Developments in research on the nutritional health-promoting properties of three traditional leafy vegetables commonly consumed in sub-Saharan Africa

Introduction: Amaranthus cruentus (Amaranthaceae), Ocimum gratissimum (Lamiaceae), and Solanum macrocarpon (Solanaceae) are leafy vegetables widely used for nutritional and medicinal purposes throughout sub-Saharan Africa. Their medicinal properties are related to the presence of bioactive compounds and other widely docu-mented components. Progress in research activities on bioactive compounds and health-promoting properties of these three leafy vegetable species were analyzed using bibliometric analysis coupled with content analysis. Methods: Data from 296 articles selected from Scopus and Web of Science databases were screened to identify publication trends, plant parts used, profiles of bioactive compounds, and analysis methods used to determine some potential health-promoting properties. Results: A growing interest in this research field was observed, particularly over the five-year period 2010-2014 (>35.0% of publications), with more attention on O. gratissimum and S. macrocarpon than A. cruentus. Leaves were the main plant parts used although growing conditions were most often not reported. Considerable efforts were made to identify bioactive compounds in the three leafy vegetables while the mechanisms governing the health-promoting properties of A. cruentus and S. macrocarpon leaf extracts are not yet fully known. Conclusion: Multidisciplinary studies integrating agriculture, environment, nutrition, and health within the same analytical framework must be undertaken for a better understanding of factors affecting the nutritional and health-promoting properties of these leafy vegetables.