The chemical composition and membrane stability activity of some herbs used in local therapy for anemia.

The chemical composition and the membrane stabilizing activity of the decoctions of the dry Hibiscus sabdariffa Linn. (Malvaceae) calyx (Sobo in a Nigerian language), Theobroma cacao Linn. (N.O. Sterculiaceae) root (cocoa) and the dry stalk of white and red cultivars of Sorghum bicolor (L.) Moench (Poaceae) were determined. These herbs are often used locally for the management of anemia. Ash content was from 3.5 to 7.2%, tannin 7-46 mg/kg catechin equivalent, ascorbic acid content 250-625 mg/kg and total anthocyanin 57-150 mg/kg cyanidin-3-glucoside equivalent. Phytate was not detected in any sample but alkaloids and saponins were present except in Sobo. The decoctions contained 0.2-2.0% of the herbs' total tannin content while the pH was 3.2-6.7. Iron and zinc content was highest in Sobo while Theobroma cacao root contained the highest calcium and magnesium. Solubility and mineral availability were highest in the decoction of Sobo and lowest but available in Theobroma cacao root decoction. The decoction of Theobroma cacao exhibited a high membrane stabilizing activity while those of Sorghum bicolor and Hibiscus sabdariffa were only average. The study indicated that the herbal decoctions could provide some minerals and also help to stabilize the red blood cells from stress injury.

Ascorbic acid and mineral availability in two Nigerian plant foods.

This paper reports the effect of various concentrations of ascorbic acid on the availability of Fe, Zn, Ca and Mg in two popular plant foods--cowpea and amaranthus vegetable--in Nigeria. Ascorbic acid enhancement of iron availability was over 300 % and zinc by 200 % from 0-100 mg concentration. Availability of iron was further increased by 200 mg ascorbic acid in amaranthus but showed a 50 % decrease in the legume. Availability of zinc was decreased by 200 mg ascorbic acid but to different levels in both plant foods. In the legume, maximum enhancement of Ca and Mg availability was exhibited at 100 mg ascorbic acid level but suppressed at higher concentrations. In amaranthus, maximum Ca enhancement was exerted by 200 mg ascorbic acid and 50 mg for Mg. Enhancement of Cu in the legume was marginally affected by ascorbic acid concentrations while inhibition of Cu was observed in amaranthus between 50-300 mg ascorbic acid concentrations. The effect of ascorbic acid on the availability of minerals seems to be concentration dependent and varies with theplant food.