Constituents of Oils from Some Medicinal Plants and their Antimicrobial Activity

Abstract

In this study, six Sudanese key species in folk medicine (Allium cepa Subsp. cepa, Cucurbita pepo, Eruca sativa, Mentha virdis, Anethum graveolens and Artemisia herpa-alba) have been investigated. These plant species are of medicinal attributes and potentials. They have been studies by GC-MS. The target plants have also been assessed for their antimicrobial activity. The GC-MS analysis of Allium cepa Subsp. Cepa oil showed the presence of 27 components. Major constituents of the oil are: i) 9, 12- octadecadienoic acid methyl ester (42.80%) ii) 9, octadecenoic acid methyl ester (16.43 %) iii) Hexsdecanoic acid methyl ester (12.80%) iv) Methyl stearate (5.90%) Cucurbita pepo oil was analyzed by GC-MS. The analysis showed 19 components. Major constituents are: i) 9, 12- octadecadienoic acid methyl ester (35.69%) ii) 9, octadecenoic acid methyl ester (27.24 %) iii) Hexsdecanoic acid methyl ester (17.28%) GC-MS analysis of Eruca sativa oil gave twenty sevencomponents. Major constituents are: i) 13- Docosenoic acid methyl ester (32.41%) ii) Cis- 11 – Eicosenoicacid methyl ester (12.66%) iii) 9, 12- octadecadienoic acid methyl ester (12.87%) iv) Hexsdecanoic acid methyl ester (7.87%) v) 9, octadecenoic acid methyl ester (6.22 %) GC-MS analysis of Mentha virdis oil gave fifty two constituents. Major components are: i) D-Carvone (39.84%) ii) D-Limonene (22.36%) GC-MS analysis of Anethum graveolens volatile oil showed the presence of 30 components: i) D-Carvone (37.83%) ii) D-Limonene (18.13%) iii) Apiol (16.16%) Artemisia herpa-alba oil was analyzed by GC-MS. Forty nine constituents were identified. Major components are: i) n-Propl cinnamate (11.89%)s ii) 2,6-Octadienal, 3,7-dimethyl, (E)-bornyl aceatate (7.60%). The target oils exhibited different responses in the antimicrobial assay. At a concentration of 100mg/ml Allium cepa oil showed good activity against Escherichia coli. However, at the same concentration, it exhibited partial activity against Staphylococcus aureus. The oil failed to give any anticadidal activity. Cucurbita pepo oil showed significant antibacterial activity against Pseudomonas aeruginosa and Staphylococcus aureus. However, Eruca sativa oil failed to give any response in the antimicrobial assay. Mentha virdis oil showed significant activity against Pseudomonas aeruginosa and Bacillus subtilis and moderate activity against Staphylococcus aureus. On the other handAnethum graveolens oil showed significant activity against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, while it showed very good activity against Staphylococcus aureus. Artemisia herpa-alba oil showed significant antibacterial activity against Pseudomonas aeruginosa and very good activity against Staphylococcus aureus.