Kuo Hsiung Lee

Bio: Kuo Hsiung Lee is an academic researcher from University of North Carolina at Chapel Hill. The author has contributed to research in topics: Cytotoxicity & Topoisomerase. The author has an hindex of 81, co-authored 875 publications receiving 29359 citations. Previous affiliations of Kuo Hsiung Lee include Providence University & China Medical University (PRC).

Rational selection of training and test sets for the development of validated QSAR models.

Abstract: Quantitative Structure–Activity Relationship (QSAR) models are used increasingly to screen chemical databases and/or virtual chemical libraries for potentially bioactive molecules. These developments emphasize the importance of rigorous model validation to ensure that the models have acceptable predictive power. Using k nearest neighbors (kNN) variable selection QSAR method for the analysis of several datasets, we have demonstrated recently that the widely accepted leave-one-out (LOO) cross-validated R2 (q2) is an inadequate characteristic to assess the predictive ability of the models [Golbraikh, A., Tropsha, A. Beware of q2! J. Mol. Graphics Mod. 20, 269-276, (2002)]. Herein, we provide additional evidence that there exists no correlation between the values of q2 for the training set and accuracy of prediction (R2) for the test set and argue that this observation is a general property of any QSAR model developed with LOO cross-validation. We suggest that external validation using rationally selected training and test sets provides a means to establish a reliable QSAR model. We propose several approaches to the division of experimental datasets into training and test sets and apply them in QSAR studies of 48 functionalized amino acid anticonvulsants and a series of 157 epipodophyllotoxin derivatives with antitumor activity. We formulate a set of general criteria for the evaluation of predictive power of QSAR models.

New developments in the chemistry and biology of the bioactive constituents of Tanshen.

Abstract: Tanshen, the rhizome of Salvia miltiorrhiza Bunge, has been used in Chinese traditional medicine (TCM) for multiple therapeutic remedies The major constituents of Tanshen include water-soluble phenolic acids and lipophilic tanshinones Phenolic acids possess antioxidant and anticoagulant activities, whereas tanshinones show antibacterial, antioxidant, and antineoplastic activities This review will focus on recent developments concerning the chemical constituents of Tanshen and their biological activities These chemical and biological studies continue to increase our understanding about a scientific basis for the traditional clinical use of Tanshen and can also contribute to the development of new drug candidates Recently, in the author's laboratory, a new compound, neo-tanshinlactone, was discovered to have potent selective antibreast cancer activity This compound might serve as a lead for developing promising antibreast cancer clinical trials candidates © 2006 Wiley Periodicals, Inc Med Res Rev, 27, No 1, 133–148, 2007

Anti-AIDS agents, 11. Betulinic acid and platanic acid as anti-HIV principles from Syzigium claviflorum, and the anti-HIV activity of structurally related triterpenoids.

Abstract: Betulinic acid [1] and platanic acid [2], isolated from the leaves of Syzigium claviflorum, were found to be inhibitors of HIV replication in H9 lymphocyte cells. Evaluation of anti-HIV activity wich eight derivatives of 1 revealed that dihydrobetulinic acid [3] was also a potent inhibitor of HIV replication. The C-3 hydroxy group and C-17 carboxylic acid group, as well as the C-19 substituents, contribute to enhanced anti-HIV activity. The inhibitory activity of these compounds against protein kinase C (PKC) was also examined, since a correlation between anti-HIV and anti-PKC activities has been suggested. However, there was no apparent correlation between anti-HIV activity and the inhibition of PKC among these compounds

Recent progress in the development of coumarin derivatives as potent anti‐HIV agents

Abstract: Numerous plant-derived compounds have been evaluated for inhibitory effects against HIV replication, and some coumarins have been found to inhibit different stages in the HIV replication cycle. This review article describes recent progress in the discovery, structure modification, and structure-activity relationship studies of potent anti-HIV coumarin derivatives. A dicamphanoyl-khellactone (DCK) analog, which was discovered and developed in our laboratory, and calanolide A are currently in preclinical studies and clinical trials, respectively.

6-Alkylamino- and 2,3-dihydro-3'-methoxy-2-phenyl-4-quinazolinones and related compounds: their synthesis, cytotoxicity, and inhibition of tubulin polymerization.

Abstract: As part of our continuing search for potential anticancer candidates among 2-phenyl-4-quinolones and 2-phenyl-4-quinazolinones, two series of 6,7,2‘,3‘,4‘,5‘-substituted 2-phenyl-4-quinazolinones a...

Plant Products as Antimicrobial Agents

Abstract: The use of and search for drugs and dietary supplements derived from plants have accelerated in recent years. Ethnopharmacologists, botanists, microbiologists, and natural-products chemists are combing the Earth for phytochemicals and “leads” which could be developed for treatment of infectious diseases. While 25 to 50% of current pharmaceuticals are derived from plants, none are used as antimicrobials. Traditional healers have long used plants to prevent or cure infectious conditions; Western medicine is trying to duplicate their successes. Plants are rich in a wide variety of secondary metabolites, such as tannins, terpenoids, alkaloids, and flavonoids, which have been found in vitro to have antimicrobial properties. This review attempts to summarize the current status of botanical screening efforts, as well as in vivo studies of their effectiveness and toxicity. The structure and antimicrobial properties of phytochemicals are also addressed. Since many of these compounds are currently available as unregulated botanical preparations and their use by the public is increasing rapidly, clinicians need to consider the consequences of patients self-medicating with these preparations.

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.