Extract from Ceratonia siliqua Exhibits Depigmentation Properties

Area of Science:

• Pharmacology
• Dermatology
• Natural Product Chemistry

Background:

• Skin hyper-pigmentation stems from excessive melanin production by melanocytes.
• Melanin synthesis involves tyrosine oxidation catalyzed by tyrosinase.
• Plant-derived tyrosinase inhibitors are sought for cosmetic and therapeutic applications.

Purpose of the Study:

• To investigate the tyrosinase inhibitory and depigmenting potential of Ceratonia siliqua extracts.
• To isolate and characterize active compounds responsible for tyrosinase inhibition.
• To evaluate the safety and efficacy of the extract in a clinical setting.

Main Methods:

• Screening of Ceratonia siliqua leaf, bark, and fruit extracts for tyrosinase inhibition and diphenolase activity.
• Bioassay-guided fractionation to isolate active compounds.
• In vitro assays measuring tyrosinase inhibition (IC50) and mRNA levels.
• Clinical patch testing for irritancy and depigmentation efficacy on human volunteers.

Main Results:

• The bark extract showed significant tyrosinase inhibition and diphenolase activity, reducing tyrosinase mRNA levels in melanocytes.
• Six compounds were isolated, with (-)-epicatechin-3-O-gallate, 1,2,3,6-tetra-O-galloyl-ß-D-glucose, and gallocatechin-3-O-gallate demonstrating potent tyrosinase inhibition.
• Clinical studies indicated the extract was non-irritant and improved even skin tone in UV-induced pigmentation at 3% concentration after 28 days.

Conclusions:

• Ceratonia siliqua bark extract contains potent tyrosinase inhibitors with depigmenting properties.
• The isolated compounds, particularly gallate derivatives, are key contributors to the observed inhibitory effects.
• The extract is safe and effective for improving skin tone and reducing hyper-pigmentation.