The effect of phenolic compounds of poplar leaves extract on cutaneous angiogenesis reaction induced in mice by human mononuclear leukocytes

The influence of ether fraction of water-soluble extract of poplar leaves (Populus nigra L.) and nine phenolic acids (cinnamic and benzoic acids derivatives) on human mononuclear (MNL) leukocytes angiogenic activity was studied. Ether fraction, containing mainly phenolic acids, increased cutaneous angiogenesis induced in mice by human MNL isolated from the blood of healthy donors. Increase of angiogenic activity was also observed in case of caffeic, gallic, salicylic, ferulic and gentisic acids. Isovanillic, protocatechuic and p-hydroxybenzoic acids did not influence this parameter.

Isolation and studies of the mutagenic activity in the Ames test of flavonoids naturally occurring in medical herbs

Quercetin, rhamnetin, isohamnetin, apigenin and luteolin were isolated from medicinal herbs: Erigeron canadensis L., Anthyllis vulneraria L. and Pyrola chloranta L. The mutagenicity of these naturally occurring flavonoids was tested by the Ames method with S. typhimurium strains TA1535, TA1538, TA97, TA98, TA100 and TA102 in the presence and absence of metabolic activation. Of the above flavonoids only quercetin and rhamnetin revealed mutagenic activity in the Ames test. Quercetin induced point mutations in strains TA97, TA98, TA100 and TA102 of S. typhimurium. The presence of S9 rat liver microsome fraction markedly enhanced the mutagenic activity of quercetin in these strains. Rhamnetin appeared to be a much weaker mutagen in the Ames test. The compound induced mutations in strains TA97, TA98 and TA100 of S. typhimurium but only in the presence of metabolic activation. Comparison of the structure of the studied flavonoids with their mutagenic activity indicates that the mutagenicity of flavonoids is dependent on the presence of hydroxyl groups in the 3' and 4' positions of the B ring, and that the presence of a free hydroxy or methoxy group in the 7 position of the A ring also probably contributes to the appearance of mutagenic activity of flavonoids in the Ames test. It also appeared that the presence of methoxy groups, particularly in the B ring of the flavonoid molecule, markedly decreases the mutagenic activity of the compound.