Evaluating of Antioxidant and Antibacterial Characteristics Ginkgo Biloba Leaves

Reactive oxygen species cause disease by damaging the chemical compounds in our body. On the other hand, drug resistance is becoming a serious issue in infection treatment, globally. Ginkgo biloba has many therapeutically features. The objective of this study was to evaluate antioxidant and antibacterial activity of Iranian Ginkgo’s leaf extracts.

In this experimental study, aqueous, ethanolic (%70) and methanolic (%80) extracts were made using Ginkgo. Total Phenolic and Flavonoids Content were measured by folin– ciocalteu reagent and Chloride Aluminum color assays. The extracts’ antioxidant activity was assessed by their potential in scavenging DPPH free radicals. Disc Diffusion assay was carried out to test antibacterial potency against two strains of bacteria (Enterococcus faecalis, Listeria monocytogenes). Data analysis was performed using factorial experiment within a completely randomized design. SPSS version 16 software and Duncan's multiple range tests were used to compare the means.

Based on results, all three extracts contained extensive amount of phenolic and especially flavonoid compounds with methanolic extract being the richest in phenolic and flavonoids while aqueous extract having the least of these compounds. The most antioxidant activity was found in methanolic extract of 300 mg/mL concentration with %84.73 (P<0.05) and the least was in aqueous extract of 40 mg/mL with %18.17 (P<0.05) ROS scavenging rate, this result was proportional to the measured bioactive components of the extracts. Antibacterial activity in 200 mg/mL concentration of methanolic extract was maximum against Enterococcus faecalis while it was minimum at 50 mg/µl concentration of aqueous extract against Listeria monocytogenes strain. Antibacterial activity of all three extracts was found out to be concentration dependent.

The results indicated that Ginkgo leaves are rich in phenolic and flavonoids contents that may be reason behind their notable antioxidant and antibacterial activity. Thus, Ginkgo could be a treasure trove of antioxidants and therapeutic compounds. However, more studies are required in regard to Ginkgo’s various characteristics.