STUDIES ON THE ANTIDIARRHOEAL AND ANTIMICROBIAL EFFECT OF THE METHANOL EXTRACT OF HARUNGANA MADAGASCARIENSIS LEAVES

ABSTRACT

Harugana.madagascariensis  leaf  is  a  rich  source  of  flavonoid  saponin,carbohydratesterpenoid, steroids, phenolics,tannin and   has been reported to have medicinal property as well as some physiological potentials. This study evaluated the antidiarrhoeal and antimicrobial activity of methanol extract of Harugana madagascariensis leaves. The qualitative phytochemical constituents of the extract showed the relative presence of flavonoids   in relatively high concentration, tannins,     reducing sugars, steroids, phenols, alkanoids, terpenoids and saponins in moderately high concentration, whereas soluble carbohydrates, glycosides and hydrogen cyanides were in low concentration. The median lethal dose (LD50) of the extract recorded no death at the highest dose of 5000 mg/kg b.w. In the castor oil induced diarrhoea, the group treated with 50 and 200 mg/kg b.w of extract had significantly (p < 0.05) reducced wet feacal droppings when compared with positive control (group 2). Group treated with 100 mg/kg b.w(p.o) was significantly (p < 0.05) higher  wet feacal droppings at 1 hr when compared to 4 hr. The wet feacal dropping of the group treated with 100mg/kg b.w (p.o) of extract was observed to be non-significantly (p > 0.05) lower when compared with positive control. Group treated with 200 mg/kg b.w (p.o) of extract was significantly (p < 0.05) higher wet feacal droppings at 1hr when compared with 4hrs. In the castor oil-induced enteropolling assay in rats, all the treatrd  groups  (50 -200) mg/kg b.w of extract   non-significantly (p > 0.05) decreased the intestinal fluid accumulation when compared with group 2 (positive control). The treated groups (50-200) mg/kg b.w extract reduced the fluid accumulation in a dose dependent manner with a percentage inhibition of 10.09%,  19.74%,  and  27.63%  respectively.  The  result  of  the  methanol  extract  of  H

Magascariensis on weight of the intestinal contents of the castor oil-inducced enteropoling showed a non-significant increase (P > 0.05) in group 2 and 5 rats administered 50 and 100 mg/kg b.w of the extract when compared with positive control while the weight of the intestinal contents for the group treated with 200 mg/kg b.w(p.o) was significantly (P < 0.05) lower  when compared with group 2 ( positive control).   The effect was observed to be in a dose dependent manner in all the treated groups (50-200) mg/kg b.w extract reducing the weight of intestinal  content with percentage inhibition of 18.82%, 27.53%, and  50.59% respectively.  The  result  of  methanol  extract  of  H.madagascariensis  on  gastrointestinal transits showed that the intestinal motility effect of the extract at all the tested doses  (50-200) mg/kg b.w extract  was  significantly (p < 0.05) lower when compared with group 2 (positive control). The   K+, Na+, HCO3- and Cl- ion concentration of all the treated groups was significant (p < 0.05) higher when compared with group 2 (positive control).   The creatinine and  urea  level  of  the  group  treated  with  50,  100  and  200  mg/kg  b.w  of  extract  was significantly (p < 0.05) lower when compared with positive control.  There was a decrease (p < 0.05) in sensitivity of methanol extracts of H.madagascariensis in all the tested organism when compared with standard drug (ciprofloxacin).The result showed that standard drug (ciproflaxacin) produced the least minimum inhibitory concentration (MIC) in all the bacteria samples. The MBC on all the tested organisms were also found to be higher for the extract when compared with the standard drug.

CHAPTER ONE

INTRODUCTION

Medicinal plants play a key role in human health care. About 80% of the world population relies on the use of traditional medicine, which is predominantly based on plant material (WHO. 1993). Scientific studies available on a good number of medicinal plants indicate that promising phytochemicals can be developed for many health problems (Gupta, 1994). Herbal drugs have gained importance in recent years because of their efficacy and cost effectiveness. These drugs are invariably single plant extracts or fractions or mixtures of fractions/ extracts from different plants, which have been carefully standardized for their safety and efficacy (Subramoniam and Pushpangadan, 1999). The use of herbal drugs in the treatment of diarrhea is a common practice in Africa (Abdullahi et al., 2001). At the beginning of 1980s, deaths caused by diarrhea were estimated at 4.6 millions every year for children under the age of 5 years (Snyder and Merson, 1982). E.coli is also considered to be a significant cause of diarrhea diseases among travelers (Adachi et al.,2001). Diarrhea diseases caused several million of death in the world annually (Field, 2003). In developing    countries they are the most  common  cause of  mobility  and  mortality (Amstrong and  Cohen,  1999).  The poor sanitary conditions (environmental and educational) and malnutrition pre-dispose children to a risk of diarrhea disease.  Harungana madagascariensis  lam. is a tropical shrub ubiquitous to the tropical rainforest   margins and stream banks ((Moronkola et al. 2015). The plant exudate is used by people of Ondo state (South-West) Nigeria to cure acute enteritis, scabies, and jaundice (Gill, 1992). The leaves and stem bark are used as herbal medicine in treating anemia, malaria, and skin diseases (Gbolade et al., 2009). Aqueous leaf extract of H. madagascariensis  has  been  shown  to  have  antimicrobial  activity  on  different  strains  of bacteria (Bacillus, Subtitis, Staphylococcus aureus, Eschericha coli and Salmolella typhi), hence this is used in substantiating its use for gastro-intestinal disorder (Okoli et al., 2002) .In other to confirm the efficacy of Harungana madegascaransis   in traditional medicine, this study was designed to investigate the antidiarrhoeal and antimicrobial effect of its leaf extract on albino rats.

1.1.      Plant description

Harungana Madagascariensis lam ex poir is a member of hypericeae. It is a tropical shrub ubiquitous to the tropical rainforest margins and stream banks (Moronkola et al., 2015).  The plant is native to Central Africa, Democratic Republic of Congo, Sudan, Ethiopia, Lesotho and South Africa.   Its English names include blood tree, organe-milk tree, and dragonish blood tree. It can also be called haronga, or Harungana. Its French name is bio harongue ((Moronkola et al. 2015). Among the Igbo (South-East), the  plant is called  Oturu, In Yoruba and Benin it is known as elepo and itue respectively (Gill 1992). The plants grow to a height of about 4-7m, and sometimes it reaches 10-25m with cylindrical trunk and golden-green and spreading crown. Its leaves are opposite, simple, ovate or elliptical with prominent veining and taper apex ((Moronkola et al. 2015).

Scientific classification of Harugana madagascariensis

Kingdom                    –          Plantae Unranked                    –          Angiosperms Unranked                    –          Eudicots Order                          –          Malpighiales Family                        –          Hypericaceae

Genus                         –          Harungana Lam

Species                       –          H. madagascariensis

Binomial Name          –          Harungana madagascariensis lam . ex poiret

Synonyms                   –          Haronga  madagascariensis Choisy

Fig. 1: Structural view of the plant Harungana madagasccariensis.(oturu)

1.1.1 Origin and geographical distribution:

The  plant  is  native  to  Central  Africa,  Democratic  Republic  of  Congo,  Sudan  Ethiopia, Lesotho and South Africa.

1.1.2 Ethenomedicinal uses of Harungana madagascariensis

Its sap is used in the treatment of scabies and as anthelmintic (tapeworm) while the leaves are used as a remedy for heamorhages, diarrhoea, gonorrhoea, sore throats, headache, and fevers. Resin from the flower stalk is believed to ease colic and to check infection after childbirth while decoctions of the bark are drunk as a remedy for malaria or jaundice. Roots are used to hasten breast development in young women while roots and barks are boiled in water and the infusion drunk twice a day to interrupt the menses. Young leaves are sometimes used as a medicine for asthma and the fruits are occasionally used in cases of abortion with the belief that the red juice averts bleeding (Orwa et al. 2009). In African traditional medicine, different parts of the plant are highly valued for the treatment of diverse human diseases. For example, in Sierra Leone, the red juice is employed to arrest postpartum bleeding while in Liberia, puerperal infection is treated by eating the unopened bud sheaths heaten up with palm oil (Olagunju et al., 2004). The pounded bark along with Pentaclethrra macrophylla is equally employed in treating leprosy while the red sap washed out of the stem bark is drunk as a

remedy for tapeworm infection, craw-craw or as dressing materials for wounds among Ghanainans (Irvine, 1961). Decoction of the plant root and stem bark is also used as remedy for dysentery, bleeding piles, trypanosomosis, fever, cold and cough (Gill, 1992). The plant exudate is used by the Ondo people (South-West Nigeria) to cure acute enteritis, scabies, and jaundice  (Gill,  1992).  The  boiled  decoction  of  plant  leaves  is  equally  reputed  for  the treatment of malaria (Agbor et al., 2004). Recently, the antifungal and antibacterial activities of different extracts of the plant stem bark were reported (Iwalewa et al., 2007; Agbor et al.,

2004). Among Yoruba herbalists (South West, Nigeria), the aqueous root decoction of the plant is employed in the treatment of suspected liver or kidney diseases (Adeneye et al.,

2008). However, despite its extensive use, scientific validation of its therapeutic uses is lacking. In view of this, the present study was designed to evaluate the antidiarrhoeal and antimicrobial  activities of Harugana madagascariensis leaves.

1.1.3 Ecology

Harungana  Madagascariensis  occurs  at  medium  to  low attitudes  in  evergreen  forest.  It occurs at forest margins and along river and stream banks. It is a common and widely distributed tree from the Sudan to South Africa. It is often a pinion when a forest has been cleared. The species are widespread in tropical Africa, and it is found in clearings in forest region and fringing forest in Savana regions.  It is found all over Sierra leone in young farm bush, usually associated with Trema musanga and  Nauclea latifolia. In Uganda, it is found in forest edges and in secondary scrub and is usually associated with Maesopsis eminii and Trema orientails. The trees have a general brownish-yellow appearance in the field. It forms dense thickets which excludes other species and can possibly become a permanent component of tropical rainforest, potentially making it weedy. Its altitude range is from 0-

1800m, annual rainfall ranges from 1100-1800mm and its mean annual temperature is about 20-30oC.

1.2       Phytochemistry

Phytochemicals are plant derived chemicals which are beneficial to human health and disease prevention. The term is generally used to refer to those chemicals that may have biological significance, for example, antioxidants that are not established as essential nutrients, when in excess could be detrimental. It is pertinent to state that in as much as they help to strengthen the body defense mechanism serving mostly as antioxidants, moderate consumption is highly recommended so that they will not serve as anti-nutrient to the body (Ifemeje et al; 2014).

Scientists estimate that there are thousands of known phytochemicals having the potential to affect diseases such as cancer, stroke and metabolic syndrome and those caused by microorganisms (Saidulu et al., 2014). Potential phytochemicals in freshly harvested plant foods are often destroyed or removed by local and modern processing techniques. For this reason, industrially processed foods likely contain fewer phytochemicals and may   be less beneficial than unprocessed foods. Absence or deficiency of phytochemicals in processed foods may contribute to increased risk of preventable diseases (Rao and Rao, 2007). It stated that the most important of these bioactive compounds of plants are alkaloids, flavonoids, tannins, and phenolic compounds (Ibrahim and Fagbohun, 2012). This is not to say that others are not important but the few mentioned occur commonly in plants. The beneficial medicinal effects of plant materials typically result from the combination of secondary products present in plants. These secondary metabolites such as alkaloids, steroids, tannins, and phenol compounds, which are synthesised and deposited in specific parts or in all parts of the plant (Joseph and Raj, 2010). Generally, leaves are the favourable storage site.  Fruits also contain a substantial amount of active ingredients, and thus are often consumed as juice via oral  administration  to  obtain  the  desired  compounds.  Other  parts  of  plants  that  can  be extracted for therapeutic compounds are roots, aerial parts, flowers, seeds, stem barks, etc. (Chang et al., 2012).

Plant secondary metabolites are used as the basis for the production of valuable synthetic compounds such as pharmaceuticals, cosmetics, or more recently nutraceuticals (Bourgaud et al., 2001). These secondary metabolites are largely viewed as potential sources of new drugs, antibiotics,  insecticides  and  herbicides  (Crozier  et  al.,  2006).  This  is  because  of  their biological significance and potential health effects, such as antioxidant, anticancer, anti- aging, anti-atherosclerotic, antimicrobial and anti-inflammatory activities.

1.2.1 Phytochemical components in plant:

1.2.1.1 Saponin

Saponins are terpene glycosides. They are one of many secondary metabolites found in natural souces. Specifically, they are amphipathic glycosides grouped in terms of phenomenology, by the soap-like foaming they produce when shaken in aqueous solutions, and, in terms of structure, by their composition of one or more hydrophilic glycoside moieties combined  with  a  lipophilic  triterpene  derivative  (Negi  et  al.,  2013).  Research  sources disclosed that saponins exert various biological benefits, such as anti-inflammatory, anti-

diabetic, anti-atherosclerotic and serve protective functions like gastro-protective, hepatoprotective  and  hypolipidemic.  Besides,  saponins  are  effective in  maintaining  liver function, lowering blood cholesterol, preventing peptic ulcer, and osteoporosis as well as platelet agglutination. The beneficial effects of saponins have been applied commercially in drugs and medicines, emulsifiers, taste modifiers, sweeteners and precursors of hormone synthesis (Guclu-ustundag and Mazza, 2007).

Saponins are used widely for their effects on ammonia emissions in animal feeding. The mode of action seems to be an inhibition of the urease enzyme, which splits up excreted urea in feces into ammonia and carbon dioxide. Animal trials have shown that a reduced ammonia level in farming operations causes fewer damages to the respiratory tract of animals, and may help to make them less vulnerable to diseases. Dietary saponins are highly toxic to cold- blooded animals due to its haemolytic property, in which it ruptures erythrocytes and release haemoglobin.

1.2.1.2 Alkaloids

Alkaloids are a group of naturally occurring chemical compounds that contain mostly basic nitrogen atoms. There are other related groups of compounds with neutral and even weakly acidic properties (Raj and Bansal, 2004).  The nicotine molecule contains both pyridine and pyrrolidine rings.  Alkaloids are readily available in leaves, bark, roots and seeds of plants with diverse biological functions. Some alkaloids stimulate the nervous system; others can cause  paralysis,  elevate  blood  pressure  or  lower  it.  Certain  alkaloids  such  as  quinine, morphine etc, act as pain relievers, and tranquilizers. Although alkaloids act on a diversity of metabolic systems in humans and other animals, they almost uniformly invoke a bitter taste.High level of alkaloids exerts toxicity and adverse effects to humans, especially in physiological and neurological activities. For instance, consumption of tropane alkaloids will cause rapid heartbeat, paralysis and in fatal case may lead to death.  Moreover, uptake of high dose of tryptamine alkaloids will lead to staggering gate and death.  As an illustration, lower dose of alkaloids mediate important pharmacological activities, such as analgesic, reducing blood pressure, killing tumor cells, stimulating circulation and respiration (Makkar et al., 2007). Alkaloids like muscarine found in toxic variety of mushroom may produce nausea, vomiting,  diarrhea  and  in  large  quantity  can  cause  acute  necrosis  of  liver  and  death (Chatterjea and Shinde, 2012).

1.2.1.3 Tannins

Tannin is an astringent, it is a bitter plant polyphenolic compound that binds to precipitate proteins and various organic compounds including amino acids. Tannins are usually subdivided into two groups: hydrolyzable tannins (HT) and proanthocyanidins (PA). Hydrolyzable tannins are gallic acid and ellagic acid esters of core molecules that consist of polyols such as sugars and phenolics such as catechin. Hydrolyzable tannins are more susceptible to enzymatic and non-enzymatic hydrolysis than PA. They are also  more soluble in water. Hydrolyzable tannins are further classified according to the products of hydrolysis, gallotannins yield gallic acid and glucose while ellagitannins yield ellagic acid and glucose (Haslem, 2012). Proanthocyanidins are polymers of flavan-3-ol linked through an interflavan carbon bond that is not susceptible to hydrolysis. Proanthocyanidins are more commonly referred to as condensed tannins. Tannins have shown potential antiviral (Lu et al; 2004), antibacterial (Akiyama et al., 2001) and anti-parasitic effects (Kolodzie and Kiderlen,  2005). It was also reported that certain tannins were able to inhibit HIV replication selectivity and it is also used as diuretic. Plant tannin has been recognized for their pharmacological properties and is known to make trees and shrubs a difficult meal for many caterpillars. Tannin compounds are widely distributed in many species of plants, where they play a role in protection from predation,   as pesticides, and in plant growth regulation. The astringency from the tannins  causes the dry and puckery feeling in the mouth following the consumption of unripened fruit or red wine (McGee, 2004).

1.2.1.4 Phenols

Plant secondary compounds are usually classified according to their biosynthetic pathways. Three large molecular families are generally considered: phenolics, terpenes and steroids, and alkaloids. A good  example  of  a  widespread metabolite family is  the  phenolics,  because  these molecules are involved in lignin synthesis, they are common to all higher plants. Phenolic compounds are potent antioxidants and free radical scavengers which can act as hydrogen donors, reducing agents, metal chelators and singlet oxygen quenchers (Chew et al. 2009). Studies have shown that phenolic compounds such as catechin and quercetin are very efficient in stabilising phospholipid bilayers against peroxidation induced by reactive oxygen species (Gülçin et al., 2010).   Their activity is probably due to their ability to complex with extracellular and soluble proteins and to complex with bacterial cell walls. Phenols, are a class of chemical compounds consisting of a hydroxyl group

(-OH)   bonded   directly   to   an   aromatic   hydrocarbon   group.   It   is   sometimes   called phenolics.The simplest of the class is phenol, which is also called carbolic acid, C6H5OH. Phenolic compounds are classified as simple phenols or polyphenols based on the number of phenol units in the molecule (Khoddami et al., 2013). It is a crystalline aromatic organic compound which is a constituent of coal tar. Dilute solutions of phenol are useful antiseptics, but strong solutions of phenols are caustic and scarring to tissues. Phenols are widely used in the manufacture of resins, plastics, insecticides, explosives, dyes and detergents and as raw materials for the productions of medicinal drugs such as aspirin. In plants, the phenolic units are esterified or methylated and are submitted to conjugation, which means that the natural phenols are mostly found in the glycoside form instead of the glycone form. This property of undergoing conjugation with other molecules enables it to scavenge free radicals and thus inhibit the oxidative mechanisms that can lead to degenerative diseases such as cancer (Khoddami et al., 2013). Notable sources of natural phenols in human nutrition include berries, tea, beer, olive oil, chocolate or cocoa, coffee, popcorn, fruits and fruit based drinks (including cider, wine and vinegar) and vegetables. Herbs and spices, nuts (walnuts, peanut) and algae are also potentially significant for supplying certain natural phenols. Phenols have reported anti-tumour  properties and also exhibit antiviral and antimicrobial, hypotensive, and antioxidant properties.

1.2.1.5 Terpenoids

Terpenoids are condensation products of C5 isoprene units which are important constituents of essential oils (Pichersky and Gershenzon , 2002). They have been shown to be active against bacteria, fungi, viruses, and protozoa. The mechanism of action of terpenes is not fully understood but is speculated to involve membrane disruption by the lipophilic compounds (Cowan, 2013).

1.2.1.6 Flavanoids

Flavonoids   are a class of plant secondary metabolites. Its name came from the Latin word flavus meaning yellow; their colour in nature. Flavonoids were referred to as vitamin  P (probably because of the effect they had on the permeability of vascular capillaries) from the mid-1930s to early 50s, but the term has since fallen out of use. Flavonoids such as the catechins are the most common group of polyphenolic compounds in the human diet and are found ubiquitously in plants (Spencer, 2008). They are generally found in a variety of foods, such as oranges, tangerines, berries, apples and onions (Middleton et al., 2000). The widespread distribution of flavonoids, their variety and their relatively

low toxicity compared to other active plant compounds (for instance alkaloids) mean that many animals, including humans, ingest significant quantities in their diet.     Flavonoids also have anti- allergic, anti-inflammatory, anti-microbial (Cushnie and Lamb, 2011), anti-cancer and anti-diarrheal activities (Romagnolo and Selmin, 2012).  Tannins and flavonoids are thought to be responsible for antidiarrhoeal activity by increasing colonic water and electrolyte reabsorption (Palomba 2006).

1.3       Diarrhoea

Diarrhea is an annoying and occasionally deadly symptom of an acute or chronic health problem. It is a common complaint for all age groups. Diarrhea is defined by the World Health Organization (WHO) as three or more watery or loose bowel movements in a 24 hour period. However, the lay population may claim they have diarrhea when they have other problems, such as fecal impaction (Schiller, 2009). Therefore when evaluating a person with complaints of diarrhea, it is imperative to closely question the patient about associated signs and symptoms.

1.3.1    Diarrhoea in children

Children, especially infants, are more vulnerable to dehydration since their body surface to volume ratio is higher than adults, their metabolism is higher and their functional reserves are lower (Burpee and Duggan, 2008). Caregivers should be made aware of the signs of dehydration and encouraged to seek medical attention if the signs are encountered. ORT is the first line of defense for children and infants to ward off dehydration. All ages should continue to eat age appropriate foods if they are not dehydrated to maintain caloric needs (Koslap-Petraco, 2006). Few medications are indicated for treatment of diarrhea children. If diarrhea persists after ORT is started or if dehydration occurs, the child should be evaluated rather than being given over the counter medications. Of special note, children should not be given medications with bismuth subsalicylate when they have flulike symptoms or chicken pox because of the potential complication of Reye’s syndrome (Turkwoski, 2007).

1.3.2    Diarrhoea in elderly

The elderly are at higher risk for more severe outcomes from diarrhea than the younger population. They tend to have less reserve to withstand the effect resulting from dehydration or decreased caloric intake (Schiller, 2009). The gastrointestinal tract changes with advancing age resulting in slowed transit time and decreased blood flow to the gut (Zarowitz, 2009). Other organs are affected by aging and play a part in availability of medication in the blood. These changes may result more in circulating drug in the elder’s blood stream and toxicity can become an issue. It may be prudent to decrease dosages of drugs and to lengthen the time between doses to guard against toxicity. It was stated that loperamide and bismuth subsalicylate have safety profiles that allow these drugs to be used for non-infectious diarrhea in the elderly (Zarowitz, 2009). However, caution should be taken against the use loperamide if C. difficile infection is suspected and against the use of bismuth subsalicylate if the patient is on blood thinners. She also reported that drugs such as diphenoxylate should be used with caution in the elderly due to the possibility of sedation (Zarowitz, 2009).

₦5,000.00 – DOWNLOAD FULL PROJECT DOWNLOAD FULL PROJECT Added to cart

---

---

---

---

Related Project Topics :