Phenolic Compounds Characterization and Antioxidant Properties of Monocultivar Olive Oils from Northeast Algeria

In Algeria, the olive tree is one of the main fruit species and plays a very important socioeconomic role. The objective of this study was firstly, to identify and quantify the phenolics of some Algerian olive oils, and secondly, to assess the antioxidant activity of the samples. The olive oils used in this study were derived from Algerian cultivars, including Tefahi, Gelb Elfarroudj, Chemlal, and imported cultivar Manzanilla and Zebboudj. For this purpose, gas chromatography—mass spectrometry (GC-MS) was used to identify olive oil fatty acids profile, while the individual phenolic compounds were assessed by ultra-high-performance liquid chromatography–electrospray ionization–high-resolution mass spectrometry (UHPLC-HESI-MS). To verify the antioxidant capacity, five in vitro free radical assays were used. Questionable values of particular physico-chemical parameters, such as the high value of free acidity and the low concentration of monounsaturated fatty acids in oil from the Zebboudj cultivar, indicate that improvements in olive cultivation and oil production practices are needed. Gelb Elfarroudj, Tefahi, and Manzanilla oils contain quantities of monounsaturated fatty acids in accordance with EU regulations. The oil obtained from the Zebboudj cultivar is not usable for food purposes due to the high value in free acidity and the low concentration of monounsaturated fatty acids. Tefahi and Manzanilla cultivars have given oils with the best antioxidant activity as compared to other studied cultivars; this is attributable to their composition in bioactive phenolic compounds, such as secoiridoids, which play an important role in human health as scavengers of free radicals. The results are interesting for producers and consumers to promote the culture of olive oils derived in particular from the Tefahi cultivar. However, in order to improve the health qualities of this oil, the agronomic techniques essentially linked to the time of harvesting of the olives destined for oil production must be improved

Phytochemicals, Antioxidant and Antiproliferative Properties of Rosmarinus officinalis L on U937 and CaCo-2 Cells

Rosmarinus officinalis L., a medicinal herb from the labiates family, has been reported to have potential benefit in the treatment and prevention of several diseases. In particular its phenolics have demonstrated protective effects on various types of cancer through several mechanisms. The present study aimed to determine the effects of rosemary phenolic extracts on human cell functions, with particular regard to their anti-proliferative properties in three cell types U937, CaCo-2 and the peripheral blood mononuclear cells (PBMCs). The radical scavenging and Ferric reducing abilities of the extracts have been assessed as well as their cyto-toxicity and effects on cell cycle distribution and apoptosis. About 13 compounds were identified with dominance of rosmarinic acid in the methanolic extract and phenolic diterpens in the ethyl acetate fraction (Carnosol, Carnosic acid and methyl Carnosate). The total polyphenolic content was important in the first extract with 2.589 ± 0.005 g/100 g in gallic acid equivalent compared to 0.763 ± 0.005 g/100 g. The methanolic fraction displayed higher antioxidant activity (DPPHIC50: 0.510 mg/mL and FRAP: 1.714 ± 0.068 mmol Fe(2+)/g) while ethyl acetate showed pronounced antiproliferative effects (IC50: 14.85 ± 0.20µg/mL and 14.95 ± 2.32 µg/mL respectively for U937 and CaCo-2 cells). The anti-proliferative effect was associated with a cell cycle arrest in S phase for U937 (62% of the population at 5 µg/mL) with a concomitant decrease in G1 and G2/M phases. Tested extracts displayed in addition early apoptotic effects in U937 and late apoptosis in CaCo-2 cells. The obtained data indicate that the identified phenolics are at least partially responsible for the observed cytotoxicity

Flavonoid profile, antioxidant and cytotoxic activity of different extracts from Algerian Rhamnus alaternus L. bark

BACKGROUND: Rhamnus alaternus (Rhamnaceae) L. has been traditionally used for treatment of many diseases. OBJECTIVE: In this study, we determined the antioxidant/free radical scavenger properties, the flavonoid profile and the cytotoxicity of aqueous and methanolic extracts obtained by maceration from Algerian R. alaternus bark, like also of aqueous extract prepared by decoction according to the traditional method. This to estimate the usefulness of the drug traditional preparation and compare it with those made in the laboratory. MATERIALS AND METHODS: The antioxidant activity of the extracts was evaluated using five different redox-based assays, all involving one redox reaction with the oxidant. High-performance liquid chromatography/diode array detection/electrospray ionization mass spectrometry analysis was used to identify and quantify the flavonoids content. Cytotoxicity on human monocytic leukemia cells (U937) was also carried out. RESULTS: All the extracts tested showed a good antioxidant/free radical scavenger activity and a similar flavonoid fingerprint. However, the methanolic one presented the best antioxidant activity that can be due to the highest flavonoid amount and significantly reduced the proliferation of leukemia cells. The results confirm that the extract prepared by decoction contains efficient antioxidant compounds and this justifies in part the therapeutic and preventive usefulness. Moreover, the methanolic extract exerted excellent cytotoxicity on U937 that could be attributed to kaempferol and rhamnocitrin glycosides