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Citrus Phytochemicals

Citrus Phytochemicals. Designer Foods Functional Foods Hypernutritious Foods Nutraceuticals. Phytochemicals Naturally occurring biologically active components Found in plant. Phytonutrient Plant chemical with known nutrient properties Consumed as part of a usual diet.

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Citrus Phytochemicals

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  1. Citrus Phytochemicals

  2. Designer Foods Functional Foods Hypernutritious Foods Nutraceuticals

  3. Phytochemicals • Naturally occurring biologically • active components • Found in plant • Phytonutrient • Plant chemical with known nutrient • properties • Consumed as part of a usual diet Biologically active or Protect against Disease Health Canada, 1998

  4. Bioactive Compounds “Extranutritional” constituents that typically are naturally occurring in small quantities in plant products and lipid rich foods. Kitts, 1994 Can J. Physiol Pharmacology 1994

  5. Nutraceutical • Product isolated or purified from foods • Sold in medicinal forms - pill, powder, capsule • Functional Food • A conventional food • Consumed as part of a usual diet • Provide health benefit beyond basic nutrition Biologically active or Protect against Disease Health Canada, 1998

  6. Chemopreventive agents • Micronutrients • vitamins, beta carotene, molybdenum, calcium • Phytochemicals • Synthetics • vitamin derivatives • piroxicam • tamoxifen

  7. Carotenoids Indole Saponins Coumarins Dietary Fiber Isoflavones Protease inhibitors Phytochemicals

  8. Organosulfides Isothiocynates Indoles Dithiolthiones Polyphenols Flavonoids Tannins Folic acid Contd. Phytochemicals

  9. Chemopreventive agents (Based on their mechanisms of action) • Blocking agents • Suppressing agents

  10. CANCER CHEMOPREVENTIVE AGENTS 1. BLOCKING AGENTS -- prevent carcinogens from reaching or reacting with the DNA, the genetic information. 2. SUPPRESSIVE AGENTS -- inhibit the expression of cancer in cells that have already been exposed to a carcinogen.

  11. Cancer Producing Compounds Blocking Agents Cells Attacked By Cancer Producing Compounds Suppressing Agents Cancer Wattenburg, 1993

  12. Chemopreventive agents • Blocking agents • Flavonoids • Indoles • Isothiocynates • Diallyl sulfides • D-limonene

  13. MECHANISM OF ACTION (BLOCKING AGENTS) 1. Inhibit the formation of the active carcinogen. 2. Increase the rate at which the active carcinogen is inactivated. 3. Act as scavengers for the active forms of carcinogens.

  14. Chemopreventive agents • Suppressing agents • D-limonene • Diallyl sulfides • vitamin D • vitamin A and retinoids • monoterpenes • carotenoids • polyphenols • protease inhibitors • selenium • calcium

  15. Anticarcingenic mechanisms • Antioxidant effects • Increased activity of enzymes that detoxify carcinogens • Effect on cell differentiation • Blocked formation of nitrosamines • Altered estrogen metabolism • Decreased cell proliferation • Maintenance of normal DNA repair

  16. THREE-PHASE MECHANISM FOR CHEMICAL CARCINOGENESIS 1. INITIATION - normal cells to latent tumor cells. 2. PROMOTION - latent tumor cells to carcinoma in situ. 3. PROGRESSION - carcinoma in situ to invasive carcinoma.

  17. Procarcinogens Phase II enzymes Phase I enzymes Glutathione S-transferase Limonoids Carcinogens Flavonoids Electrophiles Promotion DNA Damage Tumor Lycopene, Lutein, Zeaxanthin and Beta carotene Initiation Oxidative damage Free radicals

  18. Health Promoting Compounds • Carotenoids • Lycopene -Prostate Cancer • Beta carotene • Lutein and zeaxanthin-Blindness • Beta cryptoxanthin

  19. Carotenoid Concentrations • Lycopene- Grapefruit • 3362 ug/100 g wet wt (Mangels et al.,1993) • 350 ug/100 g wet wt (Gross et al., 1987)

  20. Carotenoid Concentrations (ug/100g)

  21. Lycopene Beta carotene Texas Florida

  22. LIMONOIDS WITH • ANTICANCER ACTIVITY • Limonin • Limonin 17-ß-D-glucopyranoside • Limonin carboxymethoxime • Deoxylimonin

  23. INACTIVE LIMONOIDS • Limonol • Deoxylimonic acid • Ichangensin • 17,19-didehydrolimonoic acid • Nomilinic acid 17-ß-D-glucopyranoside

  24. LIMONOIDS WITH • PARTIAL ACTIVITY • Nomilin • Nomilin 17-ß-D-glucopyranoside • Obacunone

  25. EPIDEMILOGICAL EVIDENCE 1. oral cavity. 5. pancreas. 2. larynx. 6. lung. 3. esophagus. 7. colon. 4. stomach. 8. rectum.

  26. LIMONOID GLUCOSIDES 1. Tasteless. 2. Soluble in water. 3. Human consumption (already pre- sent in citrus and citrus products in relatively high concentrations). 4. Can be prepared from by-products of juice processing plants (seeds and citrus molasses).

  27. Limonoid Concentrations • Limonoid glucosides • Limonin 17-beta D-glucopyranoside (54-180 ppm) • Oranges-320 ppm • Grapefruit -195 ppm • Lemon-90 ppm • LG 1000

  28. ROLE OF METABOLISM IN CHEMICAL CARCINOGENESIS P-450 PHASE I PRO CARCINOGENS OXIDATION REDUCTION HYDROLYSIS DNADAMAGE PHASE II ULTIMATE CARCINOGEN GST GSH GSH-CONJUGATION PRODUCT EXCRETION TUMOR

  29. GST-catalyzed Conjugation of CDNB to GSH GST Cl GS NO2 NO2   GSH HCl NO2 NO2 1-chloro-2,4-dinitrobenzene Dinitrophenyl glutathione INSOLUBLE SOLUBLE Toxic Less toxic

  30. Isolation, Purification and Characterization of Putative Bioactive Compounds

  31. Isolated Citrus Bioactive Compounds Limonoids and Flavonoids Limonoid Aglycone Limonoid Glucosides

  32. Phase II Enzymes GST and QR Isolation and Characterization Bioactive Compounds Animal Studies Cell Culture Phase I Enzymes CYP450’s Flavonoids Limonoids

  33. Colon Cancer Colon Cancer

  34. Experimental Diets Significantly Reduced Total ACF Number a p<0.05 b TOTAL ACF

  35. Experimental Diets Significantly Reduced High Multiplicity ACF a p<0.05 b HMACF

  36. Objective To investigate the possibilities of various citrus limonoids and flavonoids to reduce plasma cholesterol

  37. LDL/HDL Cholesterol Ratio Comparison Jun Yu d d d d c b a

  38. Total Antioxidant capacity • ORAC- Oxygen Radical Absorbance Capacity can be measured by COBAS FARA II analyzer

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