Dynamic changes in flavonoid, phenolic, and polysaccharide contents in leaves and fruits of sea buckthorn during the growing season in southeastern Tibet plateau

Abstract

• Tibet sea buckthorn is a valuable source of natural functional ingredients. • Antioxidant activity of leaf extracts was higher than that of fruit extracts. • Contents of flavonoids, phenolics, and polysaccharides varied monthly. • Meteorological factors affected polysaccharide and flavonoid contents. • The best harvest month differed for different target components. Sea buckthorn, a medicinal and edible plant, is rich in flavonoids, phenolics, and polysaccharides. We detected monthly variations in the contents of three types of active compounds and the antioxidant activity of leaf and fruit extracts, and explored the effects of meteorological factors on active component contents. The highest flavonoid content in leaves and fruits was in July, and this did not coincide with the maximum contents of phenolics and polysaccharides. Compared with fruit extracts, leaf extracts showed higher antioxidant activity in the DPPH radical scavenging assay, the ferric ion reducing antioxidant power assay, and the total radical trapping antioxidant parameter assay. We detected significant correlations between some meteorological factors and the contents of bioactive components. The results reveal variations in the contents of bioactive components in sea buckthorn throughout the growing season in southeastern Tibet, and reveal the best time to harvest materials for optimum resource use.