المستخلص: |
Erucaria pinnata (family Brassicaceae) is growing in Sirt region, Libya. The plant was extracted with n-hexane in a soxhlet and fractionated into fatty alcohols, fatty acids and unsaponifiable matters. The GLC analysis of fatty acid methyl esters revealed the presence of six acids in which palmitic acid is the main one (65.10%). While, the GLC analysis of the unsaponifiable matters revealed the presence of a series of long chain hydrocarbons with n-C20 and n-C29 are the main ones (13.45% and 12.88%, respectively), in addition to three sterols. The total glucosinolates were extracted with aqueous methanol, purified and hydrolyzed with myrosinase enzyme. The obtained isothiocyanates after enzymatic hydrolysis were identified using GC/MS as 8-methylsulfinyl octylisothiocyanate, 4- methylsulfinyl-3-butenyl isothiocynate, 2-phenylethyl isothiocyanate and 3-methylthio-2-propenyl isothiocynate. The antimicrobial activity of the plant extracts in addition to total glucosinolates and isothiocyanates using disc diffusion method was studied against some Gram -ve, Gram +ve bacteria and fungi. The results proved that, the tested Gram -ve bacteria were resistance to all concentrations of all tested extracts with the exception of total isothiocyanates, glucosinolates and butanol extract respectively, and which exhibited different inhibition effects against all tested microorganisms. Total isothiocyanates exhibited the highest inhibition activity against all tested microorganisms. However, ethyl acetate extract exhibited different inhibition effects against all tested Gram +ve bacteria only. While, the fatty alcohols and unsaponifiable matters showed no inhibition effects by any means against all tested microorganisms at all concentrations used. Above all, the results clearly showed that all inhibition effects exhibited were concentration dependant.
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