Aim: In management of metabolic syndrome and type 2 diabetes the role of diet is important. Indian diet contains large amount of sugar & starches that set off unpredictable blood sugar fluctuations, increasing the risk of diabetic complications. The aim is study the effect of Mulberry tea as it is known to contains 1-deoxynojirimycin (DNJ), a potent glycosidase inhibitor and has been hypothesized to suppress abnormally high post prandial blood glucose levels .
Method: The study is designed in follow-up diabetic patients, 20 diabetics as controls were given plain tea and 28 patients were given mulberry tea containing DNJ to measure effect based on FBS and PPBS.
Fasting blood glucose sample was collected, followed by standard breakfast and one cup of 70ml tea with 1 teaspoon of sugar. The postprandial blood glucose was measured again at 90minutes in all 48 patients.
Results: Fasting value in control group 178.55±35.61 and cases 153.50±48.10. After consumption of plain tea and mulberry tea the post-prandial value was287.20±56.37 and 210.21±58.73
respectively the significance is t=4.492; p<0.001** and the effect size is very large(1.31).
Conclusion: Mulbery tea suppresses post prandial rise of blood glucose levels .
INTRODUCTION
The prevalence of type 2 diabetes and the burden of disease caused by it have increased very rapidly worldwide.1 This has been fuelled by ageing populations,2 poor diet,3 and the concurrent epidemic of obesity.4 5 .The health and economic consequences of this diabetes epidemic are huge and rising.6 Strong evidence from randomized controlled trials shows that behavioral or pharmacological interventions can maintain better control of type 2 diabetes in up to two thirds of high risk cases.7 8 9. The World Health Organization predicts that this number will rise dramatically by the year 2035. According to WHO in India 31.7 million diabetic patients in the year 2010 and the data predicts 79.4 million in 2035 (10). Diabetes mellitus is a metabolic disease of endocrine system, and it has been shown that chronic hyperglycemia is the etiologic factor more relevant of the diabetic complications and promotes biochemical disturbances causing oxidative stress and chronic inflammatory process.
In management of type 2 diabetes the role of diet is critical. However, in the south Indian home the right diet and lifestyle choices are difficult for many patients because of the large amount of sugars and finely processed carbohydrates that constitute the diet. A diet loaded with refined carbohydrates and starches can set off unpredictable blood sugar fluctuations, which can increase the risk of diabetic complications. In recent years, there has been a growing interest in natural remedies that can help manage type 2 diabetes.(11) One natural ingredient has shown particular promise is the mulberry leaf. Mulberry leaves are the food source of silkworms and have been used for generations in traditional Chinese medicine as a "cooling" herb to remove excess heat from the body. The leaf is also used in some Indian foods.
The mulberry plant, 'Morus Alba' is a short-lived, fast-growing and small to medium sized mulberry tree, which grows to 10-20 m tall. Mulberry contains 1-deoxynojirimycin (DNJ), a potent glucosidase inhibitor, can be extracted from the mulberry leaf, and has been hypothesized to be beneficial for the suppression of abnormally high blood glucose levels.(12) It holds back complex carbohydrates, starches, maltose and sucrose from breaking down into glucose. As a result it prevents the increase of sugar levels in blood after a meal. Polysaccharide (starch, glycogen or the like) contained in food is hydrolyzed by α-amylase in saliva and pancreas and converted into oligosaccharide such as maltose, isomaltose or the like, then decomposed to glucose by disaccharide degrading enzyme such as α-glucosidase or the like in the small intestine and absorbed. Thus, α-amylase and α-glucosidase perform an important role as a digestive enzyme for carbohydrate in the body, mulberry tea may play an important role in reducing the postprandial blood glucose level. Therefore a single blinded study has been taken up among type-2 diabetic patients to observe the change in blood glucose following consumption of mulberry tea vs. plain tea.
MATERIALS AND METHODS
The study design was to select follow-up diabetic patients at Sri Jayadeva institute of cardiovascular sciences and Research, to measure both fasting blood glucose followed by routine standard breakfast and one cup of 70ml tea with 1 teaspoon of sugar. The postprandial blood glucose was measured in 48 patients after prior consent and IRB approval. Mulberry leaf extract 'mulbericha green' was provided by Karnataka state sericulture research and development institute, Bangalore.
Method: First morning sample of fasting blood was collected for glucose estimation. The patient was instructed to consume standard breakfast (two 'idlies'with 'chatni'). The mulberry tea was prepared by adding a teaspoon of 'mulbericha green' to one cup of hot water and addition of one teaspoon sugar and given to the patient to drink. Similarly the control group also consisted of diabetic patients and were given normal tea. After 90 minutes the second blood sample was collected for measurement of postprandial blood glucose. Analysis was carried out on Roche Hitachi 912 analyzer. The study was approved by the Ethical committee of Sri Jayadeva institute of cardiology.
Statistical Methods: Descriptive statistical analysis has been carried out in the present study. Results on continuous measurements are presented on Mean ± SD (Min-Max) and results on categorical measurements are presented in Number (%). Significance is assessed at 5 % level of significance ,Student t test ( two tailed, independent) has been used to find the significance of study parameters on continuous scale between two groups Inter group analysis) Student t test and Chi-square test to test the homogeneity of samples based on parameters on categorical scale between two groups. The Statistical software namely SPSS 15.0, Stata 8.0, MedCalc 9.0.1 and Systat 11.0 were used for the analysis of the data and Microsoft word and Excel have been used to generate graphs, tables etc.
3. Effect Size
=
No effect (N)
d<0.20
Small effect (S)
0.20 <d<0.50
Moderate effect (M)
0.50 <d<0.80
Large effect (L)
0.80<d<1.20
Very large effect (VL)
d>1.20
RESULTS
This was a comparative study with 20 controls and 28 patients with mulberry tea containing DNJ and was undertaken to study the effect based on FBS and PPBS.
Table 1: Comparison of age distribution
Age in years
Controls
Cases
No
%
No
%
30-40
3
15.0
3
10.7
41-50
4
20.0
11
39.3
51-60
8
40.0
9
32.1
61-70
5
25.0
5
17.9
Total
20
100.0
28
100.0
Mean ± SD
53.80±11.15
51.61±8.59
Samples are age matched with P=0.445
Table 2: Gender distribution
Gender
Controls
Cases
No
%
No
%
Male
10
50.0
16
57.1
Female
10
50.0
12
42.9
Total
20
100.0
28
100.0
Samples are gender matched with P=0.624
Table 3: Levels of FBS and PPBS in controls and Cases
Variables
Controls
Cases
Significance
Effect size
FBS
178.55±35.61
(129-262)
153.50±48.10
(93-278)
t=1.972;p=0.055+
0.57(M)
PPBS
287.20±56.37
(159-380)
210.21±58.73
(118-341)
t=4.492;p<0.001**
1.31(VL)
DISCUSSION
For type-2 diabetic patients, the body's ability to respond to the absorbed sugars and carbohydrates no longer functions properly; patients experience abrupt blood glucose elevations right after a meal. This condition is often referred to as a post-meal (postprandial) blood sugar spike. The ingestion of mulberry extract with a standard diet significantly reduced the increase in blood glucose observed over the initial 90 min of testing in control and study group. The blood glucose were markedly reduced by mulberry tea ingestion. The mulberry tea induced reduction in blood glucose presumably reflects the ability of mulberry to inhibit intestinal sucrase (13). Brownlee (14) proposed that generation of reactive oxygen species is the common pathway responsible for diabetes complications, and glucose fluctuations are associated with increased markers of oxidative injury (15). Thus, reductions in blood glucose fluctuation with mulberry extract might reduce diabetes complications.
However, levels in some patients can go lower than immediately after the spikes because of the body's "overreaction" to blood sugar elevation, resulting in blood sugar fluctuations from high to low. These fluctuations are often mentioned as the leading cause of diabetic complications.(16) In order to manage the disease, the average patient with type 2 diabetes relies on two to three different prescription medications, many of which have troubling side effects, including weight gain.
The drugs such as acarbose and miglitol, that inhibit carbohydrate digestion produce modest reductions in fasting blood glucose (17) and slow progression of glucose intolerance to overt diabetes (18). Use of these drugs has been limited by associated bloating, gas, and diarrhea (19). These or similar symptoms were not observed in our study. However, convincing evidence of lesser side effects will require further studies.
Some individuals prefer herbal over pharmaceutical preparation, and such people will find mulberry tea more acceptable and better tolerated than acarbose or miglitol. In addition, mulberry tea contains compounds such as fagomine, which induces insulin secretion (20), and antioxidants that putatively reduce lipid peroxidation (21,22,23). (Mulberry_Study.pdf)
From the viewpoint of safety, these plant-derived extracts are easily applied to food, drugs and medicines, or the like, therefore effective components or the like of the said plant-derived extracts are now being extensively researched. Many animal studies has proven that mulberry leaf extract is helpful to type 2 diabetics.The mulberry leaf extract appears to play an important role in reducing the risk factors associated with type 2 diabetes, because it promotes better blood glucose control and weight management. When fewer carbohydrates and sugars are absorbed into the bloodstream, it is it easier to achieve a healthier weight.
Alpha-glucosidases are a series of enzymes located on the intestinal brush-border. The most important carbohydrates in food, such as starch and sucrose, are hydrolyzed to monosaccharide, such as glucose and fructose, by an [alpha]-glucosidase, and then absorbed into the blood, thereby increasing blood glucose value. Usually, these processes take place in the upper portion of the small intestine and greatly increase blood glucose concentration, especially in diabetic patients. Alpha-glucosidase inhibitors can prolong the processes along the entire intestine, lengthen the duration of carbohydrate absorption, and flatten the blood glucose concentrations over time curve (Bischoff, 1993).
In our study, mulberry extract tea is suppose to inhibit brush border enzymes alpha glucosidase significantly and it may delay absorption carbohydrates that lead to flatten blood glucose concentrations. This may explain the antidiabetic effect of Morus Alba, since alpha-glucosidase inhibitory activity is involved in the carbohydrate blockers for delaying the absorption of glucose from the small intestine. These effects are similar to those for the alpha-glucosidase inhibitor, acarbose. Morus Alba water extract shows competitive type of enzyme inhibition.
CONCLUSION
Alpha-glucosidase inhibitors (AGIs; acarbose, voglibose) are widely used in the treatment of patients with type 2 diabetes. Alpha-glucosidase inhibitors are oral antidiabetic drugs. AGIs delay the absorption of carbohydrates from the small intestine and thus have a lowering effect on postprandial blood glucose and insulin levels. The present study showed on water extract of Morus Alba leaves were tested for alpha glucosidase inhibitory activity.
