Antiviral and antituberculous activity of Helichrysum melanacme constituents

Bioassay guided fractionation of the acetonic extract of Helichrysum melanacme using human Influenza virus type A and a drug-sensitive strain of Mycobacterium tuberculosis in vitro resulted in the isolation of 2 4',6'-trihydroxy-3'-prenylchalcone (1) and 4',6',5'-trihydroxy-6',6'-dimethyldihydropyrano[2',3'-2',3'] chalcone (2) as active constituents. 3-O-methylquercetin and quercetin were also isolated but were inactive against the microorganisms tested in this study.