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Hosni K.,Institute National Of Recherche Et Danalyse Physico Chimique Inrap Biotechpole Of Sidi Thabet | Hassen I.,Institute National Of Recherche Et Danalyse Physico Chimique Inrap Biotechpole Of Sidi Thabet | Chaabane H.,Institute National Of Recherche Et Danalyse Physico Chimique Inrap Biotechpole Of Sidi Thabet | Jemli M.,Institute National Of Recherche Et Danalyse Physico Chimique Inrap Biotechpole Of Sidi Thabet | And 3 more authors.
Industrial Crops and Products | Year: 2013

The main goal of the present study is to evaluate the effects of enzymatic pre-treatment on the yields, chemical composition and antimicrobial activities of the essential oils of Thymus capitatus and Rosmarinus officinalis leaves. In T. capitatus, application of cellulase, hemicellulase and combination of both enzymes induced 63.55, 23.72 and 109% increase in the essential oil yields. It also induced increment by 2.7, 31 and 38% in the amount of its main component carvacrol. In R. officinalis, enzymatic treatment resulted in enhanced oil yields by 5, 50 and 20% for cellulase, hemicellulase and the combination of both enzymes, respectively. In contrast to T. capitatus, the amount of the main component 1,8-cineole dropped by 17.73, 36.92 and 15.46% in oils extracted from cellulase, hemicellulase and cellulose/hemicellulase treated samples of R. officinalis. At the same time, the essential oils (at 1/32 and 1/4 dilution for T. capitatus and R. officinalis, respectively) were evaluated for their antimicrobial activities against 6 food-borne pathogens (Escherichia coli, Salmonella typhimurium, Streptococcus agalactiae, Staphylococcus aureus, Enterococcus feacium and Candida albicans). All investigated oils exhibited antimicrobial activity with those issued from hemicellulase treated samples being the most effective. Enzymatic pre-treatment could be useful for enhancing yield and antimicrobial activity of the essential oils, and hold a good potential for use in food and pharmaceutical industries. © 2013 Elsevier B.V..


Albouchi F.,University of Carthage | Hassen I.,Institute National Of Recherche Et Danalyse Physico Chimique Inrap Biotechpole Of Sidi Thabet | Casabianca H.,CNRS Institute of Analytical Sciences | Hosni K.,Institute National Of Recherche Et Danalyse Physico Chimique Inrap Biotechpole Of Sidi Thabet
South African Journal of Botany | Year: 2013

A comprehensive study on the volatile oil and phenolic constituents of Ailanthus altissima Swingle (Simaroubaceae) leaves was performed. Methanolic extracts of leaves and their hydrodistilled residues were screened for their antioxidant, antimicrobial and phytotoxic properties. The results showed that the leaf volatile oils were a complex mixture of more than a hundred components, mainly composed by non-terpenic compounds (tetradecanol, heneicosane, tricosane and docosane) and sesquiterpene hydrocarbons (α-curcumene and α-gurjunene). Methanolic extracts from leaves contain the highest level of total phenolic content, while those from the hydrodistilled residues showed the highest total flavonoid content. The most frequent phenolic compounds identified by HPLC-DAD-MS were gallic acid, chlorogenic acid, HHDP-galloylglucose, epicatechin, rutin, hyperoside and quercetin-3-galloyl hexoside. Evaluation of the antioxidant activities by using four complementary tests (DPPH, ABTS, 2-deoxyribose and FRAP) showed that both extracts exhibited strong concentration-dependent antioxidant activities. These extracts were efficient against Gram-positive bacteria, but not active against Gram-negative bacterial strains and the yeast Candida albicans. They also exhibited strong inhibitory effects on the germination and the radicle growth of the wild Daucus carota. This work provides scientific supports for the high antioxidant and phytotoxic activities of this species and thus, it may find potential applications in the development of natural herbicides and antioxidants for agro-food and pharmaceutical industries. © 2013 South African Association of Botanists.

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