The present work investigates the effect of ripening stage on the chemical composition of essential oil extracted from peel of four citrus: bitter orange (Citrus aurantium), lemon (Citrus limon), orange maltaise (Citrus sinensis), and mandarin (Citrus reticulate) and on their antibacterial activity. Essential oils yields varied during ripening from 0.46 to 2.70%, where mandarin was found to be the richest. Forty volatile compounds were identified. Limonene (67.90–90.95%) and 1,8-cineole (tr-14.72%) were the most represented compounds in bitter orange oil while limonene (37.63–69.71%), β-pinene (0.63–31.49%), γ-terpinene (0.04–9.96%), and p-cymene (0.23–9.84%) were the highest ones in lemon. In the case of mandarin, the predominant compounds were limonene (51.81–69.00%), 1,8-cineole (0.01–26.43%), and γ-terpinene (2.53–14.06%). However, results showed that orange peel oil was dominated mainly by limonene (81.52–86.43%) during ripening. The results showed that ripening stage influenced significantly the antibacterial activity of the oils against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. This knowledge could help establish the optimum harvest date ensuring the maximum essential oil, limonene, as well as antibacterial compounds yields of citrus.

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The Citrus species used in this study were considered valuable varieties from the point of view of antioxidant capacity and nutrition.

The antioxidant and antibacterial activities of phenolic compounds from cultivated and wild Tunisian Ruta chalepensis L. leaves, stems, and flowers were assessed. The leaves and the flowers exhibited high but similar total polyphenol, flavonoid, and tannin content. Moreover, two organs showed strong, although not significantly different, total antioxidant activity, 2,2-diphenyl-1-picrylhydrazyl scavenging ability, and reducing power. Investigation of the phenolic composition showed that vanillic acid and coumarin were the major compounds in the two organs, with higher percentages in the cultivated organs than in the spontaneous organs. Furthermore, R. chalepensis extracts showed marked antibacterial properties against human pathogen strains, and the activity was organ- and origin-dependent. Spontaneous stems had the strongest activity against Pseudomonas aeruginosa. From these results, it was concluded that domestication of Ruta did not significantly affect its chemical composition and consequently the possibility of using R. chalpensis organs as a potential source of natural antioxidants and as an antimicrobial agent in the food industry.

Anis (Pimpinella anisum L.) seeds obtained from two geographic origins Tunisia (TAS) and 31 Egypte (EAS) were studied regarding their biochemical composition and the antioxidant 32 potential of their extracts. The results showed that the highest value of oil was detected with 33 TAS compared to that of EAS ones. Ten (10) fatty acids were identified for the two locations 34 and petroselinic acid was the most prevalent in oil seeds and interestingly, TAS displayed a 35 significantly higher level of this acid than EAS. Besides, TAS exhibited slightly higher 36 essential oil yield than the Egyptian variety and that trans-anethole was the dominant for the 37 two provenances. In both accessions, the highest total phenolic, flavonoid and tannin content 38 was obtained with ethyl acetate fraction. Therefore, TAS exhibited higher chelating and 39 reducing powers than EAS which may be due to a slightly different phenolic composition 40 between the two accession seed extracts. The phenolic compositions of TAS and EAS 41 revealed that ethyl acetate extracts showed higher proportions of naringin, chlorogenic acid 42 and rosmarinic acid. However, ethanol extracts were richer in larcitrin, rosmarinic acid and 43 cirsimartin. The overall results revealed that aniseeds might constitute a novel source of 44 natural antioxidants and could be used as food additive.