Purine alkaloids and phenolic compounds in three Cola species and Garcinia kola grown in Cameroon

Abstract Accessions of Cola acuminata , Cola nitida and Cola anomala were analysed based on the variation of polyphenol and alkaloid contents in order to gain insight on the genetic relationships within and between the taxonomic entities. These compounds were analysed at 280 nm by HPLC using a Photodiode Array Detector (PDA). Catechin, epicatechin, theobromine and caffeine were detected in Cola seeds. Among the three species, C. nitida is found to be highest in flavonoid and caffeine content while C. anomala possessed high amount of theobromine. Catechin was the dominant flavonoid. Caffeine was the major alkaloid in Cola seeds and was considered as one of the signature compounds due to its concentration range. The average concentrations in C. acuminata , C. nitida and C. anomala accessions were 11066 ± 3166, 13761 ± 2728 and 7013 ± 2369 mg/kg FW respectively. Garcinia kola seeds displayed higher levels of total phenolic compounds compared to Cola sp. and lacked purine alkaloids and catechin. The former displayed many unidentified polyphenolic compounds most of which were apolar. Principal component and cluster analyses of Cola sp. categorized accessions into two groups. The first chemotype encompassed C. anomala accessions and exhibited high theobromine content. The second cluster enclosed C. nitida and C. acuminata accessions and displayed high caffeine and catechin contents. Genetic distances between the accessions varied from 0.0 to 1.26. The importance of Cola phenolic compounds and alkaloids in food chemistry and chemotaxonomy is discussed.