Chemical Composition Of Citrus Honey And Its Preventive Effect On Acute Alcoholic Liver Injury

Citrus plants in Rutaceae include grapefruit（C.maxima）,sweet orange（C.sinensis）and citrus（C.reticulata）.China is a major producer of citrus fruits in the world,and the cultivation of citrus fruits In Jiangxi is particularly prominent.At the end of2015,the planting area of citrus fruits in the province was 3331000 hectares and the output was 4101200 tons.Most citrus plants are nectar source plants with large amount of nectar.The nectar source of citrus honey in Jiangxi is very rich.The systematic study of citrus honey is of great significance.Citrus honey is a common single flower honey.It has the general physical and chemical properties of honey,contains rich phenolic compounds,and has biological activities such as antibacterial activity and antioxidant activity.At present,there have been relevant studies on citrus honey in Egypt,Spain,Italy and other countries,but there are few studies on citrus honey in China.In this paper,the physical and chemical properties of citrus honey produced in Jiangxi were studied by measuring water content,acidity,sugar composition,conductivity,p H,amylase index and 5-hydroxymethylfurfural（5-HMF）;The physical and chemical properties of citrus honey were studied.The antioxidant activity of citrus honey was determined by DPPH method,FRAP method and ABTS method.The phenolic compounds in citrus honey were qualitatively and quantitatively analyzed based on high performance liquid chromatography（HPLC）and standard samples,the phenolic compounds composition of citrus honey was studied,the chemical composition of citrus honey was further analyzed by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry（UPLC-QTOF-MS）,and the preventive effect of Citrus honey on alcoholic liver injury was explored through mouse alcoholic liver injury model.The main results are as follows:1.The conventional physical and chemical indexes of citrus honey were determined according to the national standards and the regulations of the international honey Committee.The results showed that the color of citrus honey was light amber（chroma L*:52.16-57.33,a*:-1.56-0.78,b*:5.49-12.40）.Water content（18.76%-20.48%）,p H value（4.21-4.66）,acidity(8.77-10.12 m L kg^-1),conductivity(0.16-0.17m S·cm^-1),sugar composition,5-HMF(0.20-0.58 mg kg^-1),amylase activity(5.69-7.18[m L·（g·h）^-1]),total phenol（15.39-18.47 mg/100 g）and total flavonoids content（4.03-4.51 mg/100 g）meet industry standards.Citrus honey has low 5-HMF content,high amylase activity and low content of total phenols and flavonoids.The results of ABTS,FRAP and DPPH radical scavenging showed that citrus honey had certain antioxidant capacity.ABTS was 0.48-0.53 m M,FRAP was 0.28-0.33 m M,and the IC₅₀ value of DPPH radical scavenging was 66.9-135.3 mg·m LZ^-1.2.HPLC-UV method was used to qualitatively and quantitatively determine 14phenolic compounds in citrus honey,including gallic acid(67.12-89.92μg·（100 g）^-1),protocatechin(16.07-17.00μg·（100 g）^-1),chlorogenic acid(30.07-42.78μg·（100 g）^-1),p-hydroxybenzoic acid(76.56-87.36μg·（100 g）^-1),caffeic acid(11.63-16.71μg·（100g）^-1),p-coumaric acid(35.32-54.29μg·（100 g）^-1),rutin(228.19-298.43μg·（100 g）^-1),ferulic acid(34.11-43.82μg·（100 g）^-1genistein(19.76-26.57μg·（100 g）^-1),hesperidin(76.79-83.17μg·（100 g）^-1),resveratrol(1086.65-1388.31μg·（100 g）^-1),quercetin(84.50-96.56μg·（100 g）^-1),kaempferol(115.83-140.96μg·（100 g）^-1)and hesperidin(53.76-59.57μg·（100 g）^-1).Further,41 compounds were identified in citrus honey by UPLC-Q-TOF-MS,among which 19 and 22 compounds were identified in positive and negative ion modes,including flavonoids,phenolic acids,organic acids,alkaloids,terpenoids and polyamines.3.To explore the effect of citrus honey on alcohol liver injury and intestinal flora in mice,the alcohol model was established after feeding Citrus honey to mice for 12weeks.Alcohol significantly increased serum alanine aminotransferase（ALT）and aspartate aminotransferase（AST）.High dose citrus honey could reduce the levels of ALT and AST,and low dose Citrus honey could reduce the levels of ALT.The high concentration of hematoxylin（he）can alleviate the liver edema,and the best effect is to stain the liver tissue with high concentration of he,which can alleviate the liver edema.Alcohol also leads to the ecological imbalance of intestinal flora,the increase of Firmicutes abundance and the decrease of Bacteroidetes abundance.Citrus honey can alleviate this change,and low concentration citrus honey has the best effect.Of intestinal floraβDiversity（PCo A analysis and sample level cluster analysis）and lefse analysis showed that there was little difference between citrus honey groups with different concentrations,which was closer to the blank control group,and there was great difference between alcohol model group and other groups.In conclusion,the physical and chemical indexes of citrus honey meet the national standards,with the characteristics of low content of 5-HMF and high amylase activity;Citrus honey is rich in a variety of phenolic compounds,flavonoids and other active components,and has strong antioxidant capacity,which can prevent alcoholic liver injury.This study provides a theoretical basis for the development and utilization of citrus honey,and provides a theoretical basis for the quality evaluation,authenticity identification,quality control and nectar plant traceability of citrus honey.