Search Results (19)

Fingered citron volatile oil is a volatile oil with a fresh and slightly floral aroma, extracted from fresh fingered citron. It is one of the natural perfume essential oils. At present, scholars at home and abroad mainly focus their research on fingered citron volatile oil on optimizing extraction processes, component analysis, pharmacological effects, and other aspects. With the continuous development and application of fingered citron volatile oil and related products, the research scope of fingered citron volatile oil is becoming increasingly extensive. As a narrative review, this paper summarizes and compares eight distinct extraction techniques for fingered citron volatile oil and clarifies the merits and drawbacks of each method. Steam distillation is one of the most employed approaches for volatile oil extraction in laboratory settings, whereas mechanical pressing is extensively applied and serves as the dominant and preferred industrial process for fingered citron volatile oil production. This paper also reviews its potential biological activities, including antidepressant, anti-anxiety, and sleep-improving effects, as well as the development and application of related products. Fingered citron volatile oil has been applied in products such as cigarettes and insecticides. Studying the chemical components of fingered citron volatile oil can not only help research its medicinal mechanisms but also promote the development of natural spices, providing a useful reference for the further utilization of fingered citron volatile oil in the future. Full article

Background/Objectives: Fingered citron (Citrus medica L. var. sarcodactylis (Siebold ex Hoola van Nooten) Swingle) is rich in phenolic constituents, yet systematic comparisons of free and bound phenolics across tissues and origins remain limited. This study compared the peel, pulp, and blend (whole fruit) of fingered citron from five Chinese regions: Zhejiang (ZJ), Yunnan (YN), Sichuan (SC), Guangdong (GD), and Guangxi (GX). Methods: Phenolic compositions were determined by colorimetric assays and HPLC. Antioxidant activity was assessed by ORAC and PSC, and hypoglycemic-related activity by α-glucosidase and α-amylase inhibition and glucose consumption in an insulin-resistant HepG2 (IR-HepG2) cell model. Results: Phenolic distribution followed the order peel > blend > pulp, and free > bound. HPLC identified 11 free and 5 bound phenolics, predominantly hesperidin, quercetin, and 5,7-dimethoxycoumarin. GX peel exhibited the highest free phenolic content (106.34 ± 0.23 mg GAE/100 g FW) and superior ORAC (30.56 ± 0.50 μmol TE/g FW), strongly correlating with total phenolics (r = 0.98, p < 0.01). Free phenolics showed stronger α-glucosidase and α-amylase inhibition, whereas bound phenolics produced higher glucose consumption in the IR-HepG2 cell model. The GX blend bound fraction showed the highest glucose consumption (5.48 ± 0.98 mmol/L). Conclusions: Under fresh-weight-based conditions, phenolic composition and in vitro bioactivities differed by fruit part, region, and phenolic fraction. Peel, especially GX peel, tended to show higher phenolic levels and stronger antioxidant-related performance, whereas the GX blend bound fraction showed the highest glucose-consumption-promoting activity. Full article

Finger Citron (Citrus medica L. var. sarcodactylis Swingle) holds significant potential as both a culinary ingredient and a traditional medicinal remedy; however, its precise molecular mechanisms of action remain largely unexplored. This study investigates the anti-inflammatory properties of Finger Citron extract (FCE) in RAW 264.7 macrophages stimulated by lipopolysaccharide (LPS). Using UPLC-ESI-QTF-MS, we analyzed the extract’s composition, revealing a rich presence of polyphenols and polysaccharides, with hesperidin, melitidin, and hesperetin as the predominant polyphenolic compounds. Additionally, the study elucidated the monosaccharide composition profile of polysaccharides in the extract. Furthermore, Finger Citron extract markedly suppressed the production of key inflammatory mediators, including TNF-α, IL-6, and NO. The inhibition of protein phosphorylation levels of inhibiting the mitogen-activated protein kinase (MAPK) and nuclear factor kappa-B (NF-κB) signaling was also observed, indicating that the anti-inflammatory effects of Finger Citron extract may involve the NF-κB and MAPK signaling pathway. Given these findings, Finger Citron extract has the potential to act as a natural product with anti-inflammatory activity. Full article

Background/Objectives: Chronic alcohol overconsumption triggers alcohol liver injury, and therapeutic strategies targeting alcohol-triggered oxidative stress and hepatic inflammatory responses represent potential approaches to ameliorating alcohol-related hepatotoxicity. This study aimed to determine the hepatoprotective activity of finger citron essential oil (FCEO) in alcoholic liver disease (ALD)-afflicted rats and explore its underlying mechanisms. In order to identify the effective components, we compared the effects of FCEO and D-limonene. Methods: The regulatory effects of FCEO on metabolic enzymes were systematically evaluated through in vitro experiments. In vivo studies were conducted to investigate and compare the hepatoprotective effects of FCEO and D-limonene. Staining methods, assay kits, and Western Blot were used to determine the roles of FCEO and D-limonene in the ALD rats. Results: We found that FCEO downregulated phase I metabolic enzymes and upregulated phase II metabolic enzymes in Buffalo Rat Liver-3A (BRL-3A) cells. FCEO and/or D-limonene intervention reduced transaminase levels in ALD rats and effectively alleviated inflammatory cell infiltration and lipid droplet accumulation in their liver tissue. Additionally, FCEO and D-limonene played a regulatory role in oxidative stress and inflammation-related pathways such as the MAPK/Nrf2 and NF-κB/AMPK pathways. FCEO was superior to D-limonene as an antioxidant in alleviating alcoholic liver injury. Conclusions: This study revealed the alleviative effects and mechanisms of FCEO on alcoholic liver injury, demonstrating better efficacy compared to its monomer, thus providing a strategy for the development and utilization of finger citron resources. Full article

Parthenocarpy, the development of fruit without fertilization, is a significant trait in fingered citron (Citrus medica L. var. sarcodactylis Swingle). This study aims to elucidate the regulatory mechanisms underlying parthenocarpy through comparative transcriptome analysis and phytohormone profiling between fingered citron and its non-parthenocarpic counterpart, citron. A total of 66 differentially expressed hormone-related genes were identified, with the auxin pathway emerging as the most prominent in fingered citron. Protein–protein interaction analysis revealed a potential interaction between auxin and abscisic acid (ABA). Phytohormone content analysis indicated that fingered citron exhibited higher levels of indole-3-acetic acid (IAA) and lower levels of ABA compared to citron. A weighted gene co-expression network analysis (WGCNA) suggested that the interplay between auxin and ABA is crucial for triggering parthenocarpy. Virus-induced gene silencing (VIGS) experiments demonstrated that silencing CmsABI5 led to decreased ABA levels, while auxin levels remained unchanged, resulting in disrupted parthenocarpy and increased ethylene levels, indicating a secondary hormonal response. Additionally, gene expression changes associated with failed parthenocarpy showed down-regulation of SAUR50 and up-regulation of PP2C 56, linking these changes to ABA signaling. Our findings highlight the central regulatory role of auxin in parthenocarpy in fingered citron, with ABA acting as a critical modulator. The suppression of ABA alone disrupts parthenocarpy despite stable auxin levels, emphasizing the necessity of balanced hormone interactions. This research underscores the significant role of auxin, rather than gibberellin (GA), in regulating parthenocarpy in fingered citron, contributing valuable insights to the understanding of fruit development mechanisms. Full article

Twenty-two coumarins and twenty-six flavonoids were quantitated in fingered citron in different growth periods. Limettin was the top coumarin, and diosmin was the highest flavonoid, followed by hesperidin. Antioxidant evaluation by DPPH, ABTS, and FRAP indicated extracts of fingered citron in three growth periods all showed good antioxidant activity, which was positively correlated with the concentration of extracts. The oxidative stress model of RAW264.7 cells indicated extracts from fingered citron effectively reduced the contents of NO, MDA, and ROS in cells and increased the activity of SOD, thereby alleviating cell damage. The antioxidant capacity of fingered citron in November was the highest, followed by July and September. And there was a significantly positive correlation between the total flavonoid content and the antioxidant capacity. Diosmin, hesperidin, and neohesperidin were the main contributors to antioxidation. This study has significance for utilization of fingered citron germplasm resources and development of related functional products. Full article

(1) Background: Insomnia is a neurological illness that poses a significant threat to both physical and mental health. It results in the activation of neuroglial cells, heightened neuroinflammation, oxidative stress, and disruptions in the Hypothalamic–Pituitary–Adrenal (HPA) axis. Ligusticum Chuanxiong (CX) and Finger citron (FC) are frequently utilized botanicals for addressing sleeplessness. Both herbs possess notable anti-inflammatory properties in their volatile oils. However, their effectiveness is hindered by the nasal mucosal irritation and instability they exhibit. (2) Methods: This study involved the preparation of a nanofiber composite system using carbon nanofiber (CNF) suspensions containing essential oils of Ligusticum chuanxiong–Finger citron (CXEO-FCEO-CNF). The effects and mechanisms of these essential oils in improving insomnia were investigated using an insomnia mouse model after encapsulation. (3) Results: The CXEO-FCEO-CNF had an average particle size of 103.19 ± 1.64 nm. The encapsulation rates of essential oils of Ligusticum chuanxiong (CXEO) and essential oils of Finger citron (FCEO) were 44.50% and 46.15%, respectively. This resulted in a considerable improvement in the stability of the essential oils over a period of 30 days. The essential oils effectively decreased the irritation of the nasal mucosa following encapsulation. Furthermore, CXEO-FCEO-CNF enhanced voluntary activity and sleep in mice with insomnia, notably boosted the activity of superoxide dismutase (SOD), reduced the concentration of lipoxidized malondialdehyde (MDA), decreased the levels of hormones associated with the HPA axis, and regulated the levels of neurotransmitters, resulting in a beneficial therapeutic outcome. CXEO-FCEO-CNF contains a total of 23 active ingredients, such as alpha-Asarone, (E)-methyl isoeugenol, and Senkyunolide. These ingredients primarily work by modulating the Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling system to decrease oxidative stress and inflammatory reactions. (4) Conclusions: This study presented initial evidence that the combination of CXEO and FCEO in nanofiber formulations effectively reduces the nasal mucosal irritation and instability of essential oils. Furthermore, it demonstrated the potential anti-neuroinflammatory and therapeutic effects of these formulations in treating insomnia. Overall, this study provides a theoretical foundation for developing new essential oil formulations derived from herbs. Full article

In this paper, liquid–liquid chromatography was introduced for the first time for the separation of fingered citron (Citrus medica L. var. sarcodactylis Swingle). The fingered citron cultivated in Jinhua is of significant industrial and medicinal value, with several major coumarin compounds detected in its extract. Therefore, further separation for higher purity was of necessity. A preparative liquid–liquid chromatographic method was developed by combining two elution modes (isocratic and step-gradient) with selection according to different polarities of the target sample. Five coumarin derivatives—5,7-dimethoxycoumarin (52.6 mg, 99.6%), phellopterin (4.9 mg, 97.1%), 5-prenyloxy-7-methoxycoumarin (6.7 mg, 98.7%), 6-hydroxy-7-methoxycoumarin (7.1 mg, 82.2%), and byakangelicol (10.5 mg, 90.1%)—with similar structures and properties were isolated on a large scale from 100 mg of petroleum ether (PE) extract and 100 mg of ethyl acetate (EA) extract in Jinhua fingered citron. The productivity was much improved. The anti-growth activity of the isolated coumarins was evaluated against three cancer cell lines (HeLa, A549, and MCF7) with an MTT assay. The coumarins demonstrated potential anti-tumor activity on the HeLa cell line, with 5,7-dimethoxycoumarin in particular exhibiting the best anti-growth activity (IC₅₀ = 10.57 ± 0.24 μM) by inhibiting proliferation. It inhibited colony formation and reduced the size of the tumor sphere in a concentration-dependent manner. The main mechanism was confirmed as inducing apoptosis. This work was informative for further studies aimed at exploring new natural-product-based antitumor agents. Full article

In recent years, as the desire for a healthy lifestyle has become more widespread, consumers are gaining an increasing appreciation for safe, high-quality food. Researchers are constantly seeking new ways to protect foods from insect pests and fungi. This study used GC-IMS to analyze the volatile organic compounds and flavor characteristics of Finger Citron in response to different doses of ⁶⁰Co irradiation. The principal component analysis method was used to explore the overall differences in flavor spectra, and a total of 60 compounds were identified. The fingerprints of volatile organic compounds in the samples showed that the volatile organic compounds with doses of ⁶⁰Co irradiation in about 0 kGy and 5 kGy are similar, while the 10 kGy samples are quite different. The PCA results showed that the similarity between 0 kGy and 5 kGy was slightly higher, and the difference between 10 kGy and other samples was greater. Therefore, it was determined that ⁶⁰Co irradiation with a 10 kGy intensity has a significant influence on the content of volatile oils components, while ⁶⁰Co irradiation with a 5 kGy intensity has little effect. Irradiation technology is demonstrated as a promising method of food sterilization, but the irradiation dose and chemical composition must be taken into consideration. Full article

Finger citron pickled products (FCPP), as folk remedies, are famous in southern China for protecting gastric mucosa. However, the gastric mucosa protection of FCPP has not been reported yet, and its effective mechanism is unclear. In this study, the protective mechanism of FCPP aqueous extract on gastric mucosa was investigated in vitro and in vivo for the first time, using human gastric mucosa epithelial cells (GES-1) and acute alcoholic gastric ulcer rat model respectively. Furthermore, we also investigated the main substances in the aqueous extract that exert gastroprotective activity using a GES-1 scratch test and basic chemical composition analysis. FCPP aqueous extract was found to play a protective and reparative role in GES-1 by promoting the secretion of trefoil factor thyroid transcription factor 2 (TFF2) and inhibiting the secretion of tumor necrosis factor-α (TNF-α) in cells damaged by alcohol. The ulcer index of gastric tissue induced by alcohol was significantly decreased (p < 0.01) after pretreatment with FCPP aqueous extract, indicating that FCPP aqueous extract had a good protective effect on the stomach mucosa. Moreover, FCPP aqueous extract could increase superoxide dismutase (SOD) activity and inhibit malondialdehyde (MDA) content, exhibiting good antioxidant capacity. Aqueous extract of FCPP could also effectively inhibit the increase of cytokines TNF-α, interleukin-1β (IL-1β) and interleukin-6 (IL-6) in serum of rats, and promote the increase of anti-inflammatory cytokines interleukin-10 (IL-10) to some extent. Furthermore, FCPP aqueous extract could inhibit the expression of nuclear factor kappa-B (NF-κB/P65) protein, caspase-1 protein and IL-1β protein in the gastric tissue of rats, while promoting the expression of IκBα protein, indicating that the gastric mucosa protection effects of FCPP aqueous extract were mainly dependent on the NF-κB/caspase-1/IL-1β axis. The polysaccharides in FCPP aqueous extract might be the main components that exerted gastroprotective activity, as demonstrated by GES-1 cell scratch assay. This study confirmed that FCPP aqueous extract presented promising potential in protecting gastric mucosa and avoiding gastric ulcers, which could provide an experimental basis for further utilizing the medicinal value and developing new products of FCPP. Full article

Citrus is among the most economically important fruit crops. Its vast species diversity and global production was observed by N.I. Vavilov during his international plant explorations from the early to mid-1900s. Currently, ex situ citrus collections located around the world conserve and protect citrus genetic resources, as revealed in a survey conducted in 2021. Responses were received from 43 collections in 27 countries, of which 35 provided data regarding collection composition, management practices, and security, as well as other information. The six largest citrus collections have between 1000 and 1735 accessions. The largest accession holdings are mandarins and sweet oranges, although all citrus fruit types are maintained: mandarin, sweet orange, lemon, pummelo, grapefruit, hybrids, lime, sour orange, citron, kumquat, papeda, finger lime, and crop wild relatives. Diseases pose significant threats to collections, though some collections are maintained in a clean-plant state as a result of intensive sanitation efforts. National and regional quarantine regulations often limit the export and import of citrus plants or propagative materials, thus limiting the availability of materials at an international level. Resources, both financial and human, are necessary to ensure the long-term safety and security of citrus collections on a global scale. Future efforts to develop citrus genebanking communities will provide opportunities for improved conservation, as well as collaborations and training. Full article

In addition to volatile compounds, metabolites also have a great effect on the flavour of food. Fresh finger citron cannot be eaten directly because of its spicy and bitter taste, so it is made into a preserved fruit product known as Laoxianghuang (LXH). To investigate the metabolites that have an effect on the flavour of LXH, untargeted metabolomics was performed using an ultrahigh-performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS), and the metabolites of the Laoxianghuang samples from different locations in the Chaoshan area were compared and analysed. A total of 756 metabolites were identified and distinct differences were revealed among the different Laoxianghuang samples. A total of 33 differential metabolites with the most significant changes were screened through further multivariate analytical steps, and each group of samples had unique metabolites. For instance, pomolic acid had the highest content in the JG sample, while L-glycyl-L-isoleucine was rich in the QS sample. Moreover, flavonoid metabolites made the greatest contribution to the unique flavour of Laoxianghuang. The metabolic pathways involved are the biosynthetic pathways of flavonoids, isoflavonoids, flavones, and flavonols. This study can provide some creative information for distinguishing the quality differences of Laoxianghuang from the perspective of metabolites and offer preliminary theoretical support to characterise the formation of flavour substances in Laoxianghuang. Full article

Citrus canker is a quarantined disease caused by the bacterial plant pathogen Xanthomonas citri subsp. citri (Xcc), which causes persistent surface damage, leaf and fruit drop, and tree decline in citrus plants. The citrus cultivar Citron C-05 (Citrus medica L.) is a disease-resistant genotype identified after years of screening at the National Center for Citrus Improvement (Changsha), which displays allergic, necrotic, and disease-resistant responses to Xcc. In this study, the BAK1 gene was identified in this cultivar to be a disease resistance gene involved in plant-microbe interaction between citrus and Xcc. Functional investigations of this gene revealed that both CsBAK1 (C. sinensis BAK1) or CmBAK1(C. medica BAK1) could inhibit the growth of Xcc to some extent when transiently expressed in the susceptible ‘Bingtang’ genotype of sweet orange. Critical regions of the CmBAK1 promoter sequence were identified by creating downstream deletions and exposing mutants to Xcc to determine effects on the resistance phenotype; a 426 bp region (−2000~–1574) was identified as a key functional region responsible for eliciting the hypersensitive response in plants. Through screening arrayed Citron C-05 cDNA libraries by yeast one-hybrid assays, a basic APETALA2/ETHYLENE RESPONSE FACTOR (AP2/ERF) transcription factor of CmRAP2-13 that binds directly to the 426 bp key sequence and activates expression of CmBAK1 was identified. Moreover, transcriptional analysis revealed an obvious increase in transcript levels of CsRAP2-13 in Citron C-05, American citron, and Finger citron. In this study, we present the identification of transcriptional activators that are found to interact with BAK1 proteins in response to Xcc. These results reveal a coordinated regulatory mechanism of RAP2-13, which may be involved in defence responses through the regulation of BAK1. Full article

The present work aimed to chemically characterize and evaluate the antiradical power and biological effects of Citrus medica var. sarcodactylus essential oil (EO) and hydrolate (Hy) from exocarp as well as methanol extracts, from both exocarp and mesocarp (EEX and MEX). The whole fresh fruit was also investigated by SPME-GC/MS to describe its volatile composition. EO and Hy were analyzed by GC/MS and HS-GC/MS techniques, respectively. Limonene and γ-terpinene were found to be the most abundant compounds both in the fresh parts of the fruit and in the EO, while α-terpineol and terpinen-4-ol were in the Hy. The extracts were also rich in furan and coumarin derivatives. A good antiradical activity of all samples except Hy was detected both against ABTS·+ than DPPH·, removed up to about 50%. The antibacterial activity against Bacillus cereus and Escherichia coli was evaluated by microwell dilution method to determine MIC and MBC values. EEX and MEX showed efficacy at very high concentrations against both tested bacteria. The MIC value of EO against B. cereus was 0.5% v/v, while Hy was not able to inhibit the bacterial growth at the tested concentrations. Cytotoxicity investigated on the HL60 leukemia cell line by MTT assay provided an EC₅₀ of 1.24% v/v for EO. Interesting activity of Hy was also observed. Full article

Citrus tristeza virus (CTV) is one of the most important citrus tree viruses: a graft-transmissible virus that can be vectored by several aphid species. Diaphorina citri is the insect vector of “Candidatus Liberibacter spp.”, a bacterium associated with citrus Huanglongbing (HLB). However, no detailed description of the relationship between CTV and D. citri has been reported. In this study, D. citri adults collected from CTV-infected “Shatangju” mandarin, “Newhall” sweet orange, and “fingered citron” trees in different orchards yielded CTV-positive rates of 40%, 65%, and 95%, respectively, upon detection by conventional PCR. Illumina HiSeq sequencing followed by de novo assembly recovered the primary full CTV genome from the RNA of 30 D. citri adults sampled from CTV-positive citrus plants. Molting and adult emergence did not affect the presence or titers of CTV within the D. citri; however, the persistence of CTV in psyllids varied among different host plant species. Groups of 10 D. citri (from a population 85% CTV-positive) were shown to potentially transmit CTV to two citrus species, “Shatangju” mandarin and “Eureka” lemon, yielding 58.33% and 83.33% CTV-positive plants, respectively. No transmission of CTV to orange jasmine plants occurred. Thus, this study reports on the ability of D. citri to acquire and transmit CTV, making D. citri as a vector of two important citrus pathogens, warranting further attention and investigation. Full article