The genus Tulbaghia (Alliaceae)--a review of its ethnobotany, pharmacology, phytochemistry and conservation needs

Abstract

Ethnopharmacological relevance: Tulbaghia is a monocotyledonous genus of herbaceous perennial bulbs predominantly found in Africa. The approximately 63 species have nutritive, ornamental and medicinal value. For centuries, several Tulbaghia species have found diverse uses in traditional medicine.

Aim of the review: To evaluate and document the uses, especially the medicinal value of the genus Tulbaghia. The existing gaps in knowledge and possible means for greater development are highlighted.

Methods: A comprehensive and detailed literature search using electronic search (for example, Google Scholar, Scirus and Web of Science) and ethnobotanical books was conducted.

Results: Findings based on their traditional uses and scientific evaluation indicates that Tulbaghia violacea remain the most widely used species. Compiled data indicate their efficacy in several in vitro and in vivo pharmacological properties such as antimicrobial, anti-hypertensive, antioxidant and anti-cancer activities. Some phytochemicals which are partly associated with the exhibited bioactivities have been identified and isolated from Tulbaghia violacea and Tulbaghia alliacea. The increasing high usage especially the underground organs, as well as the incessant reliance on the wild population, will eventually affect their abundance and possibly make them susceptible to extinction.

Conclusions: The great potential of the genus Tulbaghia, particularly other less popular species, remain to be exploited. Further studies on the structural activity relationship of some of the isolated compound may improve their biological potency. Their characteristic alliaceous aroma may also be of great interest to the food industry seeking novel source of unusual aromas to satisfy increasing consumer demands. In order to derive the much anticipated benefits from the species without compromising their conservation status, the use of different biotechnological approaches highlighted in this review will certainly guarantee their continuous availability.

Keywords: Alliaceae; Biological activity; Conservation; Secondary metabolites; Toxicology; Traditional medicine.