Studies On Preparation And Antitumor Bioactivities Of Functional Lipids From The Sea Cucumber Acaudina Molpadioides

Acaudina molpadioides of the order Molpadiida (Echinodermata: Holothuroidea) belongs to the family Caudinidae which is a resourceful and low-value sea cucumber. It is abundant in subtropical sandy sea area, and distributed from Shandong Province to Hainan Island in China. Sphingolipids and sterols are important functional lipids in sea cucumber, with diverse biological activitives, such as anti-virus, anti-bacterial, anti-inflammatory, immunomodulatory and cytotoxic. The current research on the functional lipids of sea cucumber mainly focused on the high-value sea cucumber of Stichopodidae. There was less research on the functional lipids of A. molpadioides and other low-value sea cucumbers.Taking A. molpadioides as raw material, this thesis mainly studies on the isolation, structural elucidation of the low polar functional lipids. The anti-S180 cell activity of the long-chain base and the low-polar functional lipids of the sea cucumber are discussed on the basis of hydrolysis of sea cucumber. The research will provide some theoretical basis and scientific groundwork for the exploration of the low-value sea cucumbers in fields of food and drug. The main contents of this thesis are concluded as follows:1. Five functional lipid compounds——one kind of ceramide, 3 cerebrosides and a sterol, which are separated form A. molpadioides by using organic solvent extraction, multi-step extractions and repeated column chromatography. All of these compounds are isolated from A. molpadioides for the first time, of which sterol: 3β-O-sulfated-ergosta-7, 9 (11), 24 (28)-triene-sodium salt is identified as a completely new compound.2. Long-chain base is prepared by hydrolysis the rough lipids of A. molpadioides and the purification technology of it is optimized by using high speed countercurrent chromatography. The two-phase solvent system is composed of hexane - methanol - water (1:2:1, V/V). The long-chain base is yielded with purity higher than 95% after purification. Compared with the traditional Si-gel chromatographic separation method, the HSCCC separation process can save 70% of the solvent consumption, shorten 88% of the separation time, and the yield rate of the target long-chain base is 3.5 times as much as the yield rate by using traditonal separation method, suggesting high speed counter current chromatography to be a more applicable technology for the purification of long-chain base of sea cucumbers.3. The antitumor effects of the five low polar functional lipids and the long-chain base from A. molpadioides on S-180 cells are investigated. Results show that the viability of S-180 cells treated with such long-chain base and liposomes containing the functional lipids of A. molpadioides are restrained in a dose-dependent and time-dependent manner. The antitumor activities of the sphingolipids show some structure-relationships. Polyhydroxy structure in the long-chain base can increase the antitumor activity significantly, and theβ-glucose residue can also enhance its antitumor activity. The antitumor activity of the long-chain base hydrolyzed from the rough lipids of A. molpadioides is much higher than that the sphingolipids isolated naturally.