Sea buckthorn (Elaeagnus rhamnoides; syn. Hippophae rhamnoides) is a thorny shrub or a small tree belonging to the Elaeagnaceae family, native to Eurasia. Sea buckthorn fruit is rich in vitamins and minerals, oils from the seeds and fruit flesh find use in medicine and the cosmetic industry or as nutraceutical supplements. Fruit, leaves and other parts of buckthorn have been used in traditional medicine, especially in China, Tibet, Mongolia, and Central Asia countries, and are a rich source of many bioactive substances. Due to its health-promoting and medicinal properties, the plant has been extensively investigated for several decades, and its phytochemical composition and pharmacological properties are well characterized. The years 2010–2021 brought significant progress in phytochemical research on sea buckthorn. Dozens of new compounds, mainly phenolics, were isolated from this plant. Numerous pharmacological studies were also performed, investigating diverse aspects of the biological activity of different extracts and natural products from sea buckthorn. This review focuses on the progress in research on sea buckthorn specialized metabolites made in this period. Pharmacological studies on sea buckthorn are also discussed. In addition, biosynthetic pathways of the main groups of these compounds have been shortly described. Graphical abstract

Effects of the phenolic fraction from Hippophae rhamnoides fruits on the production of thiobarbituric acid reactive substances (TBARS, a marker of lipid peroxidation) and the generation of superoxide anion () in human blood platelets (resting platelets and platelets stimulated by a strong physiological agonist, thrombin) were studied in vitro. We also examined antioxidant properties of this fraction against human plasma lipid peroxidation and protein carbonylation induced by a strong biological oxidant, hydrogen peroxide (H₂O₂) or H₂O₂/Fe (a donor of hydroxyl radicals). The tested fraction of H. rhamnoides (0.5– 50 µg/mL; the incubation time: 15 and 60 min) inhibited lipid peroxidation induced by H₂O₂ or H₂O₂/Fe. The H. rhamnoides phenolic fraction inhibited not only plasma lipid peroxidation, but also plasma protein carbonylation stimulated by H₂O₂ or H₂O₂/Fe. Moreover, the level of in platelets significantly decreased. In comparative experiments, the H. rhamnoides fraction was a more effective antioxidant than aronia extract or grape seed extract (at the highest tested concentration, 50 µg/mL). The obtained results suggest that H. rhamnoides fruits may be a new, promising source of natural compounds with antioxidant and antiplatelet activity beneficial not only for healthy people, but also for those with oxidative stress‐associated diseases.

Content of bioactive saponins of Medicago species suggests that they may also exert, as previously demonstrated on M. sativa, nematicidal properties exploitable for the formulation of new products for sustainable phytoparasitic nematode management. This study was addressed to highlight the bioactivity of saponins from five different Medicago species still poorly known for their biological efficacy, i.e., M. heyniana, M. hybrida, M. lupulina, M. murex and M. truncatula, against the plant parasitic nematodes Meloidogyne incognita, Xiphinema index and Globodera rostochiensis. The bioactivity of the extracts from the five Medicago species was assessed by in vitro assays on the juveniles (J2) and eggs of M. incognita and G. rostochiensis and the adult females of X. index. The suppressiveness to M. incognita of soil treatments with the Medicago plant biomasses was also investigated in a tomato experiment. The nematicidal activity of the five Medicago species was reported and discussed in relation to their phytochemical profile.