Evaluation of the antioxidant potentials of ten leafy vegetables extracts commonly consumed by the Ghanaian population

Abstract

Ten traditional leafy vegetables commonly consumed by Ghanaians have been evaluated for their antioxidant potential based on their polyphenolic and flavonoid contents. Among the plants studied the methanol extracts of Ocimum basilicum (akokobesa), and Amaranthus incurvatus (aleefo) exhibited the highest phenolic content of 16.4 mg GAE/gdw and 11.3mgdw GAE/g respectively. The highest phenolic content for water extracts were seen in Manihot esculenta (cassava; 9.29mg GAE/gdw) and Hibiscus sabdariffa (shuuré; 7.28mg GAE/g dw) and C esculanta (7.11 mg GAE/gdw). The methanol extracts of H. sabdariffa (Shuuré), Vernonia amygdalina (bitter leaves), Manihot esculenta (cassava leaves) and Ocimum basilicum (akokobesa) recorded the highest flavonoid content (FC) of 99.14 µg QE/gdw, 70.20µg QE/gdw, 70.08µg QE/gdw and 63.37µg QE/gdw respectively. For the FC of the aqueous extracts the order was; A. incurvatus > H. sabdariffa > Talinum triangulare> Colocasia esculenta > M. esculenta > V. amygdalina> O. basilicum > Solanum macrocarpon > Launaea taraxacifolia > Corchorus olitorius. A good positive correlation 2 = 0.663 was observed between polyphenolic content and antioxidant values for the aqueous extracts, however, no correlation was found between flavonoids, polyphenolics and total antioxidants. The study indicates that the leafy vegetables consumed by Ghanaians are potentially rich sources of dietary polyphenolic compounds and antioxidants, and might contribute important health and nutraceutical benefits to consumers