Planta Med 2009; 75 - SL38
DOI: 10.1055/s-0029-1234293

Antimicrobial interactions between medicinal plants in African traditional medicine

SF van Vuuren 1, AM Viljoen 2, RL van Zyl 1, H de Wet 3
  • 1Department of Pharmacy and Pharmacology, University of the Witwatersrand, 7 York Road, Parktown 2193, South Africa
  • 2Department of Pharmaceutical Sciences, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa
  • 3Department of Botany, University of Zululand, KwaDlangezwa, 3886, South Africa

In African traditional medicine it is well known that traditional healers often combine various plant species in order to enhance efficacy [1]. Using an anti-infective model, various plants from different geographical areas within southern Africa were examined to validate their use in combination. Two indigenous medicinal plants (Salvia chamelaeagnea and Leonotis leonurus) were studied to determine their anti-infective properties in combination. Synergistic interactions were observed for the Gram-positive test organisms. Artemisia afra, a renowned medicinal plant in South African traditional medicine [2], is commonly used in combination with other species to treat respiratory infections. Some examples from these interactions will be demonstrated i.e. the combination of A. afra with Osmitopsis asteriscoides. The essential oils and extracts demonstrated varied interactions. Diarrhoeal diseases are one of the highest causes of mortality in southern Africa [3]. With this in mind, an investigation was undertaken to determine which antidiarrhoeal plants are used by the Zulu people residing in the Maputaland area. The two plants most often used in combination are Psidium guajava and Brachylaena huillensis. The fractional inhibitory concentration index (ΣFIC) for this combination ranged between 0.09 (synergistic) to 2.25 (non-interactive) when tested against pathogens associated with diarrhoea. In Swaziland, the bark of Ozoroa sphaerocarpa, Breonadia salicina and Syzygium cordatum are traditionally used in a triple combination for the treatment of diarrhoea. When investigated against Escherichia coli, higher efficacy was found in the 1:1:1 combination than when tested independently. These examples validate the traditional use of combination therapy.

References: [1] Hutchings, A. et al. (1996) Zulu Medicinal Plants – an Inventory. University of Natal Press. Pietermaritzburg, South Africa.

[2] Thring, T.S.A. et al. (2006)J. Ethnopharmacol. 103:261–275.

[3] Bradshaw, D. et al. (2003) S. Afr. Med. J. 93: 682–688.