Variation in contents of active components and antibacterial activity in different parts of Thunb

BackgroundLonicera japonica Thunb has been comprehensively used as a traditional Chinese medicine which contains a variety of medicinally active substances.ObjectivesThe active constituents in various parts of L. japonica Thunb (leaves [LE], flowers fl, and green buds [GB]) were studied to rational and efficient use of this medicinal plant.MethodsUV–vis spectrophotometry was used for the determination of the total flavonoids; gas chromatography–mass spectrometric method was employed for the analysis of volatile components; and high-performance liquid chromatography technology was applied to detect nine bioactive components including chlorogenic acid, neochlorogenic acid, isochlorogenic acid C, caffeic acid, luteolin, galuteolin, hyperoside, rutin, and quercetin in different parts of L. japonica Thunb. The antimicrobial effects of LE, FL, and GB were further measured using agar plate drilling method.ResultsThe content of the total flavonoids in different portions of L. japonica Thunb has significant difference, and the content with the decreasing sequence is found in GB, LE, and FL. The contents of main volatile components were highest in FL, followed by GB and LE. Besides, the contents of galuteolin, luteolin, rutin, and isochlorogenic acid C were higher in LE than those in FL and GB, and neochlorogenic acid content was similar in LE and FL. The antimicrobial effects showed