Phase properties and lipid composition of microsomal membranes from storage leaf of garlic: modifications induced by sprouting radioinhibition

PEREZ M.B. & CROCI C.A.

Garlic Consumption and health

NOVA SCIENCE PUBLISHERS

Lugar: NEW YORK; Año: 2009; p. 231 - 244

PHASE PROPERTIES AND LIPID COMPOSITION OF MICROSOMAL MEMBRANES FROM STORAGE LEAF OF GARLIC. MODIFICATIONS INDUCED BY SPROUTING RADIOINHIBITION. Mónica B. Pérez, Clara A. Croci Laboratorio de Radioisótopos, Dpto. de Química, Universidad Nacional del Sur Avda. Alem 1253, B8000FWB Bahia Blanca, Argentina Abstract The aim of the present work was evaluate the effect of gamma rays on storage leaf of garlic bulbs in terms of phase properties of microsomal membranes and their lipid and fatty acid composition in order to correlate these features with sprouting inhibition induced by gamma irradiation. Garlic bulbs were irradiated 30 days after harvest with an average dose of 60 Gy of Co-60 gamma rays. Rough and smooth microsomal membranes were isolated by ultracentrifugation from tissues of irradiated and non-irradiated storage leaves. The integrity of the microsomes was corroborated by transmission electron microscopy. Wide-angle X-ray diffractograms of both fractions were recorded along 240 days of storage using PW 1700 diffractometer. Lipids were separated by thin layer chromatography. The fatty acid composition of major lipid fractions was studies by gas-liquid chromatography. The diffractograms featured peaks at Bragg spacing of 4.15 Å and 3.75 Å, revealing the presence of a gel (crystalline) phase, while the characteristic peak of the liquid-crystalline phase (4.6 Å) was not observed in both sorts of membranes. Irradiation was found to bring about modifications in the intensity of 4.15 Å and 3.75 Å peaks from smooth microsomal membranes, but not in the behavior along the period studied. Data from the rough microsomal fraction were erratic and unreliable. Parallel to these changes, radiation induced significant modifications in the level of smooth microsomal membrane triacyglycerols in relation to phospholipids and their fatty acids. These findings indicate that the storage leaf tissues of garlic are radiosensitive in terms of physical and chemical properties of their smooth microsomal membranes. The significance of the results in relation to prove the application of radioinhibition process in garlic bulbs is presented.