Variation of active constituents and antioxidant activity in Grunning from different stages.

It has been claimed that inflorescences of Grunning (ST) may prevent liver diseases because of its higher chlorogenic acid. There was scant information on the phytochemical profiles and antioxidant activities of the whole plant from different growing stages. The changes of active-compounds and antioxidant activities of ST from three growing stages were studied. Total phenolic and flavonoid contents were analyzed and ranged from 0.00 to 140.03 mg GAE/g and 9.10 to 460.01 mg RE/g, respectively. The pre-flowering stage ethyl acetate (PFSEA) fraction of ST appeared to contain the highest content of chlorogenic acid, and demonstrated the highest DPPH radical-scavenging activity with the IC value of 8.47 ± 0.23 µg/mL which was nearly equal to the IC value of vitamin C (7.60 ± 0.61 µg/mL). Principal component analysis suggested that the PFSEA fraction of ST might be a desirable antioxidant natural resource due to the highest potential antioxidant properties.