Dr. P.S. Murthy is in the Department of Biochemistry, University College of Medical Sciences, Delhi

The need for early diagnosis of diabetes mellitus to prevent and control complications associated it is well recognised. Due to prolonged hyperglycemia, the common microvascular complications affect the eyes (retinopathy), and kidneys (nephropathy). The macrovascular complications cause aetherosclerosis of blood vessels resulting in angina, myocardial infarction etc. besides other complications like neuropathy, cataract, pruritis etc. In view of this, the implications of glycemic threshold for diabetic complications are highly relevant. According to a recent study the risk of microalbuminuria in patients with insulin dependent diabetes mellitus (IDDM, type I) increasing abruptly above a hemoglobin value of 10.1% (equivalent to hemoglobin A1C value of 8.1%) suggests that efforts should be focused on bringing down the hemoglobin A1C values which are above this threshold to reduce the frequency of diabetic nephropathy. According to the Diabetes Control and Complications Trial of the American Diabetes Association, a reasonable goal to therapy under proper health care team in NIDDM patients is the mean blood glucose of 155 mg/dl and hemoglobin A1C value of 7.2%. There are no such systematic studies regarding the glycemic threshold for diabetic complications in non-insulin dependent diabetes mellitus (NIDDM), type II). It is highly desirable to carry out such studies in India. Clinical Biochemists have to play a significant role along with clinicians in such investigations.
Majority of the cases of diabetes are of NIDDM type. Besides diet control and exercise, insulin or oral agents are used for the treatment of NIDDM. Since biguanides have undesirable side- effects, sulfonylureas like tolbutamide, glyburide, glipizide, chlorpropamide, tolazamide etc. are the only group of chemical compounds available at present as drugs for the treatment of diabetes. There is a need for effective, safe and better oral hypoglycemic agents of different chemical nature. Medicinal plants would be highly useful for this purpose.

Role of Medicinal Plants
Plants with medicinal properties, the gift of Mother Nature to mankind, are in use for centuries in the traditional system of medicine like Ayurveda, Unani etc. in India and other countries for the treatment of diseases including diabetes mellitus. They are considered to be effective and non-toxic. They have a vast potential but are only partly explored by modern methods.
Solvent extracts, powdered material, purified or partially purified compounds of a large number of plants were tried for their hypoglycemic activities. It would be fitting to mention a few orally active hypoglycemic principles isolated by Indian scientists. Some of them are charantin (from bitter gourd) Momordica charantia, leucopelargonidin (from banyan tree bark) Ficus bengalensis which is useful in mild, but not severe diabetes. In our laboratory also we isolated three hypoglycemic compounds in a pure state and one partially purified principle (from bitter gourd) M. charantia, one compound (from fenugreek seeds), T. foenum graecum and two compounds from the bark of banyan tree, F. bengalensis. The fenugreek principle and the banyan principles are highly potent and active in severe diabetes also in experimental animals. An additional advantage in this case is that they have hypochloesterolemic effect also. Pharmacological and toxicity studies are being carried out.

Need for Modern Tests
All the above compounds even though highly active have to cross the hurdle of pharmacology, acute and chronic toxicity tests in a manner satisfactory to the drug control authorities before they can go to human trials of different phases. There is necessity for these studies even though they take long time. This is one approach. But so far no purified principle from plants is marketed for diabetes.
The second approach is to try the extracts or preparations made according to the traditional systems of medicine which are being used by the doctors of Ayurveda, Unani etc. They can be tried in humans directly according to modern methods. Examples of such extracts which have been tried by modern methods are the juice of bitter gourd and Eugenia jambolana, water extracts of banyan tree bark and fenugreek seeds. If these and others are tried systematically, more preparations tested by modern methods also will be available for treatment of diabetes mellitus. However, it is to be kept in mind that our studies have revealed that extracts of some plants have hyperglycemic principles also along with hypoglycemic principles.
The aim of the above two approaches of isolating active principles in a pure state or using preparation of the traditional systems is to bring down the fasting plasma glucose (FPG) and hemoglobin A1C from higher values to the threshold levels, in such a way as to reduce diabetic complications without the risk of hypoglycemia. A word about exercise for diabetic patients would be pertinent. Yoga training with meditation and vegetarian diet brings down FPG and glycosylated hemoglobin levels in middle aged NIDDM patients.
The suffering diabetes patients are in need of drugs and nature has provided us plant materials. It is for the biochemists, chemists, pharmacologists, toxicologists, clinicians and all systems of medicine and pharmaceutical industry to join together and explore and "re-search" (they have already been searched or discovered for us by the ancient Rishis) the plant wealth by modern methods for the benefit of diabetes patients.
Because of my particular research interest in diabetes, Ihave mentioned the cause of diabetes mellitus. But, this view applies equally well for other diseases for which the plant products are useful.

Bibliography
Implications of the diabetes control and complications trial - American Diabetes Association Position Statement, June 1993, 1-5.
Medicinal Plants of India (1975) Vol. 1 (1987) Vol. 2, Indian Council of Medical Research, New Delhi.
Lotlikar, M.M. and Rajarama Rao, M.R. (1966) Pharmacology of a hypoglycemic principle isolated from fruits of Momordia charantia, Linn, Ind. J. Pharmacy 28, 129-133.
Augusti K.T., Daniel R.S. Cherian, S. Sheela, G.S. and Nair, C.R.S. (1994) Effect of leucopelargonidin derivative from Ficus bengalensis. Linn on diabetic dogs, Ind. J. Med. Res. 99, 82-86.
Puri, D. Prabhu, K.M. and Murthy, P.S. (1994) Hypocholesterolemic effect of the hypoglycemia principle of fenugreek (Trigonella foenum graecum) seeds, Ind. J. Clin, Biochem. 9, 13-16.
Shukla, R. Anand, K. Prabhu, K.M. Murthy P.S. (1995) Hypocholesterolemic effect of water extract of the bark of banyan tree (Ficus bengalensis) in alloxan recovered, mildly diabetic and severe diabetic rabbits, Int. j. Diab. 14, 78-81.
Extracted from the Indian Journal of Clinical Biochemistry, 1995 10(2), 52-53.

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