Anti-Inflammatory and Anticancer Effects of Microalgal Carotenoids

Abstract

Acute inflammation is a key component of the immune system's response to pathogens, toxic agents, or tissue injury, involving the stimulation of defense mechanisms aimed to removing pathogenic factors and restoring tissue homeostasis. However, uncontrolled acute inflammatory response may lead to chronic inflammation, which is involved in the development of many diseases, including cancer. Nowadays, the need to find new potential therapeutic compounds has raised the worldwide scientific interest to study the marine environment. Specifically, microalgae are considered rich sources of bioactive molecules, such as carotenoids, which are natural isoprenoid pigments with important beneficial effects for health due to their biological activities. Carotenoids are essential nutrients for mammals, but they are unable to synthesize them; instead, a dietary intake of these compounds is required. Carotenoids are classified as carotenes (hydrocarbon carotenoids), such as α- and β-carotene, and xanthophylls (oxygenate derivatives) including zeaxanthin, astaxanthin, fucoxanthin, lutein, α- and β-cryptoxanthin, and canthaxanthin. This review summarizes the present up-to-date knowledge of the anti-inflammatory and anticancer activities of microalgal carotenoids both in vitro and in vivo, as well as the latest status of human studies for their potential use in prevention and treatment of inflammatory diseases and cancer.

Keywords: cancer; carotenoids; inflammation; microalgae; oxidative stress.

Figure 1

Chemical structures of the main functional carotenoids found in microalgae. Carotenes: β-Carotene (A) and xanthophylls: Lutein (B), Zeaxanthin (C), Astaxanthin (D), Fucoxanthin (E), Violaxanthin (F), β-Cryptoxanthin (G) and Canthaxanthin (H).

Figure 2

Carotenoids’ interaction on major signaling pathways implicated in inflammation or cancer. The figure shows the bioactivity of the carotenoids for different type of cells. Red arrows show the effect of the presence of ROS on several activities in the cell; dashed orange arrow refers to the detoxification pathway that is triggered when ROS are produced; pink arrows show the interconnections of different mediators; orange arrows refer to the bioactivities produced by the different microalgal carotenoids.