Different Types of Naturally based Drug Delivery Carriers: An Explanation and Expression of Some Anti-cancer Effects.

Cancer remains one of the leading causes of death worldwide and a major impediment to increasing life expectancy. However, survival rates with average standard cancer treatment strategies have not significantly improved in recent decades, with tumor metastasis, adverse drug reactions, and drug resistance still posing major challenges. Replacement therapies are essential for treating this terrible disease. Recently, there has been a dramatic increase in the use of phytochemical-derived conjugated chemotherapeutic agents due to their biocompatibility, low cytotoxicity, low resistance, and dynamic physiochemical properties that distinguish normal cells in treating various types of cancer. The use of plant-based carriers has many advantages, such as the availability of raw materials, lower cost, lower toxicity in most cases, and greater compatibility with the body's structure compared to chemical and mineral types of carriers. Unfortunately, several challenges complicate the efficient administration of herbal medicines, including physicochemical disadvantages such as poor solubility and instability, and pharmacokinetic challenges such as poor absorption and low bioavailability that can cause problems in clinical trials. Novel delivery systems such as liposomes, phytosomes, nanoparticles, and nanocapsules are more suitable as delivery systems for phytomedicinal components compared to conventional systems. The use of these delivery systems can improve bioavailability, pharmacological activity, prolonged delivery, and provide physical and chemical stability that increases half-life. This article discusses different types of phytocompounds used in cancer treatment.

Polyphenol nanoformulations for cancer therapy: experimental evidence and clinical perspective.

Cancer is defined as the abnormal cell growth that can cause life-threatening malignancies with high financial costs for patients as well as the health care system. Natural polyphenols have long been used for the prevention and treatment of several disorders due to their antioxidant, anti-inflammatory, cytotoxic, antineoplastic, and immunomodulatory effects discussed in the literature; thus, these phytochemicals are potentially able to act as chemopreventive and chemotherapeutic agents in different types of cancer. One of the problems regarding the use of polyphenolic compounds is their low bioavailability. Different types of formulations have been designed for the improvement of bioavailability of these compounds, nanonization being one of the most notable approaches among them. This study aimed to review current data on the nanoformulations of natural polyphenols as chemopreventive and chemotherapeutic agents and to discuss their molecular anticancer mechanisms of action. Nanoformulations of natural polyphenols as bioactive agents, including resveratrol, curcumin, quercetin, epigallocatechin-3-gallate, chrysin, baicalein, luteolin, honokiol, silibinin, and coumarin derivatives, in a dose-dependent manner, result in better efficacy for the prevention and treatment of cancer. The impact of nanoformulation methods for these natural agents on tumor cells has gained wider attention due to improvement in targeted therapy and bioavailability, as well as enhancement of stability. Today, several nanoformulations are designed for delivery of polyphenolic compounds, including nanosuspensions, solid lipid nanoparticles, liposomes, gold nanoparticles, and polymeric nanoparticles, which have resulted in better antineoplastic activity, higher intracellular concentration of polyphenols, slow and sustained release of the drugs, and improvement of proapoptotic activity against tumor cells. To conclude, natural polyphenols demonstrate remarkable anticancer potential in pharmacotherapy; however, the obstacles in terms of their bioavailability in and toxicity to normal cells, as well as targeted drug delivery to malignant cells, can be overcome using nanoformulation-based technologies, which optimize the bioefficacy of these natural drugs.