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 wo rk was to assay the antioxidant activities of phenolics from Crataegus monogyna Jacq. flowers and in vitro tissue culture (calli and cell su spensions) extracts. In the case of tissue culture extracts, the pheno lic production is studied at three different stages of one subculture period (initial growth period, increasing and maximal phenolic synthes is phases). Attention was paid to the main categories: flavonoids and proanthocyanidins, and to the principal individual components. Total p henolic amounts decrease in the order: fresh flowers > cell suspension cultures > callus cultures. The antioxidant activities of these diffe rent extracts against H2O2 and HOCl, have been determined in vitro. Al l the extracts are efficient and the scavenging capacity is clearly re lated to the total phenol content, The scavenging effects of the cell suspension extracts are similar to those of the flowers, Among individ ual compounds, the flavanol-type derivatives, specially the proanthocy anidin B2, are more efficient. Thus, in vitro plant tissues could be a n interesting source of bioactive molecules.