Antibacterial and antioxidant activities of three endemic plants from Algerian Sahara.

BACKGROUND: Saharan plants are known by their high content of antioxidant products like phenolic compounds due to the extreme climatic conditions. They constitute the basis of treatments used by local population for various diseases. The purposes of this study were to measure the total phenolic compounds and total fl avonoid compounds, to determine antioxidant capacity, and to evaluate the antibacterial activity of three wild Saharan medicinal plants. MATERIAL AND METHODS: Hexane and ethyl acetate fractions of ethanol:water extract and the residu of the extracted aqueous layer of Ferula vesceritensis fruits, Genista saharae aerial parts and Zilla macropterae fruits were assayed to determine their antibacterial activity using the disc diffusion method against: Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 25923) and Pseudomonas aeruginosa (ATCC 27853). In addition, the total phenolic compounds and total flavonoids and antioxydant activity using DPPH test of ethyl acetate fractions (EAF) of plant parts studied were investigated. Gallic acid, quercetin and vitamin C were used for these parameters. RESULTS: Among the extracts tested, ethyl acetate fractions of all plants and hexane fraction of F. vesceritensis showed activity against S. aureus. Good activity was shown by EAF of G. saharae. According to the results, it is observed that Z. macropterae fruits possess a good antioxidant activity. CONCLUSION: The results indicate that the ethyl acetate fraction of G. sahara Aerial parts possesses a good antibacterial activity against S. aureus, which justifies its use in traditional medicine for treating respiratory diseases. Furthermore, evaluation of in vitro antioxidant capacity of Ethyl acetate fractions of these plants, particular Z. macroptera fruits, has also provided interesting results. Zilla macroptera fruits may therefore be a good source of antioxidants.

Chemical Composition and, Cellular Evaluation of the Antioxidant Activity of Desmodium adscendens Leaves.

Desmodium adscendens plant is widely used as juice or tea in various parts of the world against a wide range of diseases. This study determines the quality and the quantity of polyphenols, flavonoids, anthocyanins, and tannins in D. adscendens leaves by UV-spectrophotometry and RP-HPLC methods. In addition, the antioxidant capacity of these phenolic compounds is evaluated by ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic)), DPPH (2,2-diphenyl-1 picrylhydrazyl), and Cellular tests. D. adscendens leaves are mainly composite of flavonoid compounds with 12.8 mg of catechin equivalent (CE)/g dw. The amounts of total polyphenol compounds are 11.1 mg of gallic acid equivalent (GAE)/g dw. The quantity of total anthocyanin and total tannin compounds is not considerable 0.0182 mg CgE/g dw and 0.39 mg CE/g dw, respectively. A direct correlation between phenolic compounds and antioxidant activity is observed (R(2) = 0.96). The RP-HPLC analyses reveal that the main phenolic compound identified in the methanol-water extract is quercetrin dihydrat (2.11 mg/mL). According to the results, it is observed that D. adscendens leaves possess a considerable scavenging antioxidant and antiradical capacity, therefore these antioxidant properties might increase the therapeutic value of this medicinal plant.