Joseph N. Yong

Potential Natural Antimycobacterial Metabolites from Some Sub-Saharan Medicinal Plants

Mycobacterial infections (particularly, tuberculosis caused by Mycobacterium tuberculosis) represent a signifi- cant threat to public health, especially south of the Sahara. The problem has been compounded by poor patient compliance due to long periods of treatment, thus resulting in the development of multi-drug resistant (MDR) and extremely drug- resistant (XDR) forms the of bacterium. It has, therefore, become imperative to seek new drugs from unexplored sources against these infections. Natural products, from ancient times, have often been used as drugs for the treatment of various ailments. They have also served as templates for the design and synthesis of new drugs. In sub-Saharan Africa particu- larly, ethnobotanical and ethnomedical knowledge of plants has been exploited to manage several different ailments, in- cluding tuberculosis. Thus research efforts have often been concentrated on plants as a source of treatment of diseases as well as drug leads. In this mini review, we report the biological activities of compounds derived from African medicinal plants with the potential for the treatment of anti-mycobacterial infections. Seventy nine (79) antimycobacterial com- pounds have been identified in sub-Sahara Africa covering the period from 1995 to 2013.

The chemistry and bioactivity of Southern African flora II: flavonoids, quinones and minor compound classes

This review is intended to highlight the relevance of natural products in drug discovery paying particular attention to those derived from Southern African medicinal plants with diverse biological activities. In this review series, a literature survey led to the collection of 864 secondary metabolites from 101 plant species from 57 plant families. A correlation between the known biological activities of isolated compounds and the ethnobotanical uses of the plants has been attempted. Part I focused on alkaloids and terpenoids, while this part is focused on the bioactivities of flavonoids, quinines and other minor, unique compound classes which correlate with their ethnobotanical uses in African traditional medicine (ATM).

The chemistry and bioactivity of Southern African flora I: a bioactivity versus ethnobotanical survey of alkaloid and terpenoid classes

As a whole, the African continent is highly endowed with a huge floral biodiversity. Natural products which have been isolated from plants growing in this region have shown interesting chemical structures with diverse biological activities, which could serve as a starting point for drug discovery. In this study, a literature survey led to the collection of 864 secondary metabolites from 101 plant species from 57 plant families. A correlation between the known biological activities of isolated compounds and the ethnobotanical uses of the plants has been attempted. This review is a survey of the bioactivities of alkaloids and terpenoids which have been isolated from Southern African flora versus the ethnobotanical uses of the plants used in Southern African traditional medicine.

Perspectives on tuberculosis pathogenesis and discovery of anti- tubercular drugs.

Based on the global burden of tuberculosis and resistant strains that have recently emerged, not responding to existing therapies, it has become urgent to search for new remedies against this global human plague that has been compounded by HIV co-infection. Thus, the search for new drugs against the disease-causing agent, Mycobacterium tuberculosis (MTB), is an ongoing effort. This review discusses the state-of-the-art in anti-tuberculosis pathogenesis and anti-TB drug research, identifying some of the challenges being faced by researchers in the field and sheds light on possible ways forward, particularly in low-income countries.