Identification and quantitative determination of blood lowering sugar amino acid in Fenugreek
Seeds of Trigonella foenum-graecum L. are used as lowering blood sugar in Iranian traditional medicine. According to recent investigations, hypoglycemic property of the plant is related to its amino acids, specially 4-hydroxyisoleucine [1,2]. In order to determine the amount of this amino acid quantitatively, plant seeds were collected from Shahreza, central part of Iran, in summer 2006 and identified in herbarium of faculty of Pharmacy, Tehran University of Medical sciences. Seeds were milled and defatted by petroleum ether and then extracted by ethanol 50%. Concentrated ethanol extract was passed through ion exchange column and amino acids were extracted using ammonium hydroxide as solvent. Finally the mixture of amino acids was injected to HPLC for identification and quantitative determination of 4-hydroxyisoleucine by using calibration curve of 4-hydroxyisoleucine. The amount of this amino acid in plant seeds was 0.4%, which is considerable compared to those reported from India (0.015%)  and Greece (0.2%) . According to the results, Iranian fenugreek seeds could be used efficiently as an antidiabetic agent.
References: 1. Sauvaire, Y. et al. (1998) Diabetes. 47: 206–210.
2. Broca, C. et al. (1999) Am. J. Physiol. Endocrinol. Metab. 277: 617–623.
3. Narender, T. et al. (2006) Bioorg. Med. Chem. Lett. 16: 293–296.
4. United States Patent 5470879 (1995) November 28.