Antioxidant activities of polyphenolic extracts from flowers, in vitro callus and cell suspension cultures of Crataegus monogyna.

Numerous plants synthesize among their secondary metabolites phenolic compounds which possess antioxidant effects. The aim of the present work was to assay the antioxidant activities of phenolics from Crataegus monogyna Jacq. flowers and in vitro tissue culture (calli and cell suspensions) extracts. In the case of tissue culture extracts, the phenolic production is studied at three different stages of one subculture period (initial growth period, increasing and maximal phenolic synthesis phases). Attention was paid to the main categories: flavonoids and proanthocyanidins, and to the principal individual components. Total phenolic amounts decrease in the order: fresh flowers > cell suspension cultures > callus cultures. The antioxidant activities of these different extracts against H2O2 and HOCl, have been determined in vitro. All the extracts are efficient and the scavenging capacity is clearly related to the total phenol content. The scavenging effects of the cell suspension extracts are similar to those of the flowers. Among individual compounds, the flavanol-type derivatives, specially the proanthocyanidin B2, are more efficient. Thus, in vitro plant tissues could be an interesting source of bioactive molecules.