Yeon-Sil Lee

Bio: Yeon-Sil Lee is an academic researcher. The author has contributed to research in topics: Aldose reductase & Uncompetitive inhibitor. The author has an hindex of 5, co-authored 10 publications receiving 121 citations.

Antioxidant Activities of Decursinol Angelate and Decursin from Angelica gigas Roots

Abstract: The anti-oxidant activities of decursinol angelate (1) and decursin (2) isolated from Angelica gigas were investigated These two coumarins exhibited decrease in serum transaminase activities elevated by hepatic damage induced by in rats They also showed increase in anti-oxidant enzyme such as hepatic cytosolic superoxide dismutase (SOD), catalase, and glutathione peroxidase (GSH-px) in rats These results suggest that decursinol angelate (1) and decursin (2) from A gigas possess not only the anti-oxidant, but also the hepatoprotective activities in rats

Comparison of the Anti-inflammatory Effects of the Extracts from Rubus coreanus and Rubus occidentalis

Abstract: The dried fruit of the Rubus coreanus, which is well-known in Korea and referred to as 'Bokbunja,' has been employed as a traditional medicine for centuries. This crude drug has been utilized in Korea for the management of impotence, spermatorrhea, enuresis, asthma, and allergic diseases. Our previous study demonstrated that the ethanol extracts of R. coreanus have anti-inflammatory effects. The principal objective of the present study was to conduct a comparison of the anti-inflammatory effects of the ethanol extracts of R. coreanus and R. occidentalis; here, we tested the unripe (URCE), half-ripened (HRCE), and ripened fruits (RCE) of R. coreanus, and the unripe (UROE), half-ripened (HROE), and ripened fruits (ROE) of R. occidentalis. We found that URCE, UROE, HRCE, and HROE reduced the production of nitric oxide and prostaglandin as well as pro-inflammatory cytokines in lipopolysaccharide-stimulated RAW264.7 murine macrophages. Interestingly, the R. coreanus extracts showed stronger inhibitory effects on the production of these inflammatory mediators than the R. occidentalis extracts.

Antitumor and Immunostimulating Activities of Acanthopanax sessiliflorus Fruits

Abstract: The antitumor and immunostimulating activities of Acanthopanax sessiliflorus fruits were investigated. Polysaccharide isolated from this plant, 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 in mice inoculated with Sarcoma-180 tumor cells. Polysaccharide was also demonstrated to exhibit phagocytosis-enhancing activity as measured by the carbon clearance in mice. Polysaccharide, when administered i.p. at 50 and 100 mg/kg/day for 3 consecutive days, exhibited a significant RCtr/RCc [the rate of regression coefficient of the animals teated (RCtr) to that of the control (RCc)], being 1.44 (PI = 1), 1.52 (PI = 2) which was approximately the same with that of enhancement of phagocytosis, its potency as expressed by the regression coefficient ratio of zymosan (RCtr/RCc = 1.55, PI = 2), a typical phagocytosis enhancer. Polysaccharide also caused a significant increase in the acid phosphatase activity representing lysosomal enzymes in macrophages at 1-100 ig/ml in vitro in compliance with in vivo results. These results suggest that the antitumor activity of polysaccharide might be related to the immunostimulating function.

Hyperin, An Aldose Reductase Inhibitor from Acanthopanax senticosus Leaves

Abstract: Hyperin from the leaves of Acanthopanax senticosus was tested for its effect on rat lens aldose reductase and demonstrated to exhibit a significant inhibition of rat lens aldose reductase activity with value of .

Inhibitory Effect of quercetin-3-O-$\alpha$-L-rhamnopyranoside from Chamaecyparis obtuse on Aldose Reductase and Sorbitol Accumulation

Abstract: Taxifolin-3-O--D-xylopyranoside and quercetin-3-O--L-rhamnopyranoside were isolated from an EtOAc-soluble extract of the leaves of Chamaecyparis obtuse. Quercetin-3-O--L-rhamnopyranoside was found to possess a potent inhibitory activity of human recombinant aldose reductase in vitro, its value being . Kinetic analysis showed that quercetin-3-O--L-rhamnopyranoside exhibited uncompetitive inhibition against DL-glyceraldehyde. Also, quercetin-3-O--L-rhamnopyranoside suppresses sorbitol accumulation in rat lens under high glucose conditions, demonstrating the potential to prevent sorbitol accumulation in vivo. These results suggest that this compound may be a promising agent in the prevention or treatment of diabetic complications.

A novel anticancer agent, decursin, induces G1 arrest and apoptosis in human prostate carcinoma cells.

Abstract: We isolated a coumarin compound decursin (C(19)H(20)O(5); molecular weight 328) from Korean angelica (Angelica gigas) root and characterized it by spectroscopy. Here, for the first time, we observed that decursin (25-100 micromol/L) treatment for 24 to 96 hours strongly inhibits growth and induces death in human prostate carcinoma DU145, PC-3, and LNCaP cells. Furthermore, we observed that decursinol [where (CH(3))(2)-C=CH-COO- side chain of decursin is substituted with -OH] has much lower effects compared with decursin, suggesting a possible structure-activity relationship. Decursin-induced growth inhibition was associated with a strong G(1) arrest (P < 0.001) in DU145 and LNCaP cells, and G(1), S as well as G(2)-M arrests depending upon doses and treatment times in PC-3 cells. Comparatively, decursin was nontoxic to human prostate epithelial PWR-1E cells and showed only moderate growth inhibition and G(1) arrest. Consistent with G(1) arrest in DU145 cells, decursin strongly increased protein levels of Cip1/p21 but showed a moderate increase in Kip1/p27 with a decrease in cyclin-dependent kinases (CDK); CDK2, CDK4, CDK6, and cyclin D1, and inhibited CDK2, CDK4, CDK6, cyclin D1, and cyclin E kinase activity, and increased binding of CDK inhibitor (CDKI) with CDK. Decursin-caused cell death was associated with an increase in apoptosis (P < 0.05-0.001) and cleaved caspase-9, caspase-3, and poly(ADP-ribose) polymerase; however, pretreatment with all-caspases inhibitor (z-VAD-fmk) only partially reversed decursin-induced apoptosis, suggesting the involvement of both caspase-dependent and caspase-independent pathways. These findings suggest the novel anticancer efficacy of decursin mediated via induction of cell cycle arrest and apoptosis selectively in human prostate carcinoma cells.

Angiotensin-converting enzyme I inhibitory activity of phlorotannins from Ecklonia stolonifera

Abstract: As part of our study of the isolation of antihypertensive agents derived from natural marine products, the bioactivity of 10 edible Korean seaweeds were screened by angiotensin converting enzyme (ACE) inhibitory and peroxynitrite assays. Among the crude extracts of selected sea-weeds, including five Phaeophyta (Ecklonia stolonifera, E. cava, Pelvetia siliquosa, Hizikia fusiforme, and Undaria pinnatifida), four Rhodophyta (Gigartina tenella, Gelidium amansii, Chondria crassicaulis, and Porphyra tenera) and one Chlorophyta (Capsosiphon fulvescens), the ethanol extracts of E. stolonifera, E. cava, P. siliquosa, U. pinnatifida, and G. tenella exhibited significant inhibitory properties against ACE at more than 50% inhibition at a concentration of 163.93 μg/mL. Phloroglucinol 1, eckstolonol 2, eckol 3, phlorofucofuroeckol A 4, and dieckol 5 had been isolated previously, and triphlorethol-A 6 and fucosterol 7 were isolated for the first time from E. stolonifera. Also, the ACE inhibitory and peroxynitrite scavenging properties of phlorotannins 1–6 were evaluated, along with fucosterol 7 obtained from E. stolonifera. Among profound peroxynitrite scavenging compounds 1–6, phlorotannins 3, 4 and 5 were also determined to manifest marked inhibitory activity against ACE, with 50% inhibition concentration (IC50) values of 70.82±0.25, 12.74¯0.15, and 34.25±3.56 μM, respectively.