Tozatti Marcos G, Ferreira Daniele S, Flauzino Lúzio G Bocalon, Moraes Thaís da Silva, Martins Carlos H G, Groppo Milton, Andrade e Silva Márcio L, Januário Ana H, Pauletti Patricia M, Cunhaa Wilson R
Nat Prod Commun. 2016 Apr;11(4):493-6.
The antimicrobial activity and possible synergistic effects of extracts and compounds isolated from Usnea steineri were evaluated against four resistant bacterial species. A phytochemical study of the acetone extract of U. steineri resulted in the isolation and characterization of difractaic acid and (+)-usnic acid as the main compounds. The acetone extract showed strong activity (less than 10 µg/mL) against resistant strains of Staphylococcus epidermidis and Enterococcus faecalis, and (+)-usnic acid exhibited strong activity against S. epidermidis (MIC 3.12 µg/mL), S. aureus and S. haemnolyticus (MIC 12.5 µg/mL). Combinations of penicillin and tetracycline with (+)-usnic acid did not show any synergistic antimicrobial effects. Difractaic acid was inactive. Our results showed that the acetone extract of U. steineri possesses significant in vitro antimicrobial activity, which is likely related to the presence of (+)-usnic acid.
对从纤细松萝中分离得到的提取物和化合物针对四种耐药细菌的抗菌活性及可能的协同作用进行了评估。对纤细松萝丙酮提取物的植物化学研究导致分离和鉴定出二弗拉酸和（+）-松萝酸作为主要化合物。丙酮提取物对表皮葡萄球菌和粪肠球菌的耐药菌株显示出较强活性（小于10μg/mL），并且（+）-松萝酸对表皮葡萄球菌（MIC 3.12μg/mL）、金黄色葡萄球菌和溶血葡萄球菌（MIC 12.5μg/mL）表现出较强活性。青霉素和四环素与（+）-松萝酸的组合未显示出任何协同抗菌作用。二弗拉酸无活性。我们的结果表明，纤细松萝的丙酮提取物具有显著的体外抗菌活性，这可能与（+）-松萝酸的存在有关。
