Lipids of the acetone-insoluble fraction from red-clover (Trifolium pratense) leaves

Trifolium L.--a review on its phytochemical and pharmacological profile

Plants from the genus Trifolium have been used in traditional medicine by many cultures. In Turkish folk medicine, for example, some Trifolium species are used for their expectorant, analgesic, antiseptic properties and also to treat rheumatic aches. Some species are also grown as pasture crops for animals in the Mediterranean. The high quercetin concentration and soyasaponin occurrence make the seeds of some Trifolium species a potential source of health beneficial phytochemicals for use in human nutrition. However, Trifolium pratense has also gained popularity due to research into its use for the treatment for menopausal symptoms. This paper provides an overview of the phytochemical and pharmacological profile of Trifolium species.

Degradation of monogalactosyl diglyceride and digalactosyl diglyceride by sheep pancreatic enzymes

1. Saline extract of sheep pancreas acetone-dried powder was shown to catalyse acyl ester hydrolysis of spinach leaf galactosyl diglycerides and also galactosylglucosyl diglyceride of Lactobacillus casei. 2. Sodium deoxycholate stimulated the enzyme activity. Ca(2+) had no effect on the hydrolysis of monogalactosyl diglyceride, but it enhanced that of digalactosyl diglyceride. When added together, there was considerably less activity with both the substrates. 3. Optimal hydrolysis was observed at pH7.2. 4. The initial point of hydrolysis was at position-1, leading to the formation of monogalactosyl monoglyceride and digalactosyl monoglyceride. Further hydrolysis to the corresponding galactosylglycerols and later to galactose and glycerol was also observed, indicating the presence of alpha- and beta-galactosidases in the enzyme preparation. 5. Formation of monogalactosyl diglyceride from digalactosyl diglyceride by the action of alpha-galactosidase was noted. 6. Monogalactosyl diglyceride was also hydrolysed by beta-galactosidase to a limited extent, giving rise to diacylglycerol and galactose. 7. Attempts at purification of monogalactosyl diglyceride acyl hydrolase by using protamine sulphate treatment, Sephadex G-100 filtration and DEAE-cellulose chromatography gave a partially purified enzyme which showed 9- and 81-fold higher specific activity towards monogalactosyl diglyceride and digalactosyl diglyceride respectively. This still showed acyl ester hydrolysis activity towards methyl oleate, phosphatidylcholine and triacylglycerol. 8. When sheep, rat and guinea-pig tissues were compared, guinea-pig tissues showed the highest activity towards both monogalactosyl diglyceride and digalactosyl diglyceride. In all the species pancreas showed higher activity than intestine.

Comparison of column chromatographic methods for the quantitative determination of mono- and digalactodiglycerides in fresh alfalfa (Medicago sativa)

Three column chromatographic procedures for separating and recovering the galactolipids in fresh alfalfa extracts were compared. Silicic acid chromatography yielded pure fractions by thin-layer chromatography, infrared absorption, and chemical analysis. The carbon-Celite column gave the highest yield of monogalactodiglyceride. Of the 1.2% total lipids of fresh alfalfa, approximately 12% was monogalactodiglyceride and 8% was digalactodiglyceride. Linolenic acid accounted for about 90% of the total fatty acids in these components.

Alpha-linoleate and photosynthetic activity in Chlorella protothecoides

Green cells of Chlorella protothecoides grown in nitrogen-rich low glucose media may be reversibly transformed to entirely chlorophyll-less cells in low nitrogen high glucose media. Photosynthetic rates and fatty ester compositions were determined during light and dark bleaching and during greening. Linolenic acid content remained unchanged during greening or bleaching. During light greening chlorophyll content and photosynthetic activity increased while oleic acid content decreased dramatically. As a result, the percent composition of linolenate appeared to parallel photosynthetic capability. Implication of alpha-linolenate in oxygen production, therefore, can not be based upon fatty acid percentage composition data alone.