by Chukwuma Muanya, Nigeria Guardian
Tomorrow is World Diabetes Day! Although there is no cure yet for both type 1 and type 2 diabetes, Nigerian researchers and their foreign counterparts have identified local plants such as guava, bitter leaf, Egusi melon and figs that will not only reduce blood sugar levels and improve the function of the insulin but protect the body against common complications of diabetes such as kidney failure and heart attack.
Diabetes mellitus (DM) is a group of metabolic diseases characterized by hyperglycemia (high blood glucose level), which results from defects in insulin secretion, insulin action or both.
The chronic hyperglycaemia of DM is associated with long-term damage, dysfunction and failure of various body structures and organs especially the eyes, nerves, heart, blood vessels and also the kidney.
Existing therapy for DM are known to provide good glycaemic control, but are believed to do little in regards to the complications to various organs. Besides, these anti diabetic drugs are associated with mild to moderate side effects.
However, Nigerian researchers from the Obafemi Awolowo University (OAU), Ile-Ife, Osun State, have identified four local plants that could be used as alternative therapy in ameliorating diabetic-associated disorders of the kidney.
The plants include: Bitter leaf (Veronia amygdalina), shaft of ‘Egusi’ melon seed (Citrullus colocynthis), leaves of guava (Psidium guajava), and leaves of figs (Ficus mucuso).
The study published in Cytology & Histology investigated the effect of four herbal extract and their efficacy on the histomorphometry of the kidney in Streptozotocin (STZ) induced diabetic rats with a view to understanding their anti-diabetic properties.
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 1 diabetes in large dose as well as Type 2 diabetes with multiple low doses.
Veronia amygdalina (VA) commonly called bitter leaf belongs to the family Asteraceae. It has petiolate leaves of about six millimetre (mm) diameter and elliptic shape. The leaves are green with a characteristic odour and a bitter taste. Bitter leaf is called Ewuro by the Yorubas and Onugbu by the Igbos. The leaves have been used in traditional folk medicine as anthelmintics, anti-malarial, antimicrobial anticancer and as a laxative herb. Phytochemical substances in VA include oxalates, phylates and tannins, and also flavonoids.
Citrullus colocynthis (CC) popularly known as colocynth, bitter gourd, wild gourd and vine-of-Sodom is a tropical plant belonging to the family Cucurbitaceae. It is also commonly referred to as Egusi amongst most tribes in Nigeria including the Yorubas and Igbos of Nigeria. In the traditional medicine, it has been used in treatment of constipation, diabetes oedema, fever, jaundice leukaemia, bacterial infections, cancer and used as an abortifacient.
Psidium guajava (PG) is a semi deciduous tropical tree commonly known as ‘guava’ and belongs to the family Myrtaceae. Phytochemical constituent have been shown to include Vitamin C, B1, B2, and B6, free sugars. Guava fruits have been shown to have antioxidant properties. The fruits have been shown to possess hypoglyceamic effects in diabetic mice and human volunteers. Studies have indicated the presence of various flavonoids, terpenoids and their glycosides, and these compounds have been shown to be antidiabetic.
Ficus mucuso (FM) belongs to the family Moraceea. Commonly called figs, it is called Odan-afomo in Yoruba. The Ficus genus has wide distribution and is used traditionally as medicine, vegetable, food, fodder and fuel wood. Phytochemical analyses of FM have revealed the presence of monoterpenoids and flavonoids.
Meanwhile, the OAU researchers randomly divided forty- two healthy adult Wistar rats (Rattus novergicus) with an average weight of 153.4 g into seven groups (six in each group). STZ (65 mg/kg) dissolved in citrate buffer was administered intraperitoneally to animals in groups (B-G) while animals in group A received equivalent volume of citrate buffer. Plant extracts (100 mg/kg) were administered daily (orally) to animals in groups C-F and glimepiride (anti-diabetic drug) to animals in group G for fourteen days. After the expiration of the study the animals were sacrificed and the kidneys were excised, fixed in 10 per cent formol saline for histology and morphometric analysis.
The glomeruli of the diabetic group were atrophied which is validated by significant decrease in its density, shrinkage and increased bowman’s space. These observations were also characterized by diminished cellular proliferation, decreased cellular volume and ischemia. The histology and morphometric analysis revealed that the kidney in the group treated with Psidium guajava shows a better histoarchitectural outline of all the four plant extracts used.
The study therefore suggests that Psidium guajava could be a better alternative therapy in ameliorating diabetic-associated disorders of the kidney.
The researchers wrote: “Long-term damage, dysfunction and failure of the kidneys are a major complication of diabetes mellitus. Disorders of the kidneys are serious secondary consequence of diabetes, resulting in end stage- renal diseases. Increased glucose levels in the blood have been shown to lead to oxidative stress, which is considered as one of the causative factor for diabetes-associated kidney disorders. STZ-induced diabetic rodents are seen to develop kidney disorders similar to the early stage of human diabetic-associated disorders of the kidney. Renal hypertrophy has been reported in diabetes.
“Also diabetic nephropathy has been known to cause renal failure thus leading to mortality and morbidity.
“However the histological and histomorphometric evaluation of the present study shows atrophy rather than hypertrophy in the glomeruli of diabetic animals which is validated by significant decrease in its density and shrinkage. These observations were also characterized by diminished cellular proliferation, decreased cellular volume and ischemia.
“The primary function of the glomeruli is to assist in the production of ultrafiltrate of the plasma such as Na+, water and urea for further processing by the renal tubules thus playing a vital role in the maintenance of fluid and electrolyte homeostasis.
“Administration of the extracts improves the histoarchitecture of the kidney and by extension restores its functionality. The groups administered with PG extract demonstrated a distinct regenerative capacity over the other three extract. This was closely followed by the group administered with FM extract.
“Previous studies have reported some similar histopathological findings. The plant extracts used for the study, are common herbal plant used traditionally in the management of diabetes, amongst the Yorubas of Ile-Ife, Nigeria. Three of these plants – VA, CC, and PG; have been reported to possess anti-diabetic properties.
“The four medicinal plants used in this study are well known for their antioxidant properties which are due to their high level content of flavonoids. The present study has provided useful information in the management of kidney related disorders resulting from diabetes.”
Another study by researchers from Federal College of Forestry Mechanization, Afaka, Kaduna State, identified Vernonia amygdalinia, Acacia nilotica (scorpion mimosa), Allium sativum, Parkia biglobosa (locust bean), Adansonia digitata (baobab), Phoenix dactyfera (dates), Cocos nucifera (coconut), and Psidium guajava for treating diabetes in the study area.
The study published in International Journal of Biomechanics & Health Science is titled “Efficacy of forest plants in the treatment of diabetes in Birnin Gwari Local Government Area, Kaduna State, Nigeria.”
The researchers examined the efficacy of medicinal plants in the treatment of biabetes in Birnin Gwari Local Government Area, Kaduna State, Nigeria. Eighty Structural questionnaires were administered to identified respondents viz: traditional healer, herbs trader, farmers and civil servants in the Local Government. Descriptive analysis such as frequency tables and percentages were used for the analysis.
The result showed that Vernonia amygdalinia, Acacia nilotica (scorpion mimosa), Allium sativum, Parkia biglobosa (locust bean), Adansonia digitata (baobab), Phoenix dactyfera (dates), Cocos nucifera (coconut), and Psidium guajava were the medicinal plants used for treating diabetes in the study area.
The researchers concluded: “The importance of traditional treatment using medicinal plants cannot be over emphasized. The study has shown that diabetes, a deadly disease can be treated with common plants found around the home, for instance guava (Psidium guajava) and garlic (Allium sativum). It is however, recommended that research Institutes in collaboration with the three arms of government in Nigeria should carry out research on these medicinal plants so as to detect other multipurpose uses of the plants.”
Yet another study published in Journal of Physiology and Pharmacology Advances is has shown that the crude leaf extracts of Psidium guajava could potentially be used in treatment of Type 1 diabetes.
The researchers further explained: “In this study, diabetic rats were treated with different doses of the ethanolic extract of Psidium guajava for 21 days. Alloxan monohydrate was used to induce diabetes and it acts by selectively destroying insulin-producing beta cells in the pancreas by generating reactive oxygen species. The action of reactive oxygen species with a simultaneous massive increase in cytosolic calcium concentration causes rapid destruction of beta cells. This causes insulin- dependent diabetes mellitus (Type I diabetes).
“The results of this study indicate that the P. guajava ethanolic leaf extract has a remarkable anti-hyperglycaemic activity at all doses. The 600mg and 800 mg/kg doses of the extract produced a hypoglycemic activity comparable with that of the reference drug glibenclamide. Similar studies show the marked antidiabetic activity of the P. guajava leaves. For example, P. guajava leaf extracts not only significantly decreased blood glucose levels but also improves the levels of plasma insulin and haemoglobin in streptozotocin-induced diabetic rats
“Studies in Korea using P. guajava leaf extract administered intraperitoneally showed that the extract possesses antidiabetic effect in a type 2 diabetic mice model and this effect was, at least in part, mediated via the inhibition of protein tyrosine phosphatase1B. Other plant parts have also shown similar activity. Studies with the P. guajava bark extract clearly showed that the plant possesses potent blood glucose reducing activity. A study with the stem bark showed that the ethanolic stem bark extract exhibited statistically significant hypoglycaemic activity in alloxan-induced diabetic rats.
“The antidiabetic activity of the extract could partly be attributed to the phytochemicals present in the plant leaf extract. Alkaloids, flavonoids and tannins have been documented to have hypoglycemic, hypolipidemic, hypoazotemic, hypotensive and antioxidant effects among others. Guava leaf extracts contain flavonoids, mainly quercetin derivatives which possess dose- dependent antioxidant properties which prevent oxidative stress in tissues.
“The highest quercetin content occurs during the premature fruiting stage. Guava leaf phytoconstituents have also been shown to be potent antiglycation agents in an albumin/glucose model system and prevent the glycation-associated complications in diabetes. The active components of the guava leaf extract also inhibit alpha-glucosidase enzymes in vitro, leading to reduction of postprandial blood glucose elevation and improvement of hyperglycemia,hypertriglycemiaand hypercholesterolemia in murine models.
“Guava-leaf derived products such as Guava Leaf Tea (Bansoureicha®, Tokyo, Japan) are considered useful as an alimentotherapy for chronic diabetes cases. Other parts of P. guajava plant e.g. fruit are rich in phytochemicals like tannins, flavonoids, saponins, carotenoids and lectins some of which have proven antidiabetic activity.
“This study showed that the antidiabetic effect was dose dependent and this could be attributed to increased amounts of the phytochemicals with antidiabetic activity in higher extract doses. The high LD50 of the extract (i.e. 10,656 mg/kg) indicates that the plant extract is non-toxic and safe to use since this value is much higher than the 5000mg/kg considered safe by Organization for Economic Cooperation Development (OECD) guidelines (OECD, 2008).”
According to The Useful Plants of West Tropical Africa by H. M. Burkill, the whole of the plant is very bitter, but especially the fruit due to the presence of a bitter glycosidal principle, colocynthin.
It reads: “In the past the purgative action has been ascribed to this, but another intensely bitter weakly basic amorphous alkaloid has been detected and this is drastically purgative. Another less powerful alkaloid has also been found and also other substances. Colocynth of commerce is official in most pharmacopoeias as a purgative and has been used for dropsical and other conditions, and sometimes as a vermifuge. It is the dried pulp of the peeled fruit freed of seeds. The powder is irritating to mucous membranes, strongly hydragogue, cathartic and is usually administered mixed with other drugs on account of its griping action.
“In the British Army of World War I, ‘No. 9’, given for so many complaints on medical inspection parades, was based on this substance. In small dosage it is violent. In larger doses it is lethal. Its use as a drug was first recorded in Rome during the reign of Emperor Claudius, A.D. 41-54, whereupon, in a craze of hypochondria by the well-to-do Roman citizen, it attained much popularity — even for political murder, and perhaps of Claudius himself. Bulk to line the stomach wall is evidently able to reduce its action, and it is possible that the dish of pottage which was inedible to the multitude in the Bible, II Kings 4: 38-41 because, perhaps unwittingly, of the presence of colocynth fruit was miraculously made edible by Elisha who added meal to it.
“It is used as a purge for man and animals in Mauritania, but recognition of its violence and toxicity in Senegal, Nigeria, Gabon, and in general appears to have very greatly restricted its use in this way. In Mauritania the baked fruit is rubbed on camels affected by itch, and an unripe fruit cooked in hot sand is used to treat blennorrhagia (gonorrhoea) in man: the cooked fruit is bored centrally and the glans of the penis is inserted and kept there for an hour in which time a cure is said to be effected.
“Arabs use the ripe fruit, charred in a fire and pulverized, to prepare a gunpowder, tinder and fuses, and in Egypt, the green fruit is crushed on a piece of flannel fabric which absorbs the juice and when dried it acts like tinder. Fruits are supposed to have the property or keeping moths, etc. away from clothing, and pieces of the dried fruit (sometimes along with black pepper) pulverised and wrapped in paper are used for this purpose.
“In Mauritania the root is held to be effective in killing headlice: the root cooked in hot sand is powdered and mixed with butter from ewe’s or camel’s milk for application to the infested head of women. A bitter black extract prepared from the rind is sometimes smeared on water-bags by the Arabs to keep camels, etc. away from them. The fruit pulp is also used. Though the fruit is poisonous, the seeds are sometimes eaten. In the Hoggar area the Tebbou boil them for a whole day with a change of water. The seeds are then dried and eaten. The Tuareg of the same area steam the seeds to drive off a black oil after which the seeds can be eaten or dried for storage.
” In Sudan the seed is eaten as an emergency food. The seed-oil which resembles pumpkin seed-oil is used in India as a remedy for snake-bite, scorpion-sting, epilepsy and to promote hair-growth. Content is about 21 per cent and it is semi-drying. It is usable for illumination and as a dye to darken grey hair. The Tuareg of Hoggar treat skin-troubles on camels with it.”
The clinical investigation of Citrullus colocynthis (L.) schrad fruit in treatment of Type II diabetic patients: a randomized, double blind, placebo-controlled clinical trial.
According to a study published in Phytotherapy Residence by Iranian researchers, to determine its efficacy and toxicity, a two month clinical trial was conducted in 50 type II diabetic patients.
The study reads: “Two groups of 25 each under standard antidiabetic therapy, received 100 mg C. colocynthis fruit capsules or placebos three times a day, respectively. The patients were visited monthly and glycosylated hemoglobin (HbA1c), fasting blood glucose, total cholesterol, Low Density Lipo-protein (LDL)/’bad’ cholesterol, High Density Lipo-protein (HDL)/’good’ cholesterol, triglyceride, aspartate transaminase, alanine transaminase, alkaline phosphatase, urea and creatinine levels were determined at the beginning and after two months.
“The results showed a significant decrease in HbA1c and fasting blood glucose levels in C. colocynthis treated patients. Other serological parameters levels in both the groups did not change significantly. No notable gastrointestinal side effect was observed in either group.
“In conclusion, C. colocynthis fruit treatment had a beneficial effect on improving the glycemic profile without severe adverse effects in type II diabetic patients. Further clinical studies are recommended to evaluate the long-term efficacy and toxicity of C. colocynthis in diabetic patients.”
According to Wikipedia, aqueous and methanol extracts of colocynth showed high antimicrobial activity against Escherichia coli, Staphylococcus aureus and other bacteria. Extracts of fruits, leaves, roots and stems were also found to be potentially usable against many gram positive bacilli and fungi as Aspergillus fumigatus, Aspergillus flavus and Mucor sp.
In addition, some of these extracts were found to have an insulin tropic effect and therefore an antidiabetic effect, which may make them relevant to the treatment of diabetes mellitus.
Cucurbitacin glucosides seem potentially important for therapy against breast cancer cells because of their ability to modify cell morphology and signaling, and to induce apoptosis and changes in mitochondrial membrane potential.
Another property of colocynth is hair growth stimulation: an experiment on rats demonstrated that hair growth initiation time was significantly decreased after treatment with colocynth petroleum ether extracts.
According to The useful plants of west tropical Africa, Volume 4, by H. M. Burkill, the leaves are used for medicines: anus, haemorrhoids; cutaneous, subcutaneous parasitic infection; menstrual cycle; oral treatments; pain-killers; pulmonary troubles; small-pox, chicken-pox, measles, etc.
Scientists have demonstrated that the administration of guava extract could be used to prevent cardiovascular complications associated with diabetes.
According to the study published in Experimental and Toxicologic Pathology, “non enzymatic glycosylation (glycation) between reducing sugar and protein results in the formation of advanced glycation end products (AGEs), which is believed to play an important role in diabetes associated cardiovascular complications. Thus agents that inhibit the formation of AGEs are believed to have therapeutic potential against diabetic complications.
” In the present study we evaluated the antiglycative potential of ethyl acetate fraction of Psidium guajava leaves (PGEt) by administering the extract into streptozotocin induced diabetic rats. Daily administration of the extract for a period of one month significantly decreased the blood glucose, glycated hemoglobin and fructosamine levels in a dose dependent manner. Evaluation of the toxicity markers like SGOT and SGPT revealed the non toxic nature of the extract.
“Apart from this we evaluated the presence of cardiac isoform of liver alpha 2 macroglobulin, which is a major protein associated with earlier stages of cardiac hypertrophy. SDS-PAGE analysis showed that the level of this protein decreased significantly in extract treated groups compared to diabetic control. These findings support that the administration of PGEt extract may be beneficial for preventing cardiovascular complications associated with diabetes.”
According to The useful plants of West Tropical Africa, “the leaves are taken in Nigeria as an appetizer and digestive tonic. The Hausa of Northern Nigeria prepare a special food called fatefate or mayemaye from the leaves with butter and condiments, etc. This is taken by men as a food but by women in a belief that it renders themselves sexually more attractive. The leaves are added to horsefeed with bran, natron, etc., in Northern Nigeria to provide a strengthening or fattening tonic called in Hausa chusar doki.
“The leaves are used in Ethiopia as hops in preparing tela beer.The leaves are widely used for fevers and are known as a quinine-substitute. A leaf-decoction is taken as a laxative in Nigeria, and in Tanganyika and the sap in Ethiopia. A purgative enema is made in Ghana by macerating the leaves through a cloth and adding peppers and spices.
“A cough-medicine is made of them in Ghana, Nigeria (as an expectorant) and in Tanganyika. The leaves are rubbed directly onto the body for itch, parasitic affections, ringworm, etc., or a cold infusion is applied as a wash in Nigeria. During the puerperium a mother may take a decoction of the leaves to affect her milk so as to act as a prophylactic against worms in the baby.
“The leaves are added to horse-feed as a vermifuge and to treat internal disorders symptomized by mucal discharge from the nose. Leaves are rubbed on the breasts for weaning infants… It is valued as a tooth-cleaner and more especially as a stomachic and appetizer. It has an alleged beneficial effect on dental caries, but no antibiotic activity has been found in material from Ibadan, Southern Nigeria.
“In Northern Nigeria the Hausa use these chewsticks with natron for gastro-intestinal troubles. The root has been described as a substitute for ipecacuanha. A root-infusion is taken in Nigeria as an anthelmintic as well as for enteritis. The twigs also are used as chew-sticks, and as well are pounded for application to cuts as a haemostatic and cicatrizant.
“The bark of stem and roots is particularly bitter and is more or less astringent. Infusions are commonly taken for fever and for diarrhoea. In Nigeria an infusion is used for rheumatism. A cold infusion of root-bark with Vigna unguiculata (Leguminosae: Papilionoiideae) is taken in southern Africa for schistosomiasis. The fruit is also eaten for the same purpose… ”
“Dried flowers are used in Ethiopia to treat stomach-disorders. The fruit is used in Nigeria as an aphrodisiac, and the powdered seeds as an anthelmintic. A cardio-tonic glycoside, vernonin, has been isolated from the root with an action comparable with that of digitalin. No alkaloid has been detected.”
Cardiovascular Effects of Vernonia amygdalina in Rats and the Implications for Treatment of Hypertension in Diabetes.
Researchers from University of Lagos and Danfodio University, Sokoto, have demonstrated that the plant may also be useful in the treatment of hypertension because of its blood pressure lowering and vaso-relaxant effects.
According to the results of the study published in Researcher, the implication is that V. amygdalina may be especially useful in those increasing cases of hypertension complicated with diabetes. Recent data from toxicity studies had shown that V. amygdalina is safe when consumed in moderate quantities.
The study reads: “The cardiovascular effects of aqueous extract of Vernonia amygdalina was investigated in normotensive Sprague-Dawley rats weighing 200-250g. Intravenous (femoral vein) administration of the extract at doses of 5.0 and 10.0mg/kg caused a bi-phasic alteration of blood pressure: an initial transient rise in mean arterial pressure which later fell to a considerably lower level than the starting blood pressure. This pattern of response was most clearly noticeable with the dose of 10 mg/kg whereby the mean arterial pressure of 73.7+3.4 mmHg rose to 101.9+4.1 mmHg in the first phase (P<0.01) before it finally fell to 60.2±2.5 mmHg in the second and final phase.
“Although higher doses (50 and 100mg/kg) caused more significant reduction in mean arterial pressure than the lower doses, the initial temporary elevation in blood pressure was not observed. Cumulative addition of the plant extract to isolated rings of aorta precontracted with noradrenaline produced a dose-dependent relaxation of the aortic smooth muscle. Maximum relaxation of 31.3±3.1 per cent was observed with extract concentration of 2.7 mg/ml.
“These findings suggest that V. amygdalina has antihypertensive effect, and this could be mediated through direct vaso-relaxant mechanism. The implication of these results for the treatment of hypertension associated with diabetes is discussed.”
The researchers further explained: “The data from the present investigation showed that V. amygdalina, a plant commonly used for dietary and medicinal purposes, caused an overall blood pressure lowering effect in normotensive rats.
“The extracts caused bi-phasic alteration of blood pressure at lower doses (5.0 and 10.0mg/kg) but not at higher doses (50 and 100mg/kg). The reason for the difference in blood pressure alteration at lower and higher doses is not yet clear. The observation may imply the presence of a mixture of constituents that lower blood pressure and those that elevate it with the effect of the latter being suppressed at higher doses.
“Blood pressure depends on several factors, which include heart rate, stroke volume, and peripheral resistance. Agents that lower blood pressure do so via one or a combination of several blood pressure regulatory mechanisms.
“The results of in-vitro experiment on isolated rat aorta in this study suggested that aqueous extracts of V. amygdalina produced a dose-dependent decrease in arterial pressure through vascular relaxation mechanism. It is not possible at this stage to rule out other mechanisms that involve the autonomic nervous system such as sympathetic inhibition or/and parasympathetic stimulation. Experiments are currently in progress to clarify the issues raised above and also to see whether the blood pressure lowering effect of V. amygdalina is through acetyl cholineor/and histamine mechanisms. Acetylcholine and histamine are known to affect the smooth muscle and cause vasodilatory effect in the body.
“The close association between hypertension and diabetes had long been well established (Naidu, 1992). Adequate control of blood pressure and blood glucose with drugs and other measures like dietary and life style regulations are necessary to retard the progression of cardiovascular complications associated with hypertension and diabetes.
“Unfortunately, there are compliance problems with recommended drug schedules. This is complicated by the fact that the drug regimes may not be appropriate in developing countries like Nigeria for various cultural and socio-economic reasons associated with poverty and illiteracy.
“Furthermore the majority of the populations in most of these countries especially those in the rural areas do not have access to conventional medical facilities, so they rely mainly on traditional medicine for their health care needs. The most widely used anti- hypertensive drugs have been criticized, particularly in diabetics, because of their various adverse effects. In addition to previous reports that showed that V. amygdalina had hypoglycaemic effects in human and animal experimental subjects.
Diabetes-fighting potential spotted in culinary herbs
Also, food scientists have discovered that the popular culinary herbs rosemary, oregano and marjoram contain compounds that may have the potential to manage type 2 diabetes in a similar way to some currently prescribed drugs.
Elvira de Mejia, a professor in the Department of Food Science and Human Nutrition at the University of Illinois at Urbana-Champaign, and colleagues report their findings in the Journal of Agricultural and Food Chemistry.
The authors point out, in view of the fact type 2 diabetes affects over 10 per cent of Nigerians and eight per cent of Americans and costs both nations around N1 trillion a year, there is a need for as many ways to tackle the disease as possible.
While some people can manage the disease with changes to diet and increasing physical activity, and others do so with medication to keep blood glucose in check, not everyone can stick to changes in lifestyle or afford the prescription drugs, they add.
Herbs may offer an alternative way to keep glucose in check
Researchers found that certain herbs, such as rosemary, contain compounds that may have the potential to manage type 2 diabetes naturally.
The researchers note that recent studies have shown herbs may provide an alternative, natural way to keep glucose in check, so they decided to take a closer look.
In their paper, they describe how they investigated the properties of Greek oregano (Origanum vulgare), marjoram (Origanum majorana), rosemary (Rosmarinus officinalis), and Mexican oregano (Lippia graveolens).
They prepared extracts of these plants obtained from greenhouse-grown and commercially purchased dried forms and examined their ability to inhibit two enzymes – one called DPP-IV (also calld DPP-4) that plays a role in insulin secretion, and another called PTP1B that is involved in insulin signaling.
These enzymes have been identified as targets of drugs for managing diabetes. For example, the drugs sitagliptin and metformin are medications in the DPP-4 inhibitor family. However, searching for inhibitors of PTP1B is proving more challenging.
Prof. de Mejia and colleagues found that the greenhouse-grown herbs contained more polyphenols and flavonoids than the commercial, dried versions.
Compounds in rosemary, oregano, and marjoram showed ability to inhibit enzymes
They also found that extracts of greenhouse-grown rosemary, Mexican oregano, and marjoram were the best inhibitors of DPP-IV, while extracts from the commercial, dried versions were the best inhibitors of PTP1B.
Further analysis revealed a number of individual compounds contributed to these inhibitory effects.
The team calls for more studies to understand the role of these compounds in reducing the risk of type 2 diabetes in humans.
In January 2014, Medical News Today reported a clinical trial that found traditional Chinese herbal medicines may halt progress of type 2 diabetes. The researchers said the results show Chinese herbal medicines hold promise for slowing the progression from prediabetes to an official diabetes diagnosis.
Medicinal herbs show ability to replace diabetes medication without side effects
Researchers from University of Mississippi’s School of Pharmacy have conducted an extensive analysis of medicinal plants and proved once again that herbs can replace medications – now diabetes medications. They found that a number of herbs safely modulate cellular PPAR receptors – which means they help regulate glucose, insulin and fat metabolism.
The researchers screened extracts from a total of 263 species of herbs from 94 plant families. They found that eight of the extracts activated the PPARα (Peroxisome proliferator-activated receptor – alpha) and 22 of the plant extracts activated the PPARγ (Peroxisome proliferator-activated receptor – gamma).
Of these, five plant extracts activated both receptors. They were Daphine (Daphne gnidium), Star Anise (Illicium anisatum), Red Cedar (Juniperus virginiana), Haritaki (Terminalia chebula), and Thymelaea (Thymelaea hirsuta).
Among these, the Haritaki and Thymelaea were found to significantly stimulate both the PPARα and PPARγ receptor proteins, while inhibiting the process of adipogenesis – the process of fat cell expansion that results in a higher risk of obesity.
Haritaki and Thymelaea inhibited the process of fat cell expansion, while the Red Cedar and the Daphine actually reduced adipose (fat) cells –
Source: The Guardian