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

Christopher Okunji, Slavko Komarnytsky, Georgie Fear, Alexander Poulev, David M. Ribnicky, Peter I. Awachie, Yoichiro Ito, Ilya Raskin

Research output: Contribution to journalArticlepeer-review

36 Scopus citations

Abstract

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 μg/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 (IC50 582 μM) and compared favorably with a reference tyrosinase inhibitor (kojic acid, IC50 130 μM).

Original languageEnglish (US)
Pages (from-to)45-50
Number of pages6
JournalJournal of Chromatography A
Volume1151
Issue number1-2
DOIs
StatePublished - Jun 1 2007

All Science Journal Classification (ASJC) codes

  • Analytical Chemistry
  • Biochemistry
  • Organic Chemistry

Keywords

  • Biflavanones
  • Garcinia kola
  • High-speed counter-current chromatography (HSCCC)
  • Tyrosinase

Fingerprint Dive into the research topics of 'Preparative isolation and identification of tyrosinase inhibitors from the seeds of Garcinia kola by high-speed counter-current chromatography'. Together they form a unique fingerprint.

Cite this