Hydrolysis of wax esters on thin-layer chromatographic plates by porcine pancreatic lipase is described. The alcohols and free fatty acids produced were separated on the same plate, recovered and then analysed by gas-liquid chromatography for their compositions. Synthetic wax containing saturated fatty acids of various chain lengths and unsaturated fatty acids with varying numbers of methylene-interrupted cis double bonds, along with beeswax and Avicennia officinalis leaf wax were lipolysed. The results of on-plate lipolysis for 96 min compared well with those obtained by chemical hydrolysis in tubes. © 1983.

S MISRA

A CHOUDHURY

A KR DUTTA

A GHOSH

J DUTTA

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

Journal of Chromatography A

Two unusual lipid classes were detected by thin-layer chromatography in the neutral lipids derived from goat cauda-epididymal sperm plasma membrane. The lipids were identified as wax esters and 1-O-alkyl-2,3-diacylglycerols based on chromatographic properties, identity of their hydrolysis products, and infrared/ 1 H nuclear magnetic resonance spectral evidence. The membrane contained ca. 3 and 5 μg/mg protein of wax esters and alkyldiacylglycerols, respectively. The relative proportions of wax esters and alkyldiacylglycerols in the total neutral lipids were 1.5% and 2.4%, respectively. The lipids contained fatty acids with chain lengths of C 14 to C 22 . The major fatty acids of the wax esters were 14:0, 16:0, 16:1ω7, 18:0 and 18:1ω9. The fatty acids in alkyldiacylglycerol were 16:0, 18:0, 22:5ω3 and 22:6ω3. Alkyldiacylglycerol was particularly rich in docosahexaenoic acid 22:6ω3) representing 30% of the total fatty acids. The alcohols of wax ester were all saturated with C 20 -C 29 carbon chains. The deacylated products derived from alkyldiacylglycerols were identified as hexadecyl, octadecyl and octadec-9′-enyl glycerol ethers. © 1992 American Oil Chemists' Society.

Lipids

Occurrence of wax esters and 1-O-alkyl-2,3-diacylglycerols in goat epididymal sperm plasma membrane

Total lipids from hepatopancreas of the horseshoe crabs, Tachypleus gigas and Carcinoscorpius rotundicauda, obtained in 7.6 and 3.3% wet weight respective yields, were fractionated by various chromatographic techniques and identified by gas-liquid chromatography and spectroscopic methods. Fatty acid-containing lipids were rich in 16:0 (8.0-25%), 18:1ω9 (6.9-22%) and 18:2ω6 (6.8-18.5%); appreciable amounts of 16:1ω7, 18:3ω3, 20:5ω3 and 22:6ω3 were also present. The level of 26:0 in the hydrocarbon fractions was unusually high (64 and 68%). Carbon chain lengths of major wax esters were 44, 46 and 48 for T. gigas and 38, 40 and 42 for C. rotundicauda. 1-O-Alkyl diglycerides were 7.2 and 9.1% of the total lipids in the two species and contained 14:0(20%), 16:0(60%) and 18:0(20%) alkyl chains along with a relatively higher percentage (32-35%) of saturated fatty acids. High levels of cholesterol (>50% of total sterol) in the free and combined state were encountered in both samples, phospholipid contents being 40 and 35%, respectively, and contained highest levels of unsaturated fatty acids. © 1989 American Oil Chemists' Society.

Lipids and fatty acids of the horseshoe crabs Tachypleus gigas and Carcinoscorpius rotundicauda

Seven species of fresh mangrove leaves were found to contain saturated normal and branched chain hydrocarbons, mostly between C16 and C36 with both odd and even carbon numbers. Significant quantitative variations were found between species. Wax esters were found to contain fatty acids with chain lengths between C12 and C22. Palmitic (16:0) and stearic (18:0) acids were the major component saturated fatty acids, whereas, oleic (18:1) and linolenic (18:3) acids were the major unsaturate α-acids. Chain lengths of the alcohols of wax esters were between C14 and C36. Significant quantitative and minor qualitative differences were noted in the alcohol composition of wax esters. Hydrocarbon and wax ester compositions were characterised by the presence of low M, components in high proportions. © 1987.

Phytochemistry

Hydrocarbons and wax esters from seven species of mangrove leaves

Lipid contaminants in commercial lipases

The hydrolysis of steryl esters on thin-layer chromatographic plates by porcine pancreatic lipase is described. The sterols and fatty acids produced were separated on the same plate, recovered, and analysed by gas-liquid chromatography for their compositions. Synthetic cholesteryl esters containing various saturated and unsaturated fatty acids and synthetic steryl oleates with various sterols were lipolysed along with steryl esters of Acanthus ilicifolius, Bruguiera gymnorhiza and Rhizophora mucronata mangrove leaves. The major sterol was sitosterol which was accompanied by cholesterol, campesterol, stigmasterol and 28-isofucosterol. In addition, stigmast-7-en-3β-ol was present in R. mucronata leaves. The component fatty acids found in all three species were 16:0, 18:0, 18:1, 18:2 and 18:3. The relative proportions of the sterols and fatty acids were significantly different from the chemotaxonomic standpoint. The results obtained by carrying out plate lipolysis for 45 min at 40° compared well with those produced by conventional chemical hydrolysis. © 1984.

Sterols and fatty acids from three species of mangrove

A procedure for the phospholipase A2 hydrolysis of phosphatidylcholine on a thin-layer chromatographic plate and subsequent separation of the products on the same plate is described. A 0.2-0.8-mg amount of Russell's viper venom (phospholipase A2) in 0.2 ml of 0.005 M calcium chloride solution was applied on a 0.5-mm silica gel G plate as a band over which 2-5 mg of egg phosphatidylcholine in 0.2 ml of diethyl ether containing 5% of methanol was evenly applied. After the reaction had proceeded for 15-20 min in a diethyl ether-saturated chamber at 25°, the plate was developed with chloroform-methanol-water (65:25:4). The bands were identified and their contents extracted. The extent of hydrolysis under different reaction conditions was evaluated from the amount of lysophosphatidylcholine formed. Approximately 74.6% (maximum) conversion was obtained within 15 min at 25° using substrate to enzyme ratio of 4:1. The acyl group distribution in the 1- and 2-positions of hen egg phosphatidylcholine obtained from the gasliquid chromatographic analysis of the methyl ester corresponding to the lyso and free fatty acid band agreed with those obtained by the method of Wells and Hanahan. The method is also applicable to phosphatidylethanolamine. © 1979.

Enzymatic reactions on thin-layer chromatographic plates. II. Phospholipase A2 hydrolysis of phosphatidylcholine and separation of the products on a single plate

Journal	Journal of Chromatography A
Publisher	-
ISSN	0021-9673