Determination of the ascorbic acid content, mineral and heavy metal levels of some common leafy vegetables of Jos, Plateau State (North Central Nigeria)

Abstract

Vitamin C (Ascorbic acid) is the most important vitamin in fruits and vegetables. It is required for the prevention of scurvy and maintenance of healthy skin, gums and blood vessels. It functions in absorption of inorganic iron, reduction of plasma cholesterol level, inhibition of nitrosamine formation, enhancement of the immune system, and reaction with free radicals. Therefore Vitamin C and elemental analysis of some local leafy vegetables namely; Pumpkin leaves, Jute leaves, Bitter leaf, Cubeb leaves, Bush buck leaves, Clove basil leaves, Curry leaf, Water leaf, African Eggplant and Moringa leaves were performed. Vitamin C determination was carried out on fresh leaves using UV spectrophotometry. Element analysis was performed on dried samples using atomic spectrophotometer for readings. The vitamin C content of the samples ranged from 5.70 mg/100 ml to 815.00 mg/100 ml. Elemental analysis showed that the leafy vegetables possessed calcium content ranging from 11.50 mg/100 ml to 830.00 mg/100 ml; potassium content ranged from 2.26 mg/100 ml to 2814.15 mg/100 ml; magnesium content ranged from 29.46 mg/100 ml to 677.0 mg/100 ml; sodium content ranged from 0.21 mg/100 ml to 370.0 mg/100ml and phosphorus content ranged from 5.00 mg/100mlto 600.00 mg/100 ml. Lead was absent in the samples but some contained traces of cadmium. These findings revealed that Nigerian leafy vegetables contain an appreciable amount of vitamin C and minerals with traces of toxic elements. However, they should be included in diets to supplement the daily requirement needed for sustainable health.