Chantana AromdeeNongluksna SriubolmasSuthep WiyakruttaSupawadee SuebsasnaWatcharee KhunkittiKhon Kaen UniversityChulalongkorn UniversityMahidol University2018-05-032018-05-032011-01-01Archives of Pharmacal Research. Vol.34, No.1 (2011), 71-7719763786025362692-s2.0-79955065706https://repository.li.mahidol.ac.th/handle/20.500.14594/11636Andrographis paniculata has been reported to have antiviral, antipyretic and anticancer activities. Andrographolide, an ent-labdane diterpene, is an active constituent in this plant. In this study, andrographolide (1) and its natural derivative 14-deoxy-11,12-didehydroandrographolide (2) and 5 other semisynthetic derivatives were tested for their activity against Grampositive and Gram-negative bacteria and Candida albicans. Only derivatives bearing a 14-acetyl group showed activity, and this activity was only against Gram-positive bacteria. 14-Acetylandrographolide showed the highest potency against Bacillus subtilis; the other 14-acetylandrographolides with additional substitution at the 3- and 19-hydroxyl groups showed lower activity against Gram-positive bacteria. The morphology of B. subtilis after being treated with 14-acetylandrographolide was investigated with TEM. This is the first report on 14-acetylandrographolide's quantified antibacterial activity, and the crucial functional group of this ent-labdane that plays an important role in perturbing the morphogenesis of B. subtilis leading to cell death. © 2011 The Pharmaceutical Society of Korea and Springer Netherlands.Mahidol UniversityBiochemistry, Genetics and Molecular BiologyChemistryPharmacology, Toxicology and PharmaceuticsArticleSCOPUS10.1007/s12272-011-0108-1