Author(s): Fagbohun, O.F., Olawoye, B., Oriyomi, O.V., Joseph, J.S.

Source: Journal of Trace Elements and Minerals 5 (2023) 100081


Aim: The entire world population is increasingly shifting to the use of plant-based medicines either as supplementation or medication. These medicinal plants absorb trace elements and metals available in the soil solutions in ionic, complexed, or chelated forms and can either be deficient or toxic for human and animal consumption. Therefore, screening these medicinal plants for trace elements or metals is important according to the recommendation of WHO and European legislation (1881/2006/EC).

Methodology: In this study, the concentrations of 12 trace elements and metals (Al, B, Ba, Be, Bi, Ga, K, Li, Mg, Se, Te, and Tl) were determined from Kigelia africana leaf and fruit extracts using 700 series Agilent inductively coupled plasma – optical emission spectrometer (ICP-OES) coupled with ultrasonic CETAC U-6000AT+ Nebulizer after microwave-assisted acid digestion of the plant samples with MDS-6G closed microwave digester.

Results: The study revealed that K. africana extracts have significant trace elements with the fruit extracts having high concentrations of required trace elements (3.2 mgkg-1 Mg, 67.18 mgkg-1 K, 0.04 mgkg-1 Se, and 0.16 mgkg-1 Al). Interestingly, the fruit and leaf extracts also have the required amount of Boron (B), Bismuth (Bi), Gallium (Ga), and Lithium (Li) which are essential in human brain function, nervous system, and glucose metabolism among other therapeutic functions. Barium (Ba), Beryllium (Be), Tellurium (Te), and Thallium (Tl) are known toxic metals when accumulated in the human body and are found in low concentrations in this study.

Conclusion: This study revealed that trace elements are positively correlated when analyzed with principal component (PCA) and hierarchical cluster (HCA) analyzes. This shows that K. africana plant extract can be considered one of the most important medicinal plants with several therapeutic benefits. The concentrations of several trace elements according to recommended dietary allowance (RDA) as well as the correlation between these metals and metalloids are reported for the first time using PCA and HCA.

Keywords: ICP – OES; Trace elements; PCA; HCA; Microwave-assisted acid digestion; K. Africana