A new antitumor arabinopyranoside from Laurencia majuscula induces G2/M cell cycle arrest.

A new arabinopyranoside was isolated from the alga Laurencia majuscula (Harvey) Lucas, collected from the Xisha Islands in the South China Sea. Its structure was elucidated as hexadecyl-1-O-α-L-arabinopyranoside by spectroscopic analysis. It was found that arabinopyranoside had significant antitumor activity in LOVO and Bel-7402 cell lines. Flow cytometric analysis showed that arabinopyranoside arrested the cell cycle in the G2/M phase. Western blotting demonstrated that the protein expression of CDK1 and cyclin A related to the G2/M phase decreased markedly with arabinopyranoside treatment, with slight changes in cyclin B1 expression. Taken together, the findings identify a potential new antitumor therapeutic arabinopyranoside isolated from red alga Laurencia majuscula.