Regaloside A is a phenylpropane derived from lily of the valley that shows DPPH free radical scavenging activity at 160 ppm.Regaloside A has anti-inflammatory activity and antidepressant activity.

Regaloside A (50 μg/mL; 2 h) followed by LPS treatment (1 μg/mL; 15 min) in RAW 264.7 cells inhibits iNOS expression to 70.3% and reduces COX-2 expression to 131.6%, also lowering the p-p65/p-65 ratio to 40.7; additionally, Regaloside A (50 μg/mL; 2 h) in HASMCs exposed to TNF-α (10 ng/mL; 12 h) reduces VCAM-1 expression to 48.6%.[1]