Overview
This lecture reviews astaxanthin, a natural carotenoid, focusing on its anti-inflammatory mechanisms and its effects in various inflammation-associated diseases, highlighting recent advances and potential future research directions.
Introduction to Astaxanthin
- Astaxanthin is a lipid-soluble, red-orange carotenoid in the xanthophyll family.
- Primarily biosynthesized by microalgae, yeast, phytoplankton, and bacteria, and accumulates in seafood like salmon and shrimp.
- Natural astaxanthin is more bioactive than most other carotenoids and is approved for human consumption.
- Exhibits strong antioxidant, anti-inflammatory, neuroprotective, and immune-modulating properties.
Anti-Inflammation Mechanisms of Astaxanthin
- Inflammation is a protective response but contributes to chronic diseases if unresolved.
- Astaxanthin targets acute phase proteins (APPs), inducible enzymes (e.g., iNOS, COX-2), chemokines, and cytokines to reduce inflammation.
- Modulates multiple signaling pathways: inhibits NF-κB, MAPK (ERK1/2, JNK, p38), and JAK-STAT; activates PI3K/AKT and Nrf2 pathways.
- Suppresses production of inflammatory mediators like IL-1, IL-6, TNF-α, and MCP-1.
Astaxanthin in Chronic and Acute Diseases
- Neurological Diseases: Improves cognitive deficits in Alzheimer’s, protects neurons in Parkinson’s, and reduces neuropathic pain and brain ischemia damage.
- Diabetes: Reduces oxidative stress, inflammation, and apoptosis; protects against diabetic complications via NF-κB, MAPK, and PI3K/AKT pathways.
- Gastrointestinal Diseases: Inhibits colitis and colon cancer development by suppressing inflammatory cytokines and NF-κB activation.
- Hepatic and Renal Diseases: Improves kidney and liver injury by enhancing antioxidant activity, downregulating inflammation, and modulating Nrf2, SIRT1, and MAPK pathways.
- Eye and Skin Disorders: Ameliorates dry eye disease and atopic dermatitis via PI3K/Akt/HMGB1 and NF-κB inhibition.
Astaxanthin in Infectious Diseases
- Shows protective effects against Helicobacter pylori infection in animal models by regulating cytokine responses and reducing bacterial load.
- Human results are mixed, with some immunomodulatory effects observed but variable impact on bacterial growth or cytokine expression.
Future Directions and Conclusions
- Astaxanthin is a promising multi-target agent for inflammation-related diseases.
- Additional research is needed, particularly on its roles in viral infections and in non-mammalian models.
Key Terms & Definitions
- Carotenoid — Pigment found in plants and some animals, with antioxidant properties.
- Xanthophyll — A type of carotenoid containing oxygen.
- Acute Phase Proteins (APPs) — Proteins that change concentration in response to inflammation.
- Cytokines — Small proteins important in cell signaling during immune responses.
- NF-κB — A protein complex controlling transcription of DNA, involved in inflammation.
- PI3K/AKT Pathway — Signaling pathway promoting cell survival and growth.
- Nrf2 Pathway — Regulates antioxidant proteins to protect against oxidative damage.
Action Items / Next Steps
- Review the mechanisms of action of astaxanthin in signaling pathways.
- Study the summarized effects of astaxanthin in each disease model.
- Explore recent research on astaxanthin and viral infectious diseases for updates.