This review covers literature data summarizing, on one hand, the chemistry of essential oils and, on the other hand, their most important activities. Essential oils, which are complex mixtures of volatile compounds particularly abundant in aromatic plants, are mainly composed of terpenes biogenerated by the mevalonate pathway. These volatile molecules include monoterpenes (hydrocarbon and oxygenated monoterpens), and also sesquiterpenes (hydrocarbon and oxygenated sesquiterpens). Furthermore, they contain phenolic compounds, which are derived via the shikimate pathway. Thanks to their chemical composition, essential oils possess numerous biological activities (antioxidant, anti-inflammatory, antimicrobial, etc…) of great interest in food and cosmetic industries, as well as in the human health field.

Seeds from five varieties of Tunisian Citrus fruits, namely blood orange ( Citrus sinensis ), sweet orange ( Citrus sinensis ), lemon ( Citrus limon L.), bergamot ( Citrus bergamia ) and bitter orange ( Citrus aurantium ), were examined for their composition of lipid classes and fatty acids. In addition, the oil yield, total fatty acids, palmitic, oleic and linoleic acids were determined. Petroleum ether-extracted oils of these Citrus seeds amounted to more than 78% in the case of lemon seeds. The Citrus seed oils had three lipid classes as determined by thin-layer chromatography. Triacylglycerols were the major oil class in all varieties. Gas chromatographic analyses revealed that the main fatty acids were palmitic, oleic and linoleic acids.

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Compared with the control oil, the thyme-flavoured oil showed improved thermal stability after heating. This could be attributed to the presence of thyme pigments and antioxidant compounds allowing extended oil thermal resistance.

Four samples of Tunisian virgin olive oils of Chetoui, Chemlali, Chemchali and Oueslati varieties were analyzed for their chemical and fatty acid, total chlorophyll, total polyphenol and total aroma contents. The results showed that Chetoui was the most pigmented oil (4.45 ppm) and Oueslati oil contained the smallest amount of total chlorophylls (1.29 ppm). The Chetoui oil had the highest amount (94.37 ppm) of total polyphenols, while the Oueslati had the lowest amount (65.5 ppm). Furthermore, the Chemchali oil contained the highest level of total aroma (55.49 µg/mL of oil), followed by the Chemlali, Chetoui and Oueslati oils. The Chetoui oil was characterized by the highest level of oleic acid (70.9%) in contrast to the Chemlali, which had the lowest level of this fatty acid (58.6%). In addition, the highest level of palmitic acid characterizes the oil Chemlali (19.7%), whereas the Chetoui had the lowest (9.1%).

The present study aimed (1) to investigate the chemical composition as well as the antiinflammatory properties and in vitro antioxidant activity of Citrus aurantium peel essential oil (pEOCa) and (2) to evaluate its potential effect in vivo. The main results showed that the major components of pEOCa are Limonene and Linalool. Additionally, DPPH scavenging ability and β-carotene bleaching inhibition tests confirmed the antioxidant capacity of pEOCa. Our oil reduced the production of NO by LPS-stimulated RAW264,7 macrophages in a concentrationdependent. This inhibition occurred at a transcriptional level. pEOCa in CCl 4 treated rats alleviated hepatotoxicity as monitored by the improvement of hepatic oxidative stress biomarkers levels plasma biochemical parameters, and DNA molecule aspect. Furthermore, the mRNA gene expression of Cu-Zn SOD, CAT, and GPx increased under CCl 4 + pEOCa exposure to reach the same value to the control. Similarly, antioxidant activities of these three enzymes changed in accordance with the mRNA levels. These results were confirmed by the histological results. It seems obvious that the treatment with pEOCa prevented liver damage induced by CCl 4 , thus preventing the harmful effects of free radicals. K E Y W O R D Santioxidant activity, beneficial effect,

The aim of the present study was to investigate the extraction and the characterization of a novel heteropolysaccharide from Tunisian halophyte Lobularia maritima (LmPS). We were also interested in its antioxidant, anti‐inflammatory, and hepatoprotective effects on carbon tetrachloride (CCl4)‐induced liver injury in rats. LmPS physicochemical properties were evaluated by thin‐layer chromatography (TLC), high‐performance liquid chromatography (HPLC), thermogravimetric analysis (TGA), and UV absorption. According to TLC and HPLC results, LmPS was a heteropolysaccharide composed of glucose, galactose, and xylose. Its molecular weight was 130.62 kDa. This heteropolysaccharide was characterized by a significant antioxidant potential and was efficient against oxidative stress and CCL4‐induced hepatotoxicity in rat Wistar models (n = 8) treated with a single dose of LmPS 250 mg/kg of body weight. This was evidenced by a significant increase in serum marker enzymes specially aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), and lactate dehydrogenase (LDH). The cytokines released after stimulation of rats with LmPS showed high anti‐inflammatory profiles with an increased rate of interleukine‐10 (IL‐10) with 0.03 pg/mL compared to animals treated only with CCl4. On the contrary, we noticed a decrease of the other cytokines (tumor necrosis factor α: TNF‐α, interleukine‐6: IL‐6, transforming growth factor beta 1: TGF‐β1) with average concentration values of <0.2, 0.1, and 0.04 pg/mL, respectively. Besides, histopathological examinations revealed that CCl4 causes acute liver damage, characterized by extensive hepatocellular necrosis, vacuolization, and inflammatory cell infiltration, as well as DNA fragmentation. LmPS administration at a dose of 250 mg/kg resulted in a significant hepatoprotection, evidenced by a reduction of CCl4‐induced oxidative damage for all tested markers. These findings eagerly confirmed that LmPS was effective in the protection against CCl4‐induced hepatotoxicity and genotoxicity. It, therefore, suggested a potential therapeutic use of this polysaccharide as an alternative medicine for patients with acute liver diseases.