Antibacterial and antioxidant activity of royal jelly collected from geographical regions with different climates in the north of Iran

Royal jelly is one of the most important bee products. The biological activities of royal jelly can be influenced by various factors such as geographic origin, climatic conditions, vegetation. This study was carried out to evaluate the antibacterial and antioxidant activity of royal jelly samples collected from beehives from different geographical regions including mountain, coastal and plain regions in northern Iran. Antibacterial activity of royal jelly samples against ten bacteria was determined using agar well diffusion method. The MIC and MBC of royal jelly samples were determined by the broth microdilution method. Folin-Ciocâlteu reagent and reaction with DPPH were used to determine the total phenolic content and antioxidant potential of royal jelly samples, respectively. The MIC of samples ranged from 0.78 to 12.5% and MBC - from 3.12 to 50%. Samples collected from mountain regions showed the highest antibacterial activity with MIC for Gram-positive bacteria from 0.78 to 1.56% and for Gram-negative bacteria: from 1.56 to 3.12%. The total phenolic content and DPPH radical scavenging activity in royal jelly samples of the mountain region was significantly higher than those from the two regions with other climates. The results of this study indicated that the climate of the geographic region of sampling location had an effect on the antibacterial and antioxidant activity of royal jelly which may be due to differences in plant vegetation and the origin of the flowers of bees.