Oral herpes is a condition caused by the infection of Herpes Simplex Virus (HSV-1) inside or around the oral cavity, i.e., mouth. The symptoms of this infection are mostly dormant, but sometimes symptoms like blisters or sores that are painful appear at the site of the infection.
HSV-1 is an easily transmittable infection, common all over the world. This infection is mainly transmitted through the virus present in saliva or sore using oral to oral contact.
According to a World Health Organisation report, in 2012 HSV-1 infection affected approximately 67% population of the world. The highest number of the infection cases was observed in the Africa (87%) and the Americas had the lowest number of cases (40-50%).
Acyclovir, an anti-viral drug is considered the most effective treatment for the herpes infection. But the ever-increasing drug resistance and high cost and side-effect of this medicine are calling for the use of alternative natural remedies.
One such possible alternative is reckoned to be Aloe vera. This xerophytic succulent of lily family has the mucilaginous fluid in its thick fleshy leaves. This gel constitutes numerous compounds such as polysaccharides, enzymes, vitamins, etc.
These active compounds possess antiseptic, anti-inflammatory, antioxidant, healing, immune-stimulating, anti-cancerous and anti-ageing properties. Aloe vera is found to have anti-viral activity against many viruses, such as Influenza A virus, Encephalitis virus, Enterovirus 71, etc.
Studies have shown positive results for the anti-viral action of Aloe vera on the virus HSV-2 (causes genital herpes). This result can have a positive implication against HSV-1 as well.
With the same thought, this study is an attempt to explore the potential and effectiveness of Aloe vera against HSV-1 infection that causes oral herpes sores.
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What happened in the study?
This study was done to examine the antiviral activity of Aloe vera gel extract against the herpes simplex virus, HSV-1.
This study was conducted in vitro, i.e., in an artificial environment on Vero cell line (cells grown from the kidney cells of African green monkey). It was a twofold study, one to assess the toxicity of Aloe vera gel extract on the cell line and the other to assess the antiviral activity of the gel extract.
The examination of toxicity of the gel extract was done by adding different concentrations of the gel extract solution to the cell line, respectively.
Tests were done to see whether any concentration of the Aloe vera gel extract is toxic to the cells of the Vero cell line.
The anti-viral effect was examined by firstly, infecting the cell line with the herpes simplex virus, HSV-1. Each plate of the infected cells was then introduced with various concentrations of the Aloe vera gel extract solution, respectively.
Tests were carried out to find the intensity of infection in each plate of the cell line, respective to different gel extract concentration.
The intensity of infection was seen regarding reduction or increase in the replication of the virus in the formation of plaques ( the visible structure formed by virus upon replicating and causing cell destruction on a nutrient medium).
Control for both the studies was prepared for comparison. A replica of the healthy cell line without the gel extract and a replica of virus-infected cell line without the gel extract were controls.
What was the result?
For the first study, i.e., assessment of toxicity of the Aloe vera gel extract on the Vero cell line, the result was negative. No concentration of the gel extract was toxic for the cell line, compared to the control (healthy untreated cell line).
For the study of the anti-viral activity of the Aloe vera gel extract on the HSV-1 infected cell line, the results were as following:
- All the concentration of the gel extract inhibited the replication of the virus in a significant manner.
- Higher concentrations had considerably more anti-viral activity than the lower concentrations.
- The 5% concentration of the Aloe vera gel extract was most effective in reducing the virus plaques. 2% concentration was similar in the action.
- The gel extract concentrations 0.2%, 0.5% &1% had much lesser anti-anti-viral than the 5% concentration.
How does this occur?
The result showing non-toxicity of the Aloe vera gel extract towards the Vero cell line eliminates the possibility of any external influence on the cell line when it is infected with the virus, HSV-1.
This confirms that the infection-induced in the cell line was by the virus only.
Herpes simplex virus is an enveloped virus, glycoproteins (proteins bonded with sugar moiety) being the constituent of the envelope. The mechanism of its infection is by binding to the surface of the host cell, entering the cell and taking over the cell’s replication machinery.
The virus replicates and the cell bursts releasing new viruses and the infection spreads to the other neighbouring cells.
The antiviral activity of Aloe vera is owed to the presence of anthraquinones (naturally occurring phenolic compounds) in the gel. Some of these compounds are
Aloin and Emodins.
Anthraquinones are known to be effective against various enveloped viruses, including herpes simplex virus. One of the emodins from Aloe vera, called Aloe emodin was active against these viruses.7
The mechanism of action of the Aloe emodin against these viruses is found to be disruption of the viral envelope.5 This disruption prevents binding of the virus to the host cell which is an initial step in the process of the infection.
This prevents replication of the virus ceasing the further spread of the infection.
A polysaccharide, acemannan from the Aloe vera gel is also found to have anti-viral activity against many viruses. It is an immunostimulator which means it can inhibit viral infections by enhancing the immune responses.
The concentration-based efficiency of the gel against the virus suggests that even lower concentrations have a positive effect. But better outcomes can be achieved by using higher concentrations of the Aloe vera gel.
It can be concluded that the antiviral and immune-enhancing property of the various constituents of the Aloe vera gel extract is capable of overpowering the oral herpes infection.
What does it mean?
This means Aloe vera is a good alternative to combat oral herpes sores.
Regular use of Aloe vera gel based mouthwash or ointment products can prove to be effective in reducing the transmission of the virus through saliva.
Consumption of the fresh gel or Aloe vera juice can have a twofold effect, in the curtailment of infection by viral inhibition as well as by boosting the immune system.
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