Study of lipids, glucosinolate-derived isothiocyanates and their antimicrobial activity of erucaria pinnata

Brassicaceae is a large plant family; it includes vegetable crops, weeds, garden and wild flowers. Erucaria pinnata is one of the most common species of this family, which mainly growing in Sirt region and locally known as Saleekh. This study aim to isolate, identify lipid constituents and isothiocyanates and also to evaluate the potency of different extracts of Erucaria pinnata as antimicrobial agents. The plant was collected from Sirt region in February 2008 during the flowering stage. The aerial parts of the plant [leaves, flowers and branches] were air dried and ground until they become as a fine powder. Mass spectrophotometer GC/MS Jcol 500 Mass spectroscopy 70 cV. Agilent Technologies 6890 N Network GC System. Gas liquid chromatography Hewlett Packard HP 6890 series. Isolation of Lipids: one kg of air dried powdered plant of Erucaria pinnata was extracted with n-hexane in a Soxhlet for 24 hours till exhaustion. Extraction of the total glucosinolates and preparation of total isothiocyanates. Antimicrobial activity:the antimicrobial activity was determined using the sensitivity disk diffusion method of Kirby-Bauer and determination of inhibitory zone [I.Z.]. Used microorganisms: Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Mycobacterium phleis, Enterobacter cloacae, Aspergillus niger and Candida albicam. The GLC analysis of E. pinnata 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-C[20] and n-C[29] are the main ones [13.45% and 12.88% respectively]. Using GC/MS analysis for the obtained ITC after enzymatic hydrolysis of the total glucosinolates, were identified as 8-methylsulfinyl octyl ITC, 4-methylsulfinyl-3-butenyl ITC, 2-phenylethyl ITC and 3-methylthio-2-propenyl ITC. The results proved that, only total ITCs, glucosinolates and butanol extract exhibited different inhibition effects against all tested organisms. Ethyl acetate extract exhibited different inhibition effects against only tested Gram +vc bacteria, while, the acetone insoluble fraction and unsaponifiable matters showed no inhibition effects by any means against all tested microorganisms at all concentrations used. The lipid constituents [fatty acids and unsaponifiable matters] of Erucaria puinnata were identified, also four isothiocyanatcs were isolated and identified using GC/MS. The isolated isothiocyanates is more potent as antimicrobial than precursor glucosinolates

Investigations on the glucosinolates of lepidium sativum growing in Egypt and their biological activity

Fractionation of the glucosinolate contents of both the seeds and fresh herb of Lepidium sativum growing in Egypt were carried out. The study of the glucosinolate contents of L. sativum seeds revealed the isolation and identification of glucotropaeolin and 2- Phenyl ethyl glucosinolate while the study of glucosinolate contents of the fresh herb revealed the presence of 2- ethyl butyl glucosinolate, methyl glucosinolate, butyl glucosinolate and glucotropaeolin. The identification of the isolated glucosinolates were substantiated through using different chemical methods [enzymatic hydrolysis] and spectroscopic determinations [UV, MS and GC-MS for the corresponding isothiocyanates]. Acute toxicity studies of pet ether and alcoholic extracts of aerial parts of the plant showed that the alcoholic extract is more safe than that of pet ether extract and both extracts have a hepatoprotective activity on liver at the same concentration [50 micro g/ml]. The different extracts of the seeds and herbs of Lepidium sativum showed a potent effect against the White fly [Bemisia tabaci]. The total glucosinolate and in particular glucotropaeolin showed significant activity against the pest, which gave a highest mortality percentage on the adult stage