Herpes simplex viruses (HSV-1 and HSV-2) are responsible for long-term latent infections in humans, with periods of recurring viral replication associated to lesions around the lips, eyes, mucous membrane of the oral cavity or the genitals. The lack of an effective vaccine, the moderate to high toxicity of the available synthetic antiherpes compounds and the appearance of resistant viral strains emphasize the need for new inhibitors. Tanacetum vulgare, commonly known as tansy, has been used for treating rheumatic pain, skin eruption and diuretic conditions as well as an anthelmintic, antihypertensive, stimulant, emmenagogue, carminative, antiseptic, antihypertensive, antispasmodic and antioxidant agent. The anti HSV-1 activity of tansy aerial parts, ethyl acetate extract and the isolated compound parthenolide, has been reported recently. In this work, through a comprehensive mechanistic-based antiherpetic activity study, it was revealed that constituents other than parthenolide are responsible for the antiviral activity of tansy.
The herpes virus causes latent infections of the eye, lips and genitals. There is no effective vaccine for this virus. The current treatment methodologies are not very effective as well as toxic. Owing to the latency and morbidity of the virus, newer and more potent inhibitors are required. The tansy plant is evaluated in this study as a treatment modality for herpes infections. It was found that certain constituents in the tansy plant, other than the expected chemical compound, are the inductive agents for the antiviral activity of tansy.
The herpes simplex virus is the pathogen responsible for herpes of the oral region and the genital region. Currently used medications for herpes are not tolerated well and viral resistance to the medication is a major issue. The incidence of herpes infections has increased in recent years. Moreover, it also increases by three-fold the risk of sexually acquired HIV infection. Tansy is a herb and has been used previously to treat rheumatic pain, skin eruption, and a few other conditions. Various other functions such as antiseptic, anti-inflammatory, and antioxidant activities have also been associated with tansy. This study was done to ascertain the role of tansy in the treatment of herpes.
The aerial portions of tansy plants were obtained and were made into an extract. Various solvents were used in the preparations of the extract. These were filtered and dried. * The chemical content in these extracts was estimated using certain instruments. * The extract was grown along with the herpes viral particles. This was to assess if the extract from the tansy plants could suppress the growth of the herpes virus.
The extracts from the aerial parts of the tansy plants showed antiviral activity against the herpes simplex virus. It was found that the petroleum ether and ethyl acetate extracts could suppress both types of herpes virus. The antiviral compound dicaffeoylquinic acid (3,5-DCQA) was found to be a major constituent of the tansy plant, and showed the strongest inhibiting factors to stop herpes.
Next steps Precise molecular mechanisms and the targets for the tansy extract and its active components are not completely clear and need to be verified. More research is mandatory to identify additional, yet unknown components with antiviral properties. Future studies could investigate the antiviral activity of the underground rhizome extracts of the tansy plant.
The ability of the tansy plant extracts to suppress herpes viral growth was shown in this study. A key finding was the ineffectiveness of a component called parthenolide, which was previously considered to express the highest level of viral inhibition. Another compound, 3,5- DCQA, was found to have potent anti-herpes viral activity. This compound could have a promising role as an antiviral medication. With many potentially beneficial compounds, tansy extracts could be used in creams to treat skin lesions caused by the herpes virus. Better, effective, and more natural treatment modalities, like extracts from plants, could compensate for the absence of a vaccine for herpes.