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.

Rutaceae are widely recognized for their toxic and repellent activity exerted against mosquitoes. In our research, the essential oils extracted from fresh leaves of wild and cultivated plants of Ruta chalepensis L. (Rutaceae) were evaluated for larvicidal and repellent activity against the Asian tiger mosquito, Aedes albopictus Skuse (Diptera: Culicidae), currently the most invasive mosquito worldwide. In this research, gas chromatography and gas chromatography-mass spectrometry analyses of the essential oils from wild and cultivated plants showed only quantitative differences, in particular relatively to the amounts of ketone derivatives, while the qualitative profile evidenced a similar chemical composition. Both essential oils from wild and cultivated R. chalepensis plants were able to exert a very good toxic activity against A. albopictus larvae (wild plants, LC(50) = 35.66 ppm; cultivated plants, LC(50) = 33.18 ppm), and mortality was dosage dependent. These data are the first evidence of the toxicity of R. chalepensis against mosquitoes. Furthermore, the R. chalepensis essential oil from wild plants was an effective repellent against A. albopictus, also at lower dosages: RD(50) was 0.000215 μL/cm(2) of skin, while RD(90) was 0.007613 μL/cm(2). Our results clearly evidenced that the larvicidal and repellent activity of R. chalepensis essential oil could be used for the development of new and safer products against the Asian tiger mosquito.

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The effects of two extraction methods, used at three ripening stages on the total polyphenol contents and the antioxidant activities of Cumin (Cuminum cyminum L.) seed extracts were studied. The ripening stage effect on some physical properties of cumin seed was significant. The increase of dry matter (from 10.3 to 87.5%) during ripeness was correlated negatively with that of moisture content (from 89.7 to 12.5%). Besides results showed that the full ripe seeds were richer on polyphenols and condensed tannin than unripe ones, and consequently exhibited higher antioxidant activities. However, the unripe seeds had a higher total flavonoid content compared to those of half ripe and full ripe ones. The comparison of two extraction methods showed that soxhlet extracts contained the greatest amount of polyphenols and flavonoids, while maceration samples exhibited higher antiradical and bleaching power assay. Total phenolic contents and IC50 (concentration required to cause a 50% DPPH inhibition) values in cumin seed during their maturation allowed to conclude that antioxidant activity does not depend only on the high content of total phenolics but also on the phenolic composition. A total of 19 phenolic compounds were successfully identified by HPLC analysis during the ripening of cumin seeds. Rosmarinic acid was the major phenolic acid for the unripe seeds. Furthermore, half ripe and full ripe seeds were dominated by p-coumaric acid. These compounds might be considered as interesting bioactive natural substances that may be used in several fields, such as nutraceuticals, cosmetics and agro-food industry.

An analytical study of the biochemical composition and antioxidant activity of grape seed oil from nine Tunisian varieties (Merlot, Syrah, Sangiovese, Muscat d’Alexandrie, Razagui, Razaki, Khamri, Marsaoui and Carignan) was conducted. Seed oil yields varied from 6.31% (Khamri) to 12.70% (Merlot). All studied oils were characterized by high proportions of polyunsaturated linoleic acid ranging from 64.77 (Merlot) to 75.37% (Muscat d’Alexandrie). Grape seed oils were also rich in unsaponifiable minor components with the predominance of sterol fraction ranging from 1609.87 (Khamri) to 3814.55 (Carignan) mg/kg oil. Muscat d’Alexandrie seed oil had the highest chelating and reducing abilities while the strongest antiradical activity was obtained in Carignan variety. Antiradical ability was positively correlated with oleic acid but negatively with polyphenols and tocopherols. Multivariate analysis joined Merlot, Carignan, Syrah and Sangiovese in one group, Razagui, Razaki and Marsaoui in a second group and the third group Khamri and Muscat d’Alexandrie. Practical applications Grape seeds are generally known as by‐products coming from fruit processing industry. Grape seeds are the subject of many studies due to their richness in natural bioactive substances. The use of these natural bioactive substances has recently increased in food, cosmetic, and pharmaceutical products to replace synthetic antioxidants, which are being restricted because of their harmful health effects. This study aimed to characterize grape seed oils of nine Tunisian varieties through their fatty acids, phenols, sterols, tocopherols, triterpenoids, and antioxidant properties.

The aim of this work was to characterize Tunisian cactus pear (Opuntia ficus indica L.) flower through its lipids, essential oils, phenolics, and antioxidant activity. The total lipid content of cactus pear flower was about 2% with the neutral lipid amount, especially monoacylglycerols, being the highest. The lipids were rich in linoleic, oleic, and palmitic acids. The essential oil yield was 0.01% with the presence of 29 components in a complex mixture of monoterpenes. The main components of the essential oil were benzenacetatealdehyde, D‐3‐carene, hexanol, and α‐pinene. Solvents with different polarities had significant effect on polyphenol contents and antioxidant activity of cactus pear flower. RP‐HPLC analysis allowed characterization of 20 phenolic compounds mainly belonging to phenolic acid and flavonoid classes. Based on its phytochemical composition and antioxidant activity, cactus pear flower could be used in food, industrial, and biomedical applications. Practical applications The interest in naturally occurring antioxidants has recently increased for use in food, cosmetic, and pharmaceutical products to replace synthetic antioxidants, which are being restricted because of their carcinogenicity. The cactus pear flower constitutes one of the by‐products in cactus industry and generally discarded by separation from the fruit. This study aimed to valorize cactus pear flower through its lipids, essential oils, phenolics, and antioxidant activity.