Objective:To compare the cardioprotective efficacy of equimolar doses(50 mM/kg,p.o.)of phloretin and genistein against doxorubicin-induced cardiotoxicity in rats.Methods:Cardiotoxicity was induced in rats by intraperi...Objective:To compare the cardioprotective efficacy of equimolar doses(50 mM/kg,p.o.)of phloretin and genistein against doxorubicin-induced cardiotoxicity in rats.Methods:Cardiotoxicity was induced in rats by intraperitoneal injection of 6 mg/kg doxorubicin on alternative days till the cumulative dose reached 30 mg/kg.This study included four treatment groups of rats(n=6):the control group(0.5%carboxymethyl cellulose solution-treated),the doxorubicin-treated group(0.5%carboxymethyl cellulose solution along with doxorubicin),the genistein-treated group(50 mM/kg/day;p.o.along with doxorubicin)and phloretin-treated group(50 mM/kg/day;p.o.along with doxorubicin).On the 10th day of dosing,rats were anesthetized for recording ECG,mean arterial pressure,and left ventricular function.Oxidative stress,nitric oxide levels,and inflammatory cytokines were estimated in the cardiac tissue.Cardiac function parameters(creatine kinase MB,lactate dehydrogenase,aspartate aminotransferase,and alanine transaminase)were estimated in the serum samples.Results:Phloretin treatment inhibited doxorubicin-induced oxidative stress and also reduced nitric oxide levels in cardiac tissues of rats.Phloretin administration attenuated doxorubicin-induced alterations in hemodynamic parameters(heart rate,mean arterial blood pressure,and left ventricular function)and suppressed the expression of pro-inflammatory cytokines.The cardiac injury markers like creatine kinase MB,lactate dehydrogenase,aspartate aminotransferase,and alanine transaminase were reduced by both genistein and phloretin.All these effects of phloretin were more prominent than genistein.Conclusions:Phloretin offers cardioprotection that is comparable to genistein,a clinically validated cardioprotectant against doxorubicin-induced cardiotoxicity.Further studies are needed to confirm and establish the therapeutic utility of phloretin as a chemopreventive adjuvant to doxorubicin chemotherapy.展开更多
Reactive oxygen species [ROS] cause oxidative damage to the tissues and protection from such damages is provided by endogenous and exogenous antioxidants. Much research work has been carried out in recent years on the...Reactive oxygen species [ROS] cause oxidative damage to the tissues and protection from such damages is provided by endogenous and exogenous antioxidants. Much research work has been carried out in recent years on the beneficial effect of phenolic compounds which act as natural antioxidants and help to neutralize free radicals. So, this study was aimed to evaluate the in vitro antioxidant capacity of one of the phenolic compounds phloretin. Phloretin was used at four different concentrations like 20, 40, 60 and 80 μg/ml to determine the antioxidant activity by different methods such as total antioxidant capacity, reducing power, DPPH radical scavenging, superoxide anion radical scavenging and metal chelating assays. In addition to that the ascorbic acid was used as reference compound. The results showed that the phloretin displayed potent in vitro antioxidant capacity. It was able to scavenge different in vitro free radicals in all tested concentrations. Among the different concentrations, 80 μg of phloretin has maximum activity when compared to other concentrations in all in vitro antioxidant assays. High antioxidant property and maximum protective effect of phloretin were observed in a concentration dependent manner. The results were expressed as IC<sub>50</sub> value. The lowest IC<sub>50 </sub>value indicates the highest scavenging activity. The reducing power of the phloretin was also found in concentration dependent. According to the results of this study, we concluded that the phloretin possesses antioxidant property. Therefore, phloretin is a powerful antioxidant phytocompound which can protect biological systems against the oxidative stress. From this study, we suggest that the phloretin may be used as a dietary natural antioxidant supplement for preventing free radical related diseases.展开更多
Phloretin is an important skin-lightening and depigmenting agent from the peel of apples. Although de novo production of phloretin has been realized in microbes using the natural pathway from plants, the efficiency of...Phloretin is an important skin-lightening and depigmenting agent from the peel of apples. Although de novo production of phloretin has been realized in microbes using the natural pathway from plants, the efficiency of phloretin production is still not enough for industrial application. Here, we established an artificial pathway in the yeast to produce phloretin via assembling two genes of p-coumaroyl-CoA ligase(4CL) and chalcone synthase(CHS). CHS is a key enzyme which conventionally condenses a CoA-tethered starter with three molecules of malonyl-CoA to form the backbone of flavonoids. However, there was 33% of byproduct generated via CHS by condensing two molecules of malonyl-CoA during the fermentation process. Hence, we introduced a more efficient CHS and improved the supply of malonyl-CoA through two pathways;the by-product ratio was decreased from 33% to 17% and the production of phloretin was improved from 48 to 83.2 mg L^(-1). Finally, a fed-batch fermentation process was optimized and the production of phloretin reached 619.5 mg L^(-1), which was 14-fold higher than that of the previous studies. Our work established a platform for the biosynthesis of phloretin from the low-cost raw material 3-(4-hydroxyphenyl) propanoic acid and also illustrated the potential for industrial scale bio-manufacturing of phloretin.展开更多
Although the catabolic pathway of some flavonoids in the human colon has been elucidated,knowledge of related gut microbes and responsible enzymes is still limited.In this study,a phloretin hydrolase gene(phy)from Fla...Although the catabolic pathway of some flavonoids in the human colon has been elucidated,knowledge of related gut microbes and responsible enzymes is still limited.In this study,a phloretin hydrolase gene(phy)from Flavonifractor plautii(F.plautii)was synthesized and heterologously expressed in Escherichia coli BL21(E.coli BL 21).Phloretin hydrolase(PHY)was purified from cell extracts of recombinant E.coli BL21,and PHY's molecular weight was about 32 kDa.The purified PHY effectively cleaved phloretin into 3-(4-hydroxyphenyl)propionic acid(HPPA)and phloroglucinol(PG).PHY's kinetic parameters were determined:Km was 2.8×10^(−3)±0.4 mM and Vmax was 411.2±7.1 U/mg.Besides,PHY's optimal temperature and pH were 50℃ and 7.5,respectively,and PHY exhibited 75%activity after 5 h at 50℃.Furthermore,PHY's activity was inhibited in the presence of Ba^(2+),Cu^(2+),and Fe^(2+),while Mg^(2+) slightly elevated PHY's activity.Finally,the catalytic model between phloretin and PHY was built using molecular docking,and PHY's conformational changes were further demonstrated through the multispectral techniques.This study is conducive to understanding phloretin metabolism in the colon and adding a valuable source of PHY for food industry application.展开更多
文摘Objective:To compare the cardioprotective efficacy of equimolar doses(50 mM/kg,p.o.)of phloretin and genistein against doxorubicin-induced cardiotoxicity in rats.Methods:Cardiotoxicity was induced in rats by intraperitoneal injection of 6 mg/kg doxorubicin on alternative days till the cumulative dose reached 30 mg/kg.This study included four treatment groups of rats(n=6):the control group(0.5%carboxymethyl cellulose solution-treated),the doxorubicin-treated group(0.5%carboxymethyl cellulose solution along with doxorubicin),the genistein-treated group(50 mM/kg/day;p.o.along with doxorubicin)and phloretin-treated group(50 mM/kg/day;p.o.along with doxorubicin).On the 10th day of dosing,rats were anesthetized for recording ECG,mean arterial pressure,and left ventricular function.Oxidative stress,nitric oxide levels,and inflammatory cytokines were estimated in the cardiac tissue.Cardiac function parameters(creatine kinase MB,lactate dehydrogenase,aspartate aminotransferase,and alanine transaminase)were estimated in the serum samples.Results:Phloretin treatment inhibited doxorubicin-induced oxidative stress and also reduced nitric oxide levels in cardiac tissues of rats.Phloretin administration attenuated doxorubicin-induced alterations in hemodynamic parameters(heart rate,mean arterial blood pressure,and left ventricular function)and suppressed the expression of pro-inflammatory cytokines.The cardiac injury markers like creatine kinase MB,lactate dehydrogenase,aspartate aminotransferase,and alanine transaminase were reduced by both genistein and phloretin.All these effects of phloretin were more prominent than genistein.Conclusions:Phloretin offers cardioprotection that is comparable to genistein,a clinically validated cardioprotectant against doxorubicin-induced cardiotoxicity.Further studies are needed to confirm and establish the therapeutic utility of phloretin as a chemopreventive adjuvant to doxorubicin chemotherapy.
文摘Reactive oxygen species [ROS] cause oxidative damage to the tissues and protection from such damages is provided by endogenous and exogenous antioxidants. Much research work has been carried out in recent years on the beneficial effect of phenolic compounds which act as natural antioxidants and help to neutralize free radicals. So, this study was aimed to evaluate the in vitro antioxidant capacity of one of the phenolic compounds phloretin. Phloretin was used at four different concentrations like 20, 40, 60 and 80 μg/ml to determine the antioxidant activity by different methods such as total antioxidant capacity, reducing power, DPPH radical scavenging, superoxide anion radical scavenging and metal chelating assays. In addition to that the ascorbic acid was used as reference compound. The results showed that the phloretin displayed potent in vitro antioxidant capacity. It was able to scavenge different in vitro free radicals in all tested concentrations. Among the different concentrations, 80 μg of phloretin has maximum activity when compared to other concentrations in all in vitro antioxidant assays. High antioxidant property and maximum protective effect of phloretin were observed in a concentration dependent manner. The results were expressed as IC<sub>50</sub> value. The lowest IC<sub>50 </sub>value indicates the highest scavenging activity. The reducing power of the phloretin was also found in concentration dependent. According to the results of this study, we concluded that the phloretin possesses antioxidant property. Therefore, phloretin is a powerful antioxidant phytocompound which can protect biological systems against the oxidative stress. From this study, we suggest that the phloretin may be used as a dietary natural antioxidant supplement for preventing free radical related diseases.
基金financially supported by Talents Team Construction Fund of Northwestern Polytechnical University (NWPU)the National Natural Science Foundation of China (31701722)+1 种基金the China Postdoctoral Science Foundation (2017M620471)the National Natural Science Foundation of China (31901026)。
文摘Phloretin is an important skin-lightening and depigmenting agent from the peel of apples. Although de novo production of phloretin has been realized in microbes using the natural pathway from plants, the efficiency of phloretin production is still not enough for industrial application. Here, we established an artificial pathway in the yeast to produce phloretin via assembling two genes of p-coumaroyl-CoA ligase(4CL) and chalcone synthase(CHS). CHS is a key enzyme which conventionally condenses a CoA-tethered starter with three molecules of malonyl-CoA to form the backbone of flavonoids. However, there was 33% of byproduct generated via CHS by condensing two molecules of malonyl-CoA during the fermentation process. Hence, we introduced a more efficient CHS and improved the supply of malonyl-CoA through two pathways;the by-product ratio was decreased from 33% to 17% and the production of phloretin was improved from 48 to 83.2 mg L^(-1). Finally, a fed-batch fermentation process was optimized and the production of phloretin reached 619.5 mg L^(-1), which was 14-fold higher than that of the previous studies. Our work established a platform for the biosynthesis of phloretin from the low-cost raw material 3-(4-hydroxyphenyl) propanoic acid and also illustrated the potential for industrial scale bio-manufacturing of phloretin.
基金supported by the National Natural Science Foundation(31972089)the 2020 Team Innovation Project from the Fundamental Scientific Research Special Capital Fund of the National Universities,China(GK202001008).
文摘Although the catabolic pathway of some flavonoids in the human colon has been elucidated,knowledge of related gut microbes and responsible enzymes is still limited.In this study,a phloretin hydrolase gene(phy)from Flavonifractor plautii(F.plautii)was synthesized and heterologously expressed in Escherichia coli BL21(E.coli BL 21).Phloretin hydrolase(PHY)was purified from cell extracts of recombinant E.coli BL21,and PHY's molecular weight was about 32 kDa.The purified PHY effectively cleaved phloretin into 3-(4-hydroxyphenyl)propionic acid(HPPA)and phloroglucinol(PG).PHY's kinetic parameters were determined:Km was 2.8×10^(−3)±0.4 mM and Vmax was 411.2±7.1 U/mg.Besides,PHY's optimal temperature and pH were 50℃ and 7.5,respectively,and PHY exhibited 75%activity after 5 h at 50℃.Furthermore,PHY's activity was inhibited in the presence of Ba^(2+),Cu^(2+),and Fe^(2+),while Mg^(2+) slightly elevated PHY's activity.Finally,the catalytic model between phloretin and PHY was built using molecular docking,and PHY's conformational changes were further demonstrated through the multispectral techniques.This study is conducive to understanding phloretin metabolism in the colon and adding a valuable source of PHY for food industry application.
