Effect and Mechanism of Total Flavonoids Extracted from Cotinus coggygria against Glioblastoma Cancer In Vitro and In Vivo

Flavonoids, a major constituent of Cotinus coggygria (CC), have been reported to possess diverse biological activities, including antigenotoxic and hepatoprotective effects; however, few studies have investigated the biological activity of the total flavonoids of Cotinus coggygria, especially in terms of its cytotoxicity in cancer cells. In the present study, the Cotinus coggygria flavonoids (CCF) were extracted from Cotinus coggygria and characterized by HPLC. These results indicated that CCF extracts could inhibit cell proliferation, with IC(50) values of 128.49 µg/mL (U87), 107.62 µg/mL (U251), and 93.57 µg/mL (DBTRG-05MG). The current investigation also revealed that CCF induced apoptosis in highly malignant glioblastoma cells, a process that apparently involved the inhibition of Akt coupled with ERK protein expression. This finding suggests that the PI3K/Akt-ERK signaling pathway is regulated by CCF and leads to the inhibition of the glioblastoma cancer cells. Furthermore, a significant antitumor effect of CCF was observed in xenograft animal models of glioblastoma multiforme in vivo. Taken together, these data suggest that CCF is the active component in the Cotinus coggygria plant that offers potential therapeutic modality in the abrogation of cancer cell proliferation, including the induction of apoptosis.