Phytochemical analysis of Eucalyptus camaldulensis leaves extracts and testing its antimicrobial and schistosomicidal activities

Abstract

BackgroundThe emerging evolution of antibiotic and anthelmintic resistance and inefficiency of some synthetic drugs elicit the need to investigate new drug sources. In this context, Eucalyptus camaldulensis is an evergreen tree that has been widely used in traditional medicine for the treatment of various health disorders.ResultsOrganic solvent extracts from Eucalyptus camaldulensis leaves were assessed for their antimicrobial activity. Among these extracts, ethyl acetate (EtOAc) and water extracts showed the highest antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, and Aspergillus niger. EtOAc extract was further subjected to vacuum liquid chromatography (VLC) technique for the isolation of its polyphenolic ingredients. VLC yielded 13 fractions (1–13) that were assayed for their antimicrobial activities. Six of these fractions, namely 4, 5, 6, 7, 8, and 9, showed antimicrobial activity against all the tested microbes except the fungus Aspergillus niger. Fractions 5 and 6 having considerably the highest antimicrobial activity with inhibition zones ranged from 5 to 14 mm. Moreover, fraction 5 was tested as a larvicidal agent against miracidia and cercariae of Schistosoma mansoni. At concentration of 200 mg/L, the mortality rates of miracidia and cercariae of Schistosoma mansoni were 30%, 20%, 50%, 40%, 80%, 20%, and 100%, 80% at 5, 10, 15, and 20 min, respectively. Chromatographic isolation of the EtOAc extract led to identification of six compounds: gallic acid (1), taxifolin (2), methyl gallate (3), quercetin (4), luteolin (5), and hesperidin (6).ConclusionsEthyl acetate extract from Eucalyptus camaldulensis leaves showed a potent antimicrobial and antischistosomal activity. This activity may be attributed to the six phenolic compounds identified through structure elucidation. Thus, these compounds can be good candidates for treatment of microbes and for the control of schistosomiasis.