Amalgamation of Nanotechnology for Delivery of Bioactive Constituents in Solid Tumors

Solid tumor is one of the highly prevalent cancers among humans and the treatment is often restricted by drug resistance to chemotherapeutics. One of the main reasons might be attributed to the limited penetration ability of drugs through tumor tissues due to heterogeneity within the tumor microenvironment. Over the recent years, so much research has been carried out for developing phytochemicals as cancer therapeutic agents. These are well-established as potential candidates for preventing and treating cancer, especially solid tumors, but have limited clinical applications due to their large molecular size, low bioavailability, stability, and target specificity, along with other side effects when used at high concentrations. There has been a widely proposed nano delivery system of bioactive constituents to overcome these obstacles. This nanostructured system might be able to potentiate the action of plant constituents, by reducing the side effects at a lesser dose with improved efficacy. Indeed, nanosystems can deliver the bioactive constituents at a specific site in the desired concentration and avoid undesired drug exposure to normal tissues. Furthermore, these nanoparticles demonstrate high differential absorption efficiency in the target cells over normal cells by preventing them from interacting prematurely with the biological environment, enhancing the cellular uptake and retention effect in disease tissues, while decreasing the toxicity. This review discusses various treatment stratagems used for the management of solid tumors with special emphasis on nanocarrier systems as a potential treatment strategy for herbal drugs. This also covers a wide list of plants that are used for the treatment of solid tumors and cancers along with their mechanisms of action and enlists various nanocarrier systems used for different phytoconstituents. This review gives a brief idea about different plants and their constituents exploited for their anticancer/antitumor potential along with several nanocarrier systems employed for the same and gives future directions to stress the nanotechnology platform as a valuable approach for the prevention and treatment of solid tumors.