An ethnobotanical and antidiarrhoeal investigation of plants used traditionally in the Maputaland area homesteads

Submitted for the fulfilment of the requirement for the degree of Master of Science to the faculty of Science and Agriculture in the Department of Botany at the University of Zululand, South Africa, 2013.

Zulu people living in the rural area of Maputaland (KwaZulu-Natal, South Africa) rely heavily on medicinal plants, particularly for the treatment of diarrhoea. The main aim of this study was to determine which plants are used in this area to treat diarrhoea and to validate their antidiarrhoeal efficacy against diarrhoeal-related pathogens. An ethnobotanical survey was conducted in four different localities in northern Maputaland (Mabibi, Mseleni, Mbazwana/ Olakeni and Tshongwe) on plants that are used to treat diarrhoeal infections. Twenty three plant species were documented and collected in the survey. A muthi market survey was also performed where three more plant species namely Sarcophyte sanguinea, Ximenia caffra and Strychnos henningsii were identified to treat diarrhoea. Acacia burkei, Brachylaena transvaalensis, Cissampelos hirta and Sarcostemma viminale were recorded for the first time globally as antidiarrhoeal remedies. Psidium guajava was the most mentioned (43%) plant to be used traditionally to treat diarrhoea followed by Catharanthus roseus and Melia azedarach. Most of the interviewees mentioned the use of plants individually but some mentioned the use of plants in combinations. The following plants were said to be used in combination; Brachylaena transvaalensis with Psidium guajava; Sclerocarya birrea, Acanthospermum glabratum in combination with Krauseola mosambicina; Psidium guajava and Mangifera indica in combination with Sarcophyte sanguinea. Most plants were used as leaf decoctions. The study also revealed that the choice of plants used was based on the availability of the plant in and around the interviewees’ homestead. One new vernacular name was recorded which demonstrates the importance of recording this information. Antidiarrhoeal studies were performed with the crude extracts against diarrhoeal pathogens. Organic extracts of Terminalia sericea showed noteworthy antibacterial activity (mean MIC value of 0.04 mg/ml against Shigella flexneri). Many other plant species showed noteworthy activities against different pathogens. More than 80% of plant species screened were active against at least one out of seven of the diarrhoeal pathogens. Proteus vulgaris showed overall the least susceptibility, while Shigella flexneri proved to be the most susceptible pathogen. Aqueous extracts generally showed poorer antimicrobial activity with some exceptions i.e. Acacia burkei, Garcinia livingstonei, Sclerocarya birrea and Terminalia sericea. The antibacterial activity of plant species collected from the homesteads demonstrated better activity compared to those collected from the muthi markets. In the combination studies, synergy (ƩFIC < 0.50) was observed against at least four or more pathogens. Combinations of Acanthospermum glabratum with Psidium guajava and Brachylaena transvaalensis with Psidium guajava, proved to be the most favourable combinations. Some aqueous extracts in combination showed synergistic interactions. The combination of Acanthospermum glabratum with Krauseola mosambicina showed (76%) synergistic interactions when investigated in various ratios. The results from this study correlates to a certain extent with the use of particular plant species to treat diarrhoea infections. Furthermore there is some correlation between the best antimicrobial activities and the most frequently used plant species and plant combinations used by the lay people in the Maputaland area.

National Research Foundation