Comparative Phytochemical, Antinutrient and Trace Metal Composition of the Leaf, Flower and Seed of Moringa oleifera L. Grown in Southern Nigeria

Abstract

Secondary metabolites, proximate, anti-nutrients, mineral and trace metals distribution in three parts (leaf, flower and seed) of Moringa oleifera L. grown locally in Akwa Ibom State, Southern Nigeria were investigated and compared using standard analytical procedures. The three plant parts indicated the presence of different secondary metabolites. Saponins, terpenoids, alkaloids and glycoside were common to the three plant parts at varying levels of abundance. Proximate results (% dry weight) of the plant parts indicated the following ranges: moisture (13.65 ± 0.54 – 35.23 ± 0.05); ash (3.13 ± 0.30 – 6.54 ± 0.01); crude fibre (8.59 ± 0.02 – 14.12 ± 0.01); crude lipids (3.10 ± 0.00 – 6.18 ± 0.02) and crude protein (5.15 ± 0.01 – 10.25 ± 0.03). Anti-nutrient profile (mg/100g DW) of the three plant parts recorded the following ranges: phytate (5.30 ± 0.03 – 9.60 ± 0.70); HCN (0.04 ± 0.00 – 1.01 ± 0.00) and oxalate (0.40 ± 0.01 – 0.82 ± 0.02). The mineral composition showed that among the mineral elements investigated, Moringa oleifera leaf was the richest in iron, zinc and sodium than the flower and seed, the flower was the richest in magnesium, while the seed was found to be the richest in calcium and potassium. The trace metal composition indicated mean ranges (mg/100 g DW) as follows: (0.005 – 0.008) Cd, (0.012 – 0.003) Pb, (1.210 – 2.202) Ni, (0.180 – 0.256) Cu, (1.401 – 1.684) Cr, and Mn (0.977 – 1.105). The results of the trace elements obtained were within acceptable limit stipulated by the World Health Organization for plants. Antinutrient analysis of the extracts indicated low levels of phytic acid, oxalates, and hydrocyanides below the lethal doses. These results, therefore, validate the various ethnomedicinal uses of the leaf, flower and seed of Moringa oleifera in the treatment of many diseases.