Antimicrobial and Anticorrosion Activity of a Novel Composite Biocide against Mixed Bacterial Strains in Taiwanese Marine Environments.

Taiwan is an island with a humid subtropical climate. The relatively warm seawater results in biofouling of the surfaces of marine facilities. Biocide application is a common practice for combating and eliminating adhesive fouling. However, a single type of biocide may have limited antimicrobial effects due to the relatively high microbial diversity in marine environments. Therefore, applying a mixture of various biocides may be necessary. In this study, the antimicrobial and anticorrosion properties of a newly designed composite biocide, namely a combination of thymol and benzyldimethyldodecylammonium chloride, were investigated by applying the biocide to 304 stainless steel substrates immersed in inocula containing bacterial strains from Tamsui and Zuoying harbors. The ability of 3TB and 5TB treatments to prevent sessile cells and biofilm formation on the 304 stainless steel coupon surface was determined through scanning electron microscopy investigation. In addition, confocal laser scanning microscopy indicated that the 5TB treatment achieved a greater bactericidal effect in both the Tamsui and Zuoying inocula. Moreover, electrochemical impedance spectroscopy revealed that the diameter of the Nyquist semicircle was almost completely unaffected by Tamsui or Zuoying under the 5TB treatment. Through these assessments of antimicrobial activity and corrosion resistance, 5TB treatment was demonstrated to have superior bactericidal activity against mixed strains in both southern and northern Taiwanese marine environments.

Antioxidant and Anti-Inflammatory Phenolic Glycosides from Clematis tashiroi.

From the 95% EtOH extract of dried aerial parts of Clematis tashiroi, eight new and four known phenolic (caffeic acid, coumaric acid, ferrulic acid) glycosides were isolated and characterized. The structures of the new isolates (clematisides A-H) were elucidated by spectroscopic data interpretation as trans-4-O-(6-O-trans-caffeoyl-ß-D- glucopyranosyl)-9-O-ß-D-glucopyranosyl caffeic acid (1), trans-4-O-(6-O-trans-feruloyl-ß-D-glucopyranosyll)-9-O-ß-D-glucopyranosyl caffeic acid (2), trans-4-O-(6-O-trans-p-coumaroyl-ß-D-glucopyranosyl)-9-O-ß-D-glucopyranosyl caffeic acid (3), trans-4-O-(6-O-trans-caffeoyl-ß-D-glucopyranosyl)-9-O-ß-D-glucopyranosyl p-coumaric acid (4), trans-3-O-(6-O-trans-caffeoyl-ß-D-glucopyranosyl)-9-O-ß-D-glucopyranosyl caffeic acid (5), trans-3-O-(6-O-trans-p-coumaroyl-ß-D-glucopyranosyl)-9-O-ß-D-glucopyranosyl caffeic acid (6), 6-(3',4'-dihydroxystyryl)-2-pyrone-4-O-(6-O-trans-caffeoyl)-ß-D-glucopyranoside (7), and 6-(3',4'-dihydroxystyryl)-2-pyrone-4-O-{6-O-[4-O-(6-O-trans-caffeoyl)-ß-D-glucopyranosyl]-trans-caffeoyl}-ß-D-glucopyranoside (8), respectively. In a DPPH radical-scavenging test, compounds 1, 7, and 8 showed more potent antioxidant activity than that of the positive control, vitamin E. In addition, compound 7 also showed inhibitory activity in an antinitric oxide release assay.