Evaluation of the antidiabetic, antiobesity and antioxidant potential of Anthophycus longifolius ((Turner) Ktzing)

Obesity is a major public health problem that is associated with many metabolic disorders including diabetes, hypertension, and cardiovascular diseases. Anthophycus longifolius is a brown seaweed that have been shown to possess antioxidant, antibacterial and anti-inflammatory activities. The present study investigated the anti-diabetic, anti-obesity and oxidative stress ameliorating properties of cold water (CW) and ethanolic (EtOH) extracts of A. longifolius using in vitro and ex vivo experimental models. The extracts significantly inhibited the activities of carbohydrate and lipid digestive enzymes alpha - glucosidase (IC50 = CW: 176.9 +/- 2.1 mu g/ml; EtOH: 179.8 +/- 1.9 mu g/ml); alpha-amylase (IC50 = CW: 86.1 +/- 1.7 mu g/ml; EtOH: 77.8 +/- 1.9 mu g/ml); and pancreatic lipase (IC50 = CW: 184.3 +/- 1.7 mu g/ml; EtOH: 534.1 +/- 2.3 mu g/ml), and stimulated adipose glucose uptake (CW: 10- 50.5 mg/g adipose tissue; EtOH: 9 - 79 mg/g adipose tissue). Incubation of adipose tissues with FeSO4 significantly depleted reduced glutathione (GSH) level, super oxide dismutase (SOD) and catalase activities, while concomitantly elevated malondialdehyde (MDA) level. These changes were significantly reversed following the treatment of A. longifolius extracts. Liquid chromatography-mass spectrometry (LC-MS) analysis of the extracts revealed the presence of rhodomycinone, salsolinol, 5-hydroxyconiferyl alcohol, 2-caffeoylisocitrate and demethylalangiside in the cold water extract, while petromyzonol 24 -sulfate, atractyloside, abyssinone VI and podecdysone B in the ethanolic extract. Molecular docking analysis revealed potent interactions of the phytochemicals with GLUT4 and leptin. These results indicate the possible antidiabetic, antiobesity and oxidative stress ameliorating potentials of A. longifolius extracts at in vitro and ex vivo experimental models. The identified compounds may be responsible for the observed biological activities.