Low acute and chronic toxicity with mild unwanted effects occurring in a small percentage of patients following oral administration. Dilation of the small blood vessels has been observed in patients with cardiovascular disease. The ability to inhibit angiotensin-converting enzyme is associated with a mild antihypertensive effect. May have an effect on blood thinning drugs.
– Int J Clin Pharmacol Ther 2002 Apr;40(4):158-68 — A review of the French maritime pine bark extract (Pycnogenol), a herbal medication with a diverse clinical pharmacology. — Rohdewald P.

Displays greater biologic effects as a mixture than its purified components do individually indicating that the components interact synergistically. PYC has been reported to have a vasorelaxant activity, and the ability to enhance the microcirculation by increasing capillary permeability.
– Free Radic Biol Med 1999 Sep;27(5-6):704-24 — Antioxidant activity and biologic properties of a procyanidin-rich extract from pine (Pinus maritima) bark, pycnogenol. — Packer L, Rimbach G, Virgili F.