Description: <p>
<strong>Rhein (4,5-dihydroxyanthraquinone-2-carboxylic acid)</strong> is a
naturally occurring anthraquinone found particularly in rhubarb
(<em>Rheum palmatum</em>, <em>Rheum officinale</em> and related species), as
well as <em>Polygonum multiflorum</em>, <em>Cassia</em> species and
<em>Aloe</em>. Rhein has demonstrated anti-inflammatory, antioxidant,
antifibrotic, metabolic, neuroprotective and anticancer activities in
preclinical studies. In cancer models, rhein can suppress proliferation,
migration and invasion and promote cell-cycle arrest and apoptosis through
mechanisms involving PI3K/AKT, MAPK, NF-κB, p53, mitochondrial apoptosis,
oxidative-stress signalling and other pathways. Alzheimer-related experimental
studies also suggest neuroprotective and anti-neuroinflammatory activity,
including modulation of microglial metabolism and inflammatory signalling.
Rhein should be maintained as a separate product from emodin, aloe-emodin,
chrysophanol, physcion and whole rhubarb extracts because it is a chemically
distinct anthraquinone with its own pharmacological and toxicological profile.
Current therapeutic evidence remains predominantly preclinical, and potential
hepatic and renal toxicity as well as poor water solubility and bioavailability
should be considered when interpreting experimental findings.
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