Polyphenol Contents, Antioxidant and Antibacterial Activities of Aqueous Algerian Propolis Extracts.

The propolis, an extremely complex resinous material, exhibits valuable pharmacological and biological properties, mainly attributed to the presence of polyphenols. The composition of propolis depends on time, vegetation, and the area of collection. Total flavonoid and polyphenol contents of aqueous extracts of propolis samples from different areas of Algeria, determined by using aluminum chloride and Folin--Ciocalteu colorimetric methods, were in the range of 3.047 ± 0.004--5.273 ± 0.013 mg/g and 96.833 ± 0.027--458.833 ± 0.0005 mg/g crude extract of propolis, respectively. This study examined the antioxidant and antimicrobial activities of propolis. Aqueous extracts of propolis were obtained in order to evaluate their antioxidant activities by using 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging, β-carotene and electrochemical assays. All tested propolis samples had relatively strong antioxidant activities, which were also correlated with the total polyphenol and flavonoid content present. The percentage of inhibition of lipid peroxidation of linoleic acid emulsion during 24 h varied between 86.04 ± 0.42 and 90.60 ± 3.77% among the tested samples. The highest DPPH radical scavenging activity was observed by ABAL (Ain Abassa Aqueous Extract) with IC50 = 8.49 ± 5.07 10-5 μg/ml, and the lowest was observed by SAL (Setif Aqueous Extract) with IC50 of 21.16 ± 0.0001 μg/ml. The most important antibacterial activity was obtained with Ain Abassa extract; the zones of inhibition obtained for this excerpt vary from 15.22 to 15.5 mm. Followed by the Setif extract with areas of 12.33 to 12.75 mm, the Tizi-Ouzou extract with areas of 10.11 to 11.11 mm. This study will bring an innovation for further studies with regard to the antioxidant and antibacterial properties of the aqueous extracts of propolis. This study corroborates that Algerian propolis is a rich source of natural antioxidants, properties which could be used in the prevention of different diseases, both in humans and in animals. [ABSTRACT FROM AUTHOR]