Cytotoxicity, antimicrobial and antidiarrhoeal activities of standardised aqueous root extract of Elephantorrhiza elephantina (Burch.)

Abstract

Elephantorrhiza elephantina is used in Basotho traditional medicine to treat infectious diseases including diarrhoea. This study evaluated its aqueous extract for cytotoxicity, antimicrobial and antidiarrhoeal activities. While brine shrimp lethality assay was used for the cytotoxicity study, the antimicrobial activity was determined via a micro-plate dilution method. Using castor oil, and gastrointestinal motility models, the antidiarrhoeal activity was also investigated. The extract inhibited all the tested bacterial and Candida strains at minimum inhibitory concentrations of 0.78–3.13, and 0.78–1.56 mg/mL, respectively. For the antidiarrhoeal study, the extract dose dependently and significantly prolonged the onset time of diarrhoea, decreased the characteristic faeces features, increased intestinal Na⁺-K⁺-ATPase activity, attenuated nitric oxide content and effectively inhibited gastrointestinal motility in experimental animals. In all the antidiarrhoeal models, the extract (at 400 mg/kg) elicited effects that compared favourably with loperamide (standard drug). Judging by the LC₅₀ value of 42.04 μg/mL for the cytotoxicity assay, the extract could be adjudged highly potent and effective. The results from the present study have not only presented E. elephantina as being endowed with chemotherapeutic constituents which could be potentially useful for the development of drugs against bacterial infections, but also validate its Basotho traditional application against diarrhoea.

Keywords:

• antibacterial
• anticandida
• Basotho
• Fabaceae
• loperamide

ACKNOWLEDGEMENT

The support of Ms G. Mahanke (research assistant) and my postgraduate students at different stages of the experiment is most appreciated.

DISCLOSURE STATEMENT

We declare that we have no conflict of interest.

Additional information

Funding

The authors are especially grateful to the UFS-Qwaqwa Research Committee for funding (211427604).