Accumulation of phenylpropanoids in green and red pepper fruits of semi-hot cultivars Capsicum annuum L.

The aim of the present work was to determine differences in C and O glycosides of flavonoids, derivatives of phenolic acids, as well as capsaicinoid content in two semi-hot pepper cultivars, cv. Tornado and Tajfun. Fruits were harvested at the green and red maturity stages. Flavonoid and capsaicinoid fractions were isolated on Sep-Pak C18 cartridges with 40% and 70% methanol-water solutions, respectively. The chemical composition of both fractions was determined by HPLC method using standards of phenolic compounds obtained in the earlier work and the capsaicin standard. The flavonoid fraction contained glucose esters of phenolic acid, mainly ferulic and sinapic acid, as well as derivatives of flavonoids, quercetin, luteolin and apigenin, which occurred as O- and C- glycosides with glucose, rhamnose, and apiose. The capsaicinoid fraction contained mainly capsaicin and dihydrocapsaicin. It was found that in green fruits flavonoid O-glycosides were the predominant phenolics, while in red ones derivatives of phenolic acids. A higher loss of O-glycosides of flavonoids than of C-glycosides was observed during the maturation of the fruit of semi-hot pepper cultivars