A survey of some nutritional and phytochemical components of selected native and non-native Rhamnaceae species

Rhamnus cathartica was introduced to North America, where it has become naturalized and typically co-occurs with other buckthorns that are native within the Rhamnaceae family, and its highly invasive traits impact native flora/fauna. Species in this family have been reported to contain anthraquinones, a class of secondary compounds. However, relatively little is known about the fruit nutrition and fruit anthraquinone composition for some buckthorns native to the United States, or how they compare to R. cathartica in different regions of its own native and naturalized ranges. We report on these fruit components in R. cathartica along with lesser-studied native buckthorns. Fruits were generally low in energy density and fat content, regardless of sampling location or native status– with variation in other nutritional components and measures of antioxidant potential. All sampled fruits contained the anthraquinone emodin; however, there was generally a broader array of anthraquinones in native buckthorn fruits. We also report novel data on native Rhamnus smithii, along with complementary values on the native Frangula caroliniana. The data contributes to expanding the limited nutritional and phytochemical knowledge of these buckthorn species, which could shed light on their functional roles in the communities/ecosystem.