Studies on the Chemical Constituents and Anti-EV71, Influenza Virus Principles from Loranthaceae Plants-Korthalsella Japonica, Taxillus Tsaii and Taxillus Parasitica (I)

Human enterovirus 71 (EV71) was first isolated in the United States in 1969 and belongs to Enterovirus genus within Picornaviridae. Children less than 5 years old are particularly susceptible to EV71 infection and might cause sever forms of EV71-associated neurological diseases. In Taiwan， about 130,000 cases of hand-foot-and-mouth disease (HFMD) and herpangina were reported in the period of 8 months in 1998. There were 405 children hospitalized with HFMD associated with meningitis，encephalitis or acute flaccid paralysis and 78 people have died. In the recent studies， the wide-used picornavirus binding inhibitor，pleconaril，could，t reduce cytopathic effect (CPE) caused by EV71 isolated from 1998 outbreak epidemic in Taiwan. In USA，Europe，and Japan，there are on average over 100 million people infected with influenza every year，which means that every year，1 out of every 10 adults and 1 out of every 3 children are infected. The influenza viruses are extremely mutative and can generate drug-resisting viruses. Hence，the development of new drugs is continuously demanding new attention. There are currently two classes of drugs which can treat influenza A virus. The first class is amantadine and rimantadine，which work by suppressing the uncoating of virus. The second class of drugs are Zanamivir and Oseltmavir，which work by suppressing NA so that the virus will not be released and contaminate other cells. However，these two types of drugs also have the tendency of generating drug-resisting strains，as well as neurological side effects. In our studies on the anti-EV 71 and anti-influenza virus of natural sources，more than 50 species have been screened at present. Among them，we found the methanolic crude extracts of Korthalsella japonica，Taxillus tsaii and T parasitica (Loranthaceae) at 50 pg/ml showed complete inhibitory activity against EV 71. The methanolic extracts of K. japonica and T tsaii，T parasitica revealed the 75 % and 50 % inhibitory activity against influenza virus，separately. We are interested to investigate the constituents and bioactivities of K. japonica, T. tsaii and T. parasitica due to the less of photochemical studies. This study aims to look for bioactive anti-EV 71 and anti-influenza virus principles from K. japonica, T. tsaii and T. parasitica by virtue of bioassay-directed isolation and structural elucidation.

Project ID:PA9607-0528
External Project ID:NSC96-2113-M182-001