Analysis of Essential Oil in Sophora japonica L. Flower Buds on Different Stages of Development by Gas Chromatography-Mass Spectrometry

Abstract

To investigate, for the first time, the chemical composition of essential oil of the buds species of Sophora japonica L., a native to eastern Asia and a popular species in almost all Europe, growing in Ukraine. A hydrodistillation apparatus was used for the extraction of volatile components of buds species and then it was analysed by gas chromatography equipped with a split-splitless injector (split ratio, 1:50) and flame ionization detector (FID). The oil was analyzed under linear temperature programming applied at 4°C/min from 50°C - 340°C. Temperatures of the injector and FID detector were maintained at 280°C and 300°C, respectively. The chemical analysis of the oil was carried out using gas chromatography coupled to mass spectrometry (GC-MS), to determine the chemical composition of the volatile fraction. The essential oil content in green bud, formed bud, and beginning of bud opening ranged from 0.00002 – 0.00193 g/100 g, 0.00002 – 0.00684 g/100 g and from 0.00003 – 0.00638 g/100 g, respectively. The qualitative and quantitative analysis led to the identification of 80 components that were identified in Sophora japonica L. flower buds. Out of these 71 components are from the green flower bud and the beginning of flower bud opening stages, and 67 components are from the formed flower bud stage. The major component found in green bud was 3-methoxypyridine (0.00193 g/100 g). In both formed bud and beginning of bud opening was dodecanoic acid with concentrations of 0.00684 g/100 g and 0.00638 g/100 g, respectively. Contents of Sophora japonica L. were significantly affected by the harvesting stage of bud flower. Harvesting at the formed bud stage yielded the highest essential oil content compared to buds harvested at other stages. Flowers harvested at the green bud and beginning of bud opening stages yielded a lower quality essential oil compared with flowers harvested at the formed bud stage.