Изоастильбин

Description

Isoastilbine is a flavanonol (dihydroflavonol) glycoside. The aglycone carries hydroxyls at positions 5 and 7 of the chromanone core and a 3,4-dihydroxyphenyl catechol moiety at the second position; rhamnose (6-deoxy-α-L-mannopyranose) is attached at the third position. Configuration (2R,3S), which is why the substance is also called (2R,3S)-astilbine. The main source is the rhizome of naked smilax (Rhizoma Smilacis glabrae), also described in Astragalus membranaceus.

Basic Attributes

• CAS No.: 54081-48-0 (additional registration number 222846-33-5)
• Chemical formula: C21H22O11
• Molecular Weight: 450.39278
• Exact weight: 450.39
• Density: 1.7 ± 0.1 g/cm³
• Melting point: 278–280 °C (with decomposition)
• Flash point: 282.9 ± 27.8 °C
• Refractive index: 1.748
• Synonyms: Isoastilbin, (2R,3S)-astilbine

Activity studied

• inhibition of glucosyltransferase (GTase), IC50 = 54.3 μg/ml
• tyrosinase inhibition
• antioxidant and neuroprotective effects, including through an Nrf2-dependent mechanism
• antimicrobial and antiapoptotic effect

Scope of application

Reagent for research: models of neurodegeneration and Alzheimer's disease, work on cariogenic streptococci through inhibition of glucosyltransferase, screening of depigmenting agents by tyrosinase. A separate task is a standard sample for monitoring the authenticity and content of flavanonols in smilax raw materials.

Nomenclature remark

The structures of two flavanonol glycosides from Smilax glabra, previously described as smitilbine and neosmitilbine, have been revised to be isoastilbine and neoastilbine, respectively. Old names are still found in literature.

Storage and handling

No GHS classification has been declared. Melting is accompanied by decomposition, so heating above 270 °C is unacceptable. The container is tightly closed, stored in a dry, dark place, hung with gloves and glasses under traction.