Browsing by Author "Hechaichi Fatima Zohra"

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    Recherche de substances bioactives de quelques Centaurées de la flore de M’sila
    (University of M'Sila, 2024) Hechaichi Fatima Zohra
    Centaurea tougourensis Boiss. & Reut., Centaurea dimorpha Viv., and Centaurea parviflora, belonging to the family Asteraceae, are delete Algerian medicinal plants used in traditional medicine to treat different diseases related to hyperglycemic and inflammatory disorders, as well as in food. Several studies have investigated the biological effects of different extracts of Centaurea species, but studies involving the phenolic composition of Centaurea parviflora, Centaurea tougourensis and Centaurea dimorpha extracts are very limited. The present study aimed to assess the total phenolic content, in vitro antioxidant and antimicrobial activity and phytochemical profile of the extracts of C. parviflora. While, our study aimed to perform phenolic profiling of C. tougourensis and C. dimorpha methanolic/water extract (80/20, v/v). Regarding C. parviflora, the extraction of phenolic compounds from aerial parts was conducted using solvents of increasing polarity starting from methanol, resulting in crude extract (CE), to chloroform extract (CHE), ethyl acetate extract (EAE) and butanolic extract (BUE). The total phenolic, flavonoid and flavonol contents of the extracts were determined using the Folin–Ciocalteu and AlCl3 methods, respectively. The antioxidant activity was measured with seven methods: 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, galvinoxyl free-radical-scavenging test, 2,2′-Azino-Bis (3-Ethylbenzothiazoline-6-Sulfonic Acid) (ABTS) assay, cupric reducing antioxidant capacity (CUPRAC), reducing power, Fe+2-phenanthroline reduction assay and superoxide-scavenging test. The disc-diffusion method aimed at testing the sensitivity of bacterial strains toward our extracts. A qualitative analysis with thin-layer chromatography of the methanolic extract was performed. Moreover, HPLC-DAD-MS was used to establish the phytochemical profile of the BUE. Wherase, for C. tougourensis and C. dimorpha, the examination of phenolic compounds was by using a novel and validated ultra-performance liquid chromatography method coupled to a tandem MS instrument (LC-MS/MS) in a negative mode of electrospray ionization. Furthermore, the both methanolic extracts were assessed for their phenolic, flavonoids and flavonol contents and antioxidant properties using DPPH, FRAP, ABTS and Phenanthroline assays. for C. parviflora, the BUE was found to contain high amounts of total phenolics (175.27 ± 2.79 μg GAE/mg E), flavonoids (59.89 ± 0.91 μg QE/mg E) and flavonols (47.30 ± 0.51 μg RE/mg E). Using TLC, different components such as flavonoids and polyphenols were noted. The highest radical-scavenging ability was recorded for the BUE against DPPH (IC50 = 59.38 ± 0.72 μg/mL), galvinoxyl (IC50 = 36.25 ± 0.42 μg/mL), ABTS (IC50 = 49.52 ± 1.54 μg/mL) and superoxide (IC50 = 13.61 ± 0.38 μg/mL). The BUE had the best reducing power according to the CUPRAC (A0.5= 71.80 ± 1.22 μg/mL), phenanthroline test (A0.5 = 20.29 ± 1.16 μg/mL) and FRAP (A0.5 = 119.17 ± 0.29 μg/mL). The LC-MS analysis of BUE allowed us to identify eight compounds including six phenolic acids and two flavonoids: quinic acid, five chlorogenic acid derivatives, rutin and quercetin 3-o-glucoside. While, the results of LC-MS/MS analysis showed that methanolic extracts of C. dimorpha and C. tougourensis were found to contain 16 and 10 compounds, respectively. More specifically, 8 phenolic acids, 7 flavonoids, and 2 non-phenolic organic acids were detected in C. dimorpha fraction; and only 7 phenolic acids, 1 flavonoid, and 2 non-phenolic organic acids were detected in C. tougourensis fraction. The most abundant phenolic compound in both extracts was determined to be quinic acid, and the amount of this compound was 20533.796 and 57164.13 μg g-1 in the extracts of C. dimorpha and C. tougourensis, respectively. The results of the total phenolic and flavonoid contents showed that C. dimorpha extract have the highest values with 219.8 ± 0.47 mg GAE/g and 82.8 ± 0.9 QE/g, respectively. Thus, flavolnol contents of the C. tougourensis extract (46.3 ± 0.116 mg QE/g) was greater than that of C. dimorpha extract (29.01 ± 0.245 mg QE/g). The antioxidant potential of the C. dimorpha extract significantly exceeded that of the C. tougourensis extract, as proved by higher activity across ABTS, reducing power, and phenanthroline assays. Specifically, in the DPPH and ABTS assays, the C. dimorpha extract exhibited IC50 values of 8.79±0.19 μg/mL and 1.92±0.03 μg/mL, respectively, compared to 27.77±0.60 μg/mL and 7.75±0.36 μg/mL for the C. tougourensis extract. This preliminary investigation revealed that these species, can be used as a source of new natural products in pharmaceutical and food processing fields.