Preliminary analysis of bioactive components in aqueous garlic extract

Abstract

Limited analysis of bioactive components of garlic (Allium sativum) extracts by GC‐MS as well as analysis of amino acid and fatty acid composition and trace metal analysis were carried out. The total phenol content of garlic was 0.374 mg/g dry weight. GC‐MS determination of sulfur compounds in fresh garlic extract and fresh chopped garlic revealed similar compositions with vinyl dithins being the major component in both (40% and 46% respectively), with lesser amounts of allylmethyl trisulfide, diallyl disulfide and S‐allyl cysteine. Freezing and storage of garlic extract resulted in increased amounts of S‐allylcysteine and diallyldisulide, and decreased levels of allylmethyl trisulfide. Vinyldithins remained at approximately 40% throughout the storage period. Boiling of garlic extract vastly changed the composition with allylmethyl disulfide, allyl alcohol and dimethyl disulfide being the major components. Amino acid and metal analysis of garlic extract revealed the presence of 17 amino acids and potassium as the major metal. Fourteen fatty acids were identified in garlic extract with the major fatty acids identified as palmitic, linoleic and stearic acids;A major bioactive component from garlic extract, S‐allyl cysteine (SAC), was purified by preparative HPLC and assessed for biological activity in streptozotocin (STZ) ‐ induced diabetic rats during a 4 week daily treatment experiment. SAC (5mg/kg daily intraperitoneally) was shown to be effective in limiting weight loss and lowering blood glucose levels of diabetic rats. However, SAC was effective in decreasing polyphagia and polydipsia typical of diabetic rats.Support or Funding InformationThe study was supported by KU grant #SL 07/14.