Ethnobotany, Ethnopharmacology, and Phytochemistry of Medicinal Plants Used for Treating Human Diarrheal Cases in Rwanda: A Review.

Noel Gahamanyi,Erick V G Komba,Naasson Tuyiringire,Cheol-Ho Pan,Emmanuel Munyaneza,Emmanuel Dukuzimana

doi:10.3390/antibiotics10101231

Abstract

Diarrhea, often caused by microorganisms, has been associated with high morbidity and mortality in Africa. Increased rates of antimicrobial-resistant pathogens have reignited the quest for alternative therapies. This review aimed at identifying medicinal plants used in the treatment of human diarrheal cases in Rwanda and analyzing their ethnobotany, ethnopharmacology, and phytochemistry. We searched PubMed/Medline, Google Scholar, ScienceDirect, and the Web of Science for published articles on medicinal plants used to treat diarrhea in Rwanda. Additionally, specialized herbarium documents of different institutes were reviewed. Articles were assessed for relevance, quality, and taxonomical accuracy before being included in this review. Overall, 63 species of medicinal plants belonging to 35 families were recorded. Asteraceae was the predominant family with six species, followed by Fabaceae and Lamiaceae, with five species each. The most reported species with anti-diarrheal properties were Vernonia amygdalina Delile, Tetradenia riparia (Hochst.) Codd, Clerodendrum myricoides R. Br. and Chenopodium ugandae (Aellen) Aellen. Leaves (66.7%) and roots (17.5%) were the commonly used plant parts in the preparation of medicine. Phytochemicals from medicinal plants with antidiarrheic activities were sesquiterpene lactones (V. amygdalina); terpene, sterols, saponosides, and flavonoids (C. ugandae); saponins and tannins (T. riparia); and tannins, flavonoids, and alkaloids (C. myricoides). Six studies tested the antimicrobial activities of the plants against bacteria and viruses known to cause diarrhea. Erythrina abyssinica, Euphorbia tirucalli, Dracaena afromontana, and Ficus thonningii are socio-culturally important. Further research on toxicity and posology is needed to ensure the safety of medicinal plants.

Highlights

The present study identified 63 medicinal plant species belonging to 35 families as being traditionally used in Rwanda to treat diarrheal cases
The species most reported as having antidiarrheal properties were Vernonia amygdalina Delile, Tetradenia riparia (Hochst.)
The current review discusses the medicinal plants used for treating human diarrheal cases in Rwanda, and the commonly used medicinal plants are Vernonia amygdalina Del., Clerodendrum myricoides R

Summary

Introduction

Diarrheal diseases are among the major etiologies of morbidity and mortality worldwide, with most of the cases occurring in low- and middle-income countries (LMICs), in Sub-Saharan Africa (SSA) and South Asia [1,2,3]. Often defined as “the passing per day of three or more loose or watery stools” [7,8,9], is associated with various risk factors, including unsafe water, poor sanitation, and childhood wasting, which are common in LMICs [3]. The three major forms of diarrhea include (i) the acute watery diarrhea characterized by dehydration; (ii) persistent diarrhea lasting for more than two weeks and associated with poor absorption, loss of nutrients, and wasting; and (iii) bloody diarrhea caused by poisons, pathogens, drugs, or acute inflammations, leading to intestinal damage [4]. In Rwanda, despite efforts in preventing childhood diarrheal deaths through rotavirus immunization and making health sector reforms, diarrhea ranks as the third cause of childhood morbidity and mortality [10,11]

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