The use of synthetic drugs has increased over the recent years, but plant-based drugs are more suitable in terms of least side effects. Since ancient times mankind has been dependent on plants for the treatment of various ailments, among them widely used is curcumin, the principal polyphenol extracted from turmeric. Their medicinal and useful properties are mentioned in Indian Veda’s and Chinese medicine. Curcumin has been studied extensively for its pleiotropic activity, including anti-inflammatory, anti-oxidant and anti-tumor activity. Accumulated evidence indicated curcumin plays an inhibitory role against infection of numerous viruses. These mechanisms involve either a direct interference of viral replication machinery or suppression of cellular signaling pathways essential for viral replication, such as PI3K/Akt, NF-κB.
Combating viral diseases, especially those caused by the emerging viruses or variants have always been a challenge. Viral RNA polymerase possesses a high mutation rate (Elena & Sanjuan, 2005), owing to the lack of the proofreading capability, and evidently this trait helps viral pathogens with RNA genome to evolve resistance against pre-existing antiviral drugs. However, cost, time and effort to develop an antiviral drug takes its toll (Bolken & Hruby, 2008), as when a new mutated variant of a RNA viral pathogens emerges. Furthermore, long-term administration of antiviral drugs is known to elicit side effect like nausea, vomiting, mitochondriaxicity and insomnia depending upon the antiviral drug (Carr, 2003; Dolin et al., 1982; Fontana, 2009; Hima Bindu & Naga Anusha, 2011; Reust, 2011; Treanor et al., 2000; Winquist, Fukuda, Bridges, & Cox, 1999) Curcumin’s pleiotropic activities against virus’s emanate from its ability to modulate numerous molecular targets that contribute to various cellular events, such as transcription regulation, and the activation of cellular signaling pathways such as inflammation, and apoptosis (Joe, Vijaykumar, & Lokesh, 2004; Ravindran, Prasad, & Aggarwal, 2009) likely via intermolecular interactions. Previous researches concluded that curcumin interacts directly with almost 30 proteins, such as, DNA polymerase (Takeuchi et al., 2006), focal adhesion kinase (FAK) (Leu, Su, Chuang, & Maa, 2003), thioredoxin reductase (Fang, Lu, & Holmgren, 2005), protein kinase (PK) (Reddy & Aggarwal, 1994), lipoxygenase (LOX) (Skrzypczak-Jankun, Zhou, McCabe, Selman, & Jankun, 2003), and tubulin (Gupta, Bharne, Rathinasamy, Naik, & Panda, 2006). Moreover, in addition to modulating cellular events, curcumin limits viral infection by interfering with critical steps in their replication cycle, including but not limited to, viral attachment (Chen et al., 2010a, 2010b), and genome replication (Narayan et al., 2011; Si et al., 2007). Curcumin’s role as an antiviral agent has been studied thoroughly in the case of viruses like HIV, Herpes simplex virus (HSV), Hepatitis viruses, influenza type A virus (IAV), and Ebola virus. Since curcumin’s positive effects outweigh the negative effects and their role in targeting various cellular pathways, further inhibiting the growth and replication of viruses make it a candidate for an anti-viral drug.
Curcumin’s multipotent role against organisms like bacteria, fungi, virus as well as its synergistic effects like anti-oxidant potential, antiinflammatory, and anti-tumoral activities has made it a wonder drug. Their ability to affect a wide range of molecular targets makes it a potential candidate for the prevention and/or treatment of a number of diseases. A lot of scopes are seen in the use of curcumin-enhanced drugs that can be readily bioavailable with targeted effect against viruses. Since one of the drawbacks of curcumin is its poor bioavailability and in order to combat this issue enhanced versions of curcumin formulations like Fitomina, BCM-95CG (Biocurcumax) (Antony et al., 2008), Bio- Perine-20x, Theracurmin-27x (Antony et al., 2008), Meriva-29x (Allegri, Mastromarino, & Neri, 2010), Longvida-67x (Kurita & Makino, 2013; McFarlin et al., 2016) are available in the market with increased absorption and/or bioavailability of curcumin than the unenhanced curcumin. Moreover, the combination of curcumin and other components could uplift their anti-cancer or anti-viral potential; a synergistic effect was seen when curcumin was combined with thymoquinone against avian influenza H9N2, which suppressed the pathogenicity and significantly enhanced immune responsiveness in turkey (Umar et al., 2016). In recent years, viable drug delivery systems, which includes coupling of curcumin with Nanosuspensions were developed (Gao et al., 2010; Pandey et al., 2011; Safavy et al., 2007). The advances of nanotechnology has helped to circumvent the challenges faced with curcumin drug delivery by using various nano-carriers such as nanoparticles (Li et al., 2012; Misra & Sahoo, 2011), curcumin nanocrystals (Onoue et al., 2010), polymeric micelles (Gou et al., 2011), dendrimers, Nano liposome-encapsulated curcumin (Thangapazham, Puri, Tele, Blumenthal, & Maheshwari, 2008), polymeric micelles (Gou et al., 2011) and solid-lipid nanoparticles (Sun et al., 2010); thus by providing better permeability, resistance to metabolic processes and increased blood circulation. Despite the significant progress made in curcumin research over the years, further research is required, as many questions and challenges still exist.
Source: Journal of Functional Foods – https://www.sciencedirect.com/science/article/abs/pii/S1756464617307399?via%3Dihub
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