Nanomedicine is an increasing science area concerned with the development and fabrication of nanometer-scale structures for improved cancer care, detection, and imaging. Most cancer treatment options available in the clinic currently limit their usages with limited solubility and off-target side effects. Nanomaterials improve the bioavailability, solubility, selective organ distribution, and therapeutic effect of several biomolecules. Gene therapy using free nucleic acids can deal with vital candidate genes of cancer. However, their effect is delayed due to poor cell uptake and instability in circulation. Recently, Short interfering RNA (siRNA), highly capable of knockdown of specific genes, has emerged as a promising molecular therapeutic tool in targeted cancer treatment. Using liposomes, polymers, and dendrimers nanoparticles to deliver cancer drugs and siRNAs have been successful in recent preclinical studies. However, improving the tumor specificity of therapeutic cargo remains a major challenge. Therefore, the development of a novel tumor-targeted drug/gene delivery platform is urgently needed. Numerous novel drug delivery devices for siRNA distribution were being created to address the main challenges preventing siRNA's therapeutic potential. In the present review, we summarise the recent advancements in the nano-based drug delivery systems for siRNA delivery. Additionally, the innovative nanomedicines used for cancer therapy would be addressed. This study comprises a vast variety of siRNA drug delivery systems established in vitro and in vivo for improved intracellular delivery and selective gene regulation and addresses their features and possibilities for functional siRNA medical applications.

Curcumin, the polyphenolic pigment from turmeric has excellent therapeutic potential but due to poor aqueous solubility and metabolic instability, it has not yet been possible to use it as a drug. Structural studies have revealed that depending upon ambient pH, curcumin can remain in keto- enol tautomeric forms. The keto form is generated at acidic pH and due to the presence of the β-diketone motif in the molecule, the methylene group gets activated and can donate a hydrogen atom to reactive oxygen species which is responsible for its anti-oxidative properties. The enol form of curcumin which is present at alkaline pH becomes a planar molecule due to extensive delocalization of electrons from one aromatic ring to the other through the pi orbital of C=C bonds in the heptadione linkage. At alkaline pH, curcumin gets degraded to smaller molecules which have interestingly been shown to have therapeutic activity. Molecular interaction studies have identified the methylene group in the β-diketone domain and the methoxy as well as the phenoxy group on the aromatic rings of curcumin molecule to be the contact points with enzymes and signaling molecules and may be involved in inactivating them. The bioavailable forms of curcumin cited in this review have been formulated using curcumin entrapped or bound to polymeric nanoparticles, liposomes, phospholipid complexes,nanoemulsions, or polymeric micelles and have been tested against chronic inflammatory conditions in animal models or cell lines.