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


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 <or=1.0 mg/ml) for seven plant species. The highest activity noted against Ureaplasma urealyticum was for Psidium guajava (solvent extract) at 0.8 mg/ml. In general the aqueous extracts displayed mostly poor anti-STI activity. The most noteworthy susceptibility for the aqueous extracts was noted with the plant extract Syzygium cordatum (MIC value 0.1 mg/ml against Candida albicans). The most noteworthy activity for the essential oils was observed for Tarchonanthus camphoratus (0.8 mg/ml) against Oligella ureolytica.


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.
van Vuuren
S F
SF
Department of Pharmacy and Pharmacology, Faculty of Health Sciences, University of Witwatersrand, Parktown, South Africa. Sandy.vanvuuren@wits.ac.za
Naidoo
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D000890:Anti-Infective Agents / Q000302:isolation & purification / Q000494:pharmacology*; D019448:Ethnobotany; D016488:Medicine, African Traditional; D008826:Microbial Sensitivity Tests; D009822:Oils, Volatile / Q000302:isolation & purification / Q000494:pharmacology*; D008517:Phytotherapy / Q000379:methods; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D010946:Plants, Medicinal / Q000737:chemistry; D012749:Sexually Transmitted Diseases / Q000188:drug therapy* / Q000382:microbiology
D000890:Anti-Infective Agents; D009822:Oils, Volatile; D010936:Plant Extracts