active components of Garcinia kola seed

Author: B. Daramola ^{1, 2*}, G. O. Adegoke ¹ and S. A. Osanyinlusi ²

Received 17 June 2008, accepted 2 December 2008.

Abstract

In order to eliminate the constraint of bitterness inherent to Garcinia kola seed which may hinder its application as a natural antioxidant in food systems, a simple procedure of extraction, fractionation and assessment of organoleptic and antioxidant properties of fractionated extracts and some currently used synthetic antioxidants is communicated. Fractionation of active components of crude ethanolic extract of Garcinia kola seed was accomplished using vacuum liquid chromatography (VLC). Fractions obtained were subjected to sensory, chemical, spectroscopic and storage assessment in order to evaluate their antioxidant potentials. Fractionation yielded 6 extracts with antioxidant potentials as revealed by spectroscopic and chemical analysis. Sensory examination and antioxidant storage test showed that some fractions (designated F₄ and F₅) were yellow in appearance and had non–bitter taste in contrast to the crude extract associated with dark brown appearance with bitter taste. Statistical analysis (p = 0.05) showed that the antioxidant effectiveness (AE) of the fractionated extracts (F₄^AE = 58.44%; F₅^AE = 55.34%) were comparable to currently used synthetic antioxidants. The fractionated extracts can be used to prolong storability of food products.

Key words: Garcinia kola seed, fractionated extracts, sensory characteristics, active components, spectral characteristics, antioxidant effectiveness.