Chemical Characterization and Bioactivity of Aqueous and Organic Extracts of Echinacea purpurea (L.) Moench

• Autor(a) principal: Coelho, Joana Filipa Pereira
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10348/9316
• topic: Echinacea purpurea (L.) Moench; antimicrobial activity; cytotoxicity; phenolic compounds

Echinacea purpurea (L.) Moench is known for its medicinal properties such as antiinflammatory, antioxidant, antimicrobial, antiviral and cytotoxic, and it is the most known and used medicinal plan for its stimulating properties. E. purpurea can be used in infusions, tinctures or capsule forms and it is available on the market. The information about the cytotoxic activity of E. purpurea is scarce and this study was designed essentially to assesses the anticancer and antimicrobial properties of the plant. Five organic extracts were obtained by sequential extraction with different solvents and two aqueous extracts (decoction and infusion) of E. purpurea and it was determined and quantified their phenolic composition. The antimicrobial activity of the extracts was assessed against Escherichia coli, Klebsiella pneumoniae, Morganella morganii, Proteus mirabilis, Pseudomonas aeruginosa, Enterococcus faecalis, Listeria monocytogenes, MRSA, MSSA and Candida albicans. The cytotoxicity activity was tested against several human cancer cell lines: MCF-7 (breast adenocarcinoma), NCI-H460 (non-small cells lung cancer), HeLa (cervical carcinoma) and HepG2 (hepatocellular carcinoma). Additionally, the hepatotoxicity was tested against a non-tumor porcine liver primary cell line (PLP2). Concerning the phenolic composition, the methanol extract was the only organic extract that was rich in phenolic acids and flavonoids, both aqueous extracts possessing a much bigger content of phenolic acids than flavonoids. In what respects antimicrobial activity, the dichloromethane, ethyl acetate and acetone extracts showed moderate activity towards Escherichia coli, Klebsiella pneumoniae, Morganella morganii, Proteus mirabilis, Pseudomonas aeruginosa, Enterococcus faecalis, Listeria monocytogenes, MRSA, MSSA and Candida albicans. The dichloromethane and n-hexane extracts were the ones that stood out with great cytotoxicity against the tumor cell lines, but these extracts also showed some toxicity towards the PLP2 cell line. As the cytotoxic results were promising for the n-hexane and dichloromethane extracts, both extracts were fractionated by gradient elution column chromatography and their cytotoxicity as well as their hepatotoxicity were evaluated. With the fractionation of both extracts, fourteen fractions of the n-hexane extract and fifteen fractions of dichloromethane extract were obtained and their cytotoxicity as well as their hepatotoxicity was evaluated. All n-hexane fractions showed cytotoxic properties against HepG2 and only the last fraction of n- hexane extract didn’t show cytotoxicity towards NCI H460, HeLa and MCF-7. Five dichloromethane fractions didn’t show cytotoxicity against all tumour cell lines and only two fractions showed toxicity towards primary cell line of pork liver. In general, the cytotoxicity of the extracts was superior to that of the obtained fractions. Moreover, the phenolic compounds do not seem to contribute to the cytotoxic properties of n-hexane and dichloromethane extracts since these compounds were not detected.