Study On The Effects Of Luffa Fermentation Broth Alleviates Liver And Intestinal Injury Induced By Cyclophosphamide In Mice

Luffa cylindrica is an annual climbing herbaceous plant with pharmacological effects such as antioxidant,anti-inflammatory,immune regulation and so on.When the fruits of luffa are mature,the endocarp pulp mass gradually decreases and develops the luffa sponge.However,a large number of by-products will be discarded in the process of producing sponge from mature luffa,which causes large amount of luffa resource waste.Therefore,it is necessary to explore possible methods for the comprehensive utilization of the luffa by-products.Lactic acid bacteria(LAB)fermentation technology is a comprehensive method to improve the resource utilization of by-products in the food industry.Combining LAB fermentation technology with luffa by-products is of great significance to improve the utilization value of luffa.Hence,in this study,the mature luffa was fermented by Lactiplantibacillus plantarum P101(L.p P101)and the optimal fermentation conditions were determined by process optimization,and the influence of L.p P101 fermentation on luffa was analyzed.Furthermore,the functional activities of luffa fermentation broth in vivo were investigated by cyclophosphamide(CTX)induced mouse hepato-intestinal injury model.The main contents of this study are summarized as follows:Chapter 1: The pharmacological effects and application of luffa,the research progress of LAB fermentation technology,and the toxic effects and mechanism of CTX were introduced respectively.Chapter 2: Objective to explore the effects of L.p P101 fermentation on the physicochemical properties,functional properties and chemical composition of the luffa.Firstly,with hydroxyl radical scavenging ability as an evaluation index,the fermentation conditions were optimized by single factor experiment and orthogonal experiment.And the final fermentation conditions were determined as 5% inoculum amount,37℃ fermentation temperature and 36 h fermentation time.Secondly,under the above conditions,differences in physicochemical properties and functions of luffa before and after fermentation were analyzed.The results showed that the viable bacteria number reached 8.62 log CFU/m L,p H value decreased significantly,the total titratable acid content increased significantly,the contents of protein,total sugar and crude polysaccharide decreased significantly,and total phenol content and total flavonoid content had no significant change in the luffa solution after fermentation.Moreover,fermentation significantly increased the total antioxidant capacity of luffa solution.In addition,fermentation significantly reduced the content of free amino acid(FAA)in luffa solution,but produced new amino acids.Ultra-high performance liquid chromatography-time-of-flight mass spectrometry(UPLC-QTOF-MS)was used to preliminatively identified the chemical composition changes of luffa before and after fermentation.The results showed that 59 compounds were identified,of which 52 compounds were identified in unfermented luffa juice(LJ)and 54 compounds were identified in luffa fermentation broth(LF).Fermentation significantly affected the composition and metabolism of chemical compound,and produced more functional components with biological activities in luffa solution.Furthermore,high performance liquid chromatography–triple quadrupole mass spectrometry(HPLC-QQQ-MS)quantitative analysis showed that fermentation significantly increased the contents of lactic acid,succinic acid,salicylic acid,4-Hydroxybenzoic acid,gentian acid and protocatechuic acid in luffa solution,while significantly reduced the contents of malic acid and citric acid.Chapter 3: This chapter mainly discusses the protective effect of luffa fermentation broth on drug-induced liver injury in mice induced by CTX and its potential mechanism.Specifically,LJ and LF were administration daily via intragastric administration for 14 days,followed by daily intraperitoneal injection of CTX(80 mg/kg)for3 days.The results showed that CTX caused a decrease in liver index,an increased in serum levels of liver function indicators,and damage to liver tissue structure,leading to oxidative stress and inflammation in the liver.However,after intervention with LJ and LF,the above situation was significantly alleviated.Further mechanism analysis revealed that LJ and LF may enhance the liver antioxidant defense system and suppress the signaling of nuclear transcription factor-κB/toll-like receptor 4(NF-κB/TLR4)to maintain liver redox homeostasis and reduce the expression and secretion of inflammatory cytokines,thereby mitigating CTX-induced liver injury.Moreover,this study found that fermented LF played a more pronounced role in alleviating oxidative stress in liver than unfermented LJ.Chapter 4: This chapter mainly discusses the protective effect of luffa fermentation broth on CTX-induced intestinal injury in mice and its potential mechanism.The method of establishing a intestinal injury model was the same as that in Chapter 3.The results showed that LF had a more significant protective effect on CTX-induced intestinal injury in mice than LJ.LF increased the thymus index and the number of immune cells in the blood of mice,and promoted the secretion of immunoglobulin and cytokines in the ileum.LF also improved the pathological damage of intestinal tissue caused by CTX,restored the structure of intestinal mucosa tissue,increased the number of goblet cells,and enhanced mucin(MUC-2)and the intestinal tight junction protein.In addition,LF can significantly restore the GSH consumption caused by CTX,and up-regulate the expression levels of antioxidase-related genes and erythroid nuclear transcription-related factor 2(Nrf2)signals.Furthermore,16 S r DNA analysis results showed that LF intervention could improve the intestinal microbiota imbalance induced by CTX in mice.In conclusion,L.p P101 can normally grow,reproduce and perform metabolic activities in the mature luffa solution with relative lack of nutrients,thus changing the physicochemical properties and chemical composition of the solution and improve its potential functional properties.In addition,in vivo experiment results showed that LF performed superior protective effect against CTX-induced hepato-intestinal injury than LJ.The results of this study will provide feasible strategies for the comprehensive utilization of luffa,and also provide theoretical basis for the application prospect of luffa fermentation broth.