Study on antioxidant activities and total phenolic content of Leucaena leucocephala species

Plants contain a variety of substances called phytochemicals for example phenolic compounds and antioxidants. Antioxidants are compounds that can delay or inhibit the oxidation of lipids or other molecules by inhibiting the initiation or propagation ofoxidative chain reactions. Phenolic compounds are plant secondary metabolites, which play important roles in disease resistance. The antioxidant activity of most of the plant produced is mainly due to the presence of phenolic compounds. Among the phytochemicals. phenolic compounds are the main contributor of antioxidant activity in plant extracts due to their higher value in total phenolic content. The purpose of this study is to determine the amount of total phenolic content present in Leucaena leucocephala species and the relationship between the antioxidant activities and total phenolic content of the Leucaena leucocephala species. Bark and wood of Leucaena leucocephala species were extracted with methanol using Soxhlet Extraction. The total phenolic content was measured using Folin-Ciocalteu method based on standard calibration curve of Gallic acid using. UV-Spectrophotometer. Meanwhile, the free radical capacity was evaluated using DPPH (2, 2- diphenyl-1- picrylhydrazyl) free radical scavenging assay. The present study showed that the bottom bark had the highest total phenolic content followed by middle bark and top wood. High antioxidant activity was shown in bottom bark extracts with EC₅₀ value is 48μg/ml as compared to the other samples. There was a relationship between total phenolic content and antioxidant activities. The results of the bark of Leucaena leucocephala species suggest that these extracts have great source of natural antioxidants.