Flavonoids, present in fruits, vegetables and beverages derived from plants, have been described as health-promoting, disease-preventing dietary supplements, and have activity as cancer preventive agents. The cancer protective effects of flavonoids have been attributed to a wide variety of mechanisms, including modulating enzyme activities resulting in the decreased carcinogenicity of xenobiotics. Cytochrome P4501A1 (CYP1A1) is a Phase I enzyme which is known to be involved in the activation of procarcinogens and Glutathione S-Transferase (GST) is a Phase II enzyme which is largely responsible for the detoxification of carcinogens. In this study, it was aimed to investigate the mechanisms of inhibition of CYP1A1 and GST activities of fish by phenolic compounds/flavonoids. Leaping mullet (Liza saliens), captured from highly polluted sites of izmir Bay, expressing high levels of CYP1A, were used in order to investigate these effects. It was demonstrated that all of the phenolic compounds/flavonoids used, exert an inhibitory effect on both CYP1A1 associated 7-Ethoxyresorufin-O-deethylase (EROD) activity and GST activities of fish, although the degree of inhibition was varied with the flavonoid used. Of the flavonoids tested, the most potent inhibitor of CYP1A1 associated EROD activity was found to be quercetin. The potency of the phenolic compounds/flavonoids to inhibit CYP1A1 associated EROD activity follow the sequence of quercetin &gt / resveratrol &gt / naringenin &gt / hesperidin &gt / rutin with IC50 values of 1.32 &micro / M, 3.59 &micro / M, 9.78 &micro / M, 98.5 &micro / M and 0.64 mM respectively. Quercetin, resveratrol, hesperidin and rutin were found to inhibit EROD activity in a competitive manner, on the other hand, naringenin was found to inhibit EROD activity in a non-competitive manner. Inhibition constant (Ki) values of quercetin, resveratrol, naringenin, hesperidin and rutin were calculated from Dixon plots as 0.12 &micro / M, 0.67 &micro / M, 2.63 &micro / M, 18 &micro / M and 0.1 mM, respectively. In the case of GST enzyme, it was demonstrated that all of the phenolic compounds/flavonoids used, exert an inhibitory effect on both total GST and GST-Mu activities of fish. Of the flavonoids tested, the most effective inhibitor of total GST activity was found to be resveratrol. The potency of the phenolic compounds/flavonoids to inhibit total GST activity follow the sequence of resveratrol &gt / quercetin &gt / rutin &gt / naringenin &gt / hesperidin with IC50 values of 7.1 &micro / M, 24.5 &micro / M, 89 &micro / M, 116 &micro / M and 118 &micro / M respectively. Resveratrol, quercetin and hesperidin were found to inhibit total GST activity in a competitive manner, on the other hand, rutin and naringenin were found to inhibit GST activity in a mixed type manner. Ki values of resveratrol, quercetin, hesperidin, naringenin and rutin were calculated from Dixon plots as 3.2 &micro / M, 12.5 &micro / M, 45 &micro / M, 128 &micro / M and 150 &micro / M respectively. In the case of GST-Mu activity, the most potent inhibitor was found to be rutin. The potency of the phenolic compounds/flavonoids to inhibit GST-Mu activity follow the sequence of rutin &gt / resveratrol &gt / quercetin &gt / naringenin &gt / hesperidin with IC50 values of 66.5 &micro / M, 72.3 &micro / M, 113.5 &micro / M, 135.5 &micro / M and 196 &micro / M, respectively. In conclusion, this study indicated that flavonoids were the strong inhibitors of CYP1A1 associated EROD activity and GST activities of mullet liver. The modulation of drug-metabolizing enzymes by flavonoids is important in terms of human health, since these enzymes can activate or inactivate carcinogens. The potential role of xenobiotic metabolizers CYP1 family in the activation of carcinogens and inactivation of chemotherapeutics suggests a potential therapeutic benefits in inhibiting these enzymes. The results of the present study support the hypothesis that flavonoids may be involved in the prevention of malignant transformation, by reducing the formation of carcinogens through inhibition of enzymes such as CYP1A1 which is known to be involved in carcinogen activation.

Four in vitro models were used to measure the antioxidant activity of 11 citrus phytochemicals. The citrus limonoids and bergapten showed very weak antioxidant activity. The flavonoids demonstrated mild, to moderate, to strong antioxidant activity. In addition to some other commonly accepted structural features our data indicated that the hydroxyl group in position 6 of ring A could also increase the antioxidant activity of flavonoids. Compared with the active flavonoids, limonoids are highly oxygenated triterpenoids, with fewer hydroxyl groups to stabilize unpaired electrons (or scavenge free radicals). Bergapten lacks a hydroxyl group. This is the first report on the antioxidant activity of limonoids and neoeriocitrin. A feeding study using Syrian hamsters was followed to determine the effect of citrus limonoids and flavonoids on plasma cholesterol. Hamsters fed with limonin, limonin 17-Beta-D-glucopyranoside and grapefruit pulp significantly inhibited the increase of LDL/HDL-cholesterol (36.6%, 52.9% and 57% respectively) compared with the basal control (65.8%) and the pectin control (70%). Furthermore, hamsters fed with limonin had significantly larger LDL particle size (21.21 nm) compared with the control group (19.96 nm). Further studies demonstrated that LDLs from hamsters fed with limonin and limonin 17-Beta-D-glucopyranoside were less susceptible to oxidation. These data suggest that limonin, limonin 17-Beta-D-glucopyranoside and grapefruit pulp have potential inhibitory effects against atherogenesis. Supercritical CO2 (SC-CO2) was attempted to extract limonoids from grapefruit seeds and molasses. Limonin aglycone was successfully extracted with SC-CO2 directly from grapefruit seeds with the yield of 6.3 mg/g seeds at 48.3 MPa, 50˚C and 60 min with CO2 top feeding; and the limonin glucoside was extracted using SC-CO2 and ethanol as co-solvent from the defatted seeds with the yield of 0.73 mg/g seeds at 42 MPa, 52˚C, 45% ethanol (XEth=0.45) and 40 min with CO2 top feeding; and limonin glucoside also was extracted using SC-CO2 and ethanol with the yield of 0.61mg/g grapefruit molasses at 48.3 MPa, 50˚C and 10% ethanol (XEth=0.1), 40 min with CO2 top feeding. CO2 flow rate was around~5 l/min in experiments. The results demonstrated SC-CO2 extraction of limonoids from citrus juice industry byproducts has practical significance for future commercial production.

Thesis (Ph. D.)--Institute of Paper Chemistry, 1961. / Bibliography: leaves 62-66.

Neurodegenerative diseases are associated with loss of neurons ultimately leading to a decline in brain function. Alzheimer's disease (AD) is considered one of the most common neurodegenerative disorders that affects 16 million people worldwide. The cause of the disease remains unknown, although significant evidence proposes the amyloid Beta-peptide (A-Beta) as a potential culprit. The binding of Cu2+ by the soluble fragments of A-Beta have shown to form Type-3 copper centers and catalyze the oxidation of catechol-containing neurotransmitters. Furthermore, the use of flavonoids as antioxidants to slow or inhibit the neurotransmitter oxidation has suggested further health benefits with their consumption. A structure-function correlation is also made between the flavonoids and their reactively with Cu2+-A-Beta. Mechanistic insight into the binding of catechol and dioxygen within the tyrosinase-like mechanism are made using a metallopeptide modeling the active site of the metzinicins.

Not available

Several innovative tandem mass spectrometric strategies have been developed for the structural determination and isomer differentiation of glycosides and oligosaccharides. Specifically, collisionally activated dissociation (CAD) and infrared multiphoton dissociation (IRMPD) are used in conjunction with derivatization methods designed to exploit variations in binding energies or attach chromophores. These include metal complexation incorporating modified neutral auxiliary ligands and covalent derivatization involving site-specific reactions. The elucidation of flavonoid isomers is accomplished by electrospray ionization tandem mass spectrometry (ESI-MS/MS) via formation and CAD of metal/flavonoid complexes containing an auxiliary ligand. Addition of a metal salt and a suitable neutral auxiliary ligand to flavonoids in solution results in the formation of [M(II) (flavonoid-H) ligand]⁺ complexes by ESI which, upon collisional activated dissociation, often result in more distinctive fragmentation patterns than observed for conventional protonated or deprotonated flavonoids. We compare and explore the use of alternative pyridyl ligands, with electron-releasing substituents including 4,7-diphenyl-1,10-phenanthroline. Using this technique, three groups of flavonoid glycoside isomers are differentiated, including glycosides of apigenin, quercetin and luteolin. A tunable ESI-MS/MS strategy for differentiation of flavone and flavanone diglycoside isomers based on metal complexation with auxiliary ligands that have electron-withdrawing substituents is reported. A series of auxiliary ligands with electronwithdrawing substituents was synthesized in order to tailor the relative metal binding affinities of the ligands and thus directly influence the stabilities, and consequently the dissociation pathways, of the complexes. Upon collisionally activated dissociation, the complexes yield fragmentation patterns in which the abundances of key diagnostic ions are enhanced, thus facilitating isomer differentiation. A strategy for increasing the efficiency of IRMPD in a quadrupole ion trap (QIT) based on another metal complexation strategy is described. Two IR-active ligands (IRALs) that have an IR-active phosphonate functional groups were synthesized. The IR-active groups were therefore incorporated into the analyte complexes via metal complexation. We demonstrate this new IRMPD approach for the structural characterization of flavonoids. The fragment ions obtained by IRMPD are similar to those obtained by CAD and allow facile isomer differentiation of flavonoids. Fourier transform infrared absorption attenuated total reflectance (FTIR-ATR) and energyvariable CAD experiments indicate that the high IRMPD efficiencies stem from the very large IR absorptivities of the IR-active ligands. A simplified method for determining the sequence and branching of oligosaccharides using IRMPD in a QIT is described. An IR-active boronic acid (IRABA) reagent was synthesized and subsequently used to derivatize the oligosaccharides prior to IRMPD analysis. The IRABA ligand is designed to both enhance the efficiency of the derivatization reaction and to facilitate the photon absorption process. The resulting IRMPD spectra display oligosaccharide fragments that are formed from primarily one type of diagnostic cleavage, thus making sequencing straightforward. The presence of sequential fragment ions, a phenomenon of IRMPD, permit the comprehensive sequencing of the oligosaccharides studied in a single stage of activation. The approach is demonstrated for two series of oligosaccharides, the lacto-Nfucopentaoses (LNFPs) and the lacto-N-difucohexaoses (LNDFHs).

A diet rich in fruit and vegetables is associated with better bone health although the reason behind this remains unclear. Mounting evidence suggests that it may be particular fruit and vegetables or a variety of fruit and vegetables that are important and it has been suggested that bioactive compounds, considered to be non-essential nutrients, may play a role. The aims of this project were to study the roles of three classes of dietary compounds on bone health: flavonoids (represented by hesperetin), anthocyanidins and carotenoids. Methods The influence of six major anthocyanidins, six major carotenoids and the citrus flavanone hesperetin were examined by three methodological approaches: (i) a cross-sectional study using outcomes of bone mineral density (BMD) and markers of bone turnover, (ii) a randomised controlled trial with bone turnover markers as the outcome measures and (iii) in vitro examinations in osteoblasts and osteoclasts. The epidemiological part of this thesis was carried out in the Aberdeen Prospective Osteoporosis Screening Study (APOSS) cohort. Women were recuited to the study between 1990 and 1994 and returned for a follow-up visit between 1997 and 1999 (n=3214, mean age 54.8 y at follow-up). Measurements of BMD at the spine and hip were taken at both visits; and urinary markers of bone resorption total deoxypyridinolines (DPD) and total pyridinolines (PYD), and a serum bone formation marker N-terminal propeptides of type 1 procollagen (P1NP), were analysed at the follow-up visit. Diet was recorded by food frequency questionnaire and dietary anthocyanidins and carotenoids were estimated using a database of food compositions developed for this purpose. Analysis was carried out to determine if anthocyanidin or carotenoid intakes were associated with BMD, change in BMD (between the 2 visits), or markers of bone resorption or formation, within the APOSS population. The effect of the carotenoid lycopene on bone turnover was assessed in a 3-month randomised controlled trial in 214 apparently healthy men and women. Participants were randomised into 3 groups: high dietary lycopene (minimum 10 mg/d); low tomato diet with lycopene capsule vi (10 mg/d) or a low tomato diet as the control. Marker of bone resorption plasma carboxyterminal collagen crosslinks (CTX) and marker of bone formation serum P1NP were analysed at baseline (after washout) and after 12 weeks of intervention. In order to study if the aglycone or glycoside compounds directly affect bone metabolism, the effects of a series of anthocyanidins on osteoblast differentiation were analysed in vitro. The effects of hesperetin on osteoblast differentiation and mineralisation and on osteoclast formation and function in vitro were also assessed. Results Regarding the epidemiological part of the project, associations between both dietary anthocyanidins and carotenoids and markers of bone health were observed in the APOSS population. Higher total dietary anthocyanidin intake was found to be associated with higher spine BMD and lower concentrations of bone resorption markers. In addition higher total dietary anthocyanidin intake was associated with less BMD loss at the spine in the period between baseline and follow-up, which was illustrated by a 13.2% difference in annual percent bone loss between the highest and lowest quartiles of anthocyanidin consumption. Individual anthocyanidins were also found to be associated with different markers of bone turnover. Total dietary carotenoid intake was found to be associated with BMD at the spine and lower concentrations of bone resorption markers. Analysis of the individual carotenoids showed that lycopene was associated with higher BMD at the hip; β-carotene was associated with less BMD loss at the spine; and β-carotene, lycopene, β-cryptoxanthin and lutein/zeaxanthin were found to be associated with lower concentrations of bone resorption markers. Each of these findings remained significant after adjusting for confounding factors. In the 3-month randomised controlled trial, lycopene supplementation did not alter bone turnover markers CTX or P1NP. These results are in contrast to those of a previous, smaller randomised controlled trial in postmenopausal women where a decrease in a marker of bone resorption (N-telopeptide of collagen cross-links (NTX)) was observed. Therefore these results suggest that the potential beneficial effect of lycopene may be specific to a population at risk of bone loss. Alternatively, lycopene may have a cumulative protective effect over the lifetime but short-term effects may only be observed in groups with high bone turnover, where there is greater potential to see measureable effects. The results of the in vitro investigations of this project showed that neither anthocyanidins nor hesperetin had an affect on osteoblasts or osteoclasts at physiologically relevant concentrations. Almost all of the anthocyanidin compounds tested had no effect on osteoblast differentiation, and none at physiological concentrations. Similarly, hesperetin had no effect on osteoblast differentiation or mineralisation although it did have an effect on both osteoclast formation and function, but only at concentrations which were not considered to be physiologically relevant. These results add weight to the suggestion that the metabolites of dietary compounds may be responsible for the action on bone metabolism rather than the dietary compounds directly or that a combination of compounds, as found in foods, may be required. Conclusions Taken together, these results support the evidence that a diet rich in fruit and vegetablederived bioactive compounds is beneficial to bone health. Future work could include: observational studies to examine the association of lifetime consumption and long-term risk of fracture; larger dietary intervention trials; and in vitro studies to examine the effects of the compound metabolites and elucidate their mechanism of action.

Paprastasis rapontikas (Rhaponticum carthamoides (DC.) Iljin) priklauso graižažiedžių šeimai, savaime augantis pietų Sibire [1]. Daugiametis žolinis augalas. Sinonimai: Leuzea carthamoides, Stemmacantha carthamoides, maralinė šaknis [2]. Paprastojo rapontiko ekstraktai pasižymi plačiu spektru teigiamo poveikio: pagerina miegą, apetitą, nuotaiką, fizinę ir psichinę būklę [3], druskų apytaką, virškinimą, stabdomas navikų vystymasis [4], stimuliuoja centrinę nervų, širdies ir kraujagyslių sistemas [1], pasižymi hipolipideminiu [5], psichostimuliuojančiu [4] vabzdžius atbaidančiu, imuninę sistemą stiprinančiu poveikiu, taikomas lėtiniam alkoholizmui, impotencijai gydyti [4]. Darbo tikslas: atlikti biologiškai aktyvių junginių chromatografinę analizę paprastojo rapontiko (Rhaponticum carthamoides (DC.) Iljin) ekstraktuose. Augalinė žaliava. Analizei naudota paprastojo rapontiko augalinė žaliava (lapai) rinkta VDU KBS 2006 metų gegužės – spalio mėnesiais. Džiovinama gerai vėdinamoje patalpoje, vengiant tiesioginių saulės spindulių 15 – 20 °С temperatūroje. Eksperimentinė dalis. Metanoliniai paprastojo rapontiko ekstraktai buvo ruošiami 1g susmulkintos augalinės žaliavos užpilant 10 ml 75 % metanoliu ir paliekant 24 valandoms purtyklėje. Gautas ekstraktas filtruojamas. Optimizuotas kietafazės ekstrakcijos metodas metanoliniams paprastojo rapontiko ekstraktams; nustatyti suminiai fenolinių junginių ir flavonoidų kiekiai bei antioksidacinis aktyvumas fotometriniu metodu; atlikta... [toliau žr. visą tekstą] / Rhaponticum (Rhaponticum carthamoides (DC.) Iljin) is an herbaceous perennial plant from the family Asteraceae that inhabits the sub-alpine zone. It can be found growing wild in Southern Siberia, Kazakhstan, the Altay region. Synonyms founded in literature: Maral root, Leuzea carthamoides, Stemmacantha carthamoides. Research indicates that extracts of Rhaponticum carthamoides may have a beneficial effect on impotence, memory and learning, cardiovascular and CN systems, increasing working capacity of tired skeletal muscles, as well as anabolic and adaptogenic processes, can help break addictive behaviours. The aim of this study is to analyse the biologically active compounds in Rhaponticum carthamoides (dc.) Iljin extracts by means of chromatographic method. Raw material of Rhaponticum carthamoides (DC) Iljin. The plant material (21 samples) was collected from the collection of medicinal plants at Kaunas Botanical Garden of Vytautas Magnus University at different vegetation phases during May–October, 2006. Freshly cut plants were sorted out and dried in the drying room at 15-20°C temperature. Experimental. Into 1g of raw material 10 ml of 75% methanol was added and placed into shaker for 24 h. The methanolic extracts were filtered. For measuring of total amount of phenolics, flavonoids compounds and antioxidant activity in methanolic extracts spectrophotometer was used. For qualitative and quantitative investigation of flavonoids high performance liquid chromatography was... [to full text]

The overall aims of this project were to assess the pharmaceutical quality and consistency of commercially available solid dose Sutherlandia frutescens containing products (viz. tablets & capsules) by exploring the use of monitoring the pharmaceutical presentation, flavonoid profile and antioxidant activity levels and to develop/or adapt methods and specifications that may be used for the quality control of such products.Stability tests were conducted on all of the selected SCP. The products were stored under elevated temperatures and environmental humidity conditions and total phenol, antioxidant and chromatographic analysis was conducted on these samples. Samples of each of the SCP were hydrolyzed using HCL and then analyzed using HPLC to test the stability of the flavonoids present in each product. The SCP investigated in this study physically appeared to be of quite good “pharmaceutical” quality, but generally lacked information on the date of manufacture and lacked package inserts, or when these were present they contained insufficient information.Based on the results obtained, it is recommended that, the manufacturers of SCP pay more attention to the information provided on the package inserts and the storage conditions for their products. Further the levels of antioxidant activity, total phenols and flavonoid (sutherlandins A to D) be used as specifications to control the quality of commercially available solid dose Sutherlandia frutescens containing preparations on an individual basis.

The phytochemistry of Ochna serrulata (Hochst.) Walp. was investigated for the first time; two new dimeric chalcones (5-deoxyurundeuvine C and serrulone A) and two new biflavonoid derivatives (4,4’,7-tri-O-methylisocampylospermone A and 4”’-de-Omethylafzelone A) were isolated. These compounds were isolated along with the known compounds lophirone A, afzelone B, campylospermone A, isocampylospermone A, ochnaflavone, 2”,3”-dihydroochnaflavone, lophirone C, psilosin, 3’-O-methylpsilosin, a cyanoglucoside, epicatechin, (2’,4’- dihydroxyphenyl)acetic acid, methyl (2’,4’-dihydroxyphenyl)acetate, irisolone 4’- methyl ether, iriskumaonin 3’-methyl ether, 3',4'-dimethoxy-6,7-methylenedioxyisoflavone, lophirone L, syringaresinol and 16α,17-dihydroxy-entkauran-19-oic acid. The growth inhibitory effect of these compounds was evaluated against three cancer cell line panel of TK 10 (renal), UACC62 (melanoma) and MCF7 (breast) using a sulforhodamine B (SRB) assay. Ochnaflavone and 3’-methoxypsilosin demonstrated selectivity and only inhibited the growth of melanoma cancer cells. However, ochnaflavone showed higher activity by totally inhibiting the growth of melanoma cancer cells at 12.91 μM, whereas, 3’-O-methylpsilosin has this effect at a concentration of 14.11 μM. Lophirone C, a dimeric chalcone, demonstrated the highest cytotoxic activity amongst all isolated compounds against renal, melanoma and breast cancer cells with TGI at 35.63 μM, 11.67 μM and 30.35 μM, respectively. Lophirone A, a rearranged biflavonoid, showed TGI against these cancer cells at 58.96 μM, 26.23 μM and 40.01 μM, respectively. The rest of the compounds showed no significant cytotoxicity against the three cancer cells. The new biflavonoid, 4,4’,7-tri-O-methylisocampylospermone A demonstrated the highest antimalarial activity against chloroquine-resistant strains of Plasmodium falciparum (FCR-3) with IC50 of 11.46 μM, followed by ochnaflavone (17.25 μM). iv Serrulone A (26.52 μM), lophirone A (29.78 μM), 5-deoxyurundeuvine C (31.07 μM), lophirone C (35.31 μM), 4”’-de-O-methylafzelone A (38.43 μM), afzelone B (39.54 μM), irisolone 4’-methyl ether (40.72 μM) and syringaresinol (42.66 μM) were moderately active. The following compounds exhibited the lowest antimalarial activity, 2”,3”-dihydroochnaflavone (61.86 μM), iriskumaonin 3’-O-methyl ether (93.69 μM),3’- O-methylpsilosin (106.35 μM) and16α,17-dihydroxy-ent-kauran-19-oic acid (106.48 μM). Owing to the observed and reported biological/pharmacological activity, ochnaflavone (an ether-linked biflavone consisting of apigenin and luteolin moieties) was selected for synthetic studies. An older method, nucleophilic aromatic substitution (SNAr) was successfully applied in the construction of the diary ether. Oxidative ring cyclization of the ether-linked dimeric chalcone was achieved by using heated pyridine and iodine. The two methods can be extended further in the synthesis of other novel biflavones with ether linkage. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.