Hyperoside
Hyperoside is a naturally occurring flavonol glycoside, chemically known as quercetin-3-O-β-D-galactopyranoside, with the molecular formula C₂₁H₂₀O₁₂ and a yellow solid appearance at room temperature.[1] It serves as a key bioactive constituent in numerous medicinal plants, particularly those used in traditional Chinese and folk medicine, and is recognized for its role as a plant metabolite with potent antioxidant properties derived from its hydroxyl groups and glycosidic structure.[2] Hyperoside is widely distributed across various plant families, including Hypericaceae, Rosaceae, Polygonaceae, and others such as Erythrinaceae, Labiatae, and Leguminosae.[2] Notable sources include Hypericum perforatum (St. John's wort) and Hypericum monogynum from the Hypericaceae family, Crataegus pinnatifida (Chinese hawthorn) from Rosaceae, and Polygonum aviculare from Polygonaceae, with higher concentrations often found in plants from Southeast Asia, Europe, and North America.[1][2] It can be extracted from these sources using methods like solvent extraction or isolated through biosynthesis involving quercetin and uridine 5’-diphosphate-galactose catalyzed by enzymes in engineered Escherichia coli, achieving yields up to 18,000 mg/L.[1] These natural occurrences underscore its traditional use in herbal remedies for conditions involving oxidative stress and inflammation. The compound demonstrates a broad spectrum of pharmacological activities, primarily attributed to its ability to modulate pathways such as Nrf2/HO-1, PI3K/AKT, and NF-κB.[1][2] Key effects include antioxidant action, where it scavenges reactive oxygen species and protects against oxidative damage in models of liver and neuronal injury; anti-inflammatory properties, inhibiting pro-inflammatory cytokines like TNF-α and IL-6; and cardioprotective benefits, improving ejection fraction and reducing infarct size in ischemic heart models via AMPK/mTOR activation (e.g., 20 mg/kg/day dosing).[1][2] Additional notable activities encompass neuroprotection against Parkinson's and cerebral ischemia through SIRT1 and TRPV4 pathways, anti-cancer effects by inducing apoptosis in lung, cervical, and liver cancer cells, hepatoprotective and renal protective roles via PPARγ and miR-499-5p mechanisms, as well as antidiabetic, antithrombotic, and bone/joint protective functions.[1][3] Hyperoside exhibits low acute toxicity (LD50 > 5,000 mg/kg), though high chronic doses may cause reversible nephrotoxicity due to renal accumulation.[1] Ongoing research explores its pharmacokinetics, including poor oral bioavailability improved by nanoformulations, positioning it as a promising candidate for drug development.[1]Chemistry
Molecular structure
Hyperoside is a flavonol glycoside characterized by the molecular formula \ce{C21H20O12}.[4] Its systematic IUPAC name is 2-(3,4-dihydroxyphenyl)-3-[(2S,3R,4S,5R,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy-5,7-dihydroxychromen-4-one, commonly referred to as quercetin 3-O-β-D-galactopyranoside.[5][3] The molecular structure features a central flavonol backbone derived from the aglycone quercetin, which is 3,3',4',5,7-pentahydroxyflavone consisting of two phenyl rings (A and B) connected by a heterocyclic γ-pyrone ring (C). At the 3-position of the C-ring, quercetin is glycosylated via a β-glycosidic oxygen linkage to a β-D-galactopyranose sugar moiety, distinguishing hyperoside as a monoglycoside.[3] This arrangement positions the galactose unit equatorially at the anomeric carbon, forming a stable O-glycosidic bond that imparts specific stereochemistry to the molecule. In textual representation, the core flavone scaffold can be depicted as:- Ring A (positions 5-8): Benzene ring with hydroxyl groups at 5 and 7.
- Ring C (heterocyclic): Pyrone ring with a carbonyl at position 4 and the glycosidic attachment at 3.
- Ring B (positions 1'-4'): Phenyl ring with hydroxyls at 3' and 4'.