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Heebyung Chai

Bio: Heebyung Chai is an academic researcher from Ohio State University. The author has contributed to research in topics: Epidermoid carcinoma & Aglaia. The author has an hindex of 42, co-authored 131 publications receiving 5892 citations. Previous affiliations of Heebyung Chai include University of Mississippi & University of Illinois at Chicago.


Papers
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Journal ArticleDOI
TL;DR: As a result of bioassay–guided fractionation, betulinic acid, a pentacyclic triterpene, was identified as a melanoma–specific cytotoxic agent and antitumour activity was mediated by the 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.

829 citations

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TL;DR: Progress made in the senior author's laboratory in research work on naturally occurring sweeteners and other taste-modifying substances and on potential anticancer agents from tropical plants will be described.
Abstract: Along with compounds from terrestrial microorganisms, the constituents of higher plants have provided a substantial number of the natural product-derived drugs used currently in Western medicine. Interest in the elucidation of new structures of the secondary metabolite constituents of plants has remained high among the natural products community over the first decade of the 21st century, particularly of species that are used in systems of traditional medicine or are utilized as botanical dietary supplements. In this review, progress made in the senior author’s laboratory in research work on naturally occurring sweeteners and other taste-modifying substances and on potential anticancer agents from tropical plants will be described.

213 citations

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TL;DR: A novel approach to formulate taxol in aqueous medium for i.v. delivery was described, and the cytotoxic activity of taxol was retained when formulated as a mixed-micellar solution.
Abstract: Taxol is a promising antitumor agent with poor water solubility. Intravenous administration of a current taxol formulation in a non-aqueous vehicle containing Cremophor EL may cause allergic reactions and precipitation upon aqueous dilution. In this study a novel approach to formulate taxol in aqueous medium for i.v. delivery is described. The drug is solubilized in bile salt (BS)/phospholipid (PC) mixed micelles. The solubilization potential of the mixed micelles increased as the total lipid concentration and the molar ratio of PC/BS increased. Precipitation of the drug upon dilution was avoided by the spontaneous formation of drug-loaded liposomes from mixed micelles. The formulation can be stored in a freeze-dried form as mixed micelles to achieve optimum stability, and liposomes can be prepared by simple dilution just before administration. As judged by a panel of cultured cell lines, the cytotoxic activity of taxol was retained when formulated as a mixed-micellar solution. Further, for the same solubilization potential, the mixed-micellar vehicle appeared to be less toxic than the standard nonaqueous vehicle of taxol containing Cremophor EL.

194 citations

Journal ArticleDOI
TL;DR: A new alkaloid (-)-amabiline was isolated from the bulbs of Crinum amabile (Amaryllidaceae), and alkaloids 2, 4, and 5 were found to be the principal cytotoxic and antimalarial constituents.
Abstract: From the bulbs of Crinum amabile (Amaryllidaceae), a new alkaloid (-)-amabiline [1], together with the known alkaloids (-)-lycorine [2], (-)-buphanisine [3], (-)-augustine [4], and (+)-crinamine [5], were isolated. The structural characterization of 1 and the revised 1H- and 13C-nmr assignments of 2 are discussed. Alkaloids 2, 4, and 5 were found to be the principal cytotoxic and antimalarial constituents.

182 citations

Journal ArticleDOI
TL;DR: Two cytotoxic rocaglate derivatives possessing an unusual dioxanyloxy unit, silvestrol and episilvestrol, were isolated from the fruits and twigs of Aglaia silvestris by bioassay-guided fractionation monitored with a human oral epidermoid carcinoma (KB) cell line.
Abstract: Two cytotoxic rocaglate derivatives possessing an unusual dioxanyloxy unit, silvestrol (1) and episilvestrol (2), were isolated from the fruits and twigs of Aglaia silvestris by bioassay-guided fractionation monitored with a human oral epidermoid carcinoma (KB) cell line. Additionally, two new baccharane-type triterpenoids, 17,24-epoxy-25-hydroxybaccharan-3-one (3) and 17,24-epoxy-25-hydroxy-3-oxobaccharan-21-oic acid (4), as well as eleven known compounds, 1β,6α-dihydroxy-4(15)-eudesmene (5), ferulic acid (6), grasshopper ketone (7), apigenin, cabraleone, chrysoeriol, 1β,4β-dihydroxy-6α,15α-epoxyeudesmane, 4-hydroxy-3-methoxyacetophenone, 4-hydroxyphenethyl alcohol, ocotillone, and β-sitosterol 3-O-β-d-glucopyranoside, were also isolated and characterized. The structures of compounds 1−4 were elucidated by spectroscopic studies and by chemical transformation. The absolute stereochemistry of silvestrol (1) was established by a X-ray diffraction study of its di-p-bromobenzoate derivative, and the structure...

180 citations


Cited by
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Journal ArticleDOI
TL;DR: Some of the recent advances in flavonoid research are reviewed and the role of anthocyanins and flavones in providing stable blue flower colours in the angiosperms is outlined.

3,465 citations

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TL;DR: An updated summary of recent advances in the field of nanomedicines and nano based drug delivery systems through comprehensive scrutiny of the discovery and application of nanomaterials in improving both the efficacy of novel and old drugs and selective diagnosis through disease marker molecules is presented.
Abstract: Nanomedicine and nano delivery systems are a relatively new but rapidly developing science where materials in the nanoscale range are employed to serve as means of diagnostic tools or to deliver therapeutic agents to specific targeted sites in a controlled manner Nanotechnology offers multiple benefits in treating chronic human diseases by site-specific, and target-oriented delivery of precise medicines Recently, there are a number of outstanding applications of the nanomedicine (chemotherapeutic agents, biological agents, immunotherapeutic agents etc) in the treatment of various diseases The current review, presents an updated summary of recent advances in the field of nanomedicines and nano based drug delivery systems through comprehensive scrutiny of the discovery and application of nanomaterials in improving both the efficacy of novel and old drugs (eg, natural products) and selective diagnosis through disease marker molecules The opportunities and challenges of nanomedicines in drug delivery from synthetic/natural sources to their clinical applications are also discussed In addition, we have included information regarding the trends and perspectives in nanomedicine area

3,112 citations

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TL;DR: A number of promising new agents are in clinical development based on selective activity against cancer-related molecular targets, including flavopiridol and combretastin A4 phosphate, while some agents which failed in earlier clinical studies are stimulating renewed interest.

1,794 citations

Journal ArticleDOI
TL;DR: While the intrinsic complexity of natural product-based drug discovery necessitates highly integrated interdisciplinary approaches, the reviewed scientific developments, recent technological advances, and research trends clearly indicate that natural products will be among the most important sources of new drugs in the future.

1,760 citations

Journal ArticleDOI
TL;DR: This review covers the isolation, structure determination, synthesis and biological activity of quinoline, quinazoline and acridone alkaloids from plant, microbial and animal sources.

1,687 citations