Algal bioactives: Unlocking future frontiers in respiratory therapeutics

Respiratory diseases such as asthma, chronic obstructive pulmonary disease (COPD), lung cancer (LC), pulmonary fibrosis, and respiratory infections pose significant global health challenges. According to the World Health Organization (WHO), COPD alone accounted for approximately 3.3 million deaths in 2021. Current therapies, including corticosteroids, bronchodilators, and antifibrotic agents, help alleviate symptoms, and these conditions often become chronic and necessitate ongoing care, particularly with the associated problems such as corticosteroid insensitivity. Marine organisms, including microalgae and cyanobacteria, produce various bioactive compounds, among them fucoidan, fucoxanthin, astaxanthin, and phycocyanin that exhibit anti-inflammatory, antioxidant, anticancer, and anti-fibrotic activities. For instance, compounds such as fucoidan, fucoxanthin, astaxanthin, and phycocyanin illustrate the therapeutic potential of algae-derived bioactives. Fucoidan may help mitigate inflammation in COPD and asthma, while fucoxanthin shows promise in inhibiting LC cell proliferation. Similarly, astaxanthin aids in countering oxidative stress associated with COPD and LC, and phycocyanin appears to slow fibrosis progression by reducing inflammatory markers and limiting fibroblast proliferation. Together, these compounds highlight the diverse mechanisms through which algae-derived substances can contribute to the management of respiratory diseases. The current review examines these and other algae-derived compounds, detailing their molecular mechanisms of action and exploring emerging strategies for treating respiratory diseases.