Prevention of neuronal cell damage induced by oxidative stress in-vitro: effect of different Ginkgo biloba extracts

The effect of two different Ginkgo biloba extracts (GB1 and GB4) was studied in-vitro on cultured neurons exposed to oxidative stress caused by H2O2(50 micromol L(-1)) and FeSO4 (100 micromol L(-1). Only about 50% of the neurons were still viable at the end of the experiment (8 h) in control conditions, while the two extracts dose dependently increased the number of viable cells, in the concentration range 10-200 microg mL(-1). The two Ginkgo biloba extracts differed in their effect on hydroxyl-radical-scavenging capacity: GB1 and GB4 had an IC50 (50% inhibiting concentration) value of 78 microg mL(-1) and 186 microg mL(-1), respectively. However, both extracts inhibited apoptosis in cortical neurons after oxidative stress in-vitro. These observations make one suppose that different preparations of Ginkgo biloba have quantitatively different actions and outline the importance of the contribution of apoptosis prevention toward their neuroprotective action

Immunomodulatory activity of the lignan 7-hydroxymatairesinol potassium acetate (HMR/LignanTM) extracted from the heartwood of norway spruce (Picea abies)

The pharmacological profile of the lignan 7-hydroxymatairesinol (HMR/lignan, HMR) includes chemopreventive effects, antioxidant properties, and mild proestrogenic activity. The present study was devised to investigate the effects of HMR on THP-1 cells, an established model of human monocytes, and on human polymorphonuclear leukocytes (PMNs). In THP-1 cells, HMR concentration-dependently reduced LPS-stimulated tumor necrosis factor (TNF)-alpha secretion in the supernatant. HMR at low, sub-muM concentrations also reduced TNF-alpha mRNA, which was however enhanced by supra-muM concentrations of HMR. In human PMNs, HMR concentration-dependently reduced ROS production induced by either N-formyl-Met-Leu-Phe, phorbol myristate acetate or angiotensin II, as well as interleukin-8 production induced by either N-formyl-Met-Leu-Phe or angiotensin II. Results indicate that HMR is an effective inhibitor of both monocytic THP-1 cells and of human PMNs and warrant further studies to assess their relevance for the prevention and treatment of several conditions characterized by chronic systemic inflammation

Isoflavone content and estrogenic activity of different batches of red clover (Trifolium pratense L.) extracts: An in vitro study in MCF-7 cells

The estrogenicity of different batches of red clover (Trifolium pratense L., Fabaceae; RCL) extracts and its relationship with the isoflavone content were assessed by measuring MCF-7 cell proliferation by flow cytometry and propidium iodide staining. RCL extracts were compared to estradiol (E2) and to the main RCL isoflavones biochanin A, daidzein, genistein and formononetin. Isoflavone content in the extracts was assayed by HPLC. E2 and isoflavones increased MCF-7 proliferation in a concentration-dependent fashion, with the following potency order: E2 >>> genistein > biochanin A = daidzein > formononetin. Extracts increased MCF-7 proliferation with different potencies, which in four out of five extracts correlated with the ratios 5,7-dihydroxyisoflavones/7-hydroxyisoflavones. The efficacy of all extracts increased with decreasing genistein contents. A solution containing the main isoflavones at the average concentration of RCL extracts increased MCF-7 proliferation with higher potency and steeper concentration-response curve. The effects of E2, of RCL extracts and of the isoflavone solution were inhibited by the estrogen receptor antagonist 4-hydroxytamoxifen. Flow cytometric analysis of MCF-7 proliferation is a suitable bioassay for the estrogenicity of RCL extracts, thus expanding the characterization of individual batches beyond assessment of chemical composition and contributing to improved standardization of quality and activity. \ua9 2014 Elsevier B.V