Seasonal variation of naphthoquinones in Euclea natalensis subspecies natalensis

Abstract

Abstract Seasonal variation of naphthoquinones was investigated from eleven wild plants of Euclea natalensis A.DC. subsp. natalensis belonging to the same population. The study was carried out in Tembe National Park, KwaZulu-Natal, South Africa. Quantitative analysis of bioactive naphthoquinones (shinanolone, 7-methyljuglone, diospyrin, isodiospyrin and neodiospyrin) from the root extracts was conducted using High Performance Liquid Chromatography (HPLC). All these naphthoquinones have potent antituberculosis activity. The concentration of the best antituberculosis compound 7-methyljuglone, ranged from 0 g/kg to 3.77 g/kg between individuals of a population and among seasons. Highest amount of 7-methyljuglone was found in winter in most of the trees. Accumulation of isodiospyrin and neodiospyrin varied significantly with seasonal changes ( P P E. natalensis subsp. natalensis . Depending on the requirement of a particular naphthoquinone for research, one could harvest the roots from a given population in seasons recommended from this study.