An antimicrobial investigation of plants used traditionally in southern Africa to treat sexually transmitted infections.

AIM OF THE STUDY: Eighteen plants were assessed for antimicrobial activity against pathogens associated with prevalent urogenital/sexually transmitted infections. Plant selection was based on information obtained from the ethnobotanical literature.

MATERIALS AND METHODS: Dried plant material was submerged in a 1:1 mixture of methanol and dichloromethane for 24 h. Aqueous extracts were prepared by submerging dried plant material in sterile distilled water for 24 h followed by lyophilization. Essential oils were distilled from the two aromatic plant species (Tarchonanthus camphoratus and Croton gratissimus). Antimicrobial activity was assessed using the micro-well minimum inhibitory concentration (MIC) assay with specific modifications to facilitate fastidious growth of pathogens.

RESULTS: Tarchonanthus camphoratus (solvent extract) showed the most significant broad spectrum activity with MIC values ranging between 0.50 and 0.70 mg/ml against five of the six pathogens tested. Other noteworthy activity was found for Hypericum aethiopicum (root) at 0.3 mg/ml (Neisseria gonorrhoeae).Polygala fruticosa and the solvent root extract of Hypericum aethiopicum showed highest sensitivities towards Gardnerella vaginalis at 0.2 mg/ml. Efficacy of the solvent extracts against the pathogen Oligella ureolytica demonstrated antimicrobial activity (MIC values
CONCLUSIONS: Antimicrobial activity was observed for a number of the plant samples against at least one or more pathogen, thus validating the ethnobotanical use as an anti-infective to treat sexually transmitted diseases.