Studies on the chemical composition of plants used in traditional medicine in Congo

The knowledge of the chemical composition of herbs used medicinally in Africa is relatively low, and at the same time, the growing interest in alternative medicine prompts scientists to search for justification for the use of various plants. Due to these, the aim of the study was to analyze ten botanical species of medicinal plants originating from Congo to determine the contents of non-metals (P, Se), metallic elements (Cu, Zn, Fe, Mn, Ca, Mg, Na, K, Cd, Pb, Cr, Co, Al), phenolic compounds, and L(+) ascorbic acid and antioxidant activities. To prepare plant samples for quantitative analysis by flame atomic absorption spectrometry (FAAS) and inductively coupled plasma-optical emission spectroscopy, the microwave digestion was applied. The contents of phenolic acids, flavonoids, polyphenolic compounds, and vitamin C were assayed in extracts of medicinal plants spectrophotometrically, while the antioxidant activity was determined by ferric reducing antioxidant power (FRAP), 2,2-Diphenyl-1-picryl-hydrazyl-hydrate (DPPH), and 2,2 -Azino-bis-3-ethylbanzothiazoline-6-sulfonic acid (ABTS) techniques. The studies showed that the medicinal plants from Congo differed to a high degree. Principal component analysis demonstrated that the concentrations of Cu, Fe, Mn, and also phenolic compounds and antioxidant activity had the highest impact on sample’s differentiation. The relationship between the type of plant material (bark, root, or leaf) and its chemical composition was noticed, too.