The traditional use of southern African medicinal plants to treat oral pathogens, and studies into their relevant antimicrobial properties

• One hundred and fifty medicinal plant species are used in traditional southern African healing systems to treat oral infections and related dental conditions. • The genus Solanum was the most frequently mentioned, having 10 different species ascribed for the treatment of toothache. • Of the 149 plant species documented to treat oral infections, only 49 species have previously been tested against specific oral pathogens. • This review lists southern African plant species for the treatment of oral infections and highlights promising directions for future studies. Oral infections and dental disorders are amongst the most common diseases in humans, affecting approximately four billion people globally each year. In southern Africa, a high percentage of people rely on traditional medicines to treat illnesses, including for the treatment of oral pathogens. This study critically reviews the literature on the ethnobotanical use of plant-based traditional medicines in southern Africa to treat oral infections. A further literature search was subsequently undertaken to summarise studies that validated the traditional use of these plants, and thereby to highlight areas that require further research. A total of 149 plant species that are used to treat oral pathogens were identified. The majority of the identified plants are native to southern Africa, although 23 exotic species that are used in the healing system of at least one southern African ethnic group were also included. Toothache was the main condition treated with the traditional medicines, although plant medicines were also often used to treat oral candidiasis and mouth ulcers. Roots and leaves were most frequently used, and they were generally used either as mouthwashes or by direct application to the affected area. Despite the diverse flora of southern Africa and the ongoing use of plant medicines to treat oral infections, the effects of southern African plants against oral pathogens have been relatively poorly explored. Only 47 of the 149 identified plant species (∼32%) have been verified by laboratory screening. Furthermore, the majority of the plants that have been tested have only been screened against limited panels of oral pathogens. Of the pathogens screened, the effects of the southern African plants against Candida spp. have been the most extensively studied. In contrast, relatively few plant species have been screened against oral bacterial pathogens, except against Streptococcus mutans . Given that oral health is vital for overall health and wellbeing, a much-needed impetus towards research in this field is warranted.