Effects of repeated treatments with an extract of <i>Ginkgo biloba</i> (EGb 761) and bilobalide on glucose uptake and glycogen synthesis in rat erythrocytes: An ex vivo study

Abstract

Abstract The metabolic action of an extract of Ginkgo biloba (EGb 761) has been examined in an ex vivo study of rat erythrocytes. Oral administration of EGb 761 (100 mg/kg/day) for 5 days to Wistar rats caused an increase in the in vitro uptake of glucose by erythrocytes, especially in high‐glucose (13.32 mM) medium, an effect that was associated with an increase in intracellular energy metabolism and reflected as a significant reduction in free glucose concentration. In contrast, the lactate concentration of the erythrocytes and lactate release to the bathing medium were not modified. Conversion of glucose into glycogen was significantly increased in the erythrocytes of EGb 761‐treated animals. Taken together, these findings indicate that in vivo administration of EGb 761 exerts an action favoring the transformation of glucose into glycogen, its storage form. Oral administration of the EGb 761 constituent bilobalide (4 or 8 mg/kg/day) for 5 days caused similar changes in the uptake of glucose and its conversion into glycogen. However, in contrast to the total extract, bilobalide treatment did not increase the energy‐yielding consumption of glucose. © 1994 Wiley‐Liss, Inc.