Natural Bioactive Compounds in Alzheimer’s Disease Therapy

Dementia is the primary cause of Alzheimer’s disease (AD), a progressive neurodegenerative disorder (NDD) that increases with age. AD is one of the world's most serious healthcare issues. About 60–80% of dementia cases worldwide are caused by AD. It is characterised by the biological presence of tau-containing neurofibrillary tangles (NFT) and the β-amyloid (Aβ) peptide. The main focus for the development of AD therapy has been Aβ. Consequently, the Aβ removal from the brain is a prerequisite for effective treatment. Peptide was identified as the pathogenic agent of NDD by the Amyloid Cascade Hypothesis (ACH). Currently, very few medications available can delay the disease progression. Compounds with pharmacological activity isolated from plants, animals, and microorganisms help to treat AD. Phytochemicals possess anti-inflammatory, anti-oxidative, and anticholinesterase properties. A nutritional diet regulates health and prevents chronic inflammation and oxidative stress. AD development is influenced by phenolic compounds, omega-3 fatty acids, fat-soluble vitamins, and carotenoids, in addition to their roles as antioxidants and anti-inflammatory mediators. AD treatment has used marine-derived bioactive substances from microalgae (seaweeds). Nutraceuticals occur in pomegranate fruit. Fruit juice and peels contain significant bioactive substances used in traditional Chinese, Unani, and Ayurvedic medicine. Since AD is a complex illness, natural remedies offer the benefit of a multitarget strategy. However, many medications have undesirable side effects. Drug discovery is made easier by natural product extracts with bioactive components that combine to show neuroprotective effects.