Screening of Some Ghanaian Medicinal Plants for Phenolic Compounds and Radical Scavenging Activities

Abstract: Extracts from a total of 37 medicinal plants from 15 families were screened for their phenolic compounds and antioxidant activities. Phenolic compounds identified were gallic, vanillic, syringic, caffeic, 2,5-dihydroxybenzoic, rosmarinic and p-coumaric acids. Gallic acid varied from 0.00 – 3.14 g/L, vanillic acid varied from 0.00 – 1.32 g/L, syringic acid varied from 0.00 – 3.40 g/L, caffeic acid varied from 0.00 – 2.04 g/L, 2,5-dihydroxybenzoic acid varied 0.00 – 2.64 g/L, rosmarinic acid varied from 0.00 – 1.90 g/L and p-coumaric acid varied from 0.00 – 2.23 g/L. DPPH radical scavenging action varied from 6.70 – 94.00 %. Extract from Alchornea cordifolia contained the highest amount of each of the seven different phenolic compounds. Extract of Turraca heterophylla did not contain any of the seven phenolic compounds. Extract of Ocimum canum exhibited the lowest level of DPPH radical scavenging activity of 6.70%. Lantana camara exhibited the highest radical scavenging activity of 94.40%. Multiple analyses suggest that 43.80 % of scavenging capacity of the herbal plants results from the contributions of the seven phenolic compounds. The study showed that scavenging effect of the plant extracts is not limited to phenolics but to other secondary metabolites. The study also showed that the Ghanaian medicinal plants used for the study can be good natural sources of phenolic compounds and antioxidants.