Unusual Structures and Cytotoxicities of Chitonoidosides A, A 1 , B, C, D, and E, Six Triterpene Glycosides from the Far Eastern Sea Cucumber Psolus chitonoides

• Published in: Marine Drugs
• Main Authors: Alexandra S. Silchenko, Anatoly I. Kalinovsky, Sergey A. Avilov, Pelageya V. Andrijaschenko, Roman S. Popov, Pavel S. Dmitrenok, Ekaterina A. Chingizova, Vladimir I. Kalinin
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2021
• Subjects: Psolus chitonoides; triterpene glycosides; chitonoidosides; sea cucumber; cytotoxic activity; Biology (General); QH301-705.5; Bering Island
• Online Access: https://doi.org/10.3390/md19080449; https://doaj.org/article/0d4781bde71c4b7db2271dcdc5f3e2d1

Six new triterpene tetra-, penta- and hexaosides, chitonoidosides A ( 1 ), A 1 ( 2 ), B ( 3 ), C ( 4 ), D ( 5 ), and E ( 6 ), containing one or two sulfate groups, have been isolated from the Far-Eastern sea cucumber Psolus chitonoides , collected near Bering Island (Commander Islands) from the depth of 100–150 m. Three of the isolated compounds ( 1 , 3 and 6 ) are characterized by the unusual aglycone of new type having 18(20)-ether bond and lacking a lactone in contrast with wide spread holostane derivatives. Another unexpected finding is 3- O -methylxylose residue as a terminal unit in the carbohydrate chains of chitonoidosides B ( 3 ), C ( 4 ), and E ( 6 ), which has never been found before in the glycosides from holothurians belonging to the Psolidae family. Moreover, this monosaccharide is sulfated in the compound 4 into unprecedented 3- O -methylxylose 4- O -sulfate residue. Chitonoidoside C ( 4 ) is characterized by tetrasaccharide moiety lacking a part of the bottom semi-chain, but having disaccharide fragment attached to C-4 of Xyl1. Such architecture is not common in sea cucumber glycosides. Cytotoxic activities of the compounds 1 – 5 against mouse and human erythrocytes and human cancer cell lines: adenocarcinoma HeLa, colorectal adenocarcinoma DLD-1, and leukemia promyeloblast HL-60 cells were studied. The cytotoxic effect of chitonoidoside d ( 5 ) was the most significant in this series due to the presence of pentasaccharide disulfated sugar chain in combination with holostane aglycone. Surprisingly, the glycosides 1 and 3 , comprising the new aglycone without γ-lactone, demonstrated similar activity to the known compounds with holostane aglycones. Chitonoidoside C ( 4 ) was less cytotoxic due to the different architecture of the carbohydrate chain compared to the other glycosides and probably due to the presence of a sulfate group at C-4 in 3- O -MeXyl4.