Antibacterial pterocarpans from Erythrina subumbrans.
Seven pterocarpans, erybraedin B (1), erybraedin A (2), phaseollin (3), erythrabyssin II (4), erystagallin A (5), erythrabissin-1 (6) and erycristagallin (7), two flavanones, 5-hydroxysophoranone (8) and glabrol (9), and one isoflavone, erysubin F (10), were isolated from the stems of Erythrina subumbrans (Leguminosae). Their structures were identified by means of spectroscopy. This is the first report of the isolation of the non-alkaloidal compounds from Erythrina subumbrans and the observed dehydration of 6a-hydroxypterocarpans 5 and 6 in CDCl(3) to the corresponding pterocarpenes 11 and 12, respectively. Compounds 8 and 9 were isolated for the first time from the genus Erythrina. Compounds 2 and 4 exhibited the highest degree of activity against Streptococcus strains with an MIC range of 0.78-1.56 microg/ml, whereas compound 7 exhibited the highest degree of activity against Staphylococcus strains, including drug-resistant strains (MRSA and VRSA), with an MIC range of 0.39-1.56 microg/ml. Interestingly, compounds 2, 4, 5 and 7 were more active against several strains of Streptococcus and Staphylococcus than the standard antibiotics vancomycin and oxacillin. Compound 7 showed the highest level of activity against all VRSA strains tested, with an MIC range of 0.39-1.56 microg/ml, which were resistant to both antibiotics. These compounds may prove to be potent phytochemical agents for antibacterial activity, especially against the MRSA and VRSA strains.
Rukachaisirikul
Thitima
T
Department of Chemistry, Faculty of Science, Ramkhamhaeng University, Bangkok 10240, Thailand. thitima@ram1.ru.ac.th
Innok
Phongsak
P
Aroonrerk
Nuntana
N
Boonamnuaylap
Woraluk
W
Limrangsun
Saranya
S
Boonyon
Chanakan
C
Woonjina
Umpawan
U
Suksamrarn
Apichart
A
D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification*; D024881:Drug Resistance, Bacterial; D004895:Erythrina / Q000737:chemistry*; D047309:Flavones / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D007529:Isoflavones / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D036343:Pterocarpans / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D013210:Staphylococcus / Q000187:drug effects
D000900:Anti-Bacterial Agents; D047309:Flavones; D007529:Isoflavones; D036343:Pterocarpans