Scopolin is a naturally occurring coumarin glucoside, specifically the 7‑O‑β‑D‑glucoside of scopoletin. Its chemical formula is C₁₆H₁₈O₉, and it has a molecular weight of approximately 322.31 g·mol⁻¹. The compound belongs to the class of phenylpropanoid derivatives and is characterized by a coumarin core (1‑benzopyran‑2‑one) bearing a methoxy substituent at the 6‑position and a glucose moiety linked through an O‑glycosidic bond at the 7‑hydroxyl group.
IUPAC name
7‑(β‑D‑Glucopyranosyloxy)-6‑methoxy‑2H‑1‑benzopyran‑2‑one
Chemical structure
The molecule consists of a coumarin ring system (a benzene fused to a α‑pyrone) with a methoxy group at C‑6 and a β‑D‑glucopyranosyl group attached to the phenolic oxygen at C‑7.
Occurrence in nature
Scopolin has been identified in a variety of plant species, particularly within the families Solanaceae and Apiaceae. Notable sources include:
- Roots and aerial parts of Scopolia spp. (e.g., Scopolia carniolica).
- Leaves of Arabidopsis thaliana.
- Various members of the genus Petroselinum (parsley).
- Tobacco (Nicotiana tabacum) and other Nicotiana species.
The compound is typically isolated as a minor constituent of plant extracts using chromatographic techniques.
Biosynthesis
Scopolin is biosynthesized via the phenylpropanoid pathway. The precursor scopoletin (6‑methoxy‑7‑hydroxy‑coumarin) undergoes glucosylation catalyzed by UDP‑glucose:scopoletin glucosyltransferase, yielding the O‑glucoside scopolin. This enzymatic step enhances the compound’s water solubility and storage stability within plant tissues.
Biological activity and pharmacology
Research on scopolin has reported several bioactivities, though the extent of these effects varies among studies:
- Antioxidant activity – Scopolin exhibits free‑radical scavenging capacity in vitro, comparable to other phenolic glycosides.
- Anti‑inflammatory effects – In cell‑based assays, scopolin has been shown to attenuate the production of pro‑inflammatory mediators such as nitric oxide and cytokines.
- Neuroprotective potential – Preliminary investigations suggest protective effects against oxidative stress in neuronal cell models.
These activities are generally attributed to the phenolic coumarin moiety, with the glucose unit influencing pharmacokinetic properties. Clinical relevance in humans has not been established.
Physical and chemical properties
| Property | Value |
|---|---|
| Appearance | White to off‑white crystalline solid |
| Solubility | Soluble in water, ethanol, and methanol |
| Melting point | Approximately 210 °C (decomposition) |
| UV absorption | Strong absorption maxima near 340 nm (characteristic of coumarins) |
Analytical detection
Scopolin is commonly detected and quantified by high‑performance liquid chromatography (HPLC) coupled with UV detection or mass spectrometry (LC‑MS). The characteristic UV absorbance at ~340 nm and the molecular ion [M‑H]⁻ at m/z 321 facilitate its identification.
Regulatory and safety status
Scopolin is not listed as a regulated substance in major pharmacopoeias or food additive inventories. Toxicological data are limited; however, the compound is generally considered of low toxicity at concentrations typical of dietary plant exposure.
References
(References are drawn from peer‑reviewed journals and reputable phytochemical databases; specific citations are omitted here for brevity.)