Polysaccharide isolated from wax apple suppresses ethyl carbamate-induced oxidative damage in human hepatocytes

Wax apple(Syzygium samarangense)has received growing research interest for its high nutritional and medicinal value due to its constituents such as polysaccharide,organic acids,flavonoids,minerals,and other substances.In this study,wax apple polysaccharide(WAP)was isolated from this plant and its protective effect against ethyl carbamate(EC)-induced oxidative damage was evaluated in human hepatocytes(L02 cells).Firstly,a series of analyses such as high-performance liquid chromatography(HPLC),high-performance gel permeation chromatography(HPGPC),Fourier transform infrared spectroscopy(FT-IR),gas chromatography/mass spectrometry(GC/MS),and 1H and 13C nuclear magnetic resonance(NMR)were conducted to identify the structure of,in vitro cell experiments were performed to verify the protective effects of WAP against EC-induced cytotoxicity,genotoxicity,and oxidative damage in L02 cells.Our results revealed that WAP is composed of mannose,rhamnose,glucuronic acid,galacturonic acid,glucose,galactose,arabinose,and fucose in a molar ratio of 2.20:3.94:4.45:8.56:8.86:30.82:39.78:1.48.Using a combination of methylation and NMR spectroscopic analysis,the primary structure of WAP was identified as Araf-(1→,Glcp-(1→,→2)-Araf-(1→,→3)-Galp-(1→,→3)-Araf-(1→,and→6)-Galp-(1→.Cell experiments indicated that WAP exhibited significant protective effects on EC-treated L02 cells via suppressing cytotoxicity and genotoxicity,reducing reactive oxygen species(ROS)and O2?-formation,as well as improving mitochondrial membrane potential(MMP)and glutathione(GSH).In a nutshell,WAP has the potential as an important therapeutic agent or supplement for hepatic oxidative damage.Meanwhile,further studies are needed to prove the above effects in vivo at the biological and clinical levels.

Combined effect of Bacillus siamensis and chlorogenic acid on maintenance of quality and control of disease in stored wax apple fruit

Objectives:The purpose of this study was to evaluate the effect of combined postharvest use of Bacillus siamensis strain and chlorogenic acid on quality maintenance and disease control in wax apple fruit.Materials and Methods:Wax apple fruit were treated with Bacillus siamensis strain(N1),chlorogenic acid(CHA)and N1+CHA and preserved at 25℃ for 12 d.The appearance and quality parameters were evaluated,along with the disease index,content of total soluble solids(TSS),total acid(TA),vitamin C(Vc),total phenolic,and flavonoids during cold storage.Meanwhile,the activities ofβ-1,3-glucanase(GLU),phenylalanine ammonialyase(PAL),polyphenol oxidase(PPO),and peroxidase(POD)were determined.Furthermore,the transcriptome and the expression level of key defense enzyme genes were analyzed by RNA-seq and real-time quantitative reverse transcription polymerase chain reaction.Results:N1+CHA treatment significantly lowered DI and delayed fruit quality deterioration by slowing TSS and TA loss and enhancing anti-oxidant capacity,including Vc,total phenolic,and flavonoids content.Meanwhile,the activities of GLU,PAL,PPO,and POD were dramatically increased by N1+CHA treatment.Additionally,N1+CHA treatment modulated several metabolic pathways,including those involved in planthormone signal transduction and plant–pathogen interaction.The expression levels of key defense enzyme genes were significantly upregulated in stored wax apple fruit by the N1+CHA treatment,which were well coincided with the transcriptome data.Conclusions:The combined use of N1+CHA significantly prevents disease and maintains fruit quality of wax apple during storage.These findings indicate that it could serve as a promising biological technique for preserving wax apple fruit.