Robert S. Glew

Nutrient content of the edible leaves of seven wild plants from Niger.

Wild plants play an important role in the diet of the inhabitants of Niger. These plants tend to be drought-resistant and are gathered both in times of plenty as well as times of need. Used in everyday cooking, famine foods may be an important source of nutrients. The goal of this study was to investigate the nutritional role of wild plants in the nigérien diet. To this end, leaves of seven plants species were analyzed for their mineral, amino acid and fatty acid contents: Ximenia americana, Amaranthus viridus, Corchorus tridens, Hibiscus sabdarifa, Maerua crassifolia, Moringa oleifera, and Leptadenia hastata. Ximenia americana} contained large amounts of calcium. Large quantities of iron were present in Amaranthus viridus. All seven plants contained significant amounts of selenium and phosphorus. Corchorus tridens contained the most protein (19–25% dry weight), and its composition compared favorably to the World Health Organizations standard for essential amino acids. Moringa oleifera contained 17% protein and compared favorably with the WHO standard. Corchorus tridens contained the largest amounts of the two essential fatty acids linoleic and α-linolenic acids. These results reinforce the growing awareness that wild edible plants of the Western Sahel can contribute useful amounts of essential nutrients, including amino acids, fatty acids and trace minerals, to human diets.

Use of the trolox assay to estimate the antioxidant content of seventeen edible wild plants of niger

Although wild edible plants of the western Sahel and other parts of sub-Saharan Africa are consumed to some extent at all times of the year, greater amounts are consumed when cereal harvests are insufficient to support the populations living in these areas. The purpose of this study was to use a recently reported Trolox-based assay to measure the total antioxidant capacity of aqueous extracts of 17 plants that we gathered from southern Niger. The antioxidant contents of the aqueous extracts were compared to those of spinach and potato. Of the 17 plants, 11 had a greater antioxidant content than spinach and 14 had a greater antioxidant content than potato. The leaves of Tapinanthus globiferus had the greatest antioxidant content, and the fruit of Parinari macrophylla had the lowest. In general, leaves contained more antioxidants than either fruits or seeds. The total antioxidant capacity of the aqueous extracts was relatively high, indicating that the wild plants of the western Sahel may contain substantial amounts of water-soluble flavonoid glycosides, which are potent antioxidants and have been shown to have anticancer properties.

The trypsin inhibitor content of 61 wild edible plant foods of Niger.

In the western Sahel and many other regions of sub-Saharan Africa,wild edible plants contribute significantly to human diets, notonly during periods when cereal staples are scarce, but also whenthey are readily available. Although there have been publishedreports regarding the nutrient contents of these plant foods,little attention has been devoted to their content of antinutrientssuch as calcium chelators and inhibitors of the pancreas-derivedproteases, trypsin and chymotrypsin, which are required for theefficient digestion and absorption of dietary proteins. In thisstudy, aqueous extracts of 61 different leaves, seeds, fruits andflowers of edible plants gathered in the Republic of Niger wereanalyzed for their content of trypsin inhibitory substances usingα-N-benzoyl-DL-arginine-p-nitroanilide as the substrate andbovine trypsin as the enzyme source. Twelve of these plant foodscontained more antitrypsin activity than soybeans (1.34–8.18 vs.1.32 μg trypsin inhibited/mg dry weight). Boiling for 3 mindid not inactivate the antitrypsin activity in most of the plantextracts. These data confirm that more than half of the wildedible plant foods widely consumed by various populations whoinhabit the western Sahel contain significant quantities of heat-stable trypsin inhibitor that could possibly compromise thebioavailability of proteins present in the diets of these populations.

Furthering an understanding of West African plant foods: Mineral, fatty acid and protein content of seven cultivated indigenous leafy vegetables of Ghana

Purpose – The main purpose of this paper is to determine the content of amino acids, fatty acids and minerals in seven indigenous leafy vegetables (ILVs) in Ghana.Design/methodology/approach – Leaves from plants growing near Kumasi were milled to a fine powder, dried to constant weight in a vacuum desiccator, and analyzed for their content of the afore‐mentioned nutrients. The plants were: Hibiscus sabdarifa, Hibiscus cannabinus, Amaranthus cruentus, Corchorus oliforius, Solanum macrocarpon, Xanthomosa sagittifolium and Vigna unguiculatus.Findings – All seven ILVs contained a large amount of protein (15.5‐22.8 percent), which compared favorably to the essential amino acid pattern of a WHO standard. They all contained nutritionally useful amounts of α‐linolenic acid and had an omega‐6/omega‐3 ratio of 0.1‐0.9. The seven ILVs contained quantities of calcium, copper, iron, magnesium, manganese, molybdenum and zinc that could contribute significantly to satisfying an individuals need for these elements.Resea...

Coping strategies and nutritional health in rural Niger: recommendations for consumption of wild plant foods in the Sahel

People who live in food and water deficit regions of Sahelien West Africa employ various coping strategies as they attempt to meet their food and water needs. In this paper we discuss various coping strategies employed by rural Nigeriens living in the Tanout and Mirriya administrative regions of central Niger. In rural Niger people often harvest or buy wild plant foods to eat. Laboratory studies of the nutritional content of these plants indicate that there are benefits to eating wild plant foods. In this study we summarize the results of field research conducted during the summer of 2002 on the use of wild plant foods in three regions of rural central Niger. Comparing local use of various wild plant foods with major nutrition-related health problems including protein deficiency, essential fatty acid deficiency, iron deficiency and iron deficiency anemia, calcium deficiency rickets, and zinc deficiency, suggests potential recommendations for consumption of these plants. However, further research on the bioavailability of these nutrients is needed to confirm the potential benefits of these plants.

An indigenous plant food used by lactating mothers in West Africa: the nutrient composition of the leaves of Kigelia africana in Ghana.

Although the leaves of Kigelia africana are used to make a palm-nut soup which is consumed mainly by lactating women in many parts of sub-Saharan Africa, little is known about the nutrient qualities of this underutilized and underappreciated plant food. Leaves of Kigelia africana, called “sausage tree” in English and “nufuten” in the Twi language of Ghana, were collected in Kumasi and analyzed for their content of nutritionally important fatty acids, amino acids, minerals, and trace elements. The dried leaves contained 1.62% fatty acids, of which α-linolenic acid and linolenic acid accounted for 44% and 20%, respectively, of the total. Protein accounted for 12.6% of the dry weight and, except for lysine, its overall essential amino acid profile compared favorably to a World Health Organization protein standard for school children. Kigelia leaf contained considerable amounts of many essential elements, including calcium (7,620μg/g), iron (161μg/g), magnesium (2,310μg/g), manganese (14.6μg/g), zinc (39.9μg/g), and chromium (0.83μg/g); selenium, however, was not detected. These data indicate that Kigelia africana leaf compares favorably with many other commonly-consumed green leafy vegetables such as spinach and provides a rational basis for promoting the conservation and propagation of the plant and encouraging its wider use in the diets of populations in sub-Saharan Africa.