Structure and cytotoxic activity of ulvan extracted from green seaweed Ulva lactuca

- An ulvan from green seaweed Ulva lactuca was extracted.
- Fine chemical structure of the ulvan was determined by using SECMALL, IR, NMR and ESIMS methods.
- The ulvan showed a significant cytotoxic activity again three cancer cell lines HepG2 (Hepatocellular carcinoma), MCF7 (human breast cancer), and Hela (cervical cancer).

The structure of an ulvan obtained by water extraction from green seaweed Ulva lactuca was elucidated by using IR, NMR, SEC-MALL and ESIMS methods. The ulvan was also evaluated for its cytotoxic effects on three human cancer cell lines. The results showed that the ulvan was composed of rhamnose, galactose, xylose, manose, glucose (with a mole ratio of Rha: Gal: Xyl: Man: Glu equal to 1: 0.03: 0.07: 0.01: 0.06), uronic acid (21.5%) and sulfate content (18.9%) with a molecular weight of 347000. This ulvan mainly consists of disaccharide [→4)-β-d-GlcA-(1 → 4)-α-l-Rha3S-(1→] and other minor disaccharide β-GlcA-(1 → 2)-α-Xyl and β-GlcA-(→2)-α-Rha. The ulvan showed a significant cytotoxic activity against hepatocellular carcinoma (IC50 29.67 ± 2.87 μg/ml), human breast cancer (IC50 25.09 ± 1.36 μg/ml), and cervical cancer (IC50 36.33 ± 3.84 μg/ml).