The antioxidant effects of Crassostrea gigas extract (JCOE) in human volunteers

Since several in vitro and animal studies of an extract from Crassostrea gigas (JCOE) have demonstrated its antioxidant properties and other interesting effects, a preliminary human trial was carried out. Seven healthy male volunteers aged 23-37 received orally 3 x 2 capsules of JCOE per day for 8 days. On days 0, 1, 4, 8 and 15 (7 days after completion of the schedule) blood samples were drawn and the antioxidant potential of serum was tested. A statistically significant increase in the buffering effects of serum against hemoglobin (Hb) and lactate dehydrogenase (LDH) release from red blood cells treated with the free radical generator azobis amidino propane (AAPH) was found following JCOE treatment. At 8 days, the oxidative effects were reduced by > 90% of the pretreatment values. In these same individuals, serum levels of reduced glutathione were increased by an average of 1.5-fold over the time course of treatment. It is concluded that in normal human volunteers, JCOE capsules provide an orally available formula for enhancing the antioxidant capacity of blood serum. While the extract is known to contain some direct acting antioxidant components, at least a portion of the protective effect is facilitated by enhancement of GSH biosynthesis.