Shin Ho Lee

Bio: Shin Ho Lee is an academic researcher from Catholic University of Daegu. The author has contributed to research in topics: Antibacterial activity & Lactic acid. The author has an hindex of 5, co-authored 5 publications receiving 1452 citations.

Antibacterial activity of chitosans with different degrees of deacetylation and viscosities

Abstract: Summary Antibacterial activities of six acid-soluble [two degrees of deacetylation (DD) × three viscosities] and two water-soluble chitosans (two DD with similar viscosities) were examined against eight gram-negative (Pseudomonas fluorescens, Proteus vulgaris, Erwinia carotovora, Serratia marcescens, Escherichia coli, Vibrio parahaemolyticus, V. vulnificus, and Salmonella Typhimurium) and six gram-positive bacteria (Listeria monocytogenes, Staphylococcus aureus, Bacillus subtilis, B. cereus, Lactobacillus curvatus, and L. plantarum). Antibacterial activities of chitosans differed depending on the chitosan types and bacteria tested. Water-soluble chitosans inhibited bacterial growth by one to eight log cycles at 0.1% concentration; however, the effects were much lesser than those observed with 0.05% acid-soluble chitosans. Minimum inhibitory concentration (MIC) values (0.03% to above 0.1%) of acid-soluble chitosans were much lower than those (0.05% to above 0.8%) of water-soluble chitosans. Based on MIC values, the acid-soluble chitosan with 99% DD and lower viscosity (17.9 mPa s) was most effective in inhibiting bacteria growth among eight chitosans tested.

Antioxidant Activity and Isoflavone Profile of Rhynchosia nolubilis Seeds Pickled in Vinegar (Chokong)

Abstract: The antioxidant activity and isoflavone content of chokong, Rhynchosia nolubilis seeds pickled in vinegar at 4℃ for 2 weeks, were investigated. The polyphenol content and 2,2-diphenyl-1-pycrylhydrazyl (DPPH) radical-scavenging capacity were lower in chokong than in raw seeds. Based on isoflavone analysis, the aglycone (daidzein and genistein) content was high in chokong while the content of the corresponding glucosides (daidzin and genistin) was similar to that in raw seeds. Thermal processing, in which seeds were heated in vinegar at 121℃ for 20 min, reduced the polyphenol content but did not affect the DPPH radical-scavenging capacity compared to the pickling process. The heated seeds had a 2.6 to 2.7 times higher glucoside content and 51 to 55% lower aglycone content than chokong, depending on the kind of vinegar used. During pickling and thermal processing, vinegars were more effective at eluting antioxidants and isoflavones from seeds than other solutions such as acetic, citric acid and HCL solutions, distilled water, and phosphate buffer (pH 7.0).

Inhibition of Lipid Accumulation in 3T3-L1 Adipocytes by Extract of Chokong, Rhynchosia nolubilis Seeds Pickled in Vinegar

Abstract: The anti-obesity effect of chokong, Rhynchosia nolubilis seeds pickled in vinegars for 2 weeks at 4℃, was investigated. During the differentiation of 3T3-L1 adipocytes, the addition of ethanolic extracts of chokongs lowered the cellular triglyceride content by 8.1-9.0%, and glucose content by 12.2-27.6%, depending on the kinds of vinegar used. The activity of glycerol-3-phosphate dehydrogenase also decreased up to 56.0-59.3% by supplying those extracts. In addition, vinegars were superior to acetic acid, citric acid, and hydrochloric acid solutions, and distilled water in anti-obesity of the pickled seeds.

Chitin and Chitosan Preparation from Marine Sources. Structure, Properties and Applications

Abstract: This review describes the most common methods for recovery of chitin from marine organisms. In depth, both enzymatic and chemical treatments for the step of deproteinization are compared, as well as different conditions for demineralization. The conditions of chitosan preparation are also discussed, since they significantly impact the synthesis of chitosan with varying degree of acetylation (DA) and molecular weight (MW). In addition, the main characterization techniques applied for chitin and chitosan are recalled, pointing out the role of their solubility in relation with the chemical structure (mainly the acetyl group distribution along the backbone). Biological activities are also presented, such as: antibacterial, antifungal, antitumor and antioxidant. Interestingly, the relationship between chemical structure and biological activity is demonstrated for chitosan molecules with different DA and MW and homogeneous distribution of acetyl groups for the first time. In the end, several selected pharmaceutical and biomedical applications are presented, in which chitin and chitosan are recognized as new biomaterials taking advantage of their biocompatibility and biodegradability.