Physicochemical Properties,Chemical Composition,and Antioxidant Activity Of Dendropanax Dentiger Honey

Dendropanax dentiger（Harms）Merr.is an evergreen tree or shrub species of Dendropanax from the Araliaceae family.Roots,stems,and leaves of D.dentiger have traditionally been used as folk medicines in China for a variety of diseases.It is widely distributed throughout Jiangxi,Zhejiang,Anhui,Hunan,and Hubei Provinces in China.D.dentiger can form a relatively single plant community in many mountainous areas of Jiangxi Province,which makes it possible to obtain high purity honey from D.dentiger.Honey is a natural sweet substance brewed from nectar,secretions or honey dew collected by honeybees.It is rich in nutrients,has various biological activities,such as antioxidant,anti-bacterial,anti-inflammatory,anti-tumor,anti-virus,and liver protection,has a high economic value of edibility,medicine,and health care.Different kinds of honey have different color,flavor,chemical composition,and biological activity,which largely depends on its plant and geographical sources.Among them,honey derived from medicinal plants is of great benefit to human health,but to our knowledge,there is no information reported on D.dentiger honey（DDH）.In this study,DDH collected from different areas of Jiangxi Province were used as experimental material.The routine physicochemical parameters were systematically studied.A High Performance Liquid Chromatography-Solid Phase Extraction（HPLC-SPE）method was established for the determination of phenolic compounds in DDH,and the chemical composition of honey was analyzed by combined with UItra Performance Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometry（UPLC-Q-TOF-MS）.The antioxidant activity was evaluated in vitro and in vivo.The main research has been demonstrated as follows:1.The routine physicochemical parameters were determined according to the national standard and the International Honey Commission,including moisture,free acidity,p H,hydroxymethylfurfural,diastase activity,electrical conductivity,sugars（glucose,fructose,and sucrose,etc.）,color,the total phenolic content,and the total flavonoid content.The results showed that the physicochemical properties of DDH conformed to the national standard.It had low contents of hydroxymethylfurfural（1.56±0.68mg/kg）,sucrose（0.59±0.23%）,diastase activity（3.16±0.79mL/（g.h））,and high content of water（22.29±1.68%）,total phenolic（62.89±10.31mg GAE/100g）,and total flavonoids（40.86±4.32mg RE/100g）.The color of the DDH was amber to dark amber.2.The results of HPLC-SPE methodological study showed that the average recovery of phenolic compounds was 99.91 2.11%,the method was reliable and suitable for the determination of DDH.A total of 11 phenolic acids and 5 flavonoids were detected from DDH by this method,among which 2 phenolic acids（protocatechuic acid and chlorogenic acid）and 3 flavonoids（rutin,luteolin,andquercetin）were detected in all samples.The contents of rutin（114.25-2329.65μg/100g）were the highest,followed by protocatechuic acid（57.93-1158.85μg/100g）and chlorogenic acid（45.80-193.54μg/100g）.The contents of luteolin and quercetinwere lower,which were 48.19-127.64μg/100g and 25.24-119.03μg/100g,respectively.The HPLC fingerprint of DDH was constructed by the similarityevaluation system for chromatographic fingerprint of traditional Chinese medicine（Version 2004 A）,and 5 characteristic peaks were determined,which wereprotocatechuic acid,chlorogenic acid,rutin,luteolin,and quercetin.3.Identification and analysis of the chemical constituents in DDH were carried out by UPLC-Q/TOF-MS.A total of 190 compounds were identified by combining positive and negative ionization modes,including phenolic acids,flavonoids,organic acids,alkaloids,lipids,sugars,amino acids and their derivatives,nucleotide and their derivatives,lignans,coumarins,vitamins,and terpenoids.Among them,a total of 109substances were detected in all samples,mainly including phenolic acids,flavonoids,organic acids,and alkaloids.The response of these components accounted for 85.69%of the total components.Quantitative analysis was carried out in combination withavailable standards,the high content of abscisic acid（671.87-1492.83μg/100g）,protocatechuic acid（19.44-326.61μg/100g）,and 4-hydroxybenzoic acid（36.47-104.29μg/100g）were detected in all samples,which could be assigned as potential markers of DDH.4.DPPH⁺free radical-scavenging activity,ABTS⁺cation radical-scavenging activity,and ferric reducing antioxidant power were used to evaluate the antioxidant activity of DDH in vitro.The results showed that DDH has certain antioxidant activity,the average IC₅₀ of DPPH⁺free radical-scavenging ability was 71.86±12.41mg/m L,the equivalent of ABTS⁺cation radical-scavenging ability was 56.62±11.63μmol Trolox/100g,and the equivalent of ferric reducing antioxidant power was 58.71±8.38μmol FeSO₄·7H₂O/100g.The results of antioxidant experiments in mice showed that although the body weight of mice that had been fed DDH increased slightly,the liver weight did not increase significantly,the liver coefficient decreased by 5.13%,the oxidative damage of liver was inhibited.HE and oil red staining showed that there were no obvious pathological changes and oxidative damage in liver tissue.The activities of superoxide dismutase（SOD）and glutathione peroxidase（GSH-Px）in the liver of mice were increased by 38.57%and 33.00%,respectively,with significant difference（p<0.05）.The results indicated that DDH had strong effects on inhibiting lipid peroxidation and preventing oxidative stress.In conclusion,the physicochemical properties of DDH conformed to the national standard.It had a variety of high-quality characteristics,such as low content of HMF and sucrose,high content of total phenols and total flavones,and dark color.It was rich in a variety of bioactive compounds,including phenolic acids,flavonoids,organic acids,and alkaloids,etc.Among them,abscisic acid,protocatechuic acid,and 4-hydroxybenzoic acid were especially abundant,which could be assigned as potential markers of DDH.In addition,it had potent antioxidant activity in vitro and in vivo.This research provided fundamenta data for the study of DDH,important theoretical basis for the quality control,quality evaluation,authenticity identification,and traceability of honey,and it may help to improve the recognition of the health benefits and commercial value of DDH.