ANTI-INFLAMMATORY AND ANTIOXIDANT ACTIVITIES OF TWO DIFFERENT GINKGO BILOBA L. EXTRACTS IN HUMAN ENDOTHELIAL CELLS: A COMPARATIVE STUDY

Ginkgo biloba L. leaves extracts are widely used for their beneficial effects in cardiovascular diseases prevention and therapy or to improve mild cognitive impairment and cerebrovascular insufficiency¹. In some countries, the amount of acetone allowed in food supplements is stricter than ethanol, thus implying that the usage of standardized ethanol extracts is preferred.

The aim of the present study was to 1) to chemically profile acetone (G24) vs. ethanol (G4E) extracts from Ginkgo biloba leaves similarly standardized to identify differences among components; 2) to investigate if the extracts may be considered comparable as anti-inflammatory and antioxidant agents.

Both the extracts were prepared and standardized by LINNEA SA (Riazzino, Switzerland). Biological activities were evaluated in human endothelial cells (HUVEC) challenged with TNFα (20 ng/mL).

Both the extracts inhibited the soluble adhesion molecules ICAM-1, VCAM-1 and E-selectin release by endothelial cells (IC₅₀ reported in Tab. 1); the effect was due to the impairment of NF-kB pathway since both G4E and G24 extracts inhibited the NF-kB nuclear translocation in a concentration dependent fashion (IC₅₀ 70.4 and 77.5 mg/ml, respectively).

ROS release plays a crucial role in the endothelial inflammatory processes; G4E and G24 inhibited the intracellular ROS formation induced by oxidative stress (H₂O₂ 1 mM) with IC₅₀ 57.6 mg/ml and 38.8 mg/ml, respectively.

Since the extracts have the same standardization in flavonoid glycosides and terpene lactones and comparable IC₅₀s, these molecules seem to be responsible for the anti-inflammatory and anti-oxidant effects. Our results show that acetone and ethanol Ginkgo biloba extracts have comparable anti-inflammatory and antioxidant activities in human endothelial cells. This information will be useful for future commercialization of the extracts.

Tab. 1: IC₅₀ of the extracts on the adhesion molecules

IC50 (µg/ml)	ICAM-1	VCAM-1	E-SELECTIN
G4E	209	1.1	170
G24	129	2.0	137

[1] Tisato V, Mediators Inflamm 2013, 2013, 423 – 407.