Bak-Kwang Kim

Bio: Bak-Kwang Kim is an academic researcher from Seoul National University. The author has contributed to research in topics: Superoxide dismutase & Glutathione peroxidase. The author has an hindex of 18, co-authored 35 publications receiving 946 citations.

Anti-tumor activities of decursinol angelate and decursin from Angelica gigas

Abstract: Thein vivo anti-tumor activities of decursinol angelate (1) and decursin (2) isolated from the roots ofAngelica gigas were investigated. These two compounds, when administered consecutively for 9 days at 50 and 100 mg/kg i.p. in mice, caused a significant increase in the life span and a significant decrease in the tumor weight and volume of mice inoculated with Sarcoma-180 tumor cells. These results suggest that decursinol angelate (1) and decursin (2) fromA. gigas have anti-tumor activities.

Anti-Diabetic activities of fucosterol from Pelvetia siliquosa

Abstract: Fucosterol isolated fromPelvetia siliquosa was tested for its anti-diabetic activityin vivo. Fucosterol, when administered orally at 30 mg/kg in streptozotocin-induced diabetic rats, was caused a significant decrease in serum glucose concentrations, and exhibited an inhibition of sorbitol accumulations in the lenses. Fucosterol, when administered orally at 300 mg/kg in epinephrine-induced diabetic rats, was also caused an inhibition of blood glucose level and glycogen degradation. These results demonstrated that fucosterol is a main anti-diabetic principle from the marine algaeP. siliquosa.

Inhibitory Effects of Isorhamnetin-3-O-β- D -glucoside from Salicornia herbacea on Rat Lens Aldose Reductase and Sorbitol Accumulation in Streptozotocin-Induced Diabetic Rat Tissues

Abstract: The inhibitory effects of compounds from Salicornia herbacea (Chenopodiaceae) on rat lens aldose reductase (RLAR) and sorbitol accumulation in streptozotocin-induced diabetic rat tissues were investigated. The various fractions from the MeOH extract of S. herbacea were tested for their effects on RLAR in vitro. Among them, the EtOAc fraction was found to exhibit a potent RLAR inhibition (IC(50)=0.75 microg/ml), from which an active principle as a potent AR inhibitor was isolated and its chemical structure was elucidated as isorhamnetin-3-O-beta-D-glucoside (1) by spectral analysis. Compound 1 exhibited a potent RLAR inhibition in vitro, its IC(50) being 1.4 microM. Compound 1, when administered orally at 25 mg/kg in streptozotocin (STZ)-induced diabetic rats, caused not only a significant inhibition of serum glucose concentration but also sorbitol accumulation in the lenses, red blood cells (RBC), and sciatic nerves. These results indicate that compound 1 from S. herbacea is a leading compound for further study as a new drug for the prevention and/or treatment of diabetes and its complications.

Strategies to improve plasma half life time of peptide and protein drugs

Abstract: Due to the obvious advantages of long-acting peptide and protein drugs, strategies to prolong plasma half life time of such compounds are highly on demand. Short plasma half life times are commonly due to fast renal clearance as well as to enzymatic degradation occurring during systemic circulation. Modifications of the peptide/protein can lead to prolonged plasma half life times. By shortening the overall amino acid amount of somatostatin and replacing l-analogue amino acids with d-amino acids, plasma half life time of the derivate octreotide was 1.5 hours in comparison to only few minutes of somatostatin. A PEG2,40 K conjugate of INF-α-2b exhibited a 330-fold prolonged plasma half life time compared to the native protein. It was the aim of this review to provide an overview of possible strategies to prolong plasma half life time such as modification of N- and C-terminus or PEGylation as well as methods to evaluate the effectiveness of drug modifications. Furthermore, fundamental data about most important proteolytic enzymes of human blood, liver and kidney as well as their cleavage specificity and inhibitors for them are provided in order to predict enzymatic cleavage of peptide and protein drugs during systemic circulation.

Marine Bioactives as Functional Food Ingredients: Potential to Reduce the Incidence of Chronic Diseases

Abstract: The marine environment represents a relatively untapped source of functional ingredients that can be applied to various aspects of food processing, storage, and fortification. Moreover, numerous marine-based compounds have been identified as having diverse biological activities, with some reported to interfere with the pathogenesis of diseases. Bioactive peptides isolated from fish protein hydrolysates as well as algal fucans, galactans and alginates have been shown to possess anticoagulant, anticancer and hypocholesterolemic activities. Additionally, fish oils and marine bacteria are excellent sources of omega-3 fatty acids, while crustaceans and seaweeds contain powerful antioxidants such as carotenoids and phenolic compounds. On the basis of their bioactive properties, this review focuses on the potential use of marine-derived compounds as functional food ingredients for health maintenance and the prevention of chronic diseases.

Bioactive potential and possible health effects of edible brown seaweeds

Abstract: Marine macroalgae (seaweeds) are rich in bioactive compounds that could potentially be exploited as functional ingredients for both human and animal health applications. Despite the intensive efforts that are being made to isolate and identify new compounds with potential medicinal, health or pharmaceutical activities, very few compounds with real potency are available. Bioactive compounds that are most extensively researched include sulfated polysaccharides, phlorotannins and diterpenes. These compounds have been reported to possess strong anti-viral, anti-tumor and anti-cancer properties. At the same time, the prebiotic health potential of the polysaccharides from seaweeds is also increasingly being studied either by feeding whole seaweeds or purified polysaccharides to laboratory and farm animals. The present review discusses the pharmaceutical, health and research potential of different bioactive compounds present in brown seaweeds.

Biological activity of bee propolis in health and disease.

Abstract: Propolis is a natural product derived from plant resins collected by honeybees. It is used by bees as glue, a general-purpose sealer, and as draught-extruder for beehives. Propolis has been used in folk medicine for centuries. It is known that propolis possesses anti-microbial, antioxidative, anti-ulcer and anti-tumor activities. Therefore, propolis has attracted much attention in recent years as a useful or potential substance used in medicine and cosmetics products. Furthermore, it is now extensively used in foods and beverages with the claim that it can maintain or improve human health. The chemical composition of propolis is quite complicated. More than 300 compounds such as polyphenols, phenolic aldehydes, sequiterpene quinines, coumarins, amino acids, steroids and inorganic compounds have been identified in propolis samples. The contents depend on the collecting location, time and plant source. Consequently, biological activities of propolis gathered from different phytogeographical areas and time periods vary greatly. In this review, the activity of bee propolis will be presented with special emphasis on the antitumor activity.