Chromatography Research Today is a free monthly online journal that collates and summarizes the latest research about Chromatography, including details on column chromatography, gas chromatography (gc), liquid chromatograpy, hplc.

Preparative isolation and identification of tyrosinase inhibitors from the seeds of Garcinia kola by high-speed counter-current chromatography.

Okunji C, Komarnytsky S, Fear G, Poulev A, Ribnicky DM, Awachie PI, Ito Y, Raskin I

Biotech Center, Cook College, Rutgers University, 59 Dudley Road, New Brunswick, NJ 08901-8520, USA.

In continuation of our search for bioactive natural products that can be used for the treatment of dermatological disorders associated with melanin hyperpigmentation, 50 extracts/fractions from 21 families of medicinal plants from West and Central Africa were evaluated for inhibitory activity against tyrosinase (E:C:1.14.18.1), the rate-limiting enzyme in melanin synthesis. Four extracts including the methanol extract of Garcinia kola seeds at 100 microg/ml displayed >60% inhibition of tyrosinase activity. Preparative high-speed counter-current chromatography with solvent system composed of n-hexane-ethyl acetate-methanol-water (3:5:3:5) successfully separated the most active extract from G. kola seed. By stepwise increase of the flow-rate of the mobile phase, five major biflavanones including GB-I-glucoside (1) GB-1a (2), GB-1 (3), GB-2 (4), kolaflavonone (5) were successfully isolated in 6 h. Compound (4) was the most potent (IC(50) 582 microM) and compared favorably with a reference tyrosinase inhibitor (kojic acid, IC(50) 130 microM).

Published 9 May 2007 in J Chromatogr A, 1151(1): 45-50.
Full-text of this article is available online (may require subscription).

© 2005-2008 Chromatography Research Today. All Rights Reserved.