BackgroundThe interest in natural antioxidants, especially polyphenols, is growing more and more thanks to their positive contribution to human health. Thus, the prevention from the harmful action of oxidative stress which has been involved in many diseases such as cancer, inflammation diabetes, and cardiovascular illness.Recent research proved the bioactive compounds richness of date seeds which could be a good biological matrix of natural antioxidants. Unfortunately, an important quantity of Tunisian dates seed is discarded yearly.MethodsIn this study, different solvents extraction (water, methanol, absolute acetone and aqueous acetone 80%) were used and the evaluation of its effect on phytochemical level, in vitro antioxidant activities, in vitro hyperglycemia key enzymes inhibition and in vivo anti-inflammatory proprieties were established for Tunisian date seeds.ResultsThe result revealed that the polar solvent exhibited the highest amount of bioactive compounds. The correlation between polyphenol compounds and the antioxidant potentiality explains the powerful effect of used polar solvents on inflammation, TBARS and hyperglycemia inhibition. Furthermore, it showed its higher capacity to scavenge radicals.ConclusionsTherefore, this big waste of Tunisian seeds could be used as cheap source of natural antioxidant compounds which are considered as a health challenge for the poor countries.Electronic supplementary materialThe online version of this article (doi:10.1186/s12906-017-1751-y) contains supplementary material, which is available to authorized users.

Context To date, there are no reports to validate the Tunisian traditional and folklore claims of Eruca vesicaria (L) Cav. subsp. longirostris (Brassicaceae) for the treatment of disease. Objective Investigation of the chemical composition antimicrobial and antioxidant activity of essential oils from Eruca longirostris leaves, stems, roots and fruits. Materials and methods The essential oils of E. longirostris from leaves, stems, roots and fruits were obtained after 4 h of hydrodistillation. Chemical compositions were determined using a combination of GC/FID and GC/MS. The in vitro antimicrobial activity of the volatile constituents of E. longirostris was performed in sterile 96-well microplates against three Gram-positive, four Gram-negative bacteria and one strain as yeast. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration values were reported. Furthermore, the antioxidant activity was evaluated by DPPH and ABTS assays. Results The main compound for fruits, stems and roots was the erucin (96.6%, 85.3% and 83.7%, respectively), while b-elemene (35.7%), hexahydrofarnesylacetone (23.9%), (E)-b-damascone (15.4%), erucin (10.6%) and a-longipinene (9.6%) constituted the major compounds in the essential oil of the leaves. The experimental results showed that in all tests, essential oil of fruits showed the better antioxidant activity than the others. On the other hand, the oils of stems, fruits and roots showed significant antimicrobial activity with MIC values ranging from 0.125 to 0.31 mg/mL against Candida species, Gram-positive and Gram-negative bacteria, mainly Salmonella enterica. Conclusions The present results indicate that essential oils of E. longirostris can be used as a source of erucin. ARTICLE HISTORY

This work describes the study of the chemical composition and bioactivity of the essential oils (EOs) of the different organs (leaves, flowers, stems and roots) from Eruca vesicaria. According to the GC and GC/MS analysis, all the EOs were dominated by erucin (4‐methylthiobutyl isothiocyanate) with a percentage ranging from 17.9 % (leaves) to 98.5 % (roots). The isolated EOs were evaluated for their antioxidant (DPPH, ABTS and β‐carotene/linoleic acid), antibacterial and inhibitory property against α‐amylase and α‐glucosidase. Most EOs exhibited an interesting α‐glucosidase and α‐amylase inhibitory potential. The roots essential oil was found to be the most active with IC50 values of 0.80±0.06 and 0.11±0.01 μg mL−1, respectively. The essential oil of roots exhibited the highest antioxidant activity (DPPH, PI=92.76±0.01 %; ABTS, PI=78.87±0.19; and β‐carotene, PI=56.1±0.01 %). The isolated oils were also tested for their antibacterial activity against two Gram‐positive and three Gram‐negative bacteria. Moderate results have been noted by comparison with Gentamicin used as positive control.

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The chemical composition of the essential oils of 26 three organs (flowers, leaves and stems) from Rapistrum 27 rugosum (L.) All., was studied and screened for their possible 28 antibacterial and antioxidant properties. According to the GC 29 and GC/ MS analysis, 28 (represent 92.5% of the total oil 30 composition), 23 (93.9%), and 38 compounds (94.3%) were 31 identified from flowers, leaves and stems, respectively. The 32 major compound in the leaves essential oil was found to be 33 pentadecanal (55.3%) followed by hexahydrofarnesylacetone 34 (8.4%) and tetradecanoic acid (5.7%). 35While hexahydrofarnesylacetone (17.2%) followed by 1-36 pentadecanol (8.3%), tetradecanoic acid (5.9%), (E)-β-37 damascenone (5.7%) were the major compounds of the flowers 38 oil. Tetradecanoic acid (13.1%), hexahydrofarnesylacetone 39 (10.1%), dodecanoic acid (10.0%), isobornyl acetate (7.6%), 5-40 methylthiopentyl isothiocyanate (6.7 %) and (E)-β-ionone 41 (6.2%) were the main constituents for the leaves oil. 42The flowers essential oil exhibited the higher activity in each 43 antioxidant system (ABTS, DPPH and β-Carotene-linoleic acid 44 methods) with an important value for DPPH assay (PI = 69.88 45 ± 0.02%). Furthermore, the isolated oils were tested against 46 five Gram-positive and Gram-negative bacteria. It was found 47 that the oil of all organs exhibited interesting antibacterial 48 activities against Gram-positive bacteria, comparable to those 49 of Gentamicin, which was used as positive control.

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