Characterisation of phenolics in fruit septum of Juglans regia Linn. by ultra performance liquid chromatography coupled with Orbitrap mass spectrometer

Comprehensive Characterization of Phytochemical Composition, Membrane Permeability, and Antiproliferative Activity of Juglans nigra Polyphenols

The aim of our study was the detailed polyphenol profiling of Juglans nigra and the characterization of the membrane permeability and antiproliferative properties of its main phenolics. A total of 161 compounds were tentatively identified in J. nigra bark, leaf, and pericarp extracts by ultrahigh-performance liquid chromatography-high-resolution tandem mass spectrometry (UHPLC-HR-MS/MS). Eight compounds including myricetin-3-O-rhamnoside (86), quercetin-3-O-rhamnoside (106), quercetin-3-O-xyloside (74), juglone (141), 1,2,3,4-tetrahydro-7,8-dihydroxy-4-oxonaphthalen-1-yl-6-O-galloyl-glucoside (92), ellagic acid (143), gallic acid (14), and ethyl gallate (58) were isolated from J. nigra pericarp. The in vitro antiproliferative activity of the isolated compounds was investigated against three human cancer cell lines, confirming that juglone (141) inhibits cell proliferation in all of them, and has similar activity as the clinical standards. The permeability of the isolated compounds across biological membranes was evaluated by the parallel artificial membrane permeability assay (PAMPA). Both juglone (141) and ethyl-gallate (58) showed positive results in the blood-brain-barrier-specific PAMPA-BBB study. Juglone (141) also possesses logPe values which indicates that it may be able to cross both the GI and BBB membranes via passive diffusion.

Characterization, antioxidant and antitumor activities of phenolic compounds from Amomum villosum Lour

Amomum villosum Lour. (A. villosum), known as Sharen in China, is widely used for culinary and medicinal purposes due to containing a diverse set of bioactive compounds. In this study, the optimum ethanol extraction process was optimized and the composition and biological activities (antioxidant and antitumor) of five different fractions (dichloromethane, petroleum ether, ethyl acetate, n-butanol and H2O) extracted from the ethanol extract of A. villosum were investigated. The results showed that the optimal extraction conditions were extraction temperature 80°C, extraction time 120 min, ethanol concentration 40% and solid-liquid ratio 1:25 g/mL. Moreover, 35 bioactive compounds were successfully identified by UPLC-ESI-QTOF-MS/MS from five factions for the first time, including 12 phenolic acids and derivatives, 2 organic acids, 12 flavonoids and derivatives, 2 oxylipins and 7 proanthocyanidins. Among them, ethyl acetate fraction (Fr-EtOAc) exhibited the highest content of total phenolic (374.01 mg GAE/g DW) and flavonoid (93.11 mg RE/g DW), where vanillic acid, catechin, epicatechin and protocatechuic acid were the predominant phenolic compounds that accounting for 81.65% of the quantified bioactive compounds. In addition, Fr-EtOAc demonstrated excellent total antioxidant activity (IC50 of DPPH and ABTS assays were 0.23, 0.08 mg/mL, respectively, and FRAP assay was 322.91 mg VCE/100 g DW) and antitumor activity (1,000 μg/mL, 79.04% inhibition rate). The results could provide guidance for the industrial production and application of A. villosum.

Effect of Different Walnut and Hazelnut Leaf Compost Treatments on Yield and Phenolic Composition of Lactuca sativa L

The use of compost made from the leaves of Juglans regia has long been controversial because of its inhibitory effect due to the presence of juglone. Therefore, the aim of our study was to replicate the typical habits of farmers and gardeners, where the dried leaves are collected at the end of the season and placed in a composter. Then, the effects of the different treatments on the yield of the plant (lettuce), secondary metabolism, and possible toxicity of the compost of the grown plant were evaluated. The lowest yield of lettuce was obtained in soil with composted walnut and hazelnut leaves, while the highest yield was recorded in in soil with compost control, soil with composted walnut leaves and grass with the addition of composting agent and soil with composted walnut leaves with addition of composting agent. Some allelochemicals were still present in the compost but at such low levels that they did not affect yield. We suggest that dry walnut leaves and cut grass can be used for composting, while dry hazelnut leaves still contain some allelochemicals after two years that significantly inhibit plant growth and thus yield, so we would not recommend their use for composting.

Phytochemicals and Biological Activities of Walnut Septum: A Systematic Review

In the last few decades, scientific evidence has stressed the importance of plants in the prevention and/or supportive treatment of a plethora of diseases, many of them chronic, age-associated disorders. Juglans regia L. is a traditional plant that has been integrated into traditional medicine since ancient times. Due to the presence of biologically active compounds, walnut was used in the treatment of various maladies. Recently, investigations have focused on the walnut by-products and waste products, with research on their valuable constituents and active properties. Among these secondary products, walnut septum was analyzed in several studies, its phytochemical profile described, and some of the biological activities examined. However, compared to other walnut by-products, no comprehensive review to gather all the pertinent scientific knowledge was found in the literature. Therefore, the aim of this study was to critically assess the information furnished by peer-reviewed articles regarding the walnut septum chemical composition and the related biological activities, including antioxidant activities, anti-inflammatory effects, antimicrobial properties, antidiabetic activities, anti-tumor properties, and anti-aging potential. In conclusion, as these preclinical studies showed that walnut septum metabolites were responsible for a wide range of preventive and therapeutic uses, further research should confirm the beneficial outcomes in clinical trials.

Phytochemical Composition, Antimicrobial, Anticancer Properties, and Antioxidant Potential of Green Husk from Several Walnut Varieties (Juglans regia L.)

Husk powder was prepared from seven varieties of walnut fruit and their hulling rate, chemical compounds, and total phenolic contents were evaluated. The apolar and polar extracts were prepared, respectively, from hexane and a hydroethanolic solvent, while qualitative and semi-quantitative analyses were performed by GC/MS and UHPLC-PDA-HRMS/MS. The antioxidant, antimicrobial, and antitumor properties of green walnut husk were also evaluated. The total content of phenolic compounds varied between the varieties, ranging from 35.2 ± 0.9 to 58.0 ± 0.0 mg/g gallic acid equivalent of dry husk weight (dw). The apolar extract was found to contain alkanes, tocopherols, sterols, and fatty acids, including oleic, linoleic, and linolenic, while the polar extract showed the presence of phenolics including salicylate glucuronide, taxifolin, catechin, and quercetin isomers. The antioxidant power obtained by the PAOT (total antioxidant power) method for the husk powders ranged from 256.5 ± 5.9 to 746.8 ± 6.9 score/g dw, and seemed consistent with the total phenolic content and the results obtained by the classic antioxidant test with DPPH. The walnut husk also showed an antibacterial effect against Gram-negative and Gram-positive bacteria and cytotoxic potential against HepG2. Among the selected varieties, the green Saman had the highest antioxidant properties, while the Saman with a brown color had the lowest.

Rapid separation and identification of 96 main constituents in Huanglian Jiedu decoction via ultra-high performance liquid chromatography-Orbitrap Fusion Tribrid mass spectrometer

Huanglian Jiedu decoction is a widely used traditional Chinese medicine with a broad spectrum of therapeutic effects, including heat clearing, detoxification, and attenuation of inflammation. However, the composition of Huanglian Jiedu decoction is still unclear due to its complexity and limitations of analytical methods. In this study, we established a fast and reliable analytical method based on ultra-performance LC-Orbitrap Fusion Tribrid mass spectrometer for high-speed separation and structural identification of multiple compounds in Huanglian Jiedu decoction. The analysis was carried out using a Hypersil GOLD C18 column (2.1 × 100 mm, 1.9 μm) with gradient elution coupled to a high-definition mass spectrometer system operating in both positive and negative ESI modes. According to the chromatographic retention time, precise molecular weight, fragment ion peaks, and published data, the main chromatographic peaks were attributed to specific molecules whose chemical structures were determined. In total, 96 components were identified, including 34 flavonoids and their glycosides, 23 alkaloids, 18 organic acids, 13 terpenoids, and 8 miscellaneous compounds. This study revealed the detailed chemical composition of Huanglian Jiedu decoction, which is of great importance for quality control and further pharmacological and mechanistic studies.

Establishment and validation of analytical methods for 15 hazardous drugs by UPLC-Q/Orbitrap-HRMS

Background

Cytotoxic drug residues in pharmacy intravenous admixture services (PIVAS) have always been a major problem for pharmaceutical workers and the PIVAS environment,which is not only pollutes the PIVAS environment, but also causes serious harm to the life and health of the staff. This study aimed to establish an ultra-high performance liquid chromatography quadrupole orbitrap high resolution mass spectrometry (UPLC-Q/Orbitrap-HRMS) method for the rapid detection and monitor of 15 cytotoxic drugs.

Methods

UPLC-Q/Orbitrap-HRMS method was used to establish a rapid detection method for 15 cytotoxic drugs such as cytarabine, gemcitabine and so on. The daily precision and accuracy of this method were verified by injecting four concentrations of standard solution on the same day, and the same four concentrations of standard solution were injected within three days respectively to verify the daily precision of this method. The signal-to-noise ratio (SNR) of 10:1 was calculated as the limit of quantity. The mixed standard solution of 15 cytotoxic drugs with concentrations of 0.5, 1, 3, 10, 30, 100, 300, and 1,000 ng/mL was configured and detected by this method for linearity and range.The stability of this method was investigated using a mixture of 15 drugs (15MIX) standard solutions at high concentration (300 ng/mL) and low concentration (10 ng/mL) at room temperature for 12 and 24 hours, respectively. A standard solution of each drug, 15MIX and blank solution were taken to verify the exclusivity of the method.

Results

The results showed that the method had good specificity, and the intraday precision of all drugs was less than 10% and the intraday precision was less than 15%. At the same time, the standard curve had good linearity, R² was greater than 0.99, and the limit of quantification of most drugs was about 1 ng/mL.

Conclusions

In this study, an UPLC-Q/Orbitrap-HRMS method was established for the rapid detection of 15 cytotoxic drugs, providing technical support for the monitoring of cytotoxic drug residues in PIVAS, which is of great significance for environmental contamination mornitoring as well as occupational exposure alert.

Environmentally-driven metabolite and lipid variations correspond to altered bioactivities of black wolfberry fruit

Black wolfberry is a commonly cultivated woody plant in China, and is rich in nutrients that are beneficial for human. To characterize the endogenous metabolite differences among black wolfberry fruits grown in different geographical regions, mass spectrometry-based metabolomic and lipidomic analyses were performed in black wolfberry grown in nine locations throughout five provinces in China, from which 204 primary and specialized metabolites, and 267 lipids were identified in their fruits. Three samples from Alxa Left Banner, Jinta, and Minqin showed dramatically altered metabolite profiles, displaying higher levels of phenolic acids, soluble sugars and flavonoids, but lower levels of tricarboxylic acid cycle intermediates and aromatic amino acids. Moreover, the lipid profile of the Alxa Left Banner sample was strikingly distinct from all other samples, with high levels of monogalactosyl diacylglycerol and sulfoquinovosyl diacylglycerol, which are positively correlated with their anti-inflammatory capacities. These findings thus prompt for further studies on black wolfberry fruit for their health benefits.

A Validated Ultrasound-Assisted Extraction Coupled with SPE-HPLC-DAD for the Determination of Flavonoids in By-Products of Plant Origin: An Application Study for the Valorization of the Walnut Septum Membrane

Walnut byproducts have been shown to exert functional properties, but the literature on their bioactive content is still scarce. Among walnut byproducts, walnut septum is a dry ligneous diaphragm tissue that divides the two halves of the kernel, exhibiting nutritional and medicinal properties. These functional properties are owing to its flavonoid content, and in order to explore the flavonoid fraction, an ultrasound-assisted (UAE) protocol was combined with solid phase extraction (SPE) and coupled to high-performance liquid chromatography with diode array detection (HPLC-DAD) for the determination of flavonoids in Greek walnut septa membranes belonging to Chandler, Vina, and Franquette varieties. The proposed UAE-SPE-HPLC-DAD method was validated and the relative standard deviations (RSD%) of the within-day and between-day assays were lower than 6.2 and 8.5, respectively, showing good precision, and high accuracy ranging from 90.8 (apigenin) to 97.5% (catechin) for within-day assay, and from 88.5 (myricetin) to 96.2% (catechin) for between-day assay. Overall, seven flavonoids were determined (catechin, rutin, myricetin, luteolin, quercetin, apigenin, and kaempferol) suggesting that the walnut septum is a rich source of bioactive constituents. The quantification results were further processed using ANOVA analysis to examine if there are statistically significant differences between the concentration of each flavonoid and the variety of the walnut septum.

Walnut (J. regia) Agro-Residues as a Rich Source of Phenolic Compounds

The present study was designed to identify and quantify the major phenolic compounds (phenolics) in the inner and outer husks, buds and bark of the Persian walnut, Juglans regia L. A comparison across six different cultivars grown in Slovenia was also carried out: 'Fernor', 'Fernette', 'Franquette', 'Sava', 'Krka' and 'Rubina'. A total of 83 compounds were identified, which included 25 naphthoquinones, 15 hydroxycinnamic acids, 8 hydroxybenzoic acids, 13 flavanols, 2 flavones, 1 flavanone and 19 flavonols. For the first time, 38 phenolics in the husks, 57 phenolics in the buds and 29 phenolics in the bark were presented in J. regia within this study. Naphthoquinones were the major phenolics determined, approximately 75% of all analysed phenolics in the inner husk, 85% in the outer husk, 50% in buds and 80% in bark. The highest content of phenolics was found in the walnut buds, followed by the bark, the inner husk and the outer husk. On the basis of these high phenolic contents, walnut husks, buds and bark represented valuable by-products of the walnut tree. These data also show origin-related phenolic contents across the cultivars, and thus these phenolic profiles might serve to define the origins of different walnut cultivars.

The Analysis of Phenolic Compounds in Walnut Husk and Pellicle by UPLC-Q-Orbitrap HRMS and HPLC

Husk and pellicle as the agri-food waste in the walnut-product industry are in soaring demand because of their rich polyphenol content. This study investigated the differential compounds related to walnut polyphenol between husk and pellicle during fruit development stage. By using ultra-high performance liquid chromatography-quadrupole-orbitrap (UHPLC-Q-Orbitrap), a total of 110 bioactive components, including hydrolysable tannins, flavonoids, phenolic acids and quinones, were tentatively identified, 33 of which were different between husk and pellicle. The trend of dynamic content of 16 polyphenols was clarified during walnut development stage by high-performance liquid chromatography (HPLC). This is the first time to comprehensive identification of phenolic compounds in walnut husk and pellicle, and our results indicated that the pellicle is a rich resource of polyphenols. The dynamic trend of some polyphenols was consistent with total phenols. The comprehensive characterization of walnut polyphenol and quantification of main phenolic compounds will be beneficial for understanding the potential application value of walnut and for exploiting its metabolism pathway.

Potential Use of Vacuum Impregnation and High-Pressure Homogenization to Obtain Functional Products from Lulo Fruit (Solanum quitoense Lam.)

Lulo (Solanum quitoense Lam.) is a Colombian fruit that is mostly used in the preparation of homemade juice as well as natural remedy for hypertension. The aim of this study was to determine physicochemical and antioxidant properties (antioxidant capacity, total phenols, flavonoids and spermidine content, and polyphenolic compounds profile by liquid chromatography-mass spectrometry (LC-MS)) of the lulo fruit and its juice. Additionally, vacuum impregnation (VI) properties of the fruit and the effect of high homogenization pressure (50, 100, and 150 MPa) on the juice properties were studied. The results revealed a good availability and impregnation capacity of the pores in fruits with similar maturity index. The main differences observed between the juice and fruit derive from removing solids and bioactive components in the filtering operation. However, the effect of high-pressure homogenization (HPH) on particle size and bioactive compounds increases the antiradical capacity of the juice and the diversity in polyphenolics when increasing the homogenization pressure.

Exploration of walnut components and their association with health effects

Traditionally, walnuts have occupied an imperative position in the functional food market with consistently recognized nutritious and functional properties. In the past years, the lipid profile of walnuts has brought much scientific attention via linking a cascade of biological attributes and health-promoting effects. Over time, researchers have focused on diversified composition (polyphenols and vitamins) of different parts of walnut (flower, pellicle, and kernel) and emphasized their physiological significance. Consequently, a plethora of reports has emerged on the potential role of walnut consumption against a series of diseases including cancer, gut dysbiosis, cardiovascular, and neurodegenerative diseases. Therefore, we accumulated the updated data on composition and classification, extraction methods, and utilization of different parts of walnuts as well as associated beneficial effects under in vivo and clinical studies. Altogether, this review summarized the ameliorative effects of a walnut-enriched diet in chronic diseases which can be designated to the synergistic or individual effects of walnut components mainly through anti-oxidative and anti-inflammatory role.

Antitussive, Antioxidant, and Anti-Inflammatory Effects of a Walnut (Juglans regia L.) Septum Extract Rich in Bioactive Compounds

The antitussive, antioxidant, and anti-inflammatory effects of a walnut (Juglans regia L.) septum extract (WSE), rich in bioactive compounds were investigated using the citric acid aerosol-induced cough experimental model in rodents. Wistar male rats were treated orally for three days with distilled water (control), codeine (reference), and WSE in graded doses. On the third day, all rats were exposed to citric acid aerosols, the number of coughs being recorded. Each animal was sacrificed after exposure, and blood and lung tissue samples were collected for histopathological analysis and the assessment of oxidative stress and inflammatory biomarkers. The results of the experiment showed a significant antitussive effect of WSE, superior to codeine. This activity could be due to cellular protective effect and anti-inflammatory effect via the stimulation of the antioxidant enzyme system and the decrease of IL-6 and CXC-R1 concentration in the lung tissue of WSE-treated animals. The antioxidant and anti-inflammatory effects of WSE were confirmed by biochemical assays and histopathological analysis. This is the first scientific study reporting the antitussive effect of walnut septum, a new potential source of non-opioid antitussive drug candidates, and a valuable bioactive by-product that could be used in the treatment of respiratory diseases.

Phenolic profile and potential beneficial effects of underutilized Brazilian native fruits on scavenging of ROS and RNS and anti-inflammatory and antimicrobial properties

Brazilian native fruits (BNF) have aroused interest of researchers and consumers for their great human health benefits. In this study, five BNF (Byrsonima lancifolia, Campomanesia phaea, Jacaratia spinosa, Solanum alternatopinnatum and Acnistus arborescens) were tested for their polyphenolic compounds by LC-ESI-MS/MS, reactive species deactivation (ROO˙, O2˙-, HOCl and NO˙), anti-inflammatory properties in vivo, and in vitro antimicrobial activity - with determination of putative mechanism(s) of action. Eighty-one polyphenols were identified, which exhibited a significant capacity to deactivate both ROS and RNS. C. phaea extract had the highest capacity to scavenge ROO˙ (68.94 μmol TE per g), O2˙- (IC50: 575.36 μg mL-1) and NO˙ (IC50: 16.96 μg mL-1), which may be attributed to the presence of ellagitanins. B. lancifolia decreased neutrophil influx into the peritoneal cavity of mice by 50% as compared to carrageenan and reduced Candida albicans biofilm viability by 3 log10 possibly due to complexation with cell membrane ergosterol. In summary, the BNF presented herein are good sources of bioactive compounds with positive effects on deactivation of biological reactive species, as well as with anti-inflammatory and antimicrobial activities, which can be altogether highly beneficial to human health.

Systematic characterization of alkaloids in Eomecon chionantha Hance using ultrahigh-performance liquid chromatography-tandem quadrupole Exactive Orbitrap mass spectrometry with a four-step screening strategy

RATIONALE

Eomecon chionantha Hance (ECH), a traditional folk herb, is commonly used to treat traumatic injuries based on its analgesic and anti-inflammatory properties. Previous studies have reported that alkaloids are the major bioactive components in ECH. Therefore, identification of alkaloids from ECH contributes to the discovery of its potential active ingredients and quality control in clinic treatments.

METHODS

A four-step screening strategy was performed as follows. (1) Extracting the accurate masses of ions related to different molecules. (2) Screening different types of compounds using their molecular cations, protonated molecules, diagnostic product ions and fragmentation pathways. (3) Comparing the characteristic product ion formulae to obtain the type and number of substituents. (4) Using the biosynthetic pathways of isoquinoline alkaloids to determine the concentration of alkaloids.

RESULTS

Ultrahigh-performance liquid chromatography-tandem quadrupole Exactive Orbitrap mass spectrometry (UHPLC/Q-Exactive Orbitrap MS) analysis combined with the four-step screening strategy was used to profile the alkaloids in ECH. The structures of 95 alkaloids in ECH were unambiguously identified or reasonably assigned, of which 76 were reported in ECH for the first time. Six types of benzylisoquinoline alkaloids were identified in ECH: six benzyltetrahydroisoquinolines, nine protopines, five N-methyltetrahydroprotoberberines, six protoberberines, eight benzophenanthridines and sixty-one dihydrobenzophenanthridines.

CONCLUSIONS

This comprehensive study identified the alkaloids in ECH, thus providing a practical reference for further research. The UHPLC/Q-Exactive Orbitrap MS method, combined with the four-step screening strategy, which was developed and successfully applied to identify the alkaloids in ECH, may also be applicable for the efficient screening of other herbal medicines.

Walnut (Juglans regia L.) Septum: Assessment of Bioactive Molecules and In Vitro Biological Effects

Walnut (Juglans regia L.) septum represents an interesting bioactive compound source by-product. In our study, a rich phenolic walnut septum extract, previously selected, was further examined. The tocopherol content determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS) revealed higher amounts of α-tocopherol compared to γ- and δ-tocopherols. Moreover, several biological activities were investigated. The in vitro inhibiting assessment against acetylcholinesterase, α-glucosidase, or lipase attested a real management potential in diabetes or obesity. The extract demonstrated very strong antimicrobial potential against Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella enteritidis. It also revealed moderate (36.08%) and strong (43.27%) antimutagenic inhibitory effects against TA 98 and TA 100 strains. The cytotoxicity of the extract was assessed on cancerous (A549, T47D-KBluc, MCF-7) and normal (human gingival fibroblasts (HGF)) cell lines. Flow cytometry measurements confirmed the cytotoxicity of the extract in the cancerous cell lines. Additionally, the extract demonstrated antioxidant activity on all four cell types, as well as anti-inflammatory activity by lowering the inflammatory cytokines (interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-1 β (IL-1β)) evaluated in HGF cells. To the best of our knowledge, most of the cellular model analyses were performed for the first time in this matrix. The results prove that walnut septum may be a potential phytochemical source for pharmaceutical and food industry.

From the Soft to the Hard: Changes in Microchemistry During Cell Wall Maturation of Walnut Shells

The walnut shell is a hard and protective layer that provides an essential barrier between the seed and its environment. The shell is based on only one unit cell type: the polylobate sclerenchyma cell. For a better understanding of the interlocked walnut shell tissue, we investigate the structural and compositional changes during the development of the shell from the soft to the hard state. Structural changes at the macro level are explored by X-ray tomography and on the cell and cell wall level various microscopic techniques are applied. Walnut shell development takes place beneath the outer green husk, which protects and delivers components during the development of the walnut. The cells toward this outer green husk have the thickest and most lignified cell walls. With maturation secondary cell wall thickening takes place and the amount of all cell wall components (cellulose, hemicelluloses and especially lignin) is increased as revealed by FTIR microscopy. Focusing on the cell wall level, Raman imaging showed that lignin is deposited first into the pectin network between the cells and cell corners, at the very beginning of secondary cell wall formation. Furthermore, Raman imaging of fluorescence visualized numerous pits as a network of channels, connecting all the interlocked polylobate walnut shells. In the final mature stage, fluorescence increased throughout the cell wall and a fluorescent layer was detected toward the lumen in the inner part. This accumulation of aromatic components is reminiscent of heartwood formation of trees and is suggested to improve protection properties of the mature walnut shell. Understanding the walnut shell and its development will inspire biomimetic material design and packaging concepts, but is also important for waste valorization, considering that walnuts are the most widespread tree nuts in the world.

Phytochemical Profiling and Fingerprint Analysis of Chinese Jujube (Ziziphus jujuba Mill.) Leaves of 66 Cultivars from Xinjiang Province

Foliage of jujube (Ziziphus jujuba Mill.) as a byproduct of agriculture, is a traditional nutraceutical material in China. Previous studies have shown that it is a rich resource of polyphenols. However, information on its complete phenolic profile and the difference between cultivars is still limited. This study investigated and compared phytochemical profiles of leaves of 66 Chinese jujube cultivars. Forty-two compounds, including 22 flavonols, two flavanols, one flavanone, 13 derivatives of phenolic acids, three simple acids, and one unknown hexoside were identified/tentatively identified using high-performance liquid chromatography (HPLC) coupled with high-resolution mass spectrometry. Eight major flavonols were quantified by HPLC coupled with an ultraviolet (UV) detector. The contents of total flavonoids ranged from 2.6-25.1 mg/g dry weight (DW). Differences between cultivars were analyzed by hierarchical cluster analysis (HCA) and principal component analysis (PCA). This study presents a systematic study on the phenolic compounds in Chinese jujube leaves of different cultivars.