Antioxidant activity and biologic properties of a procyanidin-rich extractfrom pine (Pinus maritima) bark, pycnogenol

There is growing interest in the biologic activities of plant extracts such as that obtained from the bark of the French maritime pine Pinus maritima, Pycnogenol. Pycnogenol (PYC) is a standardized extract composed of a mixtu re of flavonoids, mainly procyandins and phenolic acids. Studies indicate t hat PYC components are highly bioavailable. Uniquely PYC displays greater b iologic effects as a mixture than its purified components do individually i ndicating that the components interact synergistically. PYC has been report ed to have cardiovascular benefits, such as a vasorelaxant activity, angiot ensin-converting enzyme (ACE) inhibiting activity, and the ability to enhan ce the microcirculation by increasing capillary permeability. Investigation s of the cellular mechanisms of these therapeutic effects have demonstrated that PYC has strong free radical-scavenging activity against reactive oxyg en and nitrogen species. The oligomeric components of PYC contribute signif icantly to the ESR free radical signal. PYC also participates in the cellul ar antioxidant network as indicated by its ability to regenerate the ascorb yl radical and to protect endogenous vitamin E and glutathione from oxidati ve stress. PYC modulates NO metabolism in activated macrophages by quenchin g the NO radical and inhibiting both iNOS mRNA expression and iNOS activity . The spectrum of different effects of NO in the circulation and the nervou s system suggest the potential applications of PYC in immune and circulator y disorders as well as in neurodegenerative disease. PYC can bind to protei ns, altering their structure and thereby modulating the activity of key enz ymes and proteins involved in metabolic pathways. PYC effects redox-sensiti ve signal transduction pathways and alters gene expression. Aspects of PYC' s activity are presented and discussed together with possible future implic ations and directions in the field of flavonoid research. (C) 1999 Elsevier Science Inc.