Analysis on the difference of nutrient components of black wolfberry seed grown in different regions

Black wolfberry is a traditional Chinese medicinal herb, and its seeds are abundant in bioactive nutrients. However, substances other than seed oil have been largely unknown. In this study, the basic nutrients, metabolic profiles, and antioxidant activity of black wolfberry seeds grown in four different regions were measured by physicochemical and metabolomics approaches. A total of 699 metabolites were identified, including phenolic compounds and organic acids. PLS-DA and random forest model revealed that the saccharides and amino acids were mainly contributed to characterize wolfberry seeds from different areas. The unique amino acids of wolfberry seeds in Qinghai and the unique saccharides of wolfberry seeds in Ningxia distinguished the seeds from the four regions. The KEGG pathway analysis showed that most of differentially expressed metabolites were involved in purine metabolism. Antioxidant capacity analysis showed that black wolfberry seeds grown in Gansu had the highest antioxidant activity, which may be correlated with the content of phenolic compounds, saccharides, amino acids, organic acids and fatty acids. Diurnal temperature variation was the dominant factor affecting the metabolite content in wolfberry seeds. These results provide a compressive database for the potential industrial applications of black wolfberry seeds.