Evaluation of the polyphenol contents and antioxidant activity of propolis extracted with different techniques

Abstract

Propolis is classified as an opotherapeutic medicine due to its complex chemical composition of organic secretions from bees. The chemical composition of propolis is greatly influenced by the honeybee species, botanical source and extraction techniques. Within this frame, we compared the same propolis’ polyphenol contents and antioxidant activities prepared with different techniques. Four types of extracts were prepared. The first type was prepared classically by ethyl alcohol (POH). The second and third types were extracted by sterile distilled water kept as both sterilised (PS) and non-sterilized (PN). The fourth one was prepared with full vacuumed and dried propolis with honey (PH). The antioxidant activity of extracts were evaluated with DPPH radical scavenging, ABTS radical cation scavenging, Cupric ion reducing antioxidant capacity, total phenolic content and total flavonoid content assays. POH extract showed significantly high content of total phenol and flavonoids which followed by PN, PS and PH. POH showed approximately two times much higher activity on DPPH radical (IC50=12.24 μg/mL) compared with quercetin as references. The lowest activity on DPPH is shown by PS with 56,72 μg/mL of IC50 value. The highest activity was shown by P0OH (271,75 mg GAE/g extract) which was followed by aquatic extracts and lowest value belonged to HP.The highest scavenging activity against ABTS radical cation was shown by POH (73,37 mg TE/g extract) and the lowest activity was shown by PS (34,21 mg TE/g extract). According to the results, the new aqueous extraction technique is promising with relatively high polyphenol contents and antioxidant activities. Also honey with propolis can be an alternative product, although it has relatively lower values.