The in vitro anti-herpes simplex virus type-1 and type-2 activity of Long Dan Xie Gan Tan, a prescription of traditional Chinese medicine.
ABSTRACT Long Dan Xie Gan Tan (LDXGT), a decoction of radix gentianae for purging the pathogenic inflammation of the liver, is a widely used prescription among many in traditional Chinese medicine. The prescription is primarily used to treat the disorders induced by damp-heat in the liver and the gall bladder.
In this study, the in vitro anti-herpes simplex virus type-1 (HSV-1) and type-2 (HSV-2) activity of the water extract of LDXGT was investigated.
LDXGT water extract was shown to exhibit anti-HSV activity. The IC(50) values of LDXGT against HSV-1 and HSV-2 infections were 257.5 +/- 12.2 and 494.6 +/- 1.8 microg/ml, respectively. It had a CC(50) value of 4,077.2 +/- 2.4 microg/ml towards Vero cells and showed no cytotoxic effect at a concentration of 2,000 microg/ml or below. The prescription was also found to inactivate HSV-2 infectivity in a dose-, time- and temperature-dependent manner.
In summary, the water extract of LDXGT was concluded to inhibit HSV-1 and HSV-2 infection at different magnitudes of potency, and our observations also suggested that the effect was likely mediated by directly inactivating the virus infectivity.
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ABSTRACT: Noroviruses (NoVs) are the leading cause of viral acute gastroenteritis affecting people of all ages worldwide. The disease is difficult to control due to its widespread nature and lack of an antiviral or vaccine. NoV infection relies on the interaction of the viruses with histo-blood group antigens (HBGAs) as host receptors. Here we investigated inhibition effects of Chinese medicinal herbs against NoVs binding to HBGAs for potential antivirals against NoVs. Blocking assays was performed using the NoV protrusion (P) protein as NoV surrogate and saliva as HBGAs. Among 50 clinically effective Chinese medicinal herbs against gastroenteritis diseases, two herbs were found highly effective. Chinese Gall blocked NoV P dimer binding to type A saliva at IC(50)=5.35 μg/ml and to B saliva at IC(50)=21.7 μg/ml. Similarly, Pomegranate blocked binding of NoV P dimer to type A saliva at IC(50)=15.59 μg/ml and B saliva at IC(50)=66.67 μg/ml. Literature data on preliminary biochemistry analysis showed that tannic acid is a common composition in the extracts of the two herbs, so we speculate that it might be the effective compound and further studies using commercially available, highly purified tannic acid confirmed the tannic acid as a strong inhibitor in the binding of NoV P protein to both A and B saliva (IC(50)≈0.1 μM). In addition, we tested different forms of hydrolysable tannins with different alkyl esters, including gallic acid, ethyl gallate, lauryl gallate, octyl gallate and propyl gallate. However, none of these tannins-derivatives revealed detectable inhibiting activities. Our data suggested that tannic acid is a promising candidate antiviral against NoVs.Bioorganic & medicinal chemistry 02/2012; 20(4):1616-23. · 2.82 Impact Factor
- Human Respiratory Syncytial Virus Infection, 11/2011; , ISBN: 978-953-307-718-5
- North American journal of medical sciences. 12/2012; 4(12):641-7.