Selenium content, antibacterial, antioxidant and anti-sickling activities of Zanthoxylum gilletii (De Wild) P.G. Waterman (Rutaceae)

Abstract

Aim: The aim of this study was to identify bioactive compounds, to determine the mineral content and to evaluate the antibacterial, antioxidant and anti-sickling activities of different parts of Zanthoxylum gilletii.Methods: Phytochemical composition was evaluated by general tests as well as chromatographic technics (TLC and HPLC), the mineral micronutrient content was quantified by spectroscopy ICP-OES. The antioxidant activities of the infusions extracts from leaves, stem bark and root bark of Z. gilletii were evaluated using ABTS an DPPH assays, the antibacterial activity against four bacteria strains using the micro-dilution method; and the anti-sickling activity was assessed by the Emmel test.Results: Phytochemical screening revealed the presence of polyphenols such as anthocyanins and flavonoids (stem bark) while stem and root barks contained tannins. Alkaloids were found in the leaves, saponins in leaves, stem and root barks. Leaves and root bark also contained triterpenoids and steroids, while only stem bark contained quinonic derivatives. For phenolic acids and flavonoids, stem and root barks could contain luteolin, chlorogenic acid, caffeic acid and only stem bark could contain rutin. Mineral analysis revealed the presence of macronutrients and micronutrients including calcium, iron, zinc and selenium. All aqueous extracts displayed high ABTS and DPPH radical-scavenging activities at the concentration range of 1–25 ug/mL. The in vitro Emmel test showed that the aqueous extracts of the different parts had anti-sickling properties at the concentration of 10.42 µg/mL, 20.83 µg/mL, 83.30 µg/mL for the stem bark, the leaves and the root bark respectively. The stem bark was the most active extract. The results of antibacterial activity test indicated that the all extracts exhibited the highest activity against Staphyloccocus aureus, Escherichia coli, Enterococcus spp and Pseudomonas aeruginosa. Stem barks showed moderate activity against P. aeruginosa and root barks against S. aureus and Enterococcus spp respectively.Conclusions: The bioactivities of the different parts could be attributed to alkaloids, phenolic compounds and terpenes. Stem bark showed the best antioxidant, antibacterial and anti sickling activities. Z. gilletii contains the phytochemicals that validate its use in Traditional Medicine for the management of sickle cell disease.