November 2013 – 'Antitumor Activities of Rauwolfia Vomitoria Extract and Potentiation of Carboplatin Effects Against Ovarian Cancer'
Yu J, Ma Y, Drisko J, Chen Q.
Curr Ther Res Clin Exp. 2013 Dec;75:8-14. doi: 10.1016/j.curtheres.2013.04.001.
Drs. Qi Chen and Jeanne Drisko at Kansas University Medical Center (KUMC) have been interested in ovarian as well as pancreatic cancer and have explored the potential of the Pao Pereira and Rauwolfia vomitoria extracts as alternative therapeutic agents for these cancers.
Like pancreatic cancer, ovarian cancer is frequently diagnosed late; it also develops drug resistance and is similarly difficult to treat. Following the same line of experiments used for testing the Pao Pereira extract against pancreatic cancer the researchers at KUMC studied the anti-ovarian cancer effects of the Rauwolfia vomitoria extract.
They found that Rauwolfia vomitoria was effective against ovarian cancer cells both alone and in combination with carboplatin. The combination decreased tumor size in animal experiments by 87 to 90%.
These dramatic results indicate that in the presence of Rauwolfia, drug resistance of the tumor cells is overcome and the activity of carboplatin is restored. The authors conclude that, 'Rauwolfia vomitoria has potent anti-tumor activity and in combination significantly enhances the effect of carboplatin against ovarian cancer.'
Tumor resistance to platinum-based drugs has been an obstacle to the treatment of ovarian cancer. Extract of the plant Rauwolfia vomitoria has long been used by cancer patients. However, there have not been systematic studies of its anticancer activity. Objective: In an effort to enhance the effectiveness of platinum-based drugs, we investigated the anticancer effect of a Rauwolfia vomitoria extract (Rau), both alone and in combination with carboplatin (Cp). Methods: In vitro cytotoxicity and colony formation were evaluated in several ovarian cancer cell lines. In vivo effects were evaluated in an intraperitoneal ovarian cancer mouse model. The combination of Rau and Cp was assessed using Chou-Talalay's constant ratio design and median effect analysis based on the isobologram principle to determine the combination index values. Results: Rau decreased cell growth in all 3 tested ovarian cancer cell lines dose dependently and completely inhibited formation of colonies in soft agar. Apoptosis was induced in a time- and dosedependent manner and was the predominant form of Rau-induced cell death. Synergy of Rau with Cp was detected, with combination index values o1 and dose reduction index values for Cp ranging from 1.7- to 7-fold. Tumor growth in mice was significantly suppressed by 36% or 66% with Rau treatment alone at a low (20 mg/kg) or a high dose (50 mg/kg), respectively, an effect comparable to that of Cp alone. The volume of ascitic fluid and the number of nonblood cells in ascites were also significantly decreased. Combining Rau with Cp remarkably enhanced the effect of Cp and reduced tumor burden by 87% to 90% and ascites volume by 89% to 97%. Conclusions: Rau has potent antitumor activity and in combination significantly enhances the effect of Cp against ovarian cancer.
©2013. The Authors. Published by Elsevier Inc. All rights reserved.