UPLC-ESI-MS/MS Analysis and Evaluation of Antioxidant Activity of Total Flavonoid Extract from Paeonia lactiflora Seed Peel and Optimization by Response Surface Methodology (RSM).

In this study, the ultrasound-assisted extraction (UAE) of flavonoid from Paeonia lactiflora seed peel was optimized by response surface methodology (RSM). Single-factor experiments and a three-factor three-level Box-Behnken design (BBD) were performed to explore the effects of the following parameters on flavonoid extraction: ethanol concentration (X 1), liquid-solid ratio (X 2), and ultrasonic time (X 3). The results showed that the optimal flavonoid yield (10.9045 mg RE/g) was as follows: ethanol concentration 62.93%, ultrasonic time 64.56 min, and liquid-solid ratio 24.86 mL/g. The optimized extract of P. lactiflora seed shell was further analyzed by UPLC-ESI-MS/MS, and 20 main flavonoids were identified and quantified, among which protocatechuic acid, vanillic acid, 4-hydroxybenzoic acid, and 3,4-dihydroxybenzaldehyde had the highest content. Furthermore, the results of the antioxidant test showed that the P. lactiflora seed peel extract obtained under optimized UAE conditions exhibited good antioxidant activity. The experimental results showed that ultrasound-assisted extraction was a fast, efficient, and simple method for extracting active ingredients from P. lactiflora seed peel, thereby making this byproduct a promising source of compounds in food and healthcare sectors.

Molecular cloning, expression, and characterization of BmSOD3 in silkworm (Bombyx mori).

Superoxide dismutases (SODs) play an essential role in eliminating excess reactive oxygen species and maintaining the redox balance of the immune system. To study the function of BmSOD3 in silkworm, 543-bp full-length complementary DNA-encoding BmSOD3 was cloned from silkworm. The BmSOD3 amino acids were compared to their homologs, and several highly conserved regions were analyzed. We also carried out phylogenetic analyses of the SOD gene. Our results showed that the BmSOD3 gene belonged with the ecCu/Zn SOD gene. The BmSOD3 gene was transformed into the pET28a vector for functional expression in Escherichia coli. The sodium salt-polyacrylamide gel electrophoresis results showed that the molecular weight of recombinant BmSOD3 was about 22 kDa. The recombinant protein BmSOD3 was purified to detect its properties. After purification analyses, the enzyme activity showed Cu/Zn SOD activity, and the specific activity of the purified enzyme was 0.51 U/mg. The BmSOD3 transcripts showed tissue-specific expression in the midgut and malpighian tubule. The immune microarray data for BmSOD3 showed an expression signal that had a strong response to the induction of four pathogens (Bacillus bombyseptieus, Beauveria bassiana, E. coli, and nuclear polyhedrosis virus), particularly after infection for 24 h, which indicates that the BmSOD3 gene plays a key role in response to bacterial, fungal, and viral invasion. The fusion protein also showed antibacterial activity against E. coli in vitro. Thus, the fusion protein BmSOD3 exhibits antibacterial activity and may be used in production to combat diseases caused by bacteria in silkworm.