ABSTRACT
Senna siamea is a medicinal plant native to Asia. It is widely distributed in different parts of Nigeria, where it is employed in traditional ethno-medicinal and ethno-veterinary practices for a variety of ailments. In this study, the effect of S. siamea on smooth muscle contractility of the ileum in an organ-bath was demonstrated as well as evaluating the histology and histochemistry of the colon in opioid-induced constipation in Wistar rats. Thirty (30) female Wistar rats with mean weight of 126.7g were used in this work. They were randomly grouped into five groups (I-V) of six rats each and treated as follows; Group I received Normal saline, Group II received Loperamide(3mg/kg), Group III received S. siamea(300mg/kg) and Loperamide(3mg/kg), Group IV received Loperamide and S. siamea, Group V received Bisacodyl 5mg/kg (Standard laxative). Constipation was induced in Group II for 6-days using loperamide at 3mg/kg. There was a significant improvement in the nature of stool (size and texture) of animals treated with extract (S. siamea) after induction with loperamide. Results obtained at the in vitro phase (contractility experiment) of this work showed that S. siamea possess laxative effect by relaxing the rapid contraction of the ileum of wistar rats. In this study, S. siamea was observed to relax the contractility of ileum in organ-bath (tyrode solution) which was similar to what was observed when loperamide was administered. Senna siamea was effective in treating opiate-induced constipation at the in-vitro and in-vivo phase as it ameliorate the constipative effects of loperamide. In addition, Senna siamea improved evacuation of stool by reducing the muscle tone of the Gastro-intestinal tract. There was no statistical significant difference in stool weight, organ-body weight ratio, and change in body weight of experimental animals at P≤0.05. Histological analysis using Heamatoxylin and Eosin stain revealed several enlarged and numerous goblet cells around the crypt of Lieuberkuen in the loperamide treated group (loperamide 3mg/kg) while goblet cells of extract treated groups(S.siamea 300mg/kg) were fewer and reduced in size which could be attributed to the laxative effect of the extract on the mucosa of the GIT. Goblet cells of bisacodyl (standard laxative) 5mg/kg treated group appeared fewer and enlarged. PAS was used to specifically stain neutral mucin. Mucous cells in loperamide treated group stained PAS positive with numerous and enlarged goblet cells. This is in sharp contrast with results obtained in extract treated group as fewer stained mucous cells were observed. Based on our observations, we therefore conclude that Senna siamea had laxative effect on the colon of constipated wistar rats by suppressing goblet cell production of mucous, improvement of faecal evacuation as well as its relaxing effect on the ileum.
TABLE OF CONTENTS
Cover page……………..……………………………………………………………………………i
Declaration ………………………………………………………………………………………………………………………. i
Certification ……………………………………………………………………………………………………………………. iii
Dedication ……………………………………………………………………………………………………………………… iv
Acknowledgements ………………………………………………………………………………………………………….. v
Abstract ………………………………………………………………………………………………………………………… vii
Table of contents …………………………………………………………………………………………………………… viii
List of tables ………………………………………………………………………………………………………………….. xii
List of figures ……………………………………………………………………………………………………………….. xiii
List of plates ………………………………………………………………………………………………………………….. xv
Chapter 1 ………………………………………………………………………………………………………………………… 1
Introduction ………………………………………………………………………………………………………………….. 1
1.1 Statement of the research problem …………………………………………………………………………….. 2
1.2 Justification …………………………………………………………………………………………………………….. 2
1.3 Study hypothesis …………………………………………………………………………2
1.4 Aim ……………………………………………………………………………………………………………………….. 3
1.5 Objectives ………………………………………………………………………………………………………………. 3
Chapter 2 ………………………………………………………………………………………………………………………… 4
Literature review ………………………………………………………………………………………………………….. 4
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2.0 General description of Senna siamea …………………………………………………………………………. 4
2.1 Composition of Senna siamea …………………………………………………………………………………… 6
2.1.1 Proximate composition of Senna siamea …………………………………………………………………. 6
2.1.2 Elemental and chemical composition of Senna siamea ……………………………………………… 7
2.2 Uses of Senna siamea …………………………………………………………………………………………….. 11
2.2.1 Agriculture, Ethno-medicine and Ethno-veterinary medicine of Senna siamea…………… 11
2.2.2 Pharmacology of Senna siamea ……………………………………………………………………………. 13
2.2.2.1 Anti-malarial effects ………………………………………………………………………………………… 14
2.2.2.2 Anti-diabetic and anti-lipemic effects …………………………………………………………………. 14
2.2.2.3 Other uses ………………………………………………………………………………………………………. 15
2.2.3 Laxative studies on Senna siamea ………………………………………………………………………… 16
2.2.3.1 Animal data …………………………………………………………………………………………………….. 16
2.2.3.2 Clinical data ……………………………………………………………………………………………………. 16
2.3 Epidemiology of Constipation …………………………………………………………………………………. 19
2.4 Anatomy of colon and effects of opiates that result in constipation ………………………………. 21
2.4.1 The anatomy of ileum and large intestines ……………………………………………………………… 21
2.4.1.1 The jejunum and the ileum ……………………………………………………………………………….. 21
2.4.1.2 The large intestine ……………………………………………………………………………………………. 22
2.4.1.2.1 The cecum ……………………………………………………………………………………………………. 22
2.4.1.2.2 The ascending colon ……………………………………………………………………………………… 23
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2.4.1.2.3 The transverse colon ……………………………………………………………………………………… 23
2.4.1.2.4 The descending colon ……………………………………………………………………………………. 23
2.4.2 Entero-endocrine cells and goblet cells. ………………………………………………………………… 24
2.5 Drug effects on colon ……………………………………………………………………………………………… 25
2.5.1 Senna siamea and adverse reactions ……………………………………………………………………… 26
2.5.2 Opioids ……………………………………………………………………………………………………………… 28
2.5.3 Opioid induced constipation ………………………………………………………………………………… 29
2.5.4 Selected medications for treating opioid-induced constipation ……………………………… 30
2.5.5 Toxicological studies on senna siamea …………………………………………………………………. 31
Chapter 3 ………………………………………………………………………………………………………………………. 33
Materials and methods …………………………………………………………………………………………………. 33
3.0 Materials ………………………………………………………………………………………………………………. 33
3.1 Experimental animals ……………………………………………………………………………………………. 33
3.1.1 Plant …………………………………………………………………………………………………………………. 33
3.1.2 Reagents ……………………………………………………………………………………………………………. 33
3.1.3 Instruments ………………………………………………………………………………………………………… 33
3.2 Methodology ……………………………………………………………………………………………………….. 34
3.2.1 Plant extraction ………………………………………………………………………………………………….. 34
3.2.2. In vitro experiment …………………………………………………………………………………………….. 34
3.2.3 – In vivo experiment …………………………………………………………………………………………… 36
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3.2.3.1 Experimental design ………………………………………………………………………………………… 36
3.3 Morphological study …………………………………………………………….37
3.4 Tissue processing …………………………………………………………………………………………………… 38
3.5 Histology and histochemistry ………………………………………………………………………………….. 39
Chapter 4 ………………………………………………………………………………………………………………………. 40
Results……………………………………………………………………………………………………………………….. 40
4.0 In vitro studies ………………………………………………………………………………………………………. 40
4.1 In vivo studies ……………………………………………………………………………………………………….. 50
4.1.1 Morphology ……………………………………………………………………………………………………….. 50
4.1.2 Stool analysis …………………………………………………………………………………………………….. 50
4.2 Histology………………………………………………………………………………………………………………. 54
4.3 Histochemistry…………………………………………………………………………55
Chapter 5 ………………………………………………………………………………………………………………………. 76
Discussion …………………………………………………………………………………………………………………. 76
Chapter 6 ………………………………………………………………………………………….79
Summary, Conclusion and Recommendation …………………………………………………………………. 79
6.0 Summary ………………………………………………………………………………………………………………. 79
6.1 Conclusion ……………………………………………………………………………………………………………. 80
6.2 Recommendation …………………………………………………………………………………………………… 80
References …………………………………………………………………………………………………………………….. 81
CHAPTER ONE
INTRODUCTION
Senna siamea (Cassia siamea) is a non-nitrogen fixing leguminous tree in the family Leguminosae and sub-family Caedalpinoidea. There are over 400 known species of Cassia. Senna siamea is native to south and south-east Asia from Thailand and Myanmar (Brandis 1906, Gamble 1922) to Malaysia, India, Sri Lanka and Bangladesh (Khan and Alan, 1996). It has been cultivated world-wide and is naturalized in many locations (Gutteridge, 1997). It is commonly called Bombay blackwood, cassod tree, kassod tree, pheasant wood, pheasant-wood, Siamese cassia, Siamese senna, Thai cassia, Thai copper pod, Thailand shower. In Nigeria, Senna siamea is widely distributed in the southwest and some areas in the North. It is commonly referred to as ‗ewe cassia‘ in the southwest where it is believed to cure fever and has also serve some other medicinal purposes (especially the leaves) (Ogunkunle 2006). In the North, it is known as ―Labadiya‖ and commonly planted as shelter belts. The chemical composition of Senna siamea (cassia leaves) has been determined from recent studies and contains saponins, anthraquinones, phytobatannins, alkaloids and crude proteins (Smith, 2009).
Senna siamea (S.siamea) is an ingredient found in several commercial laxative products and a US Food and Drug Administration (FDA) – approved non-prescription drug. The leaves and the fruit (pods) of Senna are used as stimulant laxatives, which function by anthraquinone cathartic action, and are generally well tolerated in the adult population, but when this is taken at much higher than recommended doses or when used chronically (laxative abuse), adverse effects may occur as reported in other substance such as ethanol (Adebisi, 2003). Constipation refers to bowel movements that are infrequent or hard to pass (Chatoor and Emmanuel, 2009) and a common cause of painful defecation. Opioids stimulate the absorption of fluids, mainly by delayed transit,
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increasing contact time for absorption, and by stimulating mucosal sensory receptors that facilitate further fluid absorption (De Luca and Coupar, 1996 )
1.1 STATEMENT OF THE RESEARCH PROBLEM
Senna siamea has been widely used as a laxative but its effect on the colon in treating opiate-induced constipation has not been fully established.Constipation occurs as an adverse drug reaction to opioid treatment for pain relief, especially among opioid-addicts and regular users. The prevalence of constipation is 2-fold higher among Africans of lower socio-economic status and in nursing home residents (Higgins et al., 2004).
1.2 JUSTIFICATION
Senna leave consumption reduces the risk of chronic constipation from unhealthy lifestyle, dieting and even in cases of abuse of certain drugs that indirectly induce constipation. Knowledge gained from this study could stimulate the minds of indigenous researchers into the field of medicinal plants and herbal remedies. Getting a natural laxative like S. siamea (without drug interaction) will be helpful in ameliorating side-effects of opioid-induced constipation among addicts and regular users. 1.3 STUDY HYPOTHESIS Aqueous extract of S. siamea will induce a laxative effect on opioid-induced constipation in Wistar rats.
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1.4 AIM
The study was aimed at evaluating the anti-constipative activity of aqueous extract of S. siamea leaves on opioid-induced constipation in colon of Wistar rats.
1.5 OBJECTIVES
The objectives of this present study were to:
i. evaluate the in-vitro effects of S. siamea on contraction of smooth muscles of intestine (ileum) before and after exposure to opiates
ii. determine the effects of S. siamea on the histology of the large intestine (distal colon) exposed to opiates
iii. histochemically assess the effect of Senna siamea on the mucin contents in the distal colon of wistar rats
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