Caffeic acid derivatives from Bupleurum chinense.

In this study, caffeic acid (CA) and its three derivatives including 3-caffeoylquinic acid (3-CQA, neochlorogenic acid), 4-caffeoylquinic acid (4-CQA, cryptochlorogenic acid), and 5-caffeoylquinic acid (5-CQA, chlorogenic acid) were identified in Bupleurum chinense aerial parts using reverse-phase high-performance liquid chromatography (RP-HPLC) with photodiode array (PDA) detector, reference compounds and chemical reactions. Separation was performed on a C18 column using gradient elution with 4% (v/v) aqueous acetic acid and acetonitrile as mobile phase at ambient temperature. In addition, the flavonoid aglycones were characterized and quantified after acid hydrolysis of the plant material. The flavonols profile showed quercetin (0.36 g per 100 g), kaempferol (1.11 g per 100 g) and isorhamnetin (0.16 g per 100 g). Total phenolic and total flavonoid contents ranged from 7.3 to 18.7% and 0.58 to 2.72% in dry plant material, respectively.