Anti-rice Blast Mold The Active Ingredient In Red Onions

Eleutherine americanana Merr.et K.Heyne(Hong-cong) is a herbal plant, widely distributed in Hainan, Yunnan and Guangxi provinces of China. Its red bulb was used as a folk medicine for the treatment of cardiac diseases. In our program of screening anti-fungal and anti-cancer agents from traditional Chinese herbal medicines, its ethanol extract was found to possess good bioactivity against the growth of Pyricularia oryzae. By bioactivity-guided isolation, 14 compounds were obtained from the active fractions. 13 of them were determined as 9,9'-dihydroxy-8,8'-dimethoxy- l,r-methyl-lH,lH'-[4,4']bi[naphtha[2,3-c]funanyl]-3,3 '-dione(l), eleutherol(2), eleutherin(3), isoeleutherin(4), -sitosterol(5), 8-hydroxy-3,4-dimethoxy-l-methyl-anthraquinone-2-carboxylic acid methyl ester(6), 4-hydroxyeleutherin (7), hongconin(8), 4,8-dihydroxy-3-methoxy-l-methyl-anthraquinone-2-car boxylic acid methyl ester(9), 6,8-dihydroxy-3,4-dimethoxy-l-methyl-anthraquinone-2-carboxylic acid methyl ester(ll), dihydro-eleutherinol(12), 2-acetyl-3,6,8-trihydroxy-l-methylanthraquinone(13), and 1,3,6- trihydroxy-8-methyl anthraquinone(14) by physico-chemical propertities and spectral data, respectively. These compounds belong to either naphthoquinones, or naphthols, or anthraquinones. Compounds 1, 11 and 13 are new compounds. Compounds 12 and 14 are reported from Eleutherine genus for the first time. Their activities against the growth of Pyricularia oryzae were tested. Some of them showed moderate activity on P. oryzae with MMDC(Minimum Morphological Deformation Concentrate) value of 30 M(3),30 M(4), 170 M(6), 130 M(7), 55 M(8), !35 M(11), 60 mol/mL(12) and 150 M(14). Additionally, MTT method showed some of these compounds could inhibit the proliferation of K562(human erythroleukemia) with IC50 value of 33 M(3), 49 M(4),266 M(6), 35 M(7), 174 M(8), 132 M(11), 154 M(12). And 6 induce apoptosis on K562 at the concentration of 300 M.