Antidiabetic and anti-inflammatory potential of sulphated polygalactans from red seaweeds Kappaphycus alvarezii and Gracilaria opuntia

ABSTRACT

Antidiabetic and anti-inflammatory potential of sulphated polygalactans isolated from the red seaweeds Kappaphycus alvarezii and Gracilaria opuntia were acquired by employing different in vitro systems. The sulphated galactopyran motif derived from G. opuntia possessed significant antidiabetic properties as identified by α-amylase (IC₅₀ 0.04 mg/mL), α-glucosidase (IC₅₀ 0.09 mg/mL) and dipeptidyl peptidase-4 (DPP-4, IC₅₀ 0.09 mg/mL) inhibitory activities. Based on the detailed nuclear magnetic resonance spectroscopy experiments the sulphated galactopyran motif of G. opuntia was designated as →3)-4-O-sulfonato-(6-O-acetyl)-β-D-galactopyranosyl-(1→4)-3,6-anhydro-(2-O-sulfonato)-α-D-galactopyranosyl-(1→3)-4-O-sulfonato-(6-O-acetyl)-β-D-xylosyl-(1→3)-4-O-sulfonato-(6-O-acetyl)-β-D-galactopyranosyl-(1→4)-3,6-anhydro-(2-O-sulfonato)-α-D-galactopyranan, while the one from K. alvarezii was demonstrated to be →4)-4-O-sulfonato-(2-O-methyl)-β-D-galactopyranosyl-(1→4)-3,6-anhydro-(2-O-methyl)-α-D-galactopyranan. The sulphated galactans from G. opuntia showed greater anti-inflammatory inhibitory activities as determined by cyclooxygenase-1 (COX-1, IC₅₀ 0.01 mg/mL), cyclooxygenase-2 (COX-2, IC₅₀ 0.03 mg/mL), and 5-lipoxygenase inhibitory activities (5-LOX, IC₅₀ 0.24 mg/mL). This study revealed that the sulfated polygalactan enriched concentrate from G. opuntia can be used as potential therapeutic candidate to suppress the hyperglycemic response in diabetic conditions and inflammatory activity. They can be used to develop functional food ingredient in nutraceutical products.

KEYWORDS:

• Kappaphycus alvarezii
• Gracilaria opuntia
• Anti-inflammatory
• Cyclooxygenase
• Lipoxygenase
• Antidiabetic
• Dipeptidyl peptidase

Acknowledgments

The authors thank the Director, Central Marine Fisheries Research Institute, for his guidance and support. Thanks are due to the Head, Marine Biotechnology Division for facilitating the research works. Fasina Makkar thanks Department of Science and Technology for fellowship.

Funding

This work is supported by the funding under the Science and Engineering Research Board (SERB) Scheme (Grant number SR/S1/OC-96/2012 SERB) from Department of Science and Technology, Ministry of Science and Technology, New Delhi, India.

Additional information

Funding

This work is supported by the funding under the Science and Engineering Research Board (SERB) Scheme (Grant number SR/S1/OC-96/2012 SERB) from Department of Science and Technology, Ministry of Science and Technology, New Delhi, India.