P-glycoprotein inhibitors of natural origin as potential tumor chemo-sensitizers: A review

• Published in: Journal of advanced research 2015-01, Vol.6 (1), p.45-62
• Main Authors: Abdallah, Hossam M., Al-Abd, Ahmed M., El-Dine, Riham Salah, El-Halawany, Ali M.
• Format: Article
• Language: English
• Subjects: Multidrug resistance (MDR); Multidrug resistance-associated protein 1 (MRP1); Natural products; P-gp (P-glycoprotein); Review
• ISSN: 2090-1232; 2090-1224
• DOI: 10.1016/j.jare.2014.11.008

[Display omitted] Resistance of solid tumors to treatment is significantly attributed to pharmacokinetic reasons at both cellular and multi-cellular levels. Anticancer agent must be bio-available at the site of action in a cytotoxic concentration to exert its proposed activity. P-glycoprotein (P-gp) is a member of the ATP-dependent membrane transport proteins; it is known to pump substrates out of cells in ATP-dependent mechanism. The over-expression of P-gp in tumor cells reduces the intracellular drug concentrations, which decreases the cytotoxicity of a broad spectrum of antitumor drugs. Accordingly, P-gp inhibitors/blockers are potential enhancer for the cellular bioavailability of several clinically important anticancer drugs such as, anthracyclines, taxanes, vinca alkaloids, and podophyllotoxins. Besides several chemically synthesized P-gp inhibitors/blockers, some naturally occurring compounds and plant extracts were reported for their modulation of multidrug resistance; however, this review will focus only on major classes of naturally occurring inhibitors viz., flavonoids, coumarins, terpenoids, alkaloids and saponins.