Thesis (PhD)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The present study employed a two-phased approach to investigate the possible mechanisms involved in the chemopreventive properties of rooibos (Aspalathus linearis) and different honeybush species (Cyclopia spp.) in vitro. In the first phase, the effect of unfermented methanol and aqueous herbal tea extracts against the growth parameters (cell viability, proliferation and apoptosis) of normal (CRL 7761); premalignant (HaCaT); and malignant (CRL 7762) skin cells was evaluated and compared to green tea extracts. The predictive potential of polyphenol content (total polyphenol and flavanol/proanthocyanidins) and antioxidant properties (ABTS; ORAC; FRAP and LPO) in the biological activity of extracts in cells was also assessed. Of the herbal teas, the methanol extract of rooibos was the most active and it inhibited the growth of skin cells presumably by inducing mitochondrial dysfunction via membrane depolarisation. At lower concentrations, this activity was associated with inhibition of cell proliferation that was selective for cancer cells whilst higher concentrations induced apoptosis that was more prominent in premalignant cells. The strong antioxidant properties of the extracts implicated the role of pro-oxidative polyphenol/iron interactions involving monomeric flavonoids and polymeric proanthocyanidins in the cytotoxic effects of rooibos. The strong relationship between total polyphenolic and flavanol/proanthocyanidins content, antioxidant properties and reduction of cell viability indicated that these parameters (polyphenols and antioxidant properties) can serve as predictive tools for the cytotoxic effects of rooibos in vitro. The aqueous extracts of honeybush species, although weaker, displayed similar effects to rooibos extracts in cells with C. genistoides being the most effective at selectively inhibiting the proliferation of cancer cells whilst the pro-apoptotic activity of C. subternata and C. intermedia was more prominent in premalignant cells. The underlying mechanisms are also likely to result from pro-oxidative mechanisms resulting from polyphenol/iron interactions that mainly involve polymeric flavanol-like proanthocyanidin compounds in honeybush. In contrast, the methanol extracts exhibited weaker cytotoxic effects and protected cancer cells from going into apoptosis. The cytoprotective effects of honeybush species are possibly mediated by the major monomeric compounds such as mangiferin and hesperidin through antioxidant mechanisms that result in reduction of oxidative stress. Due to the possible dual role of the monomeric and polymeric compounds in the honeybush extracts, the total polyphenolic content of these herbal teas may not be a good indicator of biological activity in vitro. However, as aqueous extracts displayed high flavanol/proanthocyanidins content and exceptional activity in the ABTS assay, these parameters may be considered as indicators of cytotoxicity. On the other hand, methanol extracts, particularly from the xanthone-rich species (C. genistoides and C. longifolia) which exhibited the weakest cytotoxic effects, were more active in the ORAC thus this assay may be a useful predictor for cytoprotective activity. In the second phase, an in vitro UVB/HaCaT model which used IL-1α as a biomarker for early inflammation was developed and validated with known anti-inflammatory compounds, dexamethasone and ibuprofen. It was used to determine the specific mechanisms involved in the modulatory effects of the herbal tea extracts against inflammation. Rooibos extracts and the aqueous extract of honeybush enhanced the cytotoxic effects of UVB in the model and exhibited indirect anti-inflammatory effects as they removed icIL-1α containing cells via apoptosis. In contrast, methanol extracts of honeybush exacerbated icIL-1α by protecting UVB stimulated cells from undergoing apoptosis. In conclusion, methanol extract of rooibos and aqueous extracts of honeybush species may be useful in protecting the skin after UVB exposure. These herbal tea extracts may block initiation and delay the promotion stage during skin carcinogenesis by removing premalignant cells via apoptosis and preventing onset of inflammation. In contrast, due to their cytoprotective effects, methanol extracts of honeybush may be more effective at preventing oxidative stress in skin before UVB exposure. Future studies should focus on the effects of extracts and polyphenolic fractions on the oxidative status of the cells and development of biomarkers of chemoprevention that can be utilised in vivo and in human skin. / AFRIKAANSE OPSOMMING: In hierdie studie word moontlike velkankerwerende eienskappe van rooibos (Aspalathus linearis) en ‘n aantal heuningbos (Cyclopia spp.) spesies deur twee afsonderlike benaderings bestudeer. Die eerste benadering ondersoek die effek van die kruietee op groeiparameters van velselle [lewensvatbaarheid, groei en dood van normale selle (CRL 7761), vroeë kankerselle (HaCaT) en kankerselle (CRL 7762)]. Tydens eksperimente is die moontlikheid om polifenoolinhoud (totale polifenole, en flavanol/proantosianidiene verhouding) en antioksidant-eienskappe te gebruik om die biologiese funksies van die ekstrakte in die selle te voorspel, geevalueer. Die metanolekstrak van rooibos het die groei van selle die effektiefste gestop, moontlik deur depolarisasie van die mitokondriale membraan. By lae konsentrasies van die ekstrak is die groei van kankerselle selektief gestop, terwyl vroeë kankerselle die sensitiefste by hoër konsentrasies was. Die hoë antioksidant-aktiwiteit van die rooibosekstrak kan moontlik ‘n rol speel in die indusering van sitotoksiese effekte in die selle en kan toegeskryf word aan die pro-antioksidant aktiwiteit van die polifenole weens hul interaksie met yster. ‘n Spesifieke funksie word vir die monomeriese flavonoïede en die polimeriese proantosianidiene geïmpliseer. Die sterk verwantskap tussen die totale polifenoolinhoud, flavanol/proantosianidien inhoud en antioksidant aktiwiteit met die verlaging in selgroei, maak hul relevante parameters van die voorspellingsmodel. Die waterekstrakte van heuningbos induseer ook soortgelyke maar swakker effekte met die induksie van kankersel dood, met C. genistoides die selektiefste en C. subternata en C. intermedia die aktiefste spesies wat die groei van die vroeë kanker selle inhibeer. Die onderliggende meganismes betrokke blyk ook aan ‘n pro-oksidant effek toe geskryf te wees, waartydens spesifieke polifenool/yster interaksies betrokke is. In teenstelling met rooibos, beskerm die metanolekstrak van heuningbos kankerselle teen seldood, wat moontlik verband hou met die antioksidant-eienskappe van die hoof monomeriese polifenole, mangiferien/isomangiferien en hesperidien. Vanweë die dubbele rol van die monomeriese polifenole en polimeriese verbindings in heuninghbosekstrakte is die totale polifenol inhoud nie ‘n goeie indikator van die biologiese aktiwiteit in vitro nie. Daarenteen is die flavanol/proantosianien inhoud en die hoë aktiwiteit in die ABTS antioksidanttoets goeie indikators om seldood te voorspel. In teenstelling hiermee het die metanolekstrakte van die xantoon-ryke spesies (C. genistoides en C. longifolia) ‘n baie lae effek op seldood, maar ‘n hoë aktiwitiet in die ORAC toets getoon, wat ‘n goeie rigtingwyser is om die beskermende effek in selle te voorspel. Met die tweede benadering is die anti-inflammatoriese eienskappe en die onderliggende meganismes van die kruietee ondersoek in ‘n UVB/HaCaT selmodel. Intrasellulêre interleukin 1α (IL-1α) is as merker gebruik en die model is geëvalueer deur bekende anti-inflammatoriese verbindings soos dexamethasone en ibuprofin te gebruik. Die metanolekstrak van rooibos en die waterekstrak van heuningbos het die toksiese effek van UVB in die model verhoog deur selle met verhoogde vlakke,van icIL-1α te verwyder deur middel van die induksie van seldood. Die metanolekstrak beskerm die selle teen die oksidatiewe skade wat deur UVB geïnduseer word en verwyder nie selle met hoë IL-1α vlakke nie. Ter opsomming blyk dit dat die metanolekstrak van rooibos en die waterekstrak van heuningbos moontlik gebuik kan word om die vel te beskerm teen die induksie van icIL-1α en sodoende die inisiëring van kanker te blokkeer en ook die promosie van kanker te vertraag. Die beskermende effek van die metanolekstrak kan moontlik aangewend word om die oksidatiewe skade wat deur UVB veroorsaak word teen te werk deur dit aan te wend voordat blootstelling plaasvind. Toekomstige studies behoort verdere karakterisering van die polifenoolsamestelling van die ekstrakte in te sluit en hul effek op die oksidatiewe status en anti-inflammoriese effekte van selle te bepaal ten einde sekere merkers te identifiseer vir vel studies in vivo.

Thesis MTech (Food Technology))--Cape Peninsula University of Technology, 2017. / Bambara groundnut (Vigna subterranea) an indigenous legume cultivated in Sub-Saharan Africa has been proclaimed to have medicinal properties from communities and in rural areas. However, there is not enough scientific information to validate these claims. Therefore, this study aimed to identify possible medicinal properties of Bambara groundnut (BGN), by analysing the phytochemical and antimicrobial properties of BGN seed and product extracts from Mpumalanga province within South Africa. The BGN extracts (70% methanol, 70% ethanol, milli-Q water) from seeds and products (milk and yoghurt) were screened for the presence of alkaloids, flavonoids, phenols, riboflavin and thiamine using analytical laboratory methods for basic screening, high-performance liquid chromatography (HPLC) and gas chromatography (GC) for quantification. The antimicrobial activity involved direct bioautography and minimum inhibitory concentration (MIC) against six antibiotic-resistant microorganisms, Acinetobacter baumannii ATCC 19606T, Enterococcus faecalis ATCC 29212, Klebsiella pneumoniae subsp. pneumoniae ATCC 700603, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus subsp. aureus ATCC 33591 and Candida albicans ATCC 24433. For the seed extracts, flavonoids and phenols were highly concentrated in the red and brown hulls of BGN compared to whole and dehulled BGN. Organic solvents in comparison to water yielded the highest concentration of flavonoids, whilst water yielded the highest concentration for phenols. Flavonoid compounds that were detected at the highest concentrations were rutin (24.458 ± 0.234 mg.g-1, brown hull extracted with 70% methanol), quercetin (0.070 ± 0.043 mg.g-1, red hull extracted with 70% methanol), kaempferol (0.391 ± 0.161 mg.g-1; brown hull extracted with 70% ethanol) and myricetin (1.800 ± 0.771 mg.g-1; red hull extracted with 70% methanol). For phenol compounds, gallic acid (0.009 ± 0.004 mg.g-1; brown hull extracted with milli-Q water), catechin (0.026 ± 0.041 mg.g-1; brown hull extracted with milli-Q water), methyl gallate (0.008 ± 0.013 mg.g-1; brown whole extracted with milli-Q water), chlorogenic acid (0.115 ± 0.199 mg.g-1; brown hull extracted with milli-Q water) and ellagic acid (0.105 ± 0.082 mg.g-1; red hull extracted with milli-Q water) were detected. Vitamins B1 and B2 (riboflavin and thiamine) were mostly present in milli-Q water extracts. Black-eye hull had the highest concentration of thiamine (vitamin B1) and riboflavin (vitamin B2) consisting of 0.072 mg.g-1 (extracted with milli-Q water) and 0.002 mg.g-1 (extracted with 70% ethanol and 70% methanol). Red and brown hull extracts from organic solvents (70% ethanol and 70% methanol) showed the highest antimicrobial activity, whereas the whole, dehulled and hulls (black-eye and brown-eye) extracts had no antimicrobial activity. As for BGN products extracts, flavonoid compounds that were detected at the highest concentrations were rutin (5.694 mg.g-1, whole BGN milk, milli-Q water), quercetin (0.703 mg.g-1, whole BGN yoghurt, milli-Q water) and myricetin (0.987 mg.g-1, whole BGN yoghurt, 70% ethanol).

Ampelopsis grossedentata is a wildly used herb in South China as sleep aid beverage for many years. Yet the active ingredients and mechanisms of this herb were unknown. In the present study, extract from Ampelopsis grossedentata which we named ECBRC-AG, and one of its active ingredient myricetin were proved having significant hypnotic/sedative effects in multiple animal models. ECBRC-AG shortened sleep latency, increase NREM sleep and decrease locomotor activity when treated before the onset of light period in rats. ECBRC-AG could decrease active awake and increase REM sleep in the late part of light period. ECBRC-AG also decreased the caffeine induced hyperactivity in rats. Among the three suspected active ingredients from ECBRC-AG, myricetin showed similar active profile with ECBRC-AG. Myricetin increased NREM and REM sleep, decreased sleep latency, decreased locomotor activity and also active awake. All the above evidences have implicated that myricetin is the most important active ingredient of ECBRC-AG ECBRC-AG and myricetin did not show any obvious side effects on rats. / Based on these findings, we propose that myricetin facilitates GABA function on PVN neurons through a T-type calcium channel and CaM-KII mechanism. The hypnotic/sedative effects of ECBRC-AG and myricetin are mediated by PVN. ECBRC-AG treatment decreased corticosterone levels in rats, which also indicated that PVN/HPA axis was the target of these herbal derivates. PVN has broad interactions with GABAergic, hypocretinergic, cytokine and NPY system and all these systems are proved to be deeply involved in sleep regulation. / In conclusion, the present study has identified that myricetin is the most important active ingredient of the herbal extract ECBRC-AG. We confirmed the hypnotic/sedative effects of ECBRC-AG and myricetin on rats, and also revealed the different action profiles of these herbal derivates compared with zolpidem. T-type calcium channels and the HPA axis were shown to be involved in the mechanisms of ECBRC-AG and myricetin, indicating that they may be the new targets for insomnia treatment with these herbal derivates. / Insomnia is the most common sleep disorder and affects about one third of the general population. Insomnia is always combined with physical and mental illness, as either a consequence or a contributing factor. Insomnia produces sleepiness, impairment in psychomotor performance, absenteeism, frequent accidents, memory impairment and a high risk of depression. Pharmacologic therapies are the most important interventions for insomnia. However, the currently available hypnotics are associated with residual effects and risks of abuse and dependence. More efficient and safe hypnotics are needed. / The DNA array and RT-PCR studies revealed that GABA, hypocretin, cytokine and NPY systems were involved in the mechanisms of ECBRC-AG and myricetin. In calcium imaging study, we found that myricetin induced a transient Ca 2+ influx in the primary culture of rat hypothalamus neurons. This Ca2+ influx could be blocked by T-type channel blocker mibefradil. RT-PCR study also showed that ECBRC-AG and myricetin treatment changed the mRNA expression level of T-type calcium channel al G subunit in rat hypothalamus. The present results are consistent with our previous study showing that myricetin enhanced GABA function in the neurons of rat hypothalamic paraventricular nucleus (PVN), and that blocking CaM-KII pathway eliminated this effect. / Zhang, Xiaohu. / "March 2008." / Adviser: Chan Hsiao Chang. / Source: Dissertation Abstracts International, Volume: 70-03, Section: B, page: 1516. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (p. 156-174). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Yim Wan Sze. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 95-109). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstract --- p.ii / 槪論 --- p.iv / Table of contents --- p.v / List of abbreviations --- p.xii / List of Figures --- p.xv / List of Tables --- p.xviii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Oxidation stress --- p.1 / Chapter 1.1.1 --- Free radicals --- p.2 / Chapter 1.1.1.1 --- Hydrogen peroxide --- p.3 / Chapter 1.1.1.2 --- Menadione --- p.4 / Chapter 1.1.2 --- Diseases related to oxidative stress --- p.5 / Chapter 1.1.3 --- Liver Injury --- p.5 / Chapter 1.1.4 --- Antioxidants --- p.7 / Chapter 1.1.4.1 --- Importance of antioxidant --- p.7 / Chapter 1.1.4.2 --- Examples of antioxidant --- p.7 / Chapter 1.2 --- Traditional Chinese Medicinal (TCM) formula Wu-zi-yan-zong-wan (WZ) --- p.8 / Chapter 1.2.1 --- The WZ medicinal formula --- p.8 / Chapter 1.2.2 --- Pharmacological actions of WZ --- p.9 / Chapter 1.2.3 --- Pharmacological actions of individual herbs --- p.10 / Chapter 1.2.3.1 --- Fructus Lycii --- p.10 / Chapter 1.2.3.2 --- Semen Cuscuta --- p.11 / Chapter 1.2.3.3 --- Fructus Rubi --- p.12 / Chapter 1.2.3.4 --- Semen Plantaginis --- p.12 / Chapter 1.2.3.5 --- Fructus Schisandrae --- p.13 / Chapter 1.3 --- The relationship between the liver and kidney --- p.14 / Chapter 1.4 --- Objectives of study --- p.15 / Chapter Chapter 2 --- Preparation of Aqueous Extraction of Wu-zi-yan-zong-wan --- p.17 / Chapter 2.1 --- Introduction --- p.17 / Chapter 2.2 --- Materials and Methods --- p.18 / Chapter 2.2.1 --- Preparation of Wu-zi-yan-zong-wan (WZ) --- p.18 / Chapter 2.2.1.1 --- WZ extracts from raw materials (WZ-e) --- p.18 / Chapter 2.2.1.2 --- WZ extracts from commercial available ready-to-use powders (WZ-p) --- p.20 / Chapter 2.3 --- Results --- p.22 / Chapter 2.3.1 --- Extraction Yield for WZ-e --- p.22 / Chapter Chapter 3 --- In vitro Total Antioxidant Capacity of Aqueous Extracts of Wu-zi-yan-zong-wan and its Components --- p.24 / Chapter 3.1 --- Introduction --- p.24 / Chapter 3.1.1 --- Total Antioxidants: Trolox Equavalent Antioxidant Capacity (TEAC) --- p.24 / Chapter 3.1.2 --- Objectives --- p.25 / Chapter 3.2 --- Materials and methods --- p.26 / Chapter 3.2.1 --- Materials --- p.26 / Chapter 3.2.1.1 --- Reagents --- p.26 / Chapter 3.2.1.2 --- Instruments --- p.26 / Chapter 3.2.2 --- Methods --- p.26 / Chapter 3.2.2.1 --- Total Antioxidnats: Trolox Equavalent Antioxidnat Capacity (TEAC) --- p.26 / Chapter 3.2.3 --- Statistical analysis --- p.27 / Chapter 3.3 --- Results --- p.28 / Chapter 3.3.1 --- Antioxidnat Capacity of Trolox --- p.28 / Chapter 3.3.2 --- Antioxidant capacity of WZ-e formula --- p.28 / Chapter 3.3.3 --- Antioxidant capacity of WZ-p formula --- p.28 / Chapter 3.3.4 --- The total antioxidant capacity of WZ-e and its simplified formulae --- p.32 / Chapter 3.3.5 --- The total antioxidant capacity of WZ-p and its simplified formulae --- p.32 / Chapter 3.3.6 --- Synergetic effect of WZ-e and its simplified formulae --- p.34 / Chapter 3.3.7 --- Orthogonal analysis of WZ-e and its simplified formulae on TEAC assay --- p.40 / Chapter 3.4 --- Discussion --- p.42 / Chapter Chapter 4 --- Antioxidant Activity of Aqueous Extracts of Simplified Formulae of Wu-zi-yan-zong-wan in vitro --- p.44 / Chapter 4.1 --- Introduction --- p.44 / Chapter 4.1.1 --- In vitro antioxidant --- p.44 / Chapter 4.1.2 --- Antioxidant effect of Catechins --- p.44 / Chapter 4.1.3 --- MTT assay --- p.45 / Chapter 4.1.4 --- Objectives --- p.46 / Chapter 4.2 --- Materials and methods --- p.47 / Chapter 4.2.1 --- Materials --- p.47 / Chapter 4.2.1.1 --- Cell Culture --- p.47 / Chapter 4.2.1.2 --- Reagents --- p.47 / Chapter 4.2.2 --- Methods --- p.47 / Chapter 4.2.2.1 --- Cell Culture --- p.47 / Chapter 4.2.2.2 --- MTT Cytotoxicity Assay --- p.48 / Chapter 4.2.3 --- Statistical analysis --- p.48 / Chapter 4.3 --- Results --- p.49 / Chapter 4.3.1 --- The effect of WZ-e formula on HepG2 cells --- p.49 / Chapter 4.3.2 --- The effect of hydrogen peroxide on HepG2 cells --- p.49 / Chapter 4.3.3 --- The effect of menadione on HepG2 cells --- p.52 / Chapter 4.3.4 --- The effect of catechin on HepG2 cells --- p.52 / Chapter 4.3.5 --- The effect of WZ-e and its simplified formulae against hydrogen peroxide-induced cytotoxicty on HepG2 cells --- p.55 / Chapter 4.3.6 --- The effect of WZ-e and its simplified formulae against menadione-induced cytotoxicity on HepG2 cells --- p.60 / Chapter 4.3.7 --- The effect of WZ-p on HepG2 cells --- p.65 / Chapter 4.3.8 --- The effect of WZ-p and its simplified formulae against hydrogen peroxide-induced cytotoxicity on HepG2 cells --- p.67 / Chapter 4.3.9 --- The effect of WZ-p and its simplified formulae against menadione-induced cytotoxicity on HepG2 cells --- p.72 / Chapter 4.4 --- Discussion --- p.77 / Chapter Chapter 5 --- Effect of Aqueous Extract of Wu-zi-yan-zong-wan on Menadione-induced Oxidative Damage in Mouse Liver --- p.79 / Chapter 5.1 --- Introduction --- p.79 / Chapter 5.2 --- Materials and methods --- p.81 / Chapter 5.2.1 --- Materials --- p.81 / Chapter 5.2.1.1 --- Animals --- p.81 / Chapter 5.2.1.2 --- Reagents --- p.81 / Chapter 5.2.1.3 --- Apparatus --- p.81 / Chapter 5.2.2 --- Methods --- p.82 / Chapter 5.2.2.1 --- Animal treatments --- p.82 / Chapter 5.2.2.2 --- Collection of samples --- p.82 / Chapter 5.2.2.3 --- Marker enzyme measurement (ALT) --- p.83 / Chapter 5.2.3 --- Statistical analysis --- p.83 / Chapter 5.3 --- Results --- p.84 / Chapter 5.3.1 --- Dose-dependent effect of WZ-e on menadione hepatotoxicity --- p.84 / Chapter 5.3.2 --- Dose-dependent effect of WZ-e on menadione hepatotoxicity as illustrated by histopathological observations --- p.86 / Chapter 5.3.3 --- Analyzing he effect of WZ-e and its simplified formulae on menadione-induced hepatotoxicity by Orthogonal Analysis89 --- p.89 / Chapter 5.4 --- Discussion --- p.91 / Conclusion --- p.93 / References --- p.95

Infectious diarrhoea is the second largest single cause of mortality in children under the age of five globally. Bacteria are responsible for most diarrhoeal episodes especially in developing countries, and progressive increase in antimicrobial resistance has given rise to the need to investigate other sources of therapy such as medicinal plants. Ten plant extracts were analysed for their antimicrobial activities using the agar well diffusion and broth microdilution method. Their phytochemical contents were screened, and their effect on 1, 1-diphenyl-2-picrylhydrazyl (DPPH) was used to assess their antioxidant activities. Their toxicity profiles were evaluated using the XTT Cytotoxicity Assay. Water and methanol extracts of Adansonia digitata v ABSTRACT Infectious diarrhoea is the second largest single cause of mortality in children under the age of five globally. Bacteria are responsible for most diarrhoeal episodes especially in developing countries, and progressive increase in antimicrobial resistance has given rise to the need to investigate other sources of therapy such as medicinal plants. Ten plant extracts were analysed for their antimicrobial activities using the agar well diffusion and broth microdilution method. Their phytochemical contents were screened, and their effect on 1, 1-diphenyl-2-picrylhydrazyl (DPPH) was used to assess their antioxidant activities. Their toxicity profiles were evaluated using the XTT Cytotoxicity Assay. Water and methanol extracts of Adansonia digitata seeds and pulp showed no inhibition against all the test organisms, while water and methanol extracts of A. digitata leaves showed inhibition, with minimum inhibitory concentration (MIC) ranging from 0.39 to 6.25mg/ml. Water and methanol extracts of Garcinia livingstonei and Sclerocarya birrea barks showed good activity against all the test organisms, with MICs between 0.39 and 1.56 mg/ml. Alkaloids, phenols, flavonoids, saponins, tannins, and terpenoids were found in one or more of the plant extracts, and all the plant extracts demonstrated scavenging power against DPPH.The cytotoxicity of extracts of Garcinia livingstonei, and Sclerocarya birrea barks ranged between 105.9 μg/ml and 769.9 μg/ml. The results obtained in this study validate the traditional use of A. digitata leaves, G. livingstonei and S. birrea bark in treating bacteria causing diarrhoea. / Life Sciences / M. Sc. (Life Sciences)

Colorectal cancer (CRC) is the third most prevalent and second leading causes of cancer-associated deaths globally. Over the last few decades, ent-kaurane diterpenes have been widely investigated for their anticancer potentials. Flexicaulin A (9) is a naturally occurring ent-kaurane. Previously, our lab modified the structure of 9 by replacing the C-11 hydroxyl group with carbonyl group and obtained a novel compound oxoflexicaulin A (11). However, anticancer activities and mechanistic pathway of these two compounds are yet to be explored. In the current thesis, we evaluated the cytotoxicity of compounds 9 and 11 in A549 lung, A375 melanoma, PANC1 pancreatic, HCT-116 and HT-29 colon cancer and 293T human embryonic kidney cells as well as compared the activity with a number of known natural ent-kauranes to describe their structure-activity relationship. Our study found that the presence of α, β-unsaturated ketone groups in ent-kaurane structure acted as the pharmacophore. The replacement of C-11 hydroxyl group by carbonyl in 9 (IC50: 3.68 µM) gives a novel potent anticancer compound 11 (IC50: 0.77 µM). Considering the novelty and superior activity of 11, its mechanistic pathway was studied in HCT-116 cells and compared with the natural scaffold 9. Flow cytometry analysis by Annexin V/PI staining along with fluorescent staining by DAPI showed that both compounds induced apoptosis in HCT-116 cells. Induction of apoptosis is mediated through up-regulation of tumor suppressor protein p53 and pro-apoptotic protein Bax, Bak and puma as well as promoting the cleavage of PARP while down-regulation of anti-apoptotic protein Bcl-2 and PARP. Apart from their effect on apoptosis, compounds 9 and 11 stimulated the event of senescence, a process of cellular aging, as confirmed by β-galactosidase assay. Induction of senescence is related with up-modulation of p21 and p27 while down-modulation of p16, Rb and its transcription factor E2F1. Moreover, immunofluorescence staining showed translocation of p21 and p27 from the cytoplasm to nucleus after treatment with 9 and 11. Further study found that the two ent-kauranes inhibited the protein level of two NF-κB sub-units p65 and p50 in the nucleus as well suppressed the cytoplasmic level of NF-κB inhibitor IkB-α. Both compounds also inhibited the expression and phosphorylation of STAT3 in the cytoplasm and nucleus, so as for the expression and phosphorylation of Src, an up-stream kinase of STAT3. In xenograft nude mice model, compound 11 remarkably inhibited tumor growths (volume and size) but the body weights of the mice were also reduced (p < 0. 05). Therefore, we designed to synthesis a series of prodrug analogs from 11 by adding acetal protecting group to reduce the toxicity. One of the prodrug (37) significantly attenuated the tumor volume and size (p < 0.05) at 50 mg/kg without any toxicity (p > 0.05). The prodrug 37 is actually released as compound 11 in the mice due to its cleavage in the acidic microenvironment of tumor. Taken together, antitumor effect of compound 11 in CRC model is supposed to be mediated through induction of apoptosis and senescence via modulation of NF-κB and STAT3 signaling pathway. Keywords: Colorectal cancer, ent-kaurane, flexicaulin A, oxoflexicaulin A, cytotoxicity, anticancer, apoptosis, pathway, NF-κB, STAT3.

Indiana University-Purdue University Indianapolis (IUPUI) / Enhancing osteoblast proliferation, survival, and extracellular matrix protein secretion are potential therapeutic approaches to treat bone fractures and diseases such as osteoporosis. BENS is a traditional medicine used in many countries such as India for thousands of years to treat many diseases including bone diseases. In this study, molecular, cell-based and in vivo approaches were utilized to investigate the effects of BENS on bone and cartilage regeneration. An osteosarcoma cell line (MG63) was incubated in serum free media with and without 0.8 mg/ml of BENS. BENS significantly increased cell survival up to 30 days and these cells retained their ability to proliferate in fresh media with serum. After adding BENS, there were statistically significant decreases in the expression of both anti-apoptotic and pro-apoptotic proteins. An in vivo non-critical size segmental bone defect Xenopus system was used to evaluate the ability of BENS to enhance cartilage formation. After a small segment of the anterior hemisection of the tarsus bone was excised, the frogs were divided into three groups and given subcutaneous injections of either phosphate-buffered saline or BENS once daily for 30 days and then bone/cartilage formation evaluated. The total cartilage area/total section area was significantly increased (2.6 fold) in the BENS treated samples. In an osteoporotic rat model, the anabolic properties of BENS on bone mass were assessed by histomorphometric analyses. Ovariectomized (OVX) rats received daily intraperitoneal injections for 4 weeks. Bone formation rates (BFRs) for the cortical periosteal bone surface of the midshaft tibia were 383.2, 223.9, 308.8, 304.9, and 370.9 µm3/µm2/year, and for the trabecular surface were 82.2, 113, 212.1, 157, and 165 µm3/µm2/year for the sham, OVX, PTH, 3 mg/kg BENS, and 30 mg/kg BENS groups, respectively. BENS increased both trabecular and cortical BFRs. It generated better results on cortical periosteal bone surface than did PTH. Taken together, these findings suggest that BENS promotes osteoblast survival due to its effects on altering the balance between pro-apoptotic and anti-apoptotic proteins. In addition, in vivo studies revealed that BENS enhanced cartilage formation in Xenopus and BFRs in rats. Therefore, BENS may possess anabolic bone/cartilage properties.

Hong, Sijia. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 197-234). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Colorectal cancer is the second leading cause of cancer-related mortality in Hong Kong and lack of selectivity has limited the success of conventional chemotherapy. Given the recent interest in the anti-cancer effects of traditional Chinese medicine (TCM), there are two approaches to studying its bioactivity: as a mixture of ingredients or as single compounds. The objective of the present study is to examine the anti-tumor effects of Angelicae Sinensis Radix (DG) and Garcinia hanburyi resin (TH) using both approaches, respectively, as they are traditionally used to treat inflammation. In the present study, their anti-cancer effects and the mechanisms of actions were examined for the development of potential novel chemotherapeutic drugs for colon cancer since inflammation is a predisposing factor for colon cancer. / DG extract and its three main bioactive phtbalides: n-butylidenephthalide, senkyunolide A and z-ligustilide (LGT), were found to be cytotoxic to HT-29 cells with IC50 values (24 h) of 20.70 +/- 0.85, 72.51 +/- 8.65, 18.74 +/- 1.14 and 41.98 +/- 3.64 mug/ml, respectively. The results evidenced that LGT induced G0/G 1 arrest and apoptosis, triggering cleavage of PARP, pro-caspases-3, -8 and -9 and nuclear fragmentation. LGT and cisplatin synergistically reduced the viability of HT-29 cells. More interestingly, DG extract was more potent than individual phthalides, suggesting that there are other bioactive components and/or synergistic interactions. / Individual compounds purified from TH were investigated because gambogic acid isolated from this herb has been used clinically to treat cancer, 30-Epicambogin (EPC) and guttiferone K (GUTK) showed the highest cytotoxic selectivity and potency on HT-29 cells among 15 isolated compounds. IC50 values (24 h) for EPC and GUTK in HT-29 cells were 5.36+/-0.25 and 5.39+/-0.22 muM, respectively, and both induced G0/G1 arrest by down-regulation of cyclins D1, D3, CDK4 and CDK6, while up-regulation of p21Waf1/CiP1 and p27KiP1. Both compounds triggered the activation of caspases-3, -8 and -9 in apoptosis. The in vivo anti-tumor effects of GUTK were further investigated by using a subcutaneous Colon-26 mouse tumor model. GUTK (10 mg/kg i.p.) reduced tumor volume by 33.6% and potentiated the anti-tumor effects of 5-fluorouracil when administered concurrently. / Our findings revealed that DG rather than individual phthalides, is worthy for further study as a potential anti-cancer drug, due to the synergistic interactions among multi-components in the herb. On the other hand, EPC and GUTK, isolated from TH have potential to be developed as novel anti-tumor candidates for combination use with 5-fluorouracil. The results strongly support the use of different approaches to study TCM for chemotherapy, according to its traditional and empirical use. / Subsequently, the anti-proliferative effects of DG and Chuanxiong Rhizoma (CX) extracts and mixtures containing three phthalides in the proportions similar to their presence in both extracts were examined, since CX also contains the same phthalides, but in different proportions. DG extract was significantly more potent than its corresponding phthalide mixture to inhibit cancer cell proliferation and synergistic interaction was observed among the phthalides and other bioactive components, while the phthalides in CX extract interacted antagonistically with other components. / Kan, Lai Ting Winnie. / Adviser: Ge Lin. / Source: Dissertation Abstracts International, Volume: 73-02, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 267-311). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Finally, the hepatoprotection of the 50%EtWZ was evaluated using rat model. The results indicated that the 50%EtWZ possessed potent hepatoprotective activities. The protective effect of the extract against hepatotoxicity induced by long-term treatment with ethanol might be attributed to its inhibitory action on oxidative stress. Although multiple factors could be involved in the inhibition of oxidative injury in the liver, the inhibition of CYP2E1 pathway and the enhanced GSH-related antioxidant capacity might be responsible for the protective effect. In addition, the 50%EtWZ also produced anti-inflammatory effect partly by interfering Toll-Like-Receptor-4 (TLR-4)-mediated signal pathway and reducing the production of Tumor Necrosis Factor-alpha (INF-alpha) in Kupffer cells during long-term ethanol exposure. / First, in order to determine which kind of extract possesses the strongest hepatoprotective effect on ethanol-induced cytotoxicity, various extracts were screened for cytochrome P450 2E1 isoenzyme (CYP2E1) inhibitory activity using the fluorogenic CYP2E1 substrate and HepG2 cells overexpressing human CYP2E1. The results showed that all extracts (aqueous, 50% ethanol, and 90% ethanol) of WZ produced inhibitory effect on CYP2E1. The 50% ethanol extract of WZ (50%EtWZ) displayed a stronger CYP2E1 inhibition than the aqueous and 90% ethanol extracts. The aqueous extract and 50%EtWZ showed protective effect against ethanol-induced cytotoxicity at concentrations equivalent to 100 and 1000 mug raw herb/ml. At the same concentration of 100 1.1g/ml, the 50%EtWZ exhibited a more potent protective effect. Higher degree of cytotoxicity was found in the 90% ethanol extract of WZ. Thus, 50%EtWZ was chosen for further study. / In summary, all data suggest that the inhibition of CYP2E1 pathway and the inhibition of oxidative stress by the 50%EtWZ, together with the anti-inflammatory effect on Kupffer cells, may contribute to its hepatoprotection against chronic ethanol-induced liver injury. / Second, the chemical components of the 50%EtWZ were analyzed by chromatographic fingerprints. The fingerprint revealed six hepatoprotective compounds including schisandrin B, schisandrin, deoxyschisandrin, betaine, hyperin, and quercitrin in the formula. / Third, the protective mechanism of the 50%EtWZ was investigated in E47 cells model. The 50%EtWZ protected against CYP2E1-dependent toxicity and oxidative stress induced by ethanol. The mechanism of protection involved the decrease of reactive oxygen species production and the inhibition of lipid peroxidation. The hepataprotection was associated with the maintenance of mitochondrial GSH. Pre-treating E47 cells with the 50%EtWZ significantly inhibited the expression of CYP2E1. Therefore, the protective effect of the 50%EtWZ was most likely attributed to its antioxidant activities and the inhibition of CYP2E1. In addition, the 50%EtWZ prevented ethanol-induced apoptosis and protected against oxidative damage to mitochondria which are critical for maintenance of cell viability. / Wu-Zi-Yan-Zong-Wan (WZ), a traditional medicinal formula, is used for treatment of male sexual dysfunctions. In this study, the hepatoprotection afforded by Wu-Zi-Yan-Zong-Wan treatment and its biochemical mechanism involved against chronic alcohol-induced injury were investigated. / Chen, Mengli. / "May 2008." / Adviser: Che Chun Tao. / Source: Dissertation Abstracts International, Volume: 70-03, Section: B, page: 1609. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (p. 157-179). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.