1) Buckthorn 2) California buckthorn 3) California coffee 4) Rhamnus californicus 
[n] - evergreen shrub of western United States bearing small red or black fruits
A strong antioxidant, this plant extract is an expensive, patented ingredient that is not widely available (you'll find it in Priori Skincare and RevaléSkin).
California buckthorn noun evergreen shrub of western United States bearing small red or black fruits
an evergreen shrub, Rhamnus californica, of the buckthorn family, common in the western U.S., having small, greenish flowers and red fruit that turns black, grown as a bee plant.