Sunday, November 1, 2009

Eating soursop to beat diabetes, cancer

GUYABANO or SOURSOP Part 2

Researchers have shown that a meal of soursop could be the cure for diabetes, heart disease, cancer, and diarrhoea. CHUKWUMA MUANYA reports.

THEY are known for their succulent white endocarp. They are replete in southern Nigeria. The fruit-pulp is soft with an agreeably sour flavour. It is usually eaten raw but unfortunately contains a quantity of fibre. It may be more acceptable after some preparation, that is either as juice, ice-cream, jellies but not jams.

Commonly called Soursop, Annona muricata is a plant, which belongs to the family Annonaceae. H. M. Burkill in the Useful Plants of West Tropical Africa described the Soursop plant as "a small tree attaining a height of about eight metre. A native of tropical America, but now widespread in the tropics, it is thought to have reached Africa (Angola) by 1686. The trunk and timber do not appear to have any particular uses."

Soursop is a medicinal plant that has been used as a natural remedy for a variety of illnesses. Several studies by different researchers demonstrated that the bark as well as the leaves has anti-hypertensive, vasodilator, anti-spasmodic (smooth muscle relaxant) and cardio depressant (slowing of heart rate) activities in animals.

Researchers had re-verified Soursop leaf's hypotensive (reduce blood pressure) properties in rats. Other properties and actions of Soursop documented by traditional uses include its use as anti-cancerous, anti-diabetes, anti-bacterial, anti-fungal, anti-malarial, anti-mutagenic (cellular protector), emetic (induce vomiting), anti-convulsant, sedative (induces sleep), insecticidal and uterine stimulant (helps in childbirth). It is also believed to be a digestive stimulant, antiviral, cardio tonic (tones, balances and strengthens the heart), febrifuge (cures fever), nerviness (balances/calms the nerves), vermifuge (expels worms), pediculocide (kills lice) and as an analgesic (pain-reliever).

Researchers have confirmed the anti-viral activity of ethanolic extracts of Soursop against Herpes simplex virus. Extracts of Soursop have been shown to have anti-parasitic, anti-rheumatic, astringent, anti-leishmanial and cytotoxic effects. Soursop has also been shown to be effective against Multi-Drug Resistant (MDR) cancer cell lines. Extracts of Soursop were also shown to be effective against the cancer cell line U973, and hematoma cell lines in-vitro. Extracts were also shown to be lethal to the fresh water mollusk, Biomphalaria glabrata, which act as a host for the parasitic worm Schistosoma mansoni.

But recent studies have described how extracts of Soursop reduces blood sugar in diabetics by improving insulin production, improves cardiovascular health by reducing blood fats, treat drug resistant cancer, stop diarrhoea in children, among others.

Nigerian researchers have evaluated the effects of methanolic extract of Soursop leaves on the pancreatic islet cells of streptozotocin induced- diabetic rats. The results of the study indicated that Soursop extract treatment decreased the blood glucose concentration of diabetic rats due to the regeneration/proliferation in the pancreatic Beta cells (_-cells).

The pancreas is a gland organ in the digestive and endocrine system of vertebrates. It is both an endocrine gland producing several important hormones, including insulin, glucagon and somatostatin, as well as an exocrine gland, secreting pancreatic juice containing digestive enzymes that pass to the small intestine. These enzymes help in the further breakdown of the carbohydrates, protein, and fat in the chyme.

Beta cells (beta-cells, _-cells) are a type of cell in the pancreas in areas called the islets of Langerhans. They make up 65-80 per cent of the cells in the islets. Beta cells make and release insulin, a hormone that controls the level of glucose in the blood.

Streptozotocin (Streptozocin, STZ, Zanosar) is a naturally occurring chemical that is particularly toxic to the insulin-producing beta cells of the pancreas in mammals. It is used in medicine for treating certain cancers of the Islets of Langerhans and used in medical research to produce an animal model for Type 2 diabetes.

Streptozotocin-induced hyperglycemia in rats is considered a good model for the preliminary screening of agents active against Type 2 diabetes and is widely used. Generally, destruction of _-cells starts three days after STZ administration and reaches its peak at three to four weeks in rats. Streptozotocin-induced diabetes in laboratory animals has been widely used for research on diabetes and its long-term complications.

The study titled "Effects Of Annona muricata (Soursop) On The Morphology Of Pancreatic Islet Cells Of Experimentally-Induced Diabetic Wistar Rats" was published in Internet Journal of Alternative Medicine, 2008 Volume 5 Number 2 by David Olawale Adeyemi, Omobola Aderibigbe Komolafe, Stephen Olarinde Adewole, Efere Martins Obuotor, Thomas Kehinde Adenowo.

Soursop has been found to contain numerous bioactive compounds useful for the management of various ailments including Diabetes Mellitus (DM), Type 2 diabetes, in folkloric medicine. The management of DM depends on continuous hypoglycemic therapy, which may not be consistently adhere to by the patient.

The researchers; therefore, investigated whether or not extracts of Soursop could provide lasting hypoglycemic control through regeneration of the destroyed _- cells of the pancreatic islets of experimentally induced diabetic Wistar rats.

The result of this study demonstrated that Soursop possesses anti-hyperlipidemic activities. Hyperlipidemia, hyperlipoproteinemia, dyslipidemia or hyperlipidaemia (British English) is the presence of raised or abnormal levels of lipids (fatty molecules) and/or lipoproteins in the blood.

The researchers from Obafemi Awolowo University (OAU) Ile-Ife, Osun State, include David Olawale Adeyemi, Omobola Aderibigbe Komolafe, Stephen Olarinde Adewole all of the Department of Anatomy and Cell Biology and Efere Martins Obuotor of Department of Biochemistry.

The study was published in The Internet Journal of Alternative Medicine, 2009 Volume 7 Number 1.

30 adult Wistar rats were randomly assigned into three groups (A, B and C) of ten rats each. Group A was the control, Group B was untreated diabetic group and group C was Soursop-treated group.

DM was experimentally induced in groups B and C by a single intra-peritoneal injection of 80mg/kg streptozotocin dissolved in 0.1M citrate buffer. Group A rats were intraperitoneally injected with equivalent volume of citrate buffer.

Daily intra peritoneal injection of 100mg/kg Soursop was administered to group C rats for two weeks. The rats were sacrificed and the pancreas were removed and fixed in Bouins fluid. The tissues were processed for paraffin embedding and sections of 5┬Ám thickness were produced and stained. Histopathological examination of the stained sections showed regeneration _-cells of islets of pancreas of Soursop-treated rats when compared to untreated diabetic group of rats.

The researchers concluded: "The result of this present study indicated that decreased in the blood glucose concentration of diabetic rats by Soursop treatment is due to the regeneration/proliferation in the pancreatic _-cells."

Nigerian researchers have also demonstrated the effects of methanolic extracts of Soursop on serum lipid profile changes in experimentally-induced diabetic Wistar rats with view to elucidate its possible effects on cardiovascular diseases induced by hyperglycemia.

Diabetes mellitus (DM) is associated with an increased risk of thrombotic, atherosclerotic and cardiovascular disease. Hyperlipidemia is metabolic complication of both clinical and experimental diabetes. Low-density lipoprotein (LDL)- 'bad cholesterol'- in diabetic patients leads to abnormal metabolism and is associated with increase in very low-density lipoprotein (VLDL) secretion and impaired VLDL catabolism. Ultimately this leads to atherosclerotic plaque. A number of known factors for coronary artery disease such as hypertension, obesity and dyslipidemia/hyperlipidemia are more common in diabetics than in the general population.

The World Health Organisation (WHO) predicts that the number of cases worldwide for diabetes, now as of 171 million, will touch 366 million or more by the year 2030.

Patients with DM are more likely to develop microvascular and macrovascular complications than the non-diabetic population. Dyslipidemia/hyperlipidemia is a frequent complication of DM and is characterised by low levels of high-density lipoprotein (HDL)- 'good cholesterol'- and high levels of low-density lipoprotein (LDL) and triglyceride (TG). Triglycerides, as major components of (VLDL), play an important role in metabolism as energy sources and transporters of dietary fat.

30 adult Wistar rats were randomly assigned into three groups (A, B and C) of ten rats each. Group A was the control, Group B was untreated diabetic group and group C was Soursop-treated group. The changes in the serum lipid profiles were monitored in all the animals four weeks before the commencement of the experiment and throughout the experimental period. Diabetes mellitus was induced in groups B and C by a single intra-peritoneal injection of 80mg/kg streptozotocin dissolved in 0.1M citrate buffer. The control group was intraperitoneally injected with equivalent volume of citrate buffer and all the animals were monitored for another four weeks. Daily intra peritoneal injection of 100mg/kg Soursop was administered to group C rats for two weeks and the animals were monitored for another two weeks.

The data obtained were analysed with descriptive and inferential statistics. The result of the serum lipid analysis showed a significant reduction in the serum total cholesterol, triglyceride, low-density lipoprotein cholesterol and very low-density lipoprotein cholesterol, and a significant increase in the serum high-density lipoprotein cholesterol and antiatherogenic index of Soursop-treated group when compared to untreated diabetic group of rats. Atherogenesis is the process of forming atheromas, plaques in the inner lining (the intima) of arteries.

The researchers concluded: "The result of this present study clearly shows that Annona muricata has a lipid lowering effects on serum triglycerides, total cholesterol and low-density lipoprotein cholesterol of STZ induced diabetic rats. A. muricata treatment also increase the serum level of High-density lipoprotein cholesterol termed 'good cholesterol'. There is a substantial evidence that lowering the total cholesterol, particularly LDL level will lead to a reduction in the incidence of coronary heart disease which is still the leading cause of death in diabetic patients."

Nigerian researchers have used the fruit juice of Soursop to stop diarrhoea in children and adults. The study, titled "Use of Soursop and Sweetsop Juice in the Management of Diarrhoea in Children", was published in Journal Diarrhoeal Disease Resident by Dr. Ifeoma B. Enweani of the Department of Microbiology Faculty of Natural Sciences, Edo State University, Ekpoma, Edo State.

The juice was administered onto 25 children aged six- 20 months and five adults with acute watery diarrhoea. Children with prolonged diarrhoea, malnutrition, or other major systemic illnesses were excluded. Five mL of the juice was administered on to the patients three times daily for up to 72 hours.

The fruit juice was able to resolve the diarrhoeic condition at 48 hours. This conforms to the report that at 48 hours 42 per cent of the diarrhoeic patients treated with smectite were free from diarrhoea. Zinc available in the juice had been reported to bring about significant reduction in intestinal fluid loss. This suggests that Soursop juice can be used as a complementary source for Oral Rehydration Therapy (ORT) in the management of diarrhoea in children and adults. This could reduce morbidity and mortality rate in children, specially in the developing nations.

Many active compounds and chemicals have been found in Soursop, as scientists have been studying its properties since the 1940s. Most of the research on Soursop focuses on a novel set of chemicals called Annonaceous acetogenins. Soursop produces these natural compounds in its leaf and stem, bark, and fruit seeds. Three separate research groups have confirmed that these chemicals have significant anti-tumorous properties and selective toxicity against various types of cancer cells (without harming healthy cells) publishing eight clinical studies on their findings. Many of the acetogenins have demonstrated selective toxicity to tumour cells at very low dosages-as little as one part per million. Four studies were published in 1998, which further specify the chemicals and acetogenins in Soursop, which are demonstrating the strongest anti-cancerous, antitumorous, and antiviral properties. In a 1997 clinical study, novel alkaloids found in Soursop fruit exhibited antidepressive effects in animals.

Researchers in Taiwan reported in 2003 that the main Soursop acetogenin, annonacin, was highly toxic to ovarian, cervical, breast, bladder and skin cancer cell lines at very low dosages saying; " . . . annonacin is a promising anti-cancer agent and worthy of further animal studies and, we would hope, clinical trials.

According to the Useful Plants of West Tropical Africa, the fruit contains over 11 per cent sugar, mostly glucose and fructose. It is deficient in calcium, phosphorus and vitamin A but very rich in vitamins B and C.

Source: Guardian Newspaper