Lycium ruthenicum as a Functional Food Resource: Chemical Composition, Nutritional Value, Health Benefits, and Biological Activities

Lycium ruthenicum Murr., commonly known as black goji berry, is a solanaceous shrub distributed in saline-alkaline desert environments of the Qinghai–Tibet Plateau and other arid regions. Its growing interest as a functional food resource is closely related to a rich nutritional profile and a phytochemical pattern that differs from that of the common red goji berry (Lycium barbarum). The most distinctive feature is the abundance of anthocyanins, particularly petunidin-derived compounds, which contribute to its dark fruit color and many of its reported biological properties. This review brings together evidence on the chemical composition, nutritional value, biological activities, and food-processing applications of L. ruthenicum. Anthocyanins, polysaccharides, fatty acids, amino acids, minerals, and trace elements are discussed in relation to antioxidant, anti-aging, neuroprotective, metabolic-regulatory, and immunomodulatory effects reported in current studies. Most of these health-relevant effects are currently supported by chemical/biochemical assays, in vitro studies, and animal models, whereas direct human evidence remains limited. Processing strategies, including drying, extraction, fermentation, encapsulation, and intelligent packaging, are considered alongside emerging genomic evidence related to stress tolerance and quality formation. The available evidence indicates that L. ruthenicum is a promising functional food and nutraceutical resource, although its bioavailability, safety, mechanisms of action, and clinical relevance still require more rigorous evaluation.