Novel anthraquinone derivatives from the aerial parts of Antigonon leptopus Hook & Arn

Antigonon leptopus ethanol extract yielded a known compound, quercetin-3-O-α-rhamnopyranoside and four novel anthraquinones named: 1,8-dihydroxy-6-(hydroxymethyl)-3-methoxy-2-pyrrolidinium anthraquinone, 1,8-dihydroxy-6-(methyl)-3-methoxy-2-pyrrolidinium anthraquinone, 1,8-dihydroxy-6-(hydroxymethyl)-3-methoxy-2-piperidinium anthraquinone, 1,8-dihydroxy-6-(methyl)-3-methoxy-2-piperidinium anthraquinone. Two of these new compounds were active against Bacillus subtilis and Staphylococcus aureus.