Phoency Lai

Optimization of acid hydrolysis conditions for feruloylated oligosaccharides from rice bran through response surface methodolgy.

Response surface methodology (RSM) was employed to optimize the hydrolysis conditions with trifluoroacetic acid (TFA) to obtain the maximum amount of feruloylated oligosaccharides from rice bran. The TFA concentration and hydrolysis time effects on feruloylated oligosaccharides recovery are studied. The optimum hydrolysis conditions for maximizing feruloylated oligosaccharides recovery were 193 mM TFA concentration and 1.36 h of hydrolysis time. Under these conditions the corresponding acyl ferulic group quantity was 78.63 microg in 1 mL of hydrolysate. The model was experimentally verified with a satisfactory coefficient of R (2) (= 0.96). The quantity of acyl ferulic group in the feruloylated oligosaccharides, purified using Amberlite XAD-4, was 916.12 microg/g of rice bran under the optimum hydrolysis conditions. The proposed method accounted for 54.08% of the total acyl ferulic group in rice bran. The results suggest that the proposed conditions were useful in maximizing recovery of feruloylated oligosaccharides from rice bran.

Carrageenan polysaccharides and oligosaccharides with distinct immunomodulatory activities in murine microglia BV-2 cells

This study was to investigate the anti-inflammatory activities in vitro of various carrageenans (Car) fractions (κ-, ι-, and λ-types) with well characterized molecular properties, using murine microglia BV-2 cell line treated with lipopolysaccharide (LPS) as model. It is indicated that pretreatments with the oligosaccharide fractions from κ- or ι-carrageenan acid hydrolysates (κ- and ι-CarAOS, respectively) at 125-500 μg/mL significantly and dose-dependently decreased the levels of tumor necrosis factor α (TNF-α) secreted from LPS-treated BV-2 cells, showing promisingly anti-inflammatory effects. Differently, pretreatments of most of polymeric carrageenans at 250-500 μg/mL significantly increased the TNF-α level, implying the co-inflammatory effects with LPS. The co-inflammatory effectiveness of pure carrageenans at 125 μg/mL was notable for λ-Car, followed by ι-Car, and insignificantly for κ-Car. Generally, cytokine TNF-α was a more sensitive biomarker to the presence of carrageenans than was the IL-6. The TNF-α level varied greatly at a low carrageenan concentration (125 μg/mL) and high polymer percentage (e.g. purified κ- and ι-Car). Conclusively, the anti-inflammatory effects on LPS-treated BV-2 cells could be attenuated by pretreatments with κ- and ι-CarAOS at 125-500 μg/mL.