Ischemic stroke is a leading cause of death and long-term disability in the world. Although many pathological aspects of mechanisms are considered to be involved in the stroke, accumulating evidences implicated that inflammation accounts for its progression and complications. Tumor necrosis factor-alpha (TNF-α) and nitric oxide are considered as key mediators produced by cells like microglia in the pathogenesis of the disease. Therefore, the development of therapies targeting at the suppression of nitric oxide and TNF-α productions may ameliorate the severity of ischemic stroke. Gastrodia and Uncaria Decoction (GUD) is a traditional herbal decoction that is commonly used in the therapy of post-ischemic stroke in China. Although it shows great efficacy in clinical treatment, few studies have been conducted to investigate the mechanisms of action of GUD. Furthermore, GUD contains a complex mixture of constituents and the effects of these compounds are unknown. In this study, individual herbs from GUD were extracted and the bioactive fractions were further separated using liquid-liquid partition, silica gel chromatography and high performance liquid chromatography (HPLC). The inhibitory effect of the extracts on lipopolysaccharide (LPS)-stimulated nitric oxide production in BV-2 microglial cells was utilized as the biological marker for the screening. After several rounds of purification, a purified bioactive compound was isolated. After spectroscopic analysis by nuclear magnetic resonance and gas chromatography-mass spectrometry, the compound was identified as genipin (1R,4aS,5,7aS-tetrahydro-1-hydroxy-7-(hydroxymethyl)-cyclopenta[c]pyran-4-carboxylic acid, methyl ester). Mechanisms of the suppressive action on signaling pathways were investigated in the LPS-activated BV-2 cells. Our results demonstrated that genipin can dose-dependently inhibit LPS-stimulated nitric oxide overproduction. It can also suppress mRNA levels and protein expressions of inducible nitric oxide synthase (iNOS) and TNF-αupon LPS-induction. In addition, the phosphorylations of phosphoinositide-3 kinase (PI3K) and protein kinase B (Akt) were suppressed. In contrast, the phosphorylations of mitogen-activated protein kinases (MAPKs), nuclear translocation of nuclear factor-κB (NF-κB) p65 and degradation of inhibitory κB-α (IκB-α) were not affected by genipin. Finally, genipin protected murine Neuro-2a neuroblast against neurotoxicity stimulated by the conditioned media transferred from LPS-challenged BV-2 cells. In conclusion, the anti-inflammatory effects of genipin are via the modulation of PI3K/Akt signaling pathway. Genipin and its synthetic analogues may have great potential for developing into new drugs in treating ischemic stroke. In addition, genipin can be used as the chemical marker to standardize the extract of Eucommia ulmoides Oliver as anti-inflammatory agents for treating inflammatory conditions associated with ischemic stroke. / published_or_final_version / Paediatrics and Adolescent Medicine / Master / Master of Philosophy

Parkinson’s disease (PD) is the second most common neurodegenerative disease affecting 2% of the population over 65 years old that lacks effective cure. The current available treatments for PD are largely symptomatic and palliative. Tianma Gouteng Yin (TGY) is a traditional Chinese medicine (TCM) formula belongs to the formulas that dispel wind. Nowadays, it has been a commonly prescribed formula to treat Parkinsonian-like symptoms such as tremor and paralysis in some of the patients. However, just as most of the TCM formula, the material basis and the underlying pharmacological effects of TGY are still lacking experimental evidence. In this study, a method using UHPLC/Q-TOF-MS and HPLC-ELSD has been developed and successfully applied to qualitatively and quantitatively determine the complex phytochemicals of TGY. Totally 28 phytochemicals were identified, of which 20 were simultaneously quantified. The material basis profile of TGY decoction was delineated for the first time. After full component analysis of TGY, the neuroprotective activity of TGY was verified both in vivo and in vitro. In Drosophila PD models, TGY mitigated rotenone induced toxicity and promoted α-synuclein clearance. In stereotaxic rotenone intoxication rats, TGY exerted neuroprotective effects in terms of preventing dopaminergic neurons loss and alleviating neuroinflammation. TGY alleviated rotenone induced apoptosis in SH-SY5Y cells. Furthermore, we discovered that Geniposide, an important component of TGY, is an autophagy inducer both in vivo and in vitro and is neuroprotective in transgenic Drosophila PD model. In general, our study proves that TGY is neuroprotective in PD models. In addition to the efficacy study, safety of TGY application in terms of TGY-drug interaction was also evaluated. In our study, herb-drug interactions between TGY and one of the most popular drugs used in PD treatment, Sinemet, were studied. The pharmacokinetics data showed that co-administration of TGY could suppress the absorption of Levodopa, the main component of Sinemet, for the first time. This information suggest that in clinical practice, TGY should avoid been administrated with Levodopa containing medicaments at the same time. In conclusion, the data of this study provides valuable information on the material basis, efficacy and safety of TGY. This information is useful reference for the clinical application of TGY in PD treatment. Keywords: Tianma Gouteng Yin, Parkinson’s disease, Drosophila, Rotenone, -synuclein, Geniposide, Autophagy, Sinemet, Herb-drug interaction

Hung, Sze Man. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 186-192). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts also in Chinese.