Ginkgo biloba L. leaves extract is a remedy traditionally used against age-related cardiovascular dysfunctions and cognitive impairment. Healthy effects of Ginkgo are sustained by biological studies concerning the anti-inflammatory and anti-oxidant effect at vascular level. In some countries the use of ethanol extract in food supplement is preferred to acetone, although the latter is widely cited in the scientific literature. The presence of flavone glicosides and terpene lactones is important for the efficacy of the extract, thus implying that an adequate standardization is mandatory.
This work aims to assess the equivalence between acetone (G24) and ethanol extracts (G4E) from Ginkgo biloba L. leaves in terms of either biological activity in human endothelial cells (HUVEC) challenged with TNF a (20 ng/mL) and chemical profile. Both the extracts were prepared and titrated by LINNEA SA (Riazzino, Switzerland).
The inhibitory effect of G24 and G4E on inflammatory adhesion molecules was not significantly different (IC50 reported in Table 1). The activity was due, at least in part, to the impairment of NF-κ B nuclear translocation with comparable IC50s (77.5 and 70.4 μg/ml, respectively). Notably, the extracts inhibited the release of soluble adhesion molecules (sVCAM-1, sCAM-1 and sE-SEL) with lower IC50 values than CAMs exposed on cell surface, thus suggesting the possible involvement of further mechanisms of action.
Moreover, Ginkgo biloba L. has a well-established role in the reduction of oxidative stress during endothelial inflammation. Intracellular ROS formation induced by H2O2 (500 μM) was reduced by 30% and 40% respectively for G24 and G4E (500 μg/mL), while TNF α (20-50 ng/mL) was unable to induce oxidative stress.
The present study demonstrates for the first time that ethanol and acetone extracts show comparable biological activities in human endothelial cells, providing new insights on the usage of ethanol extracts in those countries where restrictions in amount of acetone are present.
