Arbutin

Basic Information

• β-Arbutin: 497-76-7
• α-Arbutin: 84380-01-8 Molecular Formula: \(\text{C}_{12}\text{H}_{16}\text{O}_{7}\) Molecular Weight: 272.25 g/mol Classification: Naturally occurring phenolic glycoside derived from plants (e.g., bearberry, cranberry, pear) 4 13.

Description

Physical Properties

• Appearance: White crystalline powder, odorless, with a slightly sweet taste 4.
• Solubility:
  • Soluble in water (10–15 g/100 mL at 20°C) and polar solvents (e.g., ethanol, DMSO) 4.
  • Insoluble in non-polar solvents (e.g., chloroform) 4.
• Stability:
  • pH Sensitivity: Stable at neutral pH (6.5–7.5) but hydrolyzes in acidic conditions 4.
  • Thermal Stability: Melts at 195–198°C and decomposes above 218°C 4.
  • Storage: Requires refrigeration (2–8°C) under dry nitrogen to prevent hygroscopic degradation 4.

Chemical Structure

Key Data

• Purity:
  • Pharmaceutical Grade: ≥98% (HPLC) 5.
  • Cosmetic Grade: 98–99% 4.
• Optical Rotation:
  • β-Arbutin: \([\alpha]_D^{20} = -64.0° \pm 2.0°\) (3% aqueous solution) 4.
  • α-Arbutin: \([\alpha]_D^{20} = +75°\) (3% aqueous solution) 13.
• UV Absorption: Maximum absorbance at 280 nm (hydroquinone moiety) 4.
• Melting Point: 195–198°C (β-arbutin) 4.
• pH (3% Solution): 5.0–7.0 5.

Functions

Core Biological Roles

1. Skin Whitening & Hyperpigmentation Control:
   • Tyrosinase Inhibition: Blocks melanin production by competitive inhibition of tyrosinase, reducing dark spots, melasma, and post-inflammatory hyperpigmentation 9 16.
   • α-Arbutin Advantage: 10–15 times more effective than β-arbutin due to enhanced stability and cellular penetration 13 14.
2. Antioxidant Activity:
   • Neutralizes reactive oxygen species (ROS) and prevents UV-induced oxidative damage 4 9.
3. Antimicrobial & Anti-Inflammatory Effects:
   • Inhibits bacterial growth (e.g., E. coli, Staphylococcus aureus) and reduces inflammation in acne-prone skin 4 9.
4. Urinary Tract Health:
   • Metabolizes into hydroquinone in the urinary tract, exerting antibacterial effects against infections (e.g., cystitis) 11 12.

Applications

Cosmetics & Skincare

• Anti-Aging: Enhances collagen synthesis and reduces fine lines (e.g., Beauty of Joseon Glow Deep Serum) 14.
• Skin Brightening: Used in creams, serums, and masks to even skin tone (e.g., Paula’s Choice Resist Super Antioxidant Serum) 16.
• Sunscreen Formulations: Combats UV-induced pigmentation when combined with SPF 14.

Pharmaceuticals

• Urinary Tract Infections (UTIs): Oral formulations (e.g., bearberry leaf extracts) for mild infections 11.
• Topical Treatments: Creams for psoriasis and eczema due to anti-inflammatory properties