INTRODUCTION Diabetes, a chronic progressive disorder characterized by metabolic abnormalities, has reached epidemic proportions worldwide. Oral hypoglycemic agents used for the treatment of diabetes have side effects on prolonged use. The patients are using herbal medicines which have less side effects, easy availability and economic for them. Even World Health Organization (WHO) permits the use of plant drugs for diffe- rent diseases, including diabetes mellitus (II). In this study, a known anti diabetic plant, Trigonella foenumgraecum Linn., (family: Leguminosae) is used. It is called as 'Fenugreek' and commonly used as a spice in cooking. Fenugreek is cultivated in India, Egypt, Middle East and North Africa. The seeds of the plant have been used as a traditional remedy for conditions including gastrointestinal disorders, gout, wound healing and inflammation, hyperlipidemia and diabetes. In humans, fenugreek seeds exert hypoglycemic effects by stimulating glucose-dependent insulin secretion from pancreatic β-cells, as well as by inhibiting the activities of α-amylase and sucrose. Studies such as glycemic control in a double blind placebo controlled human trials 1 , application of fenugreek extract powder in a neonatal model of rats for insulinotropic property 2 , usage of reconstituted fenugreek extract powder in ischemic perfusion rat model to address diabetic nephropathy 3 , endurance and metabolic syndrome 4 and lipid lowering Isolation of (2S,3R,4S)-4-Hydroxyisoleucine from Trigonella foenum graecum Seeds N. HARI 1,* and V. MOHAN 2 1 School of Chemical & Biotechnology, SASTRA University, Tirumalaisamudram, Thanjvaur-613 401, India 2 Indus Biotech Private Limited, 1, Rahul Residency, Plot No. 6 and 7, Kondhwa, Pune-411 048, India *Corresponding author: Tel: + 91 4362 304000, Fax:+ 91 4362 264120, E-mail: n.hari@scbt.sastra.edu Received: 6 December 2013; Accepted: 17 Janaury 2014; Published online: 10 May 2014; AJC-15185 Antidiabetic compositions derived from botanical sources are well known in traditional medicines in India and other parts of the world. Extensive studies have been carried out on screening the compounds isolated from the fenugreek seeds and other parts of the vegetation for their varied activities. One amongst them is an amino acid i.e., 4-hydroxyisoleucine. This molecule has a potential of not only addressing hyperglycemia amongst diabetic patients but also act in a manner to cure hyperlipidemia, diabetic neuropathy and diabetic nephropathy. Many attempts have been made to isolate this amino acid in pure form but none of the methods were seem to be commercially viable since the content of this amino acid is only 0.3 to 0.4 % in the fenugreek seeds. In this study, an attempt was made to develop a method of isolation of pure form of 4-hydroxyisoleucine followed by scale up to yield a level of kilogram quantity. The isolated pure form of 4-hydroxyisoleucine has been subjected to structural characterization. Keywords: Isolation, (2S,3R,4S)-4-Hydroxyisoleucine, Trigonella foenumgraecum seeds. property of fenugreek powder 5 have revealed the importance of fenugreek in controlling diabetes. Fenugreek contains many bioactive compounds and 4-hydroxyisoleucine (4HI) isolated from the seeds of fenugreek showed hypoglycemic activity. Sauvaire and Ribes 6 demonstrated that 4-hydroxyisoleucine increased glucose-induced insulin release in human and rat pancreatic islet cells. 4-Hydroxyisoleucine was specific to act on pancreatic β-cells, since the levels of somatostatin and glucagon were not altered. It was also found that 4-hydroxy- isoleucine stimulated glucose uptake by increasing surface GLUT4 level in skeletal muscle cells via phosphatidylinositol- 3-kinase dependent pathway 7 . A study by Shah et al. 8 exploring the regenerative potential of pancreas in alloxan induced diabetic mice by 4-hydroxyisoleucine in comparison with pioglitazone, a commercially available drug, revealed the importance of 4-hydroxyisoleucine. Therefore, it was consi- dered important to isolate and formulate the pure form of 4-hydroxyisoleucine to address the varied ailments without any side effects. None of the published results seem to be commercially viable from the point of view of economy as the process involves lengthy chromatographic columns resulting in operational difficulties and limited output of quantity. Synthetic routes employed by Sergent et al. 9 and Kumaraswamy et al. 10 involved several steps which needed expensive reagents. In this present study, a commercially viable method of isolation without involving chromatographic techniques and involving ASIAN JOURNAL OF CHEMISTRY ASIAN JOURNAL OF CHEMISTRY Asian Journal of Chemistry; Vol. 26, No. 10 (2014), 3082-3084 http://dx.doi.org/10.14233/ajchem.2014.16831