Ipomoea batatas (L.) Lam

Fiorito, Serena, Epifano, Francesco, Preziuso, Francesca, Taddeo, Vito Alessandro & Genovese, Salvatore, 2018, Selenylated plant polysaccharides: A survey of their chemical and pharmacological properties, Phytochemistry 153, pp. 1-10 : 5-6

5.9.1. Ipomoea batatas (L.) Lam

I. batatas (sweet potato) is an edible vegetable widely consumed in many areas of Asia and the Pacific, Africa, and Americas and it is claimed to have anti-diabetic properties ( Ludvik et al., 2004). In 2017 Yuan and coworkers accomplished the microwave-assisted selenylation of the polysaccharide fraction extracted from tubers of this species, obtaining a single sample with a Se content of 12.74 mg /g. The anti-oxidant activity of this adduct was first assessed in vitro by the DPPH radical test. This assay showed that the obtained Se-P exerted a dose-dependent effect with an activity comparable to that recorded for ascorbic acid used as control (IC 50 = 0.72 μg/mL and 0.67 μg/mL respectively) and about 3.5-fold higher than the native polysaccharide.

Similar results were obtained for the ABTS test (IC 50 = 0.35 μg/mL for ascorbic acid and 0.41 μg/mL for the Se-P). In vivo tests were performed with Kunming female mice inoculated with the murine H22 hepatoma cell line and subsequently treated daily i.m. with the Se-P for 28 days. In a parallel study in vivo anti-diabetic and anti-oxidant activities were investigated in male SD rats fed with 3 doses of the Se-P (50, 100, and 200 mg /kg). Diabetes was induced by pre-treatment with streptozocin. Biochemical parameters measured were production of IL-2, TNF-α, VEGF, tumor weight, tumor inhibition rate, blood insulin level, total cholesterol, triglycerides, serum HDL and LDL, activity of CAT, SOD, and GSH, content of MDA in liver, heart, pancreas, and kidneys, and finally blood content of alkaline phosphatase, AST, ALT, total bilirubin, creatinine, and urea. Treatment with the Se-P was shown to largely decrease the release of IL-2, increase TNF-α, and to decrease the production of VEGF 1.5- to 3.5-fold better than treatment with 5-fluorouracile used as control. Furthermore, administration of the Se-P at doses of 100 and 200 mg /kg decreased tumor weights to values comparable to those recorded in animals treated with 5-fluorouracile (0.32 g, 0.30 g, and 0.28 g respectively). Weights and functionalities of target organs listed above remained unaffected upon feeding with Se-P and no lethal effects were observed in animals during the whole duration of the test. Lipids serum concentrations were all diminished after the administration of the Se-P being total cholesterol, triglycerides, HDL, and LDL values 5.8 mmol/L, 3.1 mmol/L, 3.6 mmol/L, and 0.6 mmol/L respectively for streptozocin treated animals and 2.8 mmol/L, 0.9 mmol/L, 0.9 mmol/L, and 1.7 mmol/L for animals fed with the Se-P. The last set of values were practically the same of animals treated only with the vehicle. A marked decrease of MDA concentration and a huge increase of the activities of CAT, SOD, and GSH were also recorded in all target organs. Finally, blood insulin remained unchanged in the Se-P treated group of animals respect to untreated controls.