Effects of icariin and quercetin on high glucose-induced neuronal cell apoptosis

Abstract

Purpose: To study the effects of icariin and quercetin on cell apoptotic changes in neurons induced by elevated glucose condition, and the mechanism involved.
 Methods: Neonatal male Sprague Dawley rats (n = 48) weighing 5 – 7 g were used. Neuronal cells were isolated from rat hippocampus and cultured after purification. The cells were randomly assigned to six groups: control, high glucose, icariin, quercetin, serine/threonine-specific protein kinase (Akt) inhibitor, and Akt agonist groups. The Akt inhibitor and agonist used in this study were MK-22062hci and SC79, respectively. The influence of icariin and quercetin on neuronal apoptotic changes were determined flow cytometrically, while their effects on levels of expression of Akt, p-Akt, bax and bcl-2 were determined with Western blotting.
 Results: Treatment with icariin or quercetin significantly inhibited apoptosis induced by high glucose. The concentrations of Akt, p-Akt, and bcl-2 proteins were markedly upregulated in high glucose group, relative to control (p < 0.05). The corresponding expression of bax was significantly down-regulated in high glucose group, relative to control (p < 0.05). Treatment with icariin or quercetin, or their agonists reversed high glucose-mediated alterations in these protein levels (p < 0.05).
 Conclusion: Icariin and quercetin inhibit neuronal cell apoptosis induced by high glucose through upregulation of bcl-2 expression and down- regulations of bax expression and Akt-induced protein phosphorylation. Thus, Icariin and quercetin possess potential benefits for the treatment of neurological diseases.
 Keywords: Apoptosis, High glucose condition, Hippocampal neurons, Icariin, Quercetin

Isolation, characterization and in vitro cytotoxicity studies of bioactive compounds from Alseodaphne semecarpifolia Nees

“…Epimedium is a plant commonly known as Horny Goat Weed or Yin Yang Huo, used as a tonic agent in Chinese Traditional Medicinal system [22]. Icariin has been reported to possess several pharmacological and biological properties such as antidepressant, J o u r n a l P r e -p r o o f apoptotic, immunomodulating and preventing osteoporosis [23,24]. Extensive literature indicated that Icariin also acts as a potent anticancer agent that can inhibit tumor cell growth and proliferation [25][26][27][28].…”