Researchers have identified functional foods and phytonutrients that could be effectively used to manage diabetes.Top on the list, according to the report published in the book entitled, “Food as Medicine: Functional Food Plants of Africa,” and journal Current Pharmacology Reports, are: bitter melon; Aloe vera; bitter kola; bitter leaf; clove oil; coconut oil; garlic; ginger; black pepper (utazi in Ibo); guava leaves; velvet beans; bush mango; onion; okra; plantain; scent leaf; soursop; soybeans; tea leaves; and turmeric.
Commonly called bitter melon, bitter gourd, African cucumber or balsam pear, Momordica charantia belongs to the plant family Cucurbitaceae. In Nigeria, bitter melon is called ndakdi in Dera; dagdaggi in Fula-Fulfulde; hashinashiap in Goemai; daddagu in Hausa; iliahia in Igala; akban ndene in Igbo (Ibuzo in Delta State); dagdagoo in Kanuri; akara aj, ejinrin nla, ejinrin weeri, ejirin-weewe or igbole aja in Yoruba.
Black pepper (Gongronema latifolium) is known by the Ikales of Ondo State of Nigeria as Iteji. The Ibos call the plant Utazi; the Efik/ Ibibio call it Utasi while the Yorubas call it Arokeke.
Botanically called Vernonia amygdalina, bitter leaf is of the plant family Compositae. It is called Ewuro in Yoruba and Onugbu in Ibo.Botanically called Ocimum gratissimum, scent leaf or basil belongs to the mint family Lameacea. It is called Effirin in Yoruba and Nchuanwu or Arigbe in Ibo.
The author of “Food as Medicine: Functional Food Plants of Africa” and professor of pharmacognosy, Maurice Iwu, said his team of researchers at the International Centre for Ethomedicine and Drug Development (InterCEDD), Nsukka, Enugu State, has outlined a select list of major herbs or food plants that are used as nutritional supplements in the management of diabetes and/or its complications.
Iwu noted: “…Naturally occurring phenolic compounds that are distributed widely in plants such as flavonoids, procyanidins, and catechins have been shown to be responsible for the anti-diabetic activities of many edible vegetables and fruits. They constitute an important component of human diet…
“Flavonoids and procyanidins are capable of improving, stabilizing, and sustaining insulin secretion, pancreatic islets, and pancreatic cell activities…”
Bitter melon
A study published in journal Current Pharmacology Reports has established that besides diabetes, bitter melon is effective in treating other chronic diseases such as cancer and Human Immuno-deficiency Virus (HIV)/Acquired Immune Deficiency Syndrome (AIDS).
The study is titled “Bitter Melon as a Therapy for Diabetes, Inflammation, and Cancer: a Panacea?” The researchers noted: “Over the last few decades, multiple well-structured scientific studies have been performed to study the effects of bitter melon in various diseases. Some of the properties for which bitter melon has been studied include: antioxidant, antidiabetic, anticancer, anti-inflammatory, antibacterial, antifungal, antiviral, anti-HIV, anthelmintic, hypotensive, anti-obesity, immuno-modulatory, antihyperlipidemic, hepato-protective, and neuro-protective activities. This review attempts to summarize the various literature findings regarding medicinal properties of bitter melon. With such strong scientific support on so many medicinal claims, bitter melon comes close to being considered a panacea.”
According to Food as Medicine: Functional Food Plants of Africa published 2017 by CRC Press, “…Dietary use of bitter melon or its juice decreases blood glucose levels, increases High Density Lipo-protein (HDL)/good cholesterol, and decreases triglyceride levels, thus exhibiting antiatherogenic qualities. Extract of bitter melon in supplement form has been widely used as a traditional medicine for diabetic patients. When administered alone, it has a modest hypoglycemic effect at doses of at least 2000 mg/day. This botanical supplement enhances the cellular uptake of glucose and promotes insulin release, potentiating its effect, and in animal studies has been shown to increase the number of insulin-producing beta cells in diabetic animals. Bitter melon has also been found to reduce adiposity and oxidative stress in addition to reducing blood triglycerides and Low Density Lipo-proteins (LDL)/bad cholesterol.”
Bitter leaf
The major activities found in many laboratory and clinical studies on Bitter leaf (Vernonia amygdalina) include antimalarial, antidiabetic, antioxidant, antihypercholesterolemic, anthelmintic, uterine contractility, immune boosting in HIV infections, and anti-inflammatory properties. Vernonia holds tremendous promise for development into a nutraceutical against diabetes and malaria. It has been found that a decoction containing a mixture of bitter leaf, scent leaf (Ocimum gratissimum) and West African black pepper (Gongronema latifolium, Utazi in Ibo) was found to be superior in antidiabetic activity to any one, or blends of only two, of the three plants. A proprietary product by InterCEDD Health Products and Neimeth Pharmaceuticals called Physogen Plus contains the three vegetables and bitter kola (Garcinia kola).
Black pepper
Utazi is valued as an ingredient for the preparation of bitters. It is a major constituent of the popular antidiabetic tea, Physogen, produced by InterCEDD and marketed by Neimeth Pharmaceuticals and InterCEDD Health Products (IHP). Several laboratory studies have demonstrated the possible antidiabetic activity of Utazi. Different alcoholic leaf extracts showed promising hypoglycemic and antihyperglycemic activities in a dose-dependent way on normal and alloxan-induced or streptozotocin-induced diabetic rabbits. An ethanolic leaf extract possessed significant anti-lipid peroxidative activities. In a small clinical trial, the blood glucose concentration of healthy humans was determined after consumption of leaves and showed a significant reduction in blood glucose level. Leaf extracts also showed antioxidant, anti-inflammatory, hepato-protective, anti-plasmodial, anti-asthmatic, anti-sickling, antiulcer, analgesic, antipyretic, gastrointestinal relaxing, laxative, and stomachic activities.
Bitter kola
According to Food as Medicine: Functional Food Plants of Africa, kolaviron, the mixture of bioflavonoids, benzophenones, and chromanols, and related phenolic compounds in Garcinia kola possess strong antioxidant activities. Also, a study published in African Health Sciences has established the antidiabetic effect of kolaviron; a biflavonoid complex isolated from Garcinia kola seeds, in Wistar rats.
The researchers led by O. A. Adaramoye established the hypoglycaemic effect of kolaviron (KV), (biflavonoid from Garcinia kola) in streptozotocin (STZ)-diabetic rats.They evaluated the possible protective effects of KV on cardiac, renal and hepatic tissues of STZ-diabetic rats.
The study consisted of four groups of six rats each. Groups one and two contained non-diabetic and untreated-diabetic rats, respectively. Groups three and four were made up of KV- and glibenclamide (GB) – treated diabetic rats, respectively.
The researchers found that the STZ-intoxication caused a significant increase in the relative weight of liver in diabetic rats. STZ-diabetic rats had significant increase in the levels of fasting blood glucose (FBG), á-amylase and HbA1c. A marked and significant increase in the levels of cardiac, renal and liver marker indices such as serum creatine kinase, lactate dehydrogenase, creatinine, urea and alanine aminotransferase were observed in untreated diabetic rats. Also, untreated diabetic rats had significantly elevated urinary glucose and protein and, lowered creatinine clearance. In KV- and GB- treated groups, the levels of FBG, á-amylase and HbA1c were significantly reduced, while treatment with KV significantly attenuated the cardiac, renal and liver marker indices.They concluded that KV offered significant antidiabetic and tissues protective effects in the rats.
Bush mango
Botanically called Irvingia gabonensis, Bush mango is known as Ogbono in Ibo language. Seeds of Irvingia species are used in West Africa culinary arts as mucilaginous soup thickener for the preparation of Ogbono soup. The aqueous extract has been found by laboratory studies and clinical outcome studies to have a beneficial effect on the management of type 2 diabetes. In high-fat-diet rats, the mucilage was effective in preventing increase in plasma lipid levels, improving the antioxidant enzyme levels, exerting beneficial effects on lipid metabolism, and avoiding large increase in food intake and body weight. This is due to the effect the mucilage exerts on intestinal peptide involved in the regulation of food intake, and also their gel-forming and good antioxidant properties. A proprietary formulation of Irvingia extract, Evira-IHP is marketed by IHP as an anti-obesity supplement.
Scent leaf
Ocimum species are used as vegetable spices in soups and in traditional medicine for the treatment of various diseases. Ocimum gratissimum is popularly used to treat diabetes mellitus. The hypoglycemic activity of this medicinal species has been confirmed by several in vivo studies. The plant contains several volatile components, including the hypoglycemic phenolic substances such as L-caftaric acid, L-chicoric acid, eugenyl-beta-D-glucopyranoside, and vicenin. The activity of Ocimum gratissimum decoction fractions has been shown by laboratory studies to be mainly due to the presence of chicoric acid. A hypoglycemic tetracyclic triterpene has also been isolated from the related Ocimum sanctum from India. Scent leaf is a major ingredient in the anti-diabetic tea, Vernonia-Ocimum, marketed by IHP.
Soursop
Researchers have shown that a meal of soursop could be the cure for diabetes, heart disease, cancer, and diarrhoea.Commonly called Soursop, Annona muricata is a plant, which belongs to the family Anonaceae.
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 have 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-Ieishmanial 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.
Onion and garlic
Oral administration of onion (Allium cepa) and garlic (Allium sativum) to alloxan-induced diabetic rats for 30 days ameliorated hyperglycemia, reversed weight loss and depletion of liver glycogen. The anti-diabetic bioactive principles of Allium cepa and Allium sativum were S-methylcysteinesulfoxide (SMCS) and S-allylcysteinesulfoxide (SACS) respectively.
The studies showed that SMCS and SACS exerted their anti-diabetic properties by stimulating insulin secretion as well as compete with insulin for insulin inactivating sites in the liver. Specifically, SACS inhibited gluconeogenesis in the liver. In addition, SACS from Allium sativum impeded lipid peroxidation due to its antioxidant and secretagogue actions. The capacities of Allium cepa and Allium sativum to alleviate Diabetes Mellitus (DM) in the experimental rats were comparable with diabetic rats treated with glibenclamide and insulin. The study also noted that SMCS and SACS caused significant increase in the biosynthesis of cholesterol from acetate in the liver, which was an indication of low capacities of allium products to protect the rats against risk factors associated with DM.
Aloe vera/Aloe barbedensis
A 1.0 μg of five phytosterols- lophenol, 24-methyl-lophenol, 24-ethyl-lophenol, cycloartanol, and 24-methylene-cycloartanol from Aloe vera exhibited comparable capacities to lower blood glucose levels in Type II diabetic BKS.Cg-m+/+Leprdb/J (db/db) mice following 28 day treatment. The five phytosterols caused significant decrease in blood HbA1c levels by 15 to 18 per cent.
Additionally, severe diabetic mice treated with the five phytosterols did not suffer weight loss because of rapid excretion of glucose in the urine. The findings suggested that phytosterols derived from Aloe vera gel have a long-term blood glucose lowering effect, which could be applied as agents of glycemic control in Type 2 Diabetes Mellitus. Studies showed that phytosterols stimulate the biosynthesis and/or release of insulin as well as alter the activity of carbohydrate metabolizing enzymes.
Turmeric
Turmeric, an Asian spice cultivated in Nigeria and found in many curries, has a long history of use in reducing inflammation, healing wounds and relieving pain, preventing diabetes, heart failure, and inducing weight loss.The local spice, turmeric, has entered into herbal regimen for weight loss programme. A recent United States (U.S.) study suggests that turmeric may be a new way to spice up weight loss routine.
Curcumin is a bioactive component in curry and turmeric that has been consumed daily in Asian countries for centuries without reported toxic effects.Turmeric is a spice that comes from the root of Curcuma longa, a member of the ginger family, Zingaberaceae. In traditional medicine, turmeric has been used for its medicinal properties for various indications and through different routes of administration, including topically, orally, and by inhalation.
In Nigeria, it is called atale pupa in Yoruba; gangamau in Hausa; nwandumo in Ebonyi; ohu boboch in Enugu (Nkanu East); gigir in Tiv; magina in Kaduna; turi in Niger State; onjonigho in Cross River (Meo tribe).
Turmeric, also known as curcuma, produces a root that is used to produce the vibrant yellow spice used as a culinary spice so often used in curry dishes.Though native to India and parts of Asia, and is a relative of cardamom and ginger, turmeric has been domesticated in Nigeria.
Today’s herbalists and naturopaths consider turmeric to be one of nature’s most potent anti-inflammatories and antioxidants. They say turmeric may help treat a variety of conditions related to inflammation and antioxidant damage, including cataracts, arthritis, cancer, and heart disease. It is also used to treatment of scabies and digestive disorders, promote wound healing, and strengthen the immune system.
According to a pharmacognocist at the College of Medicine University of Lagos (CMUL), Idi-Araba, Prof. Olukemi A. Odukoya, “Turmeric helps detoxify the body, and protects the liver from the damaging effects of alcohol, toxic chemicals, and even some pharmaceutical drugs. Turmeric stimulates the production of bile, which is needed to digest fat. Turmeric also guards the stomach by killing salmonella bacteria and protozoa that can cause diarrhoea.”
Plantain
Plantain (Musa paradisiaca) is cultivated in many tropical countries of the world, and it is known to be rich in iron, fiber, vitamins, minerals, and serotonin.In folklore medicine, unripe plantain is useful in the management of diabetes, treatment of anemia, and liver disorders (independent of diabetes).
A study published in Interventional Medicine and Applied Science indicated the potential of unripe plantain in the management of renal and liver complications arising from diabetes mellitus.
Okra
Various studies on Okra (Abelmoscus esculentus) showed that the extract has a hypoglycemic effect that helps decrease blood glucose level. Its properties can be a useful remedy to manage diabetes mellitus. In addition, it leads to inhibition of cholesterol absorption and subsequently decreases the level of lipid and fat in the blood.
A study published in Iran Journal of Medical Sciences concluded: “Based on the positive effects of Okra on reducing blood sugar level, the widespread use of this plant is recommended.”
According to the book, “Food as Medicine: Functional Food Plants of Africa,” okra is valued in the folk management of duodenal ulcers and diabetes. The glycosylated molecules found in okra mucilage have been related to the inhibition of adhesion of Helicobacter pylori to human gastric mucosa. Such molecules could also contribute to glucose entrapment and alpha-glucosidase inhibition that might be advantageous in the management of diabetes.
Soybeans
Soybean therapy in diabetic individuals depends on the type of diabetes and other factors such as lifestyle and metabolic needs of the patients. Soybean protein has a role in diabetes because of its content in glycine and arginine, which tend to reduce blood insulin levels. Soybean fibre may be useful because of its insulin-moderated effect.
Soybean diet may be a good option in type 2 diabetes individuals due to its effect on hypertension, hypercholesterolemia, atherosclerosis and obesity, which are very common diseases in diabetic patients.
In addition, substituting animal protein for soybean or other vegetable protein may also decrease renal hyperfiltration, proteinuria, and renal acid load and therefore reduces the risk of renal disease in type 2 diabetes.
It is generally accepted that a high fibre diet, particularly soluble fiber, is useful to control plasma glucose concentration in diabetics. In short-and long-term experiments it has been reported an improvement in blood glucose attributed to fibre intake from soybeans. The mechanisms to improve glycemic control during dietary fibre intake seem to be due to the effects of slowing carbohydrate absorption, so that dietary fibre reduces or delays the absorption of carbohydrates. It also increases faecal excretion of bile acid and therefore may cause a low absorption of fat.
Velvet beans
Velvet beans or cowhage (Mucuna pruriens) is called Werepe in Yoruba and Agabaloko or Agbala in Ibo. Results of study published in Asian Pacific Journal of Tropical Medicine showed that the administration of 5, 10, 20, 30, 40, 50, and 100 mg/kg of the crude ethanolic extract of Mucuna pruriens seeds to alloxan-induced diabetic rats (plasma glucose greater than 450 mg/dL) resulted in 18.6 per cent, 24.9 per cent, 30.8 per cent, 41.4 per cent, 49.7 per cent, 53.1 per cent and 55.4 per cent reduction, respectively in blood glucose level of the diabetic rats after eight hour of treatment while the administration of glibenclamide (5 mg/kg/day) resulted in 59.7 per cent reduction. Chronic administration of the extract resulted in a significant dose dependent reduction in the blood glucose level. It also showed that the anti-diabetic activity of Mucuna pruriens seeds resides in the methanolic and ethanolic fractions of the extract. Acute toxicity studies indicated that the extract was relatively safe at low doses; although some adverse reactions were observed at higher doses (eight-32 mg/kg body weight), no death was recorded. Furthermore, oral administration of Mucuna pruriens seed extract also significantly reduced the weight loss associated with diabetes.
The study clearly supports the traditional use of Mucuna pruriens for the treatment of diabetes and indicates that the plant could be a good source of potent anti-diabetic drug.
