Chemical composition, calcium, zinc and phytate interrelationships in Aerva lanata (Linn) Juss. ex Schult leaves.

Abstract

The proximate, nutritive and anti-nutritive composition of the leaves of Aerva lanata were determined. The leaves were found to be moderately high in carbohydrate (26.6 g/100g), crude protein (22.6 g/100g) and ash (31.2 g/100g). Mineral composition (mg/100g) revealed that the leaves were high in P (187), and moderately high in other minerals such as K (47.9), Na (39.4), Ca (51.7), Mg (41.5), Zn(44.7), Fe(11.0) and low in Mn (1.04). Heavy metals such as Cu, Pb, Cd and Cr were not detected in the leaves. The anti-nutrient levels also revealed the presence of tannic acid, saponin, alkaloids, flavonoids and oxalate, with values ranging from (0.35-11.4)%. Other antinutrients were phytic acid and phytin - phosphorus, their low level was a good indication that the leaves would be safe for human consumption. The calcium ,zinc and phytate interrelationships showed the levels of Phy:Zn,Ca:Phy,(Ca)(Phy):(Zn) to be 0.05,36.9 and 0.000067 respectively. The result suggested that the bioavailability of zinc was relatively high due to the moderate phytate content of Aerva lanata leaves.