Study On Chemical Constituents Of Garcinia Kola Seeds

The seeds of Garcinia kola Heckel commonly called bitter kola in Nigeria,belongs to the family of tropical plants known as Guttiferae.The seed coat is brown-coloured,and the kernels are pale or white.It is cultivated and distributed throughout West and Central Africa.According to the reports,biflavanones,vitamin E derivative,triterpenoids and phenylacetones are the main chemical constituents from the seeds of Garcinia kola.Modern pharmacological studies have shown that the seeds of Garcinia kola have the clinical hypoglycemic,anti-atherosclerosis,anti-hyperlipidemia,anti-bacterial,anti-plasmodium,anti-hepatotoxic and aphrodisiac effects.In order to comprehensively study the chemical compositions in Garcinia kola seeds,GC×GC-MS and UHPLC-Q/Orbitrap MS system were employed to clarify volatile compounds and non-volatile components of Garcinia kola seeds,respectively.Separation and identification methods of classical phytochemistry were adopted to investigate the main ingredients in Garcinia kola seeds.The volatile components of Garcinia kola seeds in coat,dried and fresh kernels were identified by GC×GC-MS.A total of 19,33,and 26 compounds were detected in the seed coat,dried and fresh kernels of Garcinia kola with positive and negative matching degrees greater than 800,whose content accounted for 20.84%,98.20% and 91.29% of the total volatile components,respectively.The volatile components in the seed coat give priority to aldehydes and alkanes,while the volatile components in the kernels mainly contain acids and alcohols.There were seven compounds identified both in the seed coat and dried kernels,including 6-methyl-5-hepten-2-one,acetic acid,3-methylbutanal,hexanal,?-myrcene,nonanal and benzaldehyde.There were six common volatile components in the seed coat,dried and fresh kernels,while ?-myrcene was not detected in fresh kernels of Garcinia kola seeds.In the dried and fresh kernels,19 compounds such as 2-methylpropanal,acetic acid and 6-methyl-5-Hepten-2-one were the mutual volatile components.The non-valatile compositions of Garcinia kola seeds were analyzed by UHPLC-Q/Orbitrap MS method.According to the obtained data of mass spectrum and compared with literature properties,six compounds,including five biflavanones and garcinoic acid,were identified by their formula weight,quasi-molecular ion and fragments information and the possible fragmentation pathway of the biflavanones was deduced.Biflavanones were the major chemical constituents from Garcinia kola seeds.The separation method of classical phytochemistry was adopted in the research of Garcinia kola seeds.Taking advantage of silica gel,sephadex LH-20 and pre-HPLC technologies,21 compounds were isolated from Garcinia kola seeds.By NMR,MS spectroscopic analyses,14 compounds were identified as friedelin,tocopherol,glutinol,garcinoic acid,kaempferol-3-O-?-D-glucoside,1-O-p-coumaroyl-?-D-glucopyranose,4-hydroxybenzaldehyde,indole-3-carboxaldehyde,chrysochlamic acid,?-(E)-deoxy-amplexichromanol,GB-1,GB-2,GB-1a and kolaflavanone.Glutinol,1-O-p-coumaroyl-?-D-glucopyranose,4-hydroxybenzaldehyde and indole-3-carboxaldehyde were separated from Garcinia kola seeds for the first time.In this study,we systematically studied the volatile components in Garcinia kola seeds,compared the differences of the volatile components among seed coat,kernels,dried and fresh kernels.It was clear that the main chemical components of Garcinia kola seeds were biflavanones.The possible mass spectrometry cleavage pathways of biflavanones were speculated,which enriched the study of the mass spectrometry of biflavanones.Adopted the classical phytochemical separation method,14 compounds were isolated and identified,including four biflavanones,four vitamin E derivatives,two pentacyclic triterpenes,one flavonoid glycoside,one alkaloid,one aldehyde and one phenylpropanoid glycoside,which provided the basis for the further study of the active substances of Garcinia kola seeds.