Determination of Mineral Content in Selected Medicinal Plants Used by Traditional Healers in Osun State

Medicinal plants serve as the primary source of healthcare for a significant proportion of rural communities in South West Nigeria, yet limited quantitative data exist on their mineral composition. This study determined the concentrations of macro and trace minerals in five medicinal plants commonly used by traditional healers in Osun State, namely Ocimum gratissimum, Carica papaya, Morinda lucida, Bryophyllum pinnatum, and Vernonia amygdalina. Plant samples were collected from three communities in Osun State, dried at 60 degrees Celsius, ground, and analysed for calcium, magnesium, potassium, sodium, iron, zinc, copper, manganese, and selenium using atomic absorption spectrophotometry after wet acid digestion. Vernonia amygdalina showed the highest potassium content at 4821 mg/kg dry weight, followed by Ocimum gratissimum at 3674 mg/kg. Calcium concentrations were highest in Morinda lucida at 3142 mg/kg. Iron content ranged from 182 mg/kg in Carica papaya to 489 mg/kg in Vernonia amygdalina. Zinc was present in all species, with values between 18 and 67 mg/kg. Selenium was detected in trace amounts in all samples. The mineral profiles varied across species and collection sites, possibly reflecting differences in soil composition. The high potassium, calcium, and iron content of these plants supports their traditional use in managing hypertension, bone disorders, and anaemia respectively. These data provide a scientific basis for ethnopharmacological claims and may guide the development of plant-based mineral supplements.

Keywords: medicinal plants, mineral content, traditional healers, Osun State, atomic absorption spectrophotometry