Isolation and Phytochemical Characterization of Bioactive Constituents from the Seeds of Garcinia kola, Heckel (Clusiaceae)

Aim: This study was carried out with the aim of isolating and identifying the bioactive constituents of the ethyl acetate extract from G. kola seeds that was a strong inhibitor of α-glucosidase using FT-IR and GC-MS techniques.

Place and Duration of Study: The study was carried out at Department of Pharmacognosy and Drug Development, Ahmadu Bello University, Zaria between October – December 2014.

Methodology: n-Hexane, ethyl acetate and methanol extracts were prepared gradient wise in a soxhlet apparatus at 50ºC. Column chromatographic analysis was carried out on the ethyl acetate extract. The isolate was purified and the structure elucidated by Fourier Transformed Infra Red spectroscopy and Mass Spectrophotometry.

Results: Column chromatographic analyses and purification of column fraction B of the ethyl acetate extract lead to the isolation of ZAAK. Fourier Transformed-Infra Red spectra revealed the presence of carboxylic acid and an ester in ZAAK. Gas Chromatography revealed three major peaks with retention times at 17.99 min, 20.83 min and 21.08 min, thus suggesting that ZAAK is a mixture of three compounds and were subsequently labeled ZAAK1, ZAAK2, and ZAAK3. The mass spectra identified ZAAK1 ZAAK2 and ZAAK3 as 1-pentadecanecarboxylic acid, (Z)-11-Octadecenoic acid and octadecanoic acid, 2-(2-hydroxyethoxy) ethyl ester respectively.

Conclusion: On the basis of column chromatography and spectroscopy, ZAAK was identified as a mixture of fatty acids and fatty acid ester.