Sea buckthorn (Hippophae rhamnoides L.) is a natural homologous substance of medicine and food. Polysaccharide, as one of its primary active components, has very superior biological activity and can be used as a dietary supplement for functional foods, with good commercial prospects. Although initial progress has been made in the study of sea buckthorn polysaccharides, related studies have been fragmented and lacked systematic and generalization. This manuscript presents a critical analysis and systematic summary of the extraction and purification methods, structural characterization and physicochemical properties, biological activity and potential mechanisms, and structure-activity relationships of sea buckthorn polysaccharides. Accumulating evidence has indicated that sea buckthorn polysaccharides, which were widely prepared by water extraction and column chromatography purifications, exhibited exhibit superior biological activities in vitro and in vivo, including antioxidant, immunomodulatory, anti-inflammatory, hepatorenal protective, antibacterial, antiviral, and prebiotic activities. After analysis, it was concluded that there is a correlation between the relevant activities of sea buckthorn polysaccharides and that the structure of sea buckthorn polysaccharides has a great influence on their biological activity. We reviewed the challenges and limitations of sea buckthorn polysaccharides, summarized the critical aspects, and provided suggestions for potential breakthroughs in the research and application of sea buckthorn polysaccharide.

Weizmannia coagulans (formerly Bacillus coagulans) is a spore-forming and lactic acid-producing bacterium. It has recently attracted much attention from researchers and food manufacturers due to its probiotic functions and stability in processing and storage. W. coagulans is capable of improving gut health through the regulation of gut microbiota, modulation of immunity, and improving digestibility and metabolism. Spores, germinated cells and metabolites of W. coagulans modulate the gut micro-environment and further affect other organs. W. coagulans is an environment-friendly probiotic since it can contribute to the host by reconstructing the balance of gut microbiota and only temporarily resides in the intestine after administration. W. coagulans has been generally recognized as safe (GRAS) by the US Food and Drug Administration (FDA), thus it is an ideal probiotic for improving gut health. The merit of its stability in processing and storage provides W. coagulans spores many possibilities for its use in various types of functional foods. This review presents an overview of the characteristics of W. coagulans that make it an ideal probiotic candidate and highlights the proposed health benefits with scientific evidence conferred by the administration of W. coagulans.