Trace Elements in Leaf Extracts of Eucalyptus grandis Traditionally Used to Treat Common Cold and Flu

Abstract

Background. Eucalyptus species have been used for the remediation of mine tailings dams in Zimbabwe. However, a traditional medicinal remedy (TMR) for the treatment of mild acute respiratory infections, such as common cold and flu includes the use of Eucalyptus leaves. Objectives. The aim of the present study was to determine total concentrations of selected potentially toxic trace elements (PTEs) in gold mine tailings and leaves of Eucalyptus grandis and to identify extractable fractions of PTEs in leaves via boiling for 10 minutes in water, which is the process used to create TMRs to treat common cold and flu. Methods. Mine tailings and leaves of E. grandis were randomly collected at a gold mine tailings dam between April and June 2019. They were digested for laboratory analysis using standard analytical methods. Leaves were boiled in water for 10 minutes to prepare the TMR as practiced by the local community. The concentrations of PTEs were determined spectrometrically. Significant differences between PTEs in young and mature leaves were determined by analysis of variance. Results. Mine tailings were acidic (pH 4.52±0.62) with very low content of organic matter (0.02%) and contained PTEs in increasing concentrations of cadmium (Cd) < nickel (Ni) < lead (Pb) < chromium (Cr) < copper (Cu) < zinc (Zn) (n = 27). Mature leaves of E. grandis had higher concentrations than young leaves for Cr, Pb and Zn (p <0.05) which were lower than permissible limits in medicinal plants. Overall, boiling leaves in water for 10 minutes resulted in low extraction of PTEs (< 20%). Participant Consent. Obtained Conclusions. Concentrations of PTEs in leaves and leaf extracts of E. grandis were very low. However, TMRs should not be prepared from medicinal plants growing on metalliferous environments, such as mine tailings dams, due to the presence of cumulative toxins such as Cd and Pb. Further studies are needed to investigate the effect of various boiling times and should include arsenic in the studied PTEs. Competing Interests. The authors declare no competing interests for this study.

Ellagitannins from Eucalyptus camaldulensis and their potential use in the food industry

“…Whereas among the compounds found in aqueous fractions are flavones, different glycosides, and important phenolic compounds like P: for only the compounds present without identifying the percentage; HHDP: hexahydroxy diphenic acid; -: not involving phenolic acids, ellagitannins and their derivates, gallotannins and phloroglucinol derivatives [17]. It may also present other compounds such as alkaloids, caffeine derivatives, purine derivatives, and some acids [19].…”

“…Although E. camaldulensis has compounds that could be beneficial, it also has saponins, which could have a negative effect on health. On the other hand, it has also been reported that E. camaldulensis can retain trace elements such as zinc (Zn), copper (Cu), arsenic (As), magnesium (Mg), calcium (Ca), sulfur (S), iron (Fe), aluminum (Al), boron (B) [11,19]. However, through conventional extractions for traditional treatments it has not been reported that dangerous quantities are extracted [20].…”

“…Some of secondary metabolites produced by various natural sources such as plants have antimicrobial potential against pathogenic microorganisms and can inhibit virulence factors [1]. These compounds with antibacterial properties have been used in food processing, acting as preservatives and preventing the deterioration of food products both in food pathogenic and non-pathogenic microorganisms [19], and have also been used antioxidant, and antitumor activities [44].…”