Phenolics in Citrus aurantium fruit identified by UHPLC-MS/MS and their bioactivities

Investigation of pectin deficiency in modulating the bioflavonoid profile of orange processing waste: A sustainable valorization of industrial waste

Orange processing waste (OPW) generated by the processing of oranges, as well as other citrus fruits, is a major source of pectin in the market nowadays. The residues generated during the pectin extraction process may contain many phytochemicals, including flavonoids. We use state-of-the-art techniques such as liquid chromatography high-resolution mass spectrometry (LC-HRMS/MS) and feature-based molecular network (FBMN) to annotate the flavonoids in OPWs. In particular, four flavonoids, hesperidin, naringin, diosmin, and hesperetin were quantified in the samples by LC-TDQ-MS. In total, 32 flavonoids from different classes were annotated, of which 16 were polymethoxylated flavonoids, 13 were flavonoid glycosides and 3 were flavanone aglycones. The results showed that flavonoid glycosides remain in high concentrations in OPWs from pectin factories even after pectin extraction by harsh conditions. The results show an exciting opportunity to harness the untapped potential of pectin factory waste as a renewable source for the extraction of glycoside flavonoids.

Differential distribution of characteristic constituents in peel and pulp of Aurantii Fructus Immaturus (Citrus aurantium L.) using MALDI mass spectrometry imaging

Aurantii Fructus Immaturus (AFI) was structurally divided into two parts named "peel" and "pulp". The exocarp and mesocarp of materials named "peel". The endocarp separated into multiple compartments and the cystic hair attached to it named "pulp". In order to explore the distribution and content of constituents in AFI, an efficient method to explore the distribution of constituents was developed based on matrix assisted laser desorption/ionization fourier transform ion cyclotron resonance mass spectrometry imaging (MALDI-FTICR-MSI). After simple processing, thirty-two constituents with distinct localization in the mass range of 101-1200 Da were identified by MALDI-FTICR-MSI. In addition, the identified four flavnoids (poncirin, sinensetin, 3,5,6,7,8,3',4'-heptemthoxyflavone, and tangeritin) were analyzed for differences between using LC-MS. Quantitative analysis results supported the quantitative results from MALDI-FT-ICR-MSI. The results implied that different parts had different constituents in AFI, and demonstrated MALDI-MSI have high potential in the direct analysis of constituents.

Metabolomic Analysis Reveals Patterns of Whole Wheat and Pearling Fraction Flour Quality Response to Nitrogen in Two Wheat Lines with Contrasting Protein Content

Nitrogen (N) application increases wheat yield and protein content and affects the nutritional quality of the grain. Analysis of N use efficiency revealed that N uptake efficiency is a key factor affecting protein content. Two wheat lines with significant differences in protein content were used to investigate the response of differential accumulation of metabolites to N levels and the spatial variation pattern of metabolites related to nutritional quality in wheat grains using widely targeted metabolomics analysis. The results showed that amino acids, nucleic acids, and phytohormones and their derivatives and glycolytic processes are the crucial factors affecting protein content in two wheat lines. Amino acids and derivatives, lipids, and flavonoids are the main contributors to metabolite spatial variation of grains, which were interactively regulated by nitrogen and genotypes. N application significantly increased the relative accumulation of beneficial bioactive substances in the inner layer (P3 to P5), but excessive N application may inhibit this effect and lead to poor nutritional quality.

Evaluation and Optimization of Quality Based on the Physicochemical Characteristics and Metabolites Changes of Qingpi during Storage

Qingpi, the dried immature pericarp of Citrus reticulata Blanco, is a commonly used medicinal food with some health-promoting benefits. In general, it is essential that Qingpi be stored for a period of time, but there are no reports about the number of storage years needed to obtain the best quality of Qingpi. Our aim was to determine the best storage time of Qingpi by studying the physicochemical properties and metabolite changes in product stored from 1 to 5 years. As a result, the color of Qingpi became darker during storage. Both the levels of three flavonoids (hesperidin, nobiletin, and tangeretin) and total flavonoids (TFs) and the antioxidant activity decreased during storage and the total phenolics (TPs) content fluctuated during storage. Cluster analysis was performed on the color parameters measured using a color difference meter, revealing that the color of Qingpi differed before and after 3 years of storage. A total of 9 special differential metabolites were identified that could be used to distinguish the storage years of Qingpi. This is the first study to report the quality changes of Qingpi during storage. The optimized results of the quality evaluation indicated that Qingpi should be stored for no more than 3 years.

Neuroprotective Effects of Agri-Food By-Products Rich in Phenolic Compounds

Neurodegenerative diseases are known for their wide range of harmful conditions related to progressive cell damage, nervous system connections and neuronal death. These pathologies promote the loss of essential motor and cognitive functions, such as mobility, learning and sensation. Neurodegeneration affects millions of people worldwide, and no integral cure has been created yet. Here, bioactive compounds have been proven to exert numerous beneficial effects due to their remarkable bioactivity, so they could be considered as great options for the development of new neuroprotective strategies. Phenolic bioactives have been reported to be found in edible part of plants; however, over the last years, a large amount of research has focused on the phenolic richness that plant by-products possess, which sometimes even exceeds the content in the pulp. Thus, their possible application as an emergent neuroprotective technique could also be considered as an optimal strategy to revalorize these agricultural residues (those originated from plant processing). This review aims to summarize main triggers of neurodegeneration, revise the state of the art in plant extracts and their role in avoiding neurodegeneration and discuss how their main phenolic compounds could exert their neuroprotective effects. For this purpose, a diverse search of studies has been conducted, gathering a large number of papers where by-products were used as strong sources of phenolic compounds for their neuroprotective properties. Finally, although a lack of investigation is quite remarkable and greatly limits the use of these compounds, phenolics remain attractive for research into new multifactorial anti-neurodegenerative nutraceuticals.

Effect of Citrus aurantium juice as a disinfecting agent on quality and bacterial communities of striped catfish steaks stored at -20 °C

Sodium hypochlorite is generally used as a disinfectant in washing of freshwater fishes where the safety aspect of health is of concern. Although plant-based essential oils and synthetic chemical agents have been applied, they might contain toxic substances, are expensive and can cause undesirable quality. This research aims to fill the knowledge gap necessary to validate Citrus aurantium juice as a disinfecting agent for preserving striped catfish steaks at -20 °C for 28 days. Fifty (50) ppm sodium hypochlorite was used as a commercial disinfectant (control). The results showed that a negative color characteristic (higher a* and increased b*) was found in the control but not in striped catfish steaks immersed in C. aurantium juice (TM) on days 14 and 28. No significant differences were found in the peroxide value among the treatments on days 14 and 28 (P > 0.05). A lower accumulation of trichloroacetic acid soluble peptides was detected in TM but not in control, while total volatile basic nitrogen of all treatments was up to standard of fish quality during storage. Contrastingly, the total viable count of both treatments increased to >7.0 log CFU/g on day 28 which did not meet the edible limit of standard for freshwater fishes. The spoilage microbial community was observed on days 0 and 28 of storage which showed a decrease in relative abundance of Acinetobacter, Pseudomonas, Brochothrix, Lactococcus, Carnobacterium, Psychrobacter, and Vagococcus as found in TM on day 28, when compared to the control. Thus, these results implied that C. aurantium juice could replace sodium hypochlorite as an alternative disinfecting agent to control the microbiological spoilage and physico-chemical quality of striped catfish steaks.

The chemical composition and toxic effects of aqueous extracts of Cyclocarya paliurus leaves

Cyclocarya paliurus leaves, which possess various bioactivities, have been widely used in dietary supplements or as ingredients in functional foods. However, limited information is available about the toxicity or safety concerns. In the present work, the maximum tolerated dose (MTD) and potential toxicity of the aqueous extracts of C. paliurus leaves (AECPL) were evaluated. Our results indicated that AECPL was rich in phenolics, flavonoids, and polysaccharides, which might be responsible for the health benefits of C. paliurus leaves. The MTD of AECPL was considered to be > 10,000 mg/kg BW in both male and female rats. The acute toxicity study was carried out by a 14-day repeat dose oral toxicity study. The results showed that the rats were all well-tolerated. No treatment-related mortality, abnormal clinical signs, body weight, or food consumption changes were reported during the study. Moreover, AECPL showed no adverse changes in the hematology, serum chemistry, urinalysis parameters, organ weights, gross finding, and histopathology. In this study, the non-observed-adverse-effect level of AECPL was 5,000 mg/kg BW/day, indicating AECPL was safe and can be used in the food industry.

Insights on the Extraction and Analysis of Phenolic Compounds from Citrus Fruits: Green Perspectives and Current Status

Citrus fruits (CF) are highly consumed worldwide, fresh, processed, or prepared as juices and pies. To illustrate the high economic importance of CF, the global production of these commodities in 2021 was around 98 million tons. CF's composition is considered an excellent source of phenolic compounds (PC) as they have a large amount and variety. Since ancient times, PC has been highlighted to promote several benefits related to oxidative stress disorders, such as chronic diseases and cancer. Recent studies suggest that consuming citrus fruits can prevent some of these diseases. However, due to the complexity of citrus matrices, extracting compounds of interest from these types of samples, and identifying and quantifying them effectively, is not a simple task. In this context, several extractive and analytical proposals have been used. This review discusses current research involving CF, focusing mainly on PC extraction and analysis methods, regarding advantages and disadvantages from the perspective of Green Chemistry.

Anti-inflammatory and anti-aggregating effects of rangpur in the first trimester of growth: ultra-performance liquid chromatography-electrospray mass spectrometry profile and quantification of hesperidin

BACKGROUND

Citrus fruits are a rich source of valuable molecules, and their industrial processing produces bagasses, little explored to generate important by-products. These Citrus residues, including seeds and peels, also contain numerous pharmacologically important substances. To reduce the impact of these Citrus by-products, young, harvested fruits could be used as a functional supplemental food while another part is grown until maturity for industrial production. This study therefore aims to valorize rangpur (Citrus limonia) in the first 3 months of its growth by investigating and comparing its monthly chemical profiles using ultra-performance liquid chromatography-electrospray mass spectrometry (UPLC-ESI-MS) and its anti-inflammatory and antiplatelet activity.

RESULTS

Extracts obtained from the fruits harvested in November, December, and January, 2017 and 2018 (L221117, L161217, and L160118) showed different UPLC-ESI-MS profiles. Twenty-five of the 26 detected metabolites were identified as cyclitol, pyrrolidine betaine, aryl propanoyl esters, chlorogenic acids, flavonoids, coumarins, and limonoids. Quantification studies indicated an increased concentration of hesperidin from the younger fruits to the older fruits of the series. L160118 reduced nitrogen oxide (NOx), tumor necrosis factor alpha (TNF-α), and interleukin 6 (IL-6) levels more than other extracts. Their activity followed the same trends as the hesperidin concentration in each fruit. In contrast, the most promising antiplatelet activity was observed with the extracts from the two youngest fruits. This suggests combined effects of the chemical components found in these fruits' extracts.

CONCLUSION

The extracts obtained from these young fruits showed considerable anti-inflammatory and antiplatelet activity. Overall, young rangpur could be used as raw material to produce functional foods without producing any waste. © 2022 Society of Chemical Industry.

Rapid profiling of potential antitumor polymethoxylated flavonoids in natural products by integrating cell biospecific extraction with neutral loss/diagnostic ion filtering-based high-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry

INTRODUCTION

Citri Reticulatae Pericarpium Viride (CRPV, Qing Pi in Chinese) has been widely used in traditional Chinese medicine. Polymethoxylated flavonoids (PMFs), which are a special group of flavonoids with strong antitumor activity, are broadly distributed in citrus peels. However, systematic investigation of antitumor PMFs in CRPV has received little attention to date.

OBJECTIVES

An MCF-7 cell biospecific extraction method integrated with neutral loss/diagnostic ion filtering-based HPLC-QTOF-MS/MS strategy was developed for rapid and specific profiling of antitumor PMFs and systematic identification of PMFs in CRPV.

METHODOLOGY

By incubating MCF-7 cells with CRPV extract, potential antitumor PMFs specifically bound to cells and were isolated. Then, by systematic investigation of fragmentation pathways, neutral loss and diagnostic ion filtering strategies were proposed to comprehensively and accurately identify PMFs.

RESULTS

Sixteen antitumor PMFs were unambiguously or tentatively identified. Among them, minor compound 15 (5-hydroxy-6,7,8,3',4'-pentamethoxyflavone with a free hydroxyl group at C-5) exhibited excellent antitumor activity, with an IC₅₀ value of 2.81 ± 0.76 μg/mL, which is lower than that of 5-fluorouracil (IC₅₀ , 4.92 ± 0.83 μg/mL). Nobiletin (12) and tangeretin (16), two major PMFs, presented moderate antitumor activities with IC₅₀ values of 13.06 ± 1.85 and 17.07 ± 1.18 μg/mL, respectively, and their contents were sensitively and precisely determined.

CONCLUSIONS

To the best of our knowledge, this is the first report on the systematic investigation of antitumor PMFs in CRPV. The study will lay a foundation for the quality control and clinical application of CRPV.

Comprehensive analysis of phenolics compounds in citrus fruits peels by UPLC-PDA and UPLC-Q/TOF MS using a fused-core column

In this work, a method based on ultra-high-performance liquid chromatography with a photodiode array detector (UPLC-PDA) was developed to comprehensively analyze phenolic compounds in peels of lime (Citrus × latifolia), lemon (Citrus limon), and rangpur lime (Citrus × limonia). The reverse-phase separation was achieved with a C18 fused-core column packed with the smallest particles commercially available (1.3 um). The method was successfully coupled with high-resolution mass spectrometry (HRMS), allowing the detection of 24 phenolic compounds and five limonoids in several other citrus peels species: key lime, orange and sweet orange, tangerine, and tangerine ponkan, proving the suitability for comprehensive analysis in citrus peel matrices. Additionally, the developed method was validated according to the Food and drug administration (FDA) and National Institute of Metrology Quality and Technology (INMETRO) criteria, demonstrating specificity, linearity, accuracy, and precision according to these guidelines. System suitability parameters such as resolution, tailoring, plate count were also verified.

Online Extraction–DPPH–HPLC-DAD-QTOF-MS System for Efficient Screening and Identification of Antioxidants from Citrus aurantium L. Var. amara (Rutaceae): Integrating Sample Preparation and Antioxidants Profiling

The lack of a direct connection between solid edible or medical natural products and bioactive compound profiling is a bottleneck in natural product research and quality control. Here, a novel integrated system, online extraction (OLE)–2,2′-diphenyl-1-picrylhydrazyl (DPPH)–HPLC−DAD−QTOF-MS, was fabricated to extract, screen, and identify antioxidants from the whole fruit of Citrus aurantium L. var. amara (CAVA, Rutaceae) simply, rapidly, and efficiently. The system consumes less sample (1.0 mg of CAVA powder) and requires a shorter analytical time (45 min for sample extraction, antioxidants screening, separation, and identification). Eight antioxidant flavonoids were screened and identified, and six available flavanones were sensitively, precisely, and accurately quantified. Two major flavanone glycosides, naringin (50.37 ± 0.43 mg/g) and neohesperidin (38.20 ± 0.27 mg/g), exhibit potent DPPH scavenging activities with IC₅₀ values of 111.9 ± 10.06 and 178.55 ± 11.28 μg/mL. A minor flavanone aglycone, hesperitin (0.73 ± 0.06 mg/g), presents stronger DPPH scavenging activity (IC₅₀, 39.07 ± 2.51 μg/mL). Furthermore, density functional theory calculations demonstrated their electron transport ability and chemical reactivity, which confirmed the screened results. The results indicate that the developed OLE–DPPH–HPLC−DAD−QTOF-MS system provides new perspectives for analysis of antioxidants from complex natural products, which also contribute to the quality evaluation of CAVA.

Exploring the Extraction Methods of Phenolic Compounds in Daylily (Hemerocallis citrina Baroni) and Its Antioxidant Activity

Daylily is a valuable plant resource with various health benefits. Its main bioactive components are phenolic compounds. In this work, four extraction methods, ultrasonic-assisted water extraction (UW), ultrasonic-assisted ethanol extraction (UE), enzymatic-assisted water extraction (EW), and enzymatic-assisted ethanol extraction (EE), were applied to extract phenolic compounds from daylily. Among the four extracts, the UE extract exhibited the highest total phenolic content (130.05 mg/100 g DW) and the best antioxidant activity. For the UE extract, the DPPH value was 7.75 mg Trolox/g DW, the FRAP value was 14.54 mg Trolox/g DW, and the ABTS value was 15.37 mg Trolox/g DW. A total of 26 phenolic compounds were identified from the four extracts, and the UE extract exhibited a higher abundance range of phenolic compounds than the other three extracts. After multivariate statistical analysis, six differential compounds were selected and quantified, and the UE extract exhibited the highest contents of all six differential compounds. The results provided theoretical support for the extraction of phenolic compounds from daylily and the application of daylily as a functional food.

Flavonoid glycosides and other bioactive compounds in Citrus reticulate 'Chachi' peel analysed by tandem mass spectrometry and their changes during storage

The peel of Citrus reticulate 'Chachiennsis' (Chachi) is a well-known functional food with multiple health benefits in Asia. There is an old saying "the longer time Chachi is stored, the better health benefits it has". Is it convincible? What are the critical bioactive compounds in Chachi? To answer these questions, gas chromatography-mass spectrometry (GC-MS) and ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) were used to qualify and quantify the flavonoid glycosides and other bioactive compounds of Chachi with storage time of 5-20 years. Limonene was the representative volatile compound. The level of most volatile compounds decreased along with storage. Sixteen flavonoids glycosides and twenty flavonoids were identified. Nobiletin, hesperitin, tetramethoxy flavone and pentamethoxy flavone were characteristic bioactive compounds for Chachi. Most of them accumulated during 10-year storage, thereafter decreased. Ten years could be the optimal storage time. These results indicated that the old saying should be corrected.

Citrus aurantium L. Active Constituents, Biological Effects and Extraction Methods. An Updated Review

Citrus genus is a prominent staple crop globally. Long-term breeding and much hybridization engendered a myriad of species, each characterized by a specific metabolism generating different secondary metabolites. Citrus aurantium L., commonly recognized as sour or bitter orange, can exceptionally be distinguished from other Citrus species by unique characteristics. It is a fruit with distinctive flavor, rich in nutrients and phytochemicals which possess different health benefits. This paper presents an overview of the most recent studies done on the matter. It intends to provide an in-depth understanding of the biological activities and medicinal uses of active constituents existing in C. aurantium. Every plant part is first discussed separately with regards to its content in active constituents. All extraction methods, their concepts and yields, used to recover these valuable molecules from their original plant matrix are thoroughly reported.