Comparative Study on Antioxidant Activity of Propolis of Apis mellifera from Different Regions of Nepal

Propolis is a waxy material obtained from honey bee hives. The physical and chemical property of this product is variable based on the source of hive, plant biodiversity where honeybee feed, season of collection, geographical origin etc. Propolis has several useful chemical compounds, and among them polyphenols are mainly contributing for their broad spectrum of medicinal quality such as antimicrobial, antifungal, antibacterial, and anti-inflammatory activities as well as antioxidant properties. The present study aims to analyze the ethanolic extract of propolis for their phenol and flavonoid content as well as its antioxidant characteristics. The samples (SPLs) were collected from farmers of six different locations of Nepal i.e. Jhapa, Lalitpur, Kathmandu, Banke and Chitwan districts. Total phenolic content (TPC) and total flavonoid content (TFC) were measured by Folin Ciocalteu method and the aluminum chloride method respectively expressed as the gallic acid (GAE) and quercetin (QE) and equivalent (GAE) per gram. The Diphenyl-Picrylhydrazyl (DPPH) assay method was used to evaluate the free radical scavenging activity. The antioxidant effect of propolis was reported in ascorbic acid equivalent antioxidant capacity per gram of propolis. The highest content of phenolic and flavonoid content was found in sample SPL 2. The range of these compounds' concentrations were from 127.36±5.50 mg GAE/gram to 242.7±4.50 mg GAE/gram. Similarly, total flavonoid content ranged from 1.3197±0.0261 QE mg/ grams to 5.3921±0.0261 QE mg/ grams. Whereas samples from SPL 2, and SPL 5 showed highest antioxidant properties. All samples were found to have strong antioxidant capacity which was greater than standard. It is concluded that there is no direct correlation on total antioxidant property of propolis with their total phenolic and total flavonoid content among collected samples. The phenolic characteristics of the samples were variable to the geographical location, and plant diversity of their origin.