Antioxidant and antimicrobial activities of (6E, 10E)-2, 6, 24-trimethyl pentacosa-2, 6, 10-triene from Euclea crispa leaves

Abstract

The purpose of the present study attempt to investigate the antioxidant and antimicrobial activities of isolated bioactive compound from ethanolic extract of Euclea crispa (E. crispa) leaves. Column chromatography method was used to isolate the bioactive compound from the plant leaves followed by UV-Spectroscopy. FT-IR, 1H and 13C NMR analyses were used to identify the structure of the isolated compound. Subsequently, the antioxidant activity was demonstrated by 2, 2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging assay, reducing power assay, ferric reducing antioxidant power (FRAP) assay, hydroxyl scavenging assay and nitric oxide scavenging assay while disc-diffusion assay was used to analyze the antimicrobial activity. The NMR and other spectral data confirmed that the isolated compound was (6E, 10E)-2, 6, 24-trimethylpentacosa-2, 6, 10-triene (compound-1). The DPPH radical scavenging (116.1 ± 0.9 μg/ml), hydroxyl scavenging (118.9 ± 1.0 μg/ml) and nitric oxide scavenging (124.3 ± 0.2 μg/ml) showed the significant half maximal inhibitory concentration (IC50) values on compound-1 suggesting good antioxidative potential. Additionally, it exhibited considerable activity in reducing power and FRAP (the maximum absorption of 0.41 ± 0.02 and 0.54 ± 0.02 at 500 μg/ml, respectively) when compared with standard drug. Furthermore, compound-1 showed maximum antimicrobial activity with inhibition zone against the tested microorganism of Staphylococcus aureus, Streptococcus aureus, Escherichia coli, Klebsiella pneumonia, Aspergillus niger and Aspergillus terreus. Conclusively, the isolated bioactive compound-1 from E. crispa leaves could be a new source of natural antioxidative and antimicrobial agents with potential value.