Mohammady Nagwa Gamal
Department of Botany, Faculty of Science, Muharram Beck, Alexandria University, Alexandria, Egypt.
Z Naturforsch C J Biosci. 2004 Sep-Oct;59(9-10):619-24. doi: 10.1515/znc-2004-9-1002.
Total, free and conjugated forms (steryl esters, steryl glycosides and acyl steryl glycosides) of sterols from three microalgae that are extensively used in mariculture (Tetraselmis chuii, Nannochloropsis salina and Skeletonema costatum) were examined. The results revealed that cholesterol is the only common fraction detected in all investigated species and distributed in free and all conjugated forms. However, the total sterol content of T. chuii was about 325 microg/g dry wt, most of it was concentrated amongst 24-methylcholesta-5,24-diene-3beta-ol and 24-methylcholest-5-en-3beta-ol. On the other hand, the majority of the fractions were distributed in the free form. The total sterol content of N. salina was about 180 microg/g dry wt, cholesterol was the major fraction that was detected. Nevertheless, the dominant distribution forms were esterified. While in S. costatum, the total sterol content was 76 microg/g dry wt, approximately most fractions are quantitatively alike and dominated in the free form. Furthermore, our study shows clearly that most sterols are not distributed regularly within each form, a result that encouraged us to suggest a distribution of specific sterol fraction as a free or conjugated can be used as a serving tool in chemotaxonomic studies.
对三种广泛用于海水养殖的微藻（杜氏盐藻、盐生微拟球藻和中肋骨条藻）中的甾醇的总量、游离形式和共轭形式（甾醇酯、甾醇糖苷和酰基甾醇糖苷）进行了检测。结果表明，胆固醇是所有被研究物种中唯一检测到的常见组分，以游离形式和所有共轭形式存在。然而，杜氏盐藻的总甾醇含量约为325微克/克干重，其中大部分集中在24-甲基胆甾-5,24-二烯-3β-醇和24-甲基胆甾-5-烯-3β-醇中。另一方面，大部分组分以游离形式分布。盐生微拟球藻的总甾醇含量约为180微克/克干重，检测到的主要组分是胆固醇。然而，主要的分布形式是酯化形式。而在中肋骨条藻中，总甾醇含量为76微克/克干重，几乎所有组分在数量上相似，且以游离形式为主。此外，我们的研究清楚地表明，大多数甾醇在每种形式中分布不规则，这一结果促使我们提出，特定甾醇组分以游离或共轭形式的分布可作为化学分类学研究中的一种有用工具。
