Curcumin as an Antiviral Compound

Before we get into the therapeutic & antiviral effects of turmeric against viruses and viral infections let’s first talk about “What is a Virus?”, “What causes viral infection?” and “How to fight against viral infections?”.

Viruses are like tiny parasites containing genetic materials like DNA & RNA and can cause diseases as minor as cold or as major as HIV-AIDS. Since viruses contain genetic material they can reproduce themselves into the host cells and infect them, but they are metabolically immobile when outside the host body.

Our body has its own natural resistant mechanism(immune response) against viral infections, namely – Humoral Immunity & Cell Mediated Immunity. Humoral Immunity is for when the virus is present in the humors or body fluids. Cell Mediated Immunity does not involve antibodies and is associated with immunization of cells.

Due to the lack of preventive and therapeutic options for many viral infections, numerous studies have been conducted to investigate the antiviral potential of natural compounds. For curcumin, an antiviral activity was observed against several different viruses including hepatitis viruses, influenza viruses and emerging arboviruses like the Zika virus (ZIKV) or chikungunya virus (CHIKV).

Interestingly, it has also been reported that the molecule inhibits human immunodeficiency virus (HIV), herpes simplex virus 2 (HSV-2) and human papillomavirus (HPV), indicating that curcumin reduces the spread of sexually transmitted diseases.

Curcumin Inhibits Human Immunodeficiency Virus

HIV is a lentivirus which belongs to the family of Retroviridae. HIV is the causative agent of the acquired immunodeficiency syndrome, better known as AIDS. Several studies have reported that curcumin exhibits an anti-HIV activity by directly targeting viral proteins.

  • In 1993, a research reported a modest inhibition of the HIV-1 and HIV-2 proteases by curcumin. Scientists found that the molecule binds to multiple sites of the enzyme, with micro molar concentrations leading to a suppression of enzymatic activity.
  • It has been shown that curcumin is a potent HIV integrase inhibitor, as it is able to bind acidic residues in the integrase’s catalytic core domain, preventing it from binding its substrates.
  • Another HIV protein targeted by curcumin is the Trans-Activator of Transcription (TAT), a viral transcription regulator. Upon infection, TAT is secreted and taken up by uninfected cells, which promotes the growth of HIV-induced tumors and the apoptosis of T-cells, fostering the development of AIDS. Thus, inhibiting TAT would prevent efficient viral gene transcription as well as disease progress.
  • In TAT-transduced HEK293T cells the TAT protein level decreased upon incubation with curcumin in a dose-dependent manner that can be blocked by proteasome inhibitors, indicating that curcumin causes proteasomal degradation of tat. Moreover, it has been reported that curcumin inhibits HIV proliferation by inhibiting TAT acetylation in SupT1 cells and that curcumin efficiently inhibits tat-induced transactivation of HIV-1 long terminal repeats in HeLa cells.

Curcumin Inhibits Influenza A Virus

Influenza viruses belong to the family Orthomyxoviridae and can be divided into three types: A, B, and C. The influenza A virus (IAV) mainly infects birds, but it can cause severe pandemics in domestic poultry and in humans, even though this happens rarely.

  • Several studies tested the effect of curcumin on different IAV types in vitro and found it to inhibit virus uptake, replication and particle production. Experimental work and structure-relationship modeling suggested that the inhibition was due to the molecule interfering with binding of the viral glycoprotein hemagglutinin (HA) to its cellular receptor.
  • A subsequent study confirmed this effect and explained it by curcumin's ability to modulate the features of lipid bilayers. The compound alone was as effective in dampening IAV infection as pure curcumin and a synergistic effect of the two analogs was observed.

Ginger fights influenza A

Researchers from Japan’s Toyama Medical and Pharmaceutical University tested ginger against an influenza A strain in the laboratory. They found that the ginger extract stimulated the production of TNF-alpha expression by the immune system. This provided the means for the ginger to inhibit replication of the virus.

Researchers from India’s Mahatma Gandhi Institute of Medical Sciences also studied ginger along with other natural compounds for inhibiting H1N1 influenza A. They found ginger’s content helped inhibit the virus by interacting with its binding capacity

Curcumin Inhibits Herpes viruses (Herpes simplex Virus) HSV

The most famous herpes virus is probably the herpes simplex virus, which is categorized into two types: HSV-1, commonly associated with orofacial ulcer and HSV-2, which mainly causes genital ulcers.

  • Several studies found that low micro molar, not cytotoxic amounts of curcumin dampened HSV-1 and HSV-2 infectivity. For HSV-1 this is associated with a considerably decreased expression of viral immediate early (IE) genes, which is due to a reduced RNA polymerase II recruitment to IE gene promoters.
  • Intriguingly, similar to HIV, the pretreatment of human genital epithelial cells with the curcumin reduced the shedding of HSV-2 from these cells, a mechanism that might help to stop the spread of the sexually transmitted disease. Another highly prevalent Herpesviridae member is the human cytomegalovirus (HCMV).

Ginger inhibits Herpes viruses

Researchers from Germany’s University of Heidelberg studied essential oils from ginger extracts.

The researchers found that the ginger essential oil significantly inhibited the HSV-2 virus replication within RC-37 cells. The researchers found that plaque formation was halted by 90 percent by the ginger essential oils and the thyme oil.

The researchers found that a ginger extract inhibited the infection of infection-free cells when coming into contact with the virus. They concluded that the ginger likely collapsed the viral envelope.

Curcumin Inhibits Human Papilloma virus(HPV)

Human papillomaviruses cause persistent cutaneous or mucosal infections, and the infection with at least 13 HPV types is associated with the development of multiple types of cancer. Especially the cervical cancer, the fourth-most common cancer in women, is tightly linked to HPV infection and in over 60% of the cases the high-risk HPV types 16 and 18 are detected.

  • The effect of curcumin on HPV infection and HPV-associated tumor growth has been extensively studied. Already in 1990 the group of scientists could show that the viral oncoprotein E6 of HPV-16 and 18 complexes with the tumor suppressor protein p53, targeting it for proteasomal degradation.
  • In silico modeling suggested that curcumin binds to the p53 interaction site of E6, by prohibiting it from binding p53. In addition, in vitro studies showed that curcumin inhibited E6 and E7 expression and by this rescued p53 levels.

Curcumin Inhibits Respiratory Syncytial Virus(RSV)

The human Respiratory Syncytial Virus (RSV) causes respiratory tract infections and is one of the leading causes of morbidity and mortality in children under 5 years of age.

The use of curcumin against RSV infections revealed that it prevented RSV replication and budding from human nasal epithelial cells and at the same time increased the epithelial barrier function. To enable a local application of curcumin, Yang and coworkers just recently developed two different types of nanomaterials loaded with the compound, which showed good biocompatibility and abrogated RSV infection.

Ginger combats human respiratory syncytial virus (RSV)

Human respiratory syncytial virus (RSV) is one of the most common contagious virus infections that occur in children. Symptoms include fever, stuffy nose wheezing and runny nose. Many RSV illnesses are confused with the common cold. However a bout of RSV will typically last for longer, and will typically include wheezing. In younger children this can turn fatal

The inhibition of the virus occurred more readily among the alveolar (lung) cells – illustrating the potential for the ginger to inhibit RSV infections of the lungs.

Curcumin Inhibits Noroviruses

Noroviruses are members of the Caliciviridae family, which commonly cause acute gastroenteritis in developed as well as in developing countries. The WHO ranks human noroviruses (NoV) as the number one cause of foodborne illness and the number four cause of foodborne deaths globally.

Today, the treatment of NoV infections is only symptomatic, and the focus is more on preventing the disease and its expansion. While incubation of murine norovirus (MNV) with curcumin was found to significantly neutralize subsequent infections of a mouse macrophage cell line in a time- and dose-dependent manner, it had no effect on a NoV-replicon carrying hepatoma cell line.


Curcumin Inhibits Arboviruses

The group of arboviruses comprises different viruses which are transmitted by arthropod vectors like ticks and mosquitos. Nowadays arboviruses are rapidly re-emerging worldwide, as arthropod habitats are expanding due to climate change and the increase of global traffic.

For most arboviruses, except Japanese encephalitis virus and yellow fever virus (Flaviviridae), no vaccines are available and there is a lack of specific preventing or curing treatment for all of them.

  • Recently, two studies revealed that curcumin blocks the entry of CHIKV (Tongaviridae) by inhibiting its binding to host cells. Incubation of cells with the natural compound also significantly dampened infection with Dengue virus, JEV and ZIKV (Flaviviridae) via the same mechanism. Similar as for HCV and IAV, this might be due to curcumin's influence on membrane properties.
  • In addition to inhibiting virus entry, curcumin treatment of cells already infected with DENV or JEV resulted in the intracellular accumulation of viral proteins and a reduction of viral particle production. Also Rift Valley fever virus (RVFV; Phenuiviridae) has been shown to be inhibited by curcumin: scientists observed that the molecule inhibits IKK-mediated phosphorylation of the viral NSs protein, resulting in reduced viral replication.

Curcumin (an extract of turmeric) – Boosts Immunity and Fights Infections

Turmeric is ancient Ayurvedic medicine. Its anti-inflammatory, anti-viral, anti-oxidant, anti-tumor, antibacterial and antifungal activities are responsible for its extensive use in the healthcare industry.

All these important medicinal properties of turmeric are because of its primary compound Curcumin obtained from its roots.

  • Curcumin has received worldwide attention for its multiple health benefits, which appear to act primarily through its anti-viral, antioxidant and anti-inflammatory mechanisms. Research suggests that curcumin can help in the management of oxidative and inflammatory conditions, metabolic syndrome, arthritis, anxiety, and hyperlipidemia and is a potentioan natural alternative supplement. It may also help in the management of exercise-induced inflammation and muscle soreness, thus enhancing recovery and subsequent performance in active people.
  • Despite the body’s immune responses against viral infections, they are still easily contracted and are difficult to treat. Most often, the virus cannot be destroyed once a viral disease is contracted. The symptoms of viral infections are difficult to detect in the early stages and this usually worsens the conditions.

SUMMARY

  • Turmeric is ancient Ayurvedic medicine. Its anti-inflammatory, anti-viral, anti-oxidant, anti-tumor, antibacterial, anti-fungal activities are responsible for its extensive use in the healthcare industry.
  • All these important medicinal properties of turmeric are because of its primary polyphenolic compound Curcumin obtained from its roots.
  • Despite the body’s immune responses against viral infections, they are still easily contracted and are difficult to treat.
  • Most often, the virus cannot be destroyed once a viral disease is contracted.
  • The symptoms of viral infections are difficult to detect in the early stages and this usually worsens the conditions.
  • Curcumin has been found effective against a number of life- threatening viral infections like HIV- AIDS, Herpes, Influenza, Hepatitis, Ebola, Human Papillomavirus and Rift Valley Fever Virus, etc.
  • It produces anti-viral activity by inhibiting the interaction of viral proteins with cellular receptors on host cells.