Evaluation of phenolic, flavonoid content and antioxidant capacity of the leaves, flowers, seeds and essential oil of Lavandula officinalis in comparison with synthetic antioxidants

Abstract

Background & Aim: Lavandula officinalis is one of great importance due to its aromatic compounds and medicinal uses but not many studies have been done on the antioxidant power of different plant organs. Experimental: Antioxidant ability of Lavender leaves, flowers, seeds and essential oil based on inhibition of free radicals and nitric oxide, inhibition of linoleic acid peroxidation by ferric thiocyanate and inhibition of malondialdehyde by thiobarbituric acid in compare with synthetic antioxidants Butyl Hydroxy Toluene (BHT) and Butyl Hydroxy Anisole (BHA) were measured. Results: The phenolic and flavonoid content of the leaf was 96.49±6.35 (µg gallic acid per mg dry weight of the extract) and 39.97±3.36 (µg of catechins per mg dry weight of the extract) respectively, more than other samples. In the study of antioxidant power, plant leaf extract with 48.66±5.5 μg was able to inhibit 50% of DPPH radicals, which had a weaker ability than synthetic antioxidants. The leaf extract of the plant had a higher ability than the synthetic antioxidant BHA to inhibit nitric oxide radicals and its ability was as high as BHT. The ability to inhibit the linoleic acid peroxidation of leaf and flower extracts at the beginning of the functional test showed similar BHT and BHA, at the end, the ability of leaf extract was stronger than BHA and weaker than BHT. The inhibitory potential of malondialdehyde leaf extract (82.66±1.5%) was better than BHA and weaker than BHT. Pearson correlation coefficients between phenolic content and antioxidant capacity of samples were high. Examination of leaf essential oil using GC-MS technique showed the presence of phenolic compounds in the plant. Recommended applications/industries: Due to the dangers of synthetic antioxidants in the food industry, the results of this study could introduce another application of this plant in terms of strong antioxidant properties.

Keywords

• antioxidant activity
• flavonoid content
• total phenolic content
• free radicals