ANTI-NUTRITIONAL CONSTITUENT OF COLOCASIA ESCULENTA ...

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c.1.1 Introduction CHAPTERC-l LITERATURE REVIEW Plants are the only producers of phytosterols, which are cholesterol-like chemicals. The most common phytosterols are beta-sitosterol, campesterol and stigmasterol (Ling and Jones, 1995). Phytosterols are known for their ability to lower plasma cholesterol and there have been many studies reporting their hypocholesterolaemic effects (reviewed by Ling and Jones, 1995; Pollak and Kritchevsky, 1981). Epidemiological studies have also proposed that increased dietary phytosterol intake may decrease the risk of colon cancer in humans (Hirai et aI., 1986; Nair et al., 1984). In the previous sections, Amadumbe tubers were screened for the presence of anti nutrients. From the screened anti-nutrients, a-amylase inhIbitor and saponin were extracted, isolated and identified. The saponin was structurally elucidated as gamma sitosterol. Beta-sitosterol is a structural isomer of gamma-sitosterol and is a compound with many biological activities. Therefore, gamma-sitosterol would be the perfect anti nutrient compound for nutritional evaluation. Gamma-sitosterol was not commercially available and, because beta-sitosterol is the stereoisomer, it was decided to use beta sitosterol for the nutritional evaluation. A large body of research on the cholesterol lowering activity ofbeta-sitosterol has already been conducted; thus, the effects of beta sitosterol on digestive and absorptive enzymes were investigated in this study. '::.1.2.1 Stereochemical structure Sterols are necessary cell membrane components and are produced by both animals and plants. Plant cells consist of a nmnber of complex mixtures of sterols, whereas animals 182
C.1.2.2 and fungal cells contain one major sterol: cholesterol and ergosterol, respectively. More than 100 different types of phytosterols (plant sterols) have been identified (Morean et al., 2002). Seeds, nuts, fruits and vegetable oils are some ofthe different parts of a plant that contain significant amounts ofplant sterols (Weihrauch and Gardner, 1978; Moreau et al., 2001). The phytosterol content ofthese vegetables and fruits is not influenced by intense processes such as boiling, bleaching and deodorizing since phytosterols are very stable compounds (Normen et aI., 1999; Bortolomeazzi, 2000). The human body is unable to produce plant sterols: thus, all plant sterols are regulated by dietary intake. Beta -sitosterol, stigmasterol and campesterol are the most abundant in plants (Rosenblum et al., 1993; Law 2000; Hicks and Moreau, 2001). Pbarmacochemistry and pharmacokinetics Researchers have been fascinated by the concept of a protein-mediated transport system responsible for intestinal uptake of cholesterol for more than a decade (Thwnhofer and Hauser, 1990). Identification of the molecular defects responsible for phytosterolemia (Berge et al., 2000; Lee et al., 200 I) and possible confirmation of the existence of a specific transport protein located in the brush border membrane mediating intestinal sterol absorption (Detmers et al., 2000; Hemandez et aI., 2000; Kramer et al., 2000) has shed new light on the cellular transport of cholesterol and plant sterols. Plasma phytosterol levels are generally very Iow compared to cholesterol levels in mammalian tissues. This is due primarily to poor absorption from the intestine and faster excretion from the liver (Ling and lones, 1995). Absorption of beta-sitosterol is also made difficult during its passage through the gut because these phytosterols are bound to the fibers of the plant (Bouic, 1998). The plant sterol mixture has very Iow solubility (Moghadasian, 2000): it is not soluble in either water or oil (Kim et aI., 2002). About five per cent of an ingested dose of supplemental beta-sitosterol is absorbed from the gastrointestinal tract and is transported via the portal circulation to the liver (Salen et al., 1970). Systemic circulation is 183
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ANTI-NUTRITIONAL CONSTITUENT OF COL
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ABSTRACT Colocasia esculenta 1. Sch
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• My colleagues Kayode, Stranger,
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CHAPTER A-2 : MATERIALS AND METHODS
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CHAPTER 8-1-4 : DISCUSSION Bl-A.l I
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C.3.3 EXPERIMENTAL TEST C.3.3.1 Foo
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MakP Makatini purple MakW Makatini
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Figures C3-9 Figure B-1 The activit
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Table C3-3 TableC3-4 Summary ofseru
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crop. Amadumbe is not extensively c
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section of the study therefore inve
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Figure AI-2: The aboveground portio
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Taro is produced in the Pacific Isl
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A.1.4 Anti-nutrients Foods are comp
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essential amino acids not available
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A.l.4.2 Amylase inhibitors In order
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A.l.4.4 Total polyphenols Polypheno
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A.1.4.7 when the levels are high en
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A.1.4.8 coordination sides to inhib
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However,ifsaponins have a triterpen
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A.l.6 nutritional factors naturally
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A.2.2.3 A.2.3 A.2.3.1 A.2.3.2 Speci
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A.2.3.4.2 A.2.3.4.3 A2.3.4.4 In ano
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A.2.3.6.3 \.2.3.6.3.1 \.2.3.6.3.2 L
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sulphuric acid. Absorbance was meas
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Table A3-1a: The moisture and ash c
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Table A3-1c Carbohydrate content (g
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and 4.13 mg 100 g-l DMin the unproc
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Table A3-3c: Fatty acids identified
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Table AJ-4b: The phenolic compounds
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The results of the analysis of alka
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MtW MtP EW EP MakW MakP Figure A3-3
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The crude fat analysis ofZululand C
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The relative proportion ofNa, Ca, K
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TIA indicated that the trypsin inhi
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samples in this study were also hig
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The cyanogen levels for Amadumbe tu
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CHAPTERA-5 CONCLUSION A.5.1 Nutriti
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In conclusion, Section A ofthis stu
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Alfaia S., Ribeiro G., Nobre A, Lui
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Bhattacharyya A, Rai S. and Babu CR
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Chavan U.D., Shahidi F. and Naczk M
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De la Cuadra C., Muzquiz M, Burbano
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Fatty acids. (2008) CyberlipidCente
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Grant G. (1991) Lectins. In: Toxic
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HofmanP., Vuthapanich S., Whiley A,
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Jobnson LT., Gee J.M, Price K.R., C
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MagaJA (1978) Simple phenols and ph
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Milton K. (2003) Micronutrient inta
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Noonan S.C. and Savage G.P. (1999)
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Pathirana C, Gibney MJ. and Taylor
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Quesada C., Bartolome B., Nieto 0.,
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Robertson RN., Highkin H.R., Smydzu
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Sheeba R. and Padmaja G. (1997) Mec
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Thompson L.U. (1988) Antinutrients
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Vijayakumari K, Siddhuraju P. and J
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PURIFICATION AND AMYLASE INHIBITOR
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calcium metalloenzymes, are complet
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Bl.1.2.4 Kunitz-Iike a-amylase inhi
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diabetes mellitus or obesity. Octiv
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B1.2.3.1 Extraction and purificatio
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BI.3.1 BI.3.2.1 Introduction CHAPTE
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Page 155 and 156: Bl.4.1 B1.4.2 Introduction CHAPTER
Page 157 and 158: Bl.4.3.3 results that amylase inhib
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Page 162 and 163: 12.1.2.3 Steroidal saponin The trit
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Page 167 and 168: 82.2.3.2 82.2.3.2.1 B2.2.3.2.2 Air-
Page 169 and 170: 82.2.3.3.4 • ion source temperatu
Page 173: Figure 82-3.3: Chromatogram ofsapon
Page 180 and 181: Gamma- and possibly beta-sitosterol
Page 182: whereas beta-sitosterol was. It was
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Page 192 and 193: Morton R.L., Schroeder RE., Bateman
Page 194: Price K.R, Eagles J. and Fenwick GR
Page 197 and 198: Ukpabi U.R and Ukpabi J.U. (2003) P
Page 199: SECTIONC EFFECTS OF INGESTED BETA-S
Page 203 and 204: Beta-sitosterol has been successful
Page 205: Digestive enzymes do the all import
Page 209 and 210: C.2.1 Introduction CHAPTERC-2 MATER
Page 211 and 212: C.2.2.3.3 C.2.2.4 C.2.2.4.1 C.2.2.4
Page 214: C.3.! Introduction CHAPTERC-3 RESUL
Page 219 and 220: C.3.3.3 Clinical signs The appearan
Page 221 and 222: C.3.3.5 ALT and AST values were sig
Page 223 and 224: .. - Figure C3-5: Representative ph
Page 225: Figure C3-7: Representative photomi
Page 229 and 230: C.4.1 Introduction CHAPTERC-4 DISCU
Page 231: significantly, decreased after beta
Page 234 and 235: decreased by sitosterols as a resul
Page 237 and 238: Bhattacharyya AI
Page 239 and 240: Dablqvist A (1968) Assay ofintestin
Page 242 and 243: Ivorra MD., D'OconMP., Paya M and V
Page 245 and 246: Miettinen TA, Tilvis RS. and Kesani
Page 247: Pollak O.I. and Kritchevsky D. (198
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2.1 Introduction CHAPTER 2 GENERAL
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2.4 Suggestions for future work Fur
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A.A.3 Enzyme trypsin 10 mg bovine-p
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AppendixB DETAILS OF MEmOOOLOGY BA1
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sugars were estimated from standard
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B.A.l.5.4.5 Liquid Chromatography M
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B.A.2.4 Tannin [Van-Burden and Robi
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The mixture was stirred continuousl
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B.C.l Esterification ofbeta-sitoste
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AppendixC OLEIC ACID STANDARD 230 2
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5 '11I;1 5 2 r - - - • j ,et [:=:
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