Jie Liu

Bio: Jie Liu is an academic researcher from Research Triangle Park. The author has contributed to research in topics: Oleanolic acid & Ursolic acid. The author has an hindex of 1, co-authored 1 publications receiving 599 citations.

Pentacyclic triterpene distribution in various plants - rich sources for a new group of multi-potent plant extracts.

Abstract: Pentacyclic triterpenes are secondary plant metabolites widespread in fruit peel, leaves and stem bark. In particular the lupane-, oleanane-, and ursane triterpenes display various pharmacological effects while being devoid of prominent toxicity. Therefore, these triterpenes are promising leading compounds for the development of new multi-targeting bioactive agents. Screening of 39 plant materials identified triterpene rich (> 0.1% dry matter) plant parts. Plant materials with high triterpene concentrations were then used to obtain dry extracts by accelerated solvent extraction resulting in a triterpene content of 50 - 90%. Depending on the plant material, betulin (birch bark), betulinic acid (plane bark), oleanolic acid (olive leaves, olive pomace, mistletoe sprouts, clove flowers), ursolic acid (apple pomace) or an equal mixture of the three triterpene acids (rosemary leaves) are the main components of these dry extracts. They are quantitatively characterised plant extracts supplying a high concentration of actives and therefore can be used for development of phytopharmaceutical formulations.

Recent developments in anti-inflammatory natural products.

Abstract: Many of the inflammatory diseases are becoming common in aging society throughout the world. The clinically used anti-inflammatory drugs suffer from the disadvantage of side effects and high cost of treatment (in case of biologics). Alternative to these drugs are traditional medicines and natural products, which offer a great hope in the identification of bioactive lead compounds and their development into drugs for treating inflammatory diseases. Since ancient times traditional medicines and phytopharmaceuticals are being used for the treatment of inflammatory and other disorders. The present review article describes anti-inflammatory natural products derived from plants and marine sources reported during last decade. The compounds described belong to different chemical classes such as alkaloids, steroids, terpenoids, polyphenolics, phenylpropanoids, fatty acids and lipids, and various miscellaneous compounds. The attempt is also being made to enumerate the possible leads, e.g. curcumin, resveratrol, baicalein, boswellic acid, betulinic acid, ursolic acid, and oleanolic acid, for further development with the help of structure–activity relationship (SAR) studies and their current status. In addition SAR studies carried out on the anti-inflammatory activity of flavonoid compounds and clinical studies performed on anti-inflammatory natural products are also discussed. © 2009 Wiley Periodicals, Inc. Med Res Rev, 29, No. 5, 767–820, 2009

Terpenes: substances useful in human healthcare.

Abstract: Terpenes are naturally occurring substances produced by a wide variety of plants and animals. A broad range of the biological properties of terpenoids is described, including cancer chemopreventive effects, antimicrobial, antifungal, antiviral, antihyperglycemic, anti-inflammatory, and antiparasitic activities. Terpenes are also presented as skin penetration enhancers and agents involved in the prevention and therapy of several inflammatory diseases. Moreover, a potential mechanism of their action against pathogens and their influence on skin permeability are discussed. The major conclusion is that larger-scale use of terpenoids in modern medicine should be taken into consideration.

New synthetic triterpenoids: potent agents for prevention and treatment of tissue injury caused by inflammatory and oxidative stress.

Abstract: We review the original rationale for the development and the chemistry of a series of new synthetic oleanane triterpenoids (SO), based on oleanolic acid (1) as a starting material Many of the new compounds that have been made, such as 2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oic acid (“CDDO”, 8), are highly potent (activities found at levels below 1 nM) anti-inflammatory agents, as measured by their ability to block the cellular synthesis of the enzyme inducible nitric oxide synthase (iNOS) in activated macrophages Details of the organic synthesis of new SO and their chemical mechanisms of biological activity are reviewed, as is formation of biotin conjugates for investigation of protein targets Finally, we give a brief summary of important biological activities of SO in many organ systems in numerous animal models Clinical investigation of a new SO (methyl 2-cyano-3,12-dioxooleana-1,9(11)dien-28-oate, “CDDO-Me”, bardoxolone methyl, 13) is currently in progress

Terpenoids as potential chemopreventive and therapeutic agents in liver cancer.

Abstract: Despite significant advances in medicine, liver cancer, predominantly hepatocellular carcinoma remains a major cause of death in the United States as well as the rest of the world. As limited treatment options are currently available to patients with liver cancer, novel preventive control and effective therapeutic approaches are considered to be reasonable and decisive measures to combat this disease. Several naturally occurring dietary and non-dietary phytochemicals have shown enormous potential in the prevention and treatment of several cancers, especially those of the gastrointestinal tract. Terpenoids, the largest group of phytochemicals, traditionally used for medicinal purposes in India and China, are currently being explored as anticancer agents in clinical trials. Terpenoids (also called “isoprenoids”) are secondary metabolites occurring in most organisms, particularly plants. More than 40 000 individual terpenoids are known to exist in nature with new compounds being discovered every year. A large number of terpenoids exhibit cytotoxicity against a variety of tumor cells and cancer preventive as well as anticancer efficacy in preclinical animal models. This review critically examines the potential role of naturally occurring terpenoids, from diverse origins, in the chemoprevention and treatment of liver tumors. Both in vitro and in vivo effects of these agents and related cellular and molecular mechanisms are highlighted. Potential challenges and future directions involved in the advancement of these promising natural compounds in the chemoprevention and therapy of human liver cancer are also discussed.