Phycocyanin: Biomedical Activities and Related Mechanisms of Action.

With global resources becoming increasingly strained, the development of novel sustainable resources has become particularly important. Spirulina has attracted considerable attention due to its exceptional nutritional value, abundant bioactive components, and superior environmental adaptability. A key functional component in spirulina, phycocyanin is a natural water-soluble protein pigment that exhibits diverse biological activities. In recent years, with advances in extraction and purification technologies, research on phycocyanin in the culinary, pharmaceutical, and cosmetic fields has both rapidly increased and significantly enhanced its commercial value. Despite its broad application prospects, research on its molecular mechanisms and systematic physiological effects requires further integration. This paper aims to comprehensively update the current research status of phycocyanin, systematically elucidate its biological activities as related to its anti-oxidative stress, immunomodulatory, anti-inflammatory, antitumor, and neuroprotective effects. To do so, this paper analyzes the molecular mechanisms through which phycocyanin exerts its effects, and in particular considers its regulation of key signaling pathways such as NRF2/HO-1, NF-κB, and PI3K/Akt. This review provides a detailed summary of the protective effects of phycocyanin on organs including the liver, cardiovascular system, and nervous system. It also summarizes the research progress on phycocyanin over the past 10 years, including findings related to its biological activities, functions, and related mechanisms. In conclusion, this review underscores the immense therapeutic potential of phycocyanin as a multi-target natural agent, and highlights the critical need for further clinical translation to fully harness its benefits in promoting human health and combating chronic diseases.