Ik-Soo Lee

Bio: Ik-Soo Lee is an academic researcher from Chonnam National University. The author has contributed to research in topics: Medicine & Chemistry. The author has an hindex of 32, co-authored 142 publications receiving 3653 citations. Previous affiliations of Ik-Soo Lee include University of Mississippi & DePaul University.

Discovery of betulinic acid as a selective inhibitor of human melanoma that functions by induction of apoptosis

Abstract: As a result of bioassay-guided fractionation, betulinic acid, a pentacyclic triterpene, was identified as a melanoma-specific cytotoxic agent. In follow-up studies conducted with athymic mice carrying human melanomas, tumour growth was completely inhibited without toxicity. As judged by a variety of cellular responses, antitumour activity was mediated by the induction of apoptosis. Betulinic acid is inexpensive and available in abundant supply from common natural sources, notably the bark of white birch trees. The compound is currently undergoing preclinical development for the treatment or prevention of malignant melanoma.

Antioxidant flavone glycosides from the leaves of Sasa borealis

Abstract: Sasa borealis (Poaceae) is a perennial medicinal plant which is a major source of bamboo leaves in Korea. The n-BuOH extract of S. borealis leaves exhibited significant antioxidant activity against the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and a cytoprotective effect against oxidative damage in HepG2 cells. Bioactivity-guided fractionation by column chromatography led to the isolation of two antioxidative flavonoid C-glycoside derivatives, isoorientin (2) and isoorientin 2"-O-alpha-L-rhamnoside (4) along with tricin 7-O-beta-D-glucopyranoside (1) and apigenin 6-C-beta-D-xylopyranosyl-8-C-beta-D-glucopyranoside (3). Their structures were identified on the basis of chemical and spectroscopic methods. The radical scavenging activity and cytoprotective effect against oxidative damage of all the isolated compounds were also evaluated. Isoorientin (2) and isoorientin 2-O-alpha-L-rhamnoside (4) showed potent free radical scavenging activity with IC50 values of 9.5 and 34.5 microM, respectively, and strong cytoprotective effects against t-BOOH-induced oxidative damage in HepG2 cells, at very low concentrations of 1.1 microM isoorientin and 0.8 microM isoorientin 2-O-alpha-L-rhamnoside. This is the first report of the isolation and antioxidant activity of compounds 2 and 4 from S. borealis.

The Effects of Plant Flavonoids on Mammalian Cells:Implications for Inflammation, Heart Disease, and Cancer

Abstract: Flavonoids are nearly ubiquitous in plants and are recognized as the pigments responsible for the colors of leaves, especially in autumn. They are rich in seeds, citrus fruits, olive oil, tea, and red wine. They are low molecular weight compounds composed of a three-ring structure with various substitutions. This basic structure is shared by tocopherols (vitamin E). Flavonoids can be subdivided according to the presence of an oxy group at position 4, a double bond between carbon atoms 2 and 3, or a hydroxyl group in position 3 of the C (middle) ring. These characteristics appear to also be required for best activity, especially antioxidant and antiproliferative, in the systems studied. The particular hydroxylation pattern of the B ring of the flavonoles increases their activities, especially in inhibition of mast cell secretion. Certain plants and spices containing flavonoids have been used for thousands of years in traditional Eastern medicine. In spite of the voluminous literature available, however, Western medicine has not yet used flavonoids therapeutically, even though their safety record is exceptional. Suggestions are made where such possibilities may be worth pursuing.

The functions and regulation of glutathione s-transferases in plants.

Abstract: ▪ Abstract Glutathione S-transferases (GSTs) play roles in both normal cellular metabolism as well as in the detoxification of a wide variety of xenobiotic compounds, and they have been intensively studied with regard to herbicide detoxification in plants. A newly discovered plant GST subclass has been implicated in numerous stress responses, including those arising from pathogen attack, oxidative stress, and heavy-metal toxicity. In addition, plant GSTs play a role in the cellular response to auxins and during the normal metabolism of plant secondary products like anthocyanins and cinnamic acid. This review presents the current knowledge about the functions of GSTs in regard to both herbicides and endogenous substrates. The catalytic mechanism of GST activity as well as the fate of glutathione S-conjugates are reviewed. Finally, a summary of what is known about the gene structure and regulation of plant GSTs is presented.

A review on the dietary flavonoid kaempferol.

Abstract: Epidemiological studies have revealed that a diet rich in plant-derived foods has a protective effect on human health. Identifying bioactive dietary constituents is an active area of scientific investigation that may lead to new drug discovery. Kaempferol (3,5,7-trihydroxy-2-(4-hydroxyphenyl)-4H-1-benzopyran-4-one) is a flavonoid found in many edible plants (e.g. tea, broccoli, cabbage, kale, beans, endive, leek, tomato, strawberries and grapes) and in plants or botanical products commonly used in traditional medicine (e.g. Ginkgo biloba, Tilia spp, Equisetum spp, Moringa oleifera, Sophora japonica and propolis). Some epidemiological studies have found a positive association between the consumption of foods containing kaempferol and a reduced risk of developing several disorders such as cancer and cardiovascular diseases. Numerous preclinical studies have shown that kaempferol and some glycosides of kaempferol have a wide range of pharmacological activities, including antioxidant, anti-inflammatory, antimicrobial, anticancer, cardioprotective, neuroprotective, antidiabetic, anti-osteoporotic, estrogenic/antiestrogenic, anxiolytic, analgesic and antiallergic activities. In this article, the distribution of kaempferol in the plant kingdom and its pharmacological properties are reviewed. The pharmacokinetics (e.g. oral bioavailability, metabolism, plasma levels) and safety of kaempferol are also analyzed. This information may help understand the health benefits of kaempferol-containing plants and may contribute to develop this flavonoid as a possible agent for the prevention and treatment of some diseases.