Phenolic acids and quercetin from Korean black raspberry seed protected against acetaminophen-induced oxidative stress in mice

Analysis of polyphenols in Aegle marmelos leaf and ameliorative efficacy against diabetic mice through restoration of antioxidant and anti-inflammatory status

The biomedical survey reports edible plant Aegle marmelos has been utilized for centuries by tribal communities in India as a dietary supplement for the management of diabetes. Herein, we have investigated cytotoxicity, cytoprotective and antidiabetic activity of characterized alkaloid-free hydroalcoholic extract of A. marmelos (AFEAM; 200 and 400 mg/kg). Identification of polyphenols and quantification of major compounds were done using UPLC-MS and HPTLC, respectively. AFEAM showed good cytocompatibility and cytoprotective potential against oxidative stress induced by hyperglycemia in HepG₂ cells. The AFEAM intake had significantly ameliorated the serum blood glucose level, state of dyslipidemia, level of pro-inflammatory markers (tumor necrosis factor-α, interleukin-6, and interleukin-1β), and antioxidant (superoxide dismutase, catalase, glutathione peroxidase, and malondialdehyde) status in diabetic mice. Histological examination of the treated groups showed amelioration of damaged pancreas, liver, and kidney tissues. Conclusively, AFEAM intake might be promising dietary supplements for prediabetics as well as an adjuvant to modern treatment in diabetics. PRACTICAL APPLICATIONS: Different reports have been published on Aegle marmelos but as per our understanding till date, no study has been reported on the amelioration of diabetes due to alkaloid free hydroalcoholic extract of A. marmelos /polyphenolic content in the animal model. The result of this study indicated that A. marmelos supplementation effectively ameliorates diabetes through the restoration of antioxidant and anti-inflammatory status. This study has collated sufficient scientific evidence for the dietary application of A. marmelos in society especially for prediabetics, however, it can also be used as an adjuvant to modern treatments in diabetics.

Antioxidant effects of kimchi supplemented with black raspberry during fermentation protect against liver cirrhosis-induced oxidative stress in rats

BACKGROUND/OBJECTIVES

Oxidative stress is a major effector of various diseases; accordingly, antioxidants are frequently ingested in order to prevent or alleviate disease symptoms. Kimchi contains various natural antioxidants, and it is known that the functional activity varies depending on the ingredients and fermentation state. Black raspberries (BR) contain various bioactive compounds with antioxidant effects. This study investigated the antioxidant and liver-protection effects of kimchi supplemented with black raspberry juice powder (BJP).

MATERIALS/METHODS

BJP-added kimchi (BAK; at 0.5%, 1%, and 2% concentrations of BJP) and control (without BJP) were prepared and fermented at 4℃ for 4 weeks. Changes in the antioxidant effects of BAK during fermentation were investigated. In addition, the protective activity of BAK against oxidative stress was investigated in a liver cirrhosis-induced animal model in vivo.

RESULTS

BAK groups showed the acidity and pH of optimally ripened (OR) kimchi at 2 weeks of fermentation along with the highest lactic acid bacterial counts. Additionally, BAK groups displayed a higher content of phenolic compounds and elevated antioxidant activities relative to the control, with the highest antioxidant effect observed at 2 weeks of fermentation of OR 1% BAK. After feeding the OR 1% BAK to thioacetamide-induced liver cirrhosis rats, we observed decreased glutamate oxaloacetate transaminase and glutamate pyruvate transaminase activities and elevated superoxide dismutase activity.

CONCLUSIONS

These findings showed that the antioxidant effects of OR BAK and feeding of OR 1% BAK resulted in liver-protective effects against oxidative stress.

Simultaneous determination of quercetin and its metabolites in rat plasma by using ultra-high performance liquid chromatography tandem mass spectrometry

Fast, selective, and sensitive ultra-high performance liquid chromatography method with tandem mass spectrometry detection for the determination of quercetin and its metabolites with various physico-chemical properties such as molecular weight, lipophilicity, and acid-base properties has been developed. These compounds included small hydrophilic phenolic acids and more lipophilic metabolites with preserved flavonoid structure in small amount of rat plasma. The developed method enables selective separation of phenolic acids and a pair of isomers tamarixetin and isorhamnetin with satisfactory peak shapes and a high sensitivity using mass spectrometry detection. In addition, two sample preparation procedures including protein precipitation and microextraction in packed sorbent (MEPS) were optimized. The sample acidification included in protein precipitation as well as optimizing of MEPS sorbents and elution solvents improved isolation of quercetin and related compounds from rat plasma. Finally, both methods developed for sample preparation were fully validated to demonstrate sufficient accuracy and precision and acceptable matrix effects. Both sample preparation approaches combined with mass spectrometry-based quantification allowed the simultaneous determination of quercetin and its metabolites from a small amount of biological samples of only 50 μL. Due to the fast and non-selective parallel sample preparation, the protein precipitation was eventually applied to plasma samples derived from pharmacokinetic studies.