2018 ASHS Annual Conference

Lycium barbarum L. and Lycium chinense Mill. are two species of goji used to supply root bark (Di GU Pi, mainly Epidermis) for use in Traditional Chinese Medicine (TCM). In China, goji root bark is typically harvested from plants after it has had multiple years of berry production. Therefore, the supply of goji root bark is limited and considered not favorable for traditional supplement industries. In this study, we evaluated goji root bark quality at Trout Lake Farm (TLF), an organic farm located in Central Washington, over a 3-year period (2015-2017). One type of L. chinense (sourced locally) and two types of L. barbarum (‘Guandong’ and ‘Ningxia’) were established in the open-field in June 2015. Roots were harvested at the end of each growing season in October 2015, 2016, and 2017. Root bark was separated from the root cortex, and then milled into powder. Kukoamine B content was measured by HPLC-MS, and was used as a marker to determine the quality of goji root bark. Results showed that among the three goji types grown at TLF, kukoamine B content was the highest in L. chinensis, followed by ‘Ningxia’ and was lowest in ‘Guangdong’. Furthermore, the kukoamine B concentrations in each goji root bark type were relatively stable among the three years, suggesting that its biosynthesis was proportional to growth over time. We also measured kukoamine B in 12 commercially-available goji root bark samples purchased in China and compared these results with the TLF results. Among all 15 samples tested, kukoamine B content was consistently higher in the TLF goji root bark, thus indicating that goji root bark produced in Central Washington could be a reliable high-quality supplier of organic goji root bark in high in Kukoamine B for TCM industries around the world.