Annual dynamic variation of seven active components of Lonicera japonica in leaf growth and pruning periods

Abstract

Pruning branches and leaves is the measure to stimulate the growth of Lonicera japonica flower buds, and consequently, the resources of pruned leaves are inevitably and seriously wasted in production. High-performance liquid chromatography(HPLC) was applied for content determination of seven active ingredients(chlorogenic acid, galuteolin, isochlorogenic acids A, B, and C, secologanic acid, and secoxyloganin) in L. japonica leaves from March to November. The results showed that the tillering removed from the trunk of L. japonica in March, the leaves pruned from May to July, and the leaves after the first frost date in November were rich in active ingredients, which deserved further exploitation and utilization. The total content(TC) of active ingredients in pruned L. japonica leaves in early March was the highest. The content of active ingredients in L. japonica leaves increased significantly after the first frost date, which was close to that in the bud tillers pruned in early and middle March. After the first frost date, L. japonica leaves are incapable of photosynthesis, and the harvesting of L. japonica leaves does not affect the physiological activities of the tree. In addition to huge resources, the content of active ingredients is high during this period, which is the best harvesting period of L. japonica leaves.