Determination of Total Phenolic Content and Some Selected Metals in Extracts of Moringa oleifera, Cassia tora, Ocimum gratissimum, Vernonia baldwinii and Telfairia occidentalis Plant Leaves

The main objective of this research is to determine the content of metals (Ca, Cu, Fe, Mg and Zn) and total phenols in different plant extracts of Moringa oleifera, Cassia tora, Ocimum gratissimum, Vernonia baldwinii and Telfairia occidentalis. Content were determined using Atomic Absorption Spectroscopy. The result indicate that Moringa oleifera plant extracts range from 0.25 ±0.00 to 6.13 ±0.30 mg/kg, Cassia tora plant extracts - 0.17 ±0.03 to 7.48 ±0.06 mg/kg, Ocimum gratissimum plant extracts - 0.18 ±0.00 to 5.43 ±0.12 mg/kg, Vernonia baldwinii and Telfairia occidentalis plant extracts - 0.21 ±0.03 to 7.86 ±0.12 mg/kg and 0.17 ±0.00 to 4.52 ±0.06 mg/kg, respectively. The results also revealed a lower abundance of heavy metals. The total phenolic content was determined using the modified Folin-Ciocalteu method. Herein, the phenolic content in Moringa oleifera was 8.50 ±1.23 mg Garlic Acid Equivalent g-1 (mg GAE g-1), Cassia tora - 30.00 ±0.00 mg GAE g-1, Ocimum gratissimum - 45.00 ±1.41 mg GAE g-1 , Vernonia baldwinii - 49.00 ±1.14 mg GAE g-1 and Telfairia occidentalis - 46.6 7 ±0.27 mg GAE g-1. We found the lowest total phenol content in Moringa oleifera. This also possessed high chelating activity. In contrast, Vernonia baldwinii contained the highest total phenol content, but had low chelating activity. The plant extracts with high levels of phenolic compounds exhibited good antioxidant activity.