Citrus peels prevent cancer

Laboratory evaluation of a bio-insecticide candidate from tangerine peel extracts against Trialeurodes vaporariorum (Homoptera: Aleyrodidae)

Background

The excessive use of synthetic insecticides in modern agriculture has led to environmental contamination and the development of insect resistance. Also, the prolonged use of chemical insecticides in producing flowers and tomatoes in greenhouses has caused health problems for workers and their offspring. In this study, we analyzed the efficacy of mandarin peel (Citrus reticulata L.) essential oil (EO) as a natural insecticide against greenhouse whitefly (Trieurodes vaporariorum W., Homoptera: Aleyrodidae), a common pest in greenhouse production of different crops.

Methods

Petroleum ether (PET) and n-hexane (HEX) were used as solvents to extract essential oil (EO) from tangerine peels.

Results

The yield of EO was 1.59% and 2.00% (m/m) for PET and HEX, respectively. Additionally, the insect-killing power of EO was tested by checking how many greenhouse whiteflies died at different times. The results showed that PET and HEX extracts of tangerine EO effectively controlled greenhouse whiteflies. Furthermore, with both solvents, a 12.5% (v/v) application was as practical as the commercial insecticide imidacloprid. Further characterization tests with the polarimeter, FTIR, HPLC-RP, and GC-MS showed that the essential oil (EO) contained about 41% (v/v) of d-limonene and that this compound may be responsible for the observed insecticidal properties.

Conclusion

Therefore, tangerine peel essential oil is an excellent botanical insecticide candidate for controlling greenhouse whiteflies.

Composite coatings of beeswax + naphthalene acetic acid preserved fruit quality and antioxidants in stored lemon fruits

Lemon fruits are well recognized for their richness in antioxidants. The present study was conducted to maintain the antioxidant properties of lemon fruits under long term cold storage. Fruits were given different treatments of naphthalene acetic acid (NAA) @ 50, 100 and 150 ppm plus beeswax (BW) @ 2% and were stored at 6-8 °C and 90-95% RH for 60 days. At the end of storage, fruits coated with NAA (50 ppm) + BW (2%) retained 42.14 and 34.61% antioxidants, 62.72 and 56.54% phenolic content and 17.72 and 13.80% hydroxyl radical scavenging capacity in peel and pulp, respectively as compared to the control. This treatment also resulted in lesser weight loss (5.27%), higher ascorbic acid content (46.31 mg 100 ml-1 juice) and titratable acidity (5.23%). Hence, NAA + BW coatings were promising for the maintenance of the postharvest antioxidant quality of stored lemons.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01364-4.

Sweet orange peel waste as a feed additive in growth promoting and protective effect against Aeromonas hydrophila of juvenile bagrid catfish Mystus nemurus

Sweet orange Citrus sinensis peel is a phytobiotic agricultural waste with bioactive compounds that have potential functional properties as a growth promoter and immune stimulator. This study aims to evaluate the dietary effects of sweet orange peel (SOP) as a feed additive on growth enhancement of juvenile bagrid catfish Mystus nemurus and their disease resistance ability against Aeromonas hydrophila infection. Four experimental diets were formulated to contain 0 (SOP0, control), 4 (SOP4), 8 (SOP8) and 12 g/kg (SOP12) SOP. After 90 d of the feeding experiment, improvement in weight gain, specific growth rate, feed conversion ratio, and protein efficiency ratio were observed in the fish fed with SOP4. While fish survival was not significantly affected, hepatosomatic and viscerosomatic indices were significantly higher in fish fed with SOP12. Muscle protein was higher in fish fed with SOP4, SOP8, and SOP12 than in control but muscle lipids showed an opposite trend. A 14-d post-challenge test against A. hydrophila revealed no significant effect on the fish survival. Nevertheless, fish fed SOP4 encountered delayed bacterial infection compared to other treatments and fish fed with SOP0 and SOP4 performed numerically better survival. Infected fish showed skin depigmentation, haemorrhagic signs at the abdomen and anus, internal bleeding, and stomach and intestine enlargement. In conclusion, SOP4 could be recommended as a growth promoter while slightly delaying A. hydrophila infection in M. nemurus.

Exploring the synergistic pharmacological mechanism of Huoxiang Drink against irritable bowel syndrome by integrated data mining and network pharmacology

Irritable bowel syndrome (IBS) is the most common functional gastrointestinal disorder, characterized by abdominal pain, bloating, and changes in bowel habits. Huoxiang Drink (HD), derived from traditional Chinese medicine, has been reported to effectively treat digestive disorders caused by external cold and internal dampness. However, the pharmaceutical targets and mechanisms for HD against IBS remain unclear. Data mining, bioinformatics analysis, and network pharmacology were employed to explore the potential pharmacological mechanisms of HD against IBS. In this study, we screened 50 core targets to investigate the pharmacological mechanisms of HD against IBS. Enrichment analysis revealed that HD may participate in various signaling pathways, especially the inflammation-related tumor necrosis factor, signaling pathway and hypoxia-inducible factor signaling pathway. Molecular docking results confirmed that MOL000098 (Quercetin), MOL000006 (Luteolin), MOL005828 (Nobiletin), MOL005916 (Irisolidone), and MOL004328 (Naringenin), as key active ingredients in HD, bound to core targets (tumor protein P53, tumor necrosis factor, matrix metalloproteinases 9, and vascular endothelial growth factor-A) for topical treatment of IBS. This study suggested that HD offered a potential therapeutic strategy against IBS. Our findings may facilitate the efficient screening of active ingredients in HD and provide a theoretical basis for further validating the clinical therapeutic effects of HD on treating IBS.

Ethanol Extract of Citrus grandis 'Tomentosa' Exerts Anticancer Effects by Targeting Skp2/p27 Pathway in Non-Small Cell Lung Cancer

SCOPE

This study aims to investigate the anticancer properties of Citrus grandis 'Tomentosa' (CGT) in non-small cell lung cancer (NSCLC).

METHODS AND RESULTS

The ethanol extract of CGT (CGTE) is prepared by using anhydrous ethanol and analyzed by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), revealing that the main chemical components in CGTE are flavonoids and coumarins, such as naringin, rhoifolin, apigenin, bergaptol, and osthole. CGTE at concentrations without inducing cell death significantly inhibits cell proliferation via inducing cell cycle G1 phase arrest by MTT, colony formation, and flow cytometry assays, implying that CGT has anticancer potential. CGTE markedly inhibits the activity of Skp2-SCF E3 ubiquitin ligase, decreases the protein level of Skp2, and promotes the accumulation of p27 by co-immunoprecipitation (co-IP) and in vivo ubiquitination assay; whereas Skp2 overexpression rescues the effects of CGTE in NSCLC cells. In subcutaneous LLC allograft and A549 xenograft mouse models, CGTE, without causing obvious side effects in mice, significantly inhibits lung tumor growth by targeting the Skp2/p27 signaling pathway.

CONCLUSION

These findings demonstrate that CGTE efficiently inhibits NSCLC proliferation both in vitro and in vivo by targeting the Skp2/p27 signaling pathway, suggesting that CGTE may serve as a therapeutic candidate for NSCLC treatment.

Transcriptome and UPLC-MS/MS reveal mechanisms of amino acid biosynthesis in sweet orange 'Newhall' after different rootstocks grafting

Sweet orange 'Newhall' (C. sinensis) is a popular fruit in high demand all over the world. Its peel and pulp are rich in a variety of nutrients and are widely used in catering, medicine, food and other industries. Grafting is commonly practiced in citrus production. Different rootstock types directly affect the fruit quality and nutritional flavor of citrus. However, the studies on citrus metabolites by grafting with different rootstocks are very limited, especially for amino acids (AAs). The preliminary test showed that there were significant differences in total amino acid content of two rootstocks (Poncirus trifoliata (CT) and C. junos Siebold ex Tanaka (CJ)) after grafting, and total amino acid content in the peel was higher than flesh. However, the molecular mechanism affecting amino acid differential accumulation remains unclear. Therefore, this study selected peel as the experimental material to reveal the amino acid components and differential accumulation mechanism of sweet orange 'Newhall' grafted with different rootstocks through combined transcriptome and metabolome analysis. Metabolome analysis identified 110 amino acids (AAs) and their derivatives in sweet orange 'Newhall' peels, with L-valine being the most abundant. L-asparagine was observed to be affected by both developmental periods and rootstock grafting. Weighted gene co-expression network analysis (WGCNA) combined with Redundancy Analysis (RDA) revealed eight hub structural genes and 41 transcription factors (TFs) that significantly influenced amino acid biosynthesis in sweet orange 'Newhall' peels. Our findings further highlight the significance of rootstock selection in enhancing the nutritional value of citrus fruits and might contribute to the development of functional citrus foods and nutritional amino acid supplements.

Hetero-grafting affects flavonoid biosynthesis in sweet orange 'Newhall' (Citrus sinensis) peels: a metabolomics and transcriptomics analysis

Citrus cultivation involves the widespread practice of grafting, which has a significant impact on citrus development and fruit quality and yield. However, understanding the effect of flavonoid compounds after different rootstock grafting have been limited. Flavonoid compounds, found at the highest levels in citrus peels, contribute to improving fruit quality and nutritional value. In this study, scion-rootstock interaction was investigated at various developmental stages when sweet orange 'Newhall' was hetero-grafted with two commonly used rootstocks (Poncirus trifoliate population, C. junos Siebold ex Tanaka). Physiological index detection showed a higher concentration of total flavonoid content in peels of sweet orange 'Newhall' grafted on Poncirus trifoliate population (ct) than C. junos Siebold ex Tanaka (cj). Further metabolomic analysis identified 703 flavonoid compounds, including flavones, flavonols, and flavanones. Out of the 25 flavonoids affected by different rootstock grafting and developmental stages, most were flavones. Transcriptomic analysis identified 8,562 differentially expressed genes (DEGs). Co-expression and Pearson's correlation analysis discovered six hub structure genes and 19 transcription factors (TFs) that affected flavonoid biosynthesis. In addition to increasing the transcript levels of genes that synthesize flavones, flavonols, and flavanones, the scion-rootstock interaction also affected the expression of many TFs. Taken together, our findings suggested that hetero-grafting could promote the accumulation of flavonoid compounds in citrus peels during the development stages. These results offered fresh perspectives on grafting's application usefulness and the enhancement of the accumulation of nutritive flavonoid components by grafting in citrus.

An Insight into Citrus medica Linn.: A Systematic Review on Phytochemical Profile and Biological Activities

Plant species are a reservoir of natural compounds that can potentially be used to treat different diseases. Citrus medica Linn. belonging to the Rutaceae family, has been used for centuries in medicine for its antioxidant, anti-inflammatory, antimicrobial, antiviral, and antihyperglycemic properties. These activities are ascribable not only to the presence of health-promoting macronutrients and micronutrients, such as carbohydrates, minerals, amino acids, and vitamins, but also to specialized metabolites, such as flavonoids (apigenin, hesperetin, hesperidin, naringin, naringenin, rutin, quercetin, and diosmin), coumarins (citropten, scoparone, and bergapten), terpenes (limonene, γ-terpinene, limonin, and nomilin), and phenolic acids (p-coumaric acid, trans-ferulic acid, and chlorogenic acid). In recent years, particular attention has been focused on the antioxidant, anti-inflammatory, antimicrobial activity, antidiabetic, anticancer, and neuroprotective activity of C. medica. However, although many studies have reported this species' chemical and biological properties, the literature has never been analyzed via a systematic approach. For this reason, using PubMed and Scopus as databases, we performed a systematic review of C. medica's chemical composition and biological properties to inspire new research approaches and increase its curative application.

Widely targeted metabolomic profiling combined with transcriptome analysis sheds light on flavonoid biosynthesis in sweet orange 'Newhall' (C. sinensis) under magnesium stress

Sweet orange 'Newhall' peels (SOPs) are abundant in flavonoids, making them increasingly popular in the realms of nutrition, food, and medicine. However, there is still much unknown about flavonoid components in SOPs and the molecular mechanism of flavonoid biosynthesis when subjected to magnesium stress. The previous experiment conducted by the research group found that the total flavonoid content of Magnesium deficiency (MD) was higher than Magnesium sufficiency (MS) in SOPs. In order to study the metabolic pathway of flavonoids under magnesium stress, an integrative analysis of the metabolome and transcriptome was performed in SOPs at different developmental stages, comparing MS and MD. A comprehensive analysis revealed the identification of 1,533 secondary metabolites in SOPs. Among them, 740 flavonoids were classified into eight categories, with flavones identified as the dominant flavonoid component. The influence of magnesium stress on flavonoid composition was evaluated using a combination of heat map and volcanic map, which indicated significant variations between MS and MD varieties at different growth stages. The transcriptome detected 17,897 differential genes that were significantly enriched in flavonoid pathways. Further analysis was performed using Weighted gene correlation network analysis (WGCNA) in conjunction with flavonoid metabolism profiling and transcriptome analysis to identify six hub structural genes and ten hub transcription factor genes that play a crucial role in regulating flavonoid biosynthesis from yellow and blue modules. The correlation heatmap and Canonical Correspondence Analysis (CCA) results showed that CitCHS had a significant impact on the synthesis of flavones and other flavonoids in SOPs, as it was the backbone gene in the flavonoid biosynthesis pathway. The qPCR results further validated the accuracy of transcriptome data and the reliability of candidate genes. Overall, these results shed light on the composition of flavonoid compounds in SOPs and highlight the changes in flavonoid metabolism that occur under magnesium stress. This research provides valuable insights for improving the cultivation of high-flavonoid plants and enhancing our understanding of the molecular mechanisms underlying flavonoid biosynthesis.

Effects of ageing time on the properties of polysaccharide in tangerine peel and its bacterial community

To evaluate the effect of aging time on the quality of tangerine peel (TP) from the perspective of TP polysaccharide (TPP), five polysaccharide samples with different aging times named TPP-0/1/5/10/15 were prepared. Under the conditions of pH 0.5, solid-liquid ratio 1:25 and 80 °C, the TPPs extraction yield ranged from 20.35% to 27.68%. Compared with TPP-0, TPP-1/5/10/15 possesses low molecular weight (Mw) and high methoxy group content. In addition, TPP-15 had the most potent antioxidant activity. And the content of acidic polysaccharides in TPPs was negatively correlated with neutral polysaccharides during aging. Based on the analysis of 16srDNA, the dominant bacteria (Brevundimonas and Pseudomonas) in TP-10 might be critical flora to affect TP quality. This study provided basic information on the relationship between the TPPs and aging time, which could promote a new view to develop TP, and shorten the aging time during TP production.

Toward Achieving Rapid Estimation of Vitamin C in Citrus Peels by NIR Spectra Coupled with a Linear Algorithm

Citrus peels are rich in bioactive compounds such as vitamin C and extraction of vitamin C is a good strategy for citrus peel recycling. It is essential to evaluate the levels of vitamin C in citrus peels before reuse. In this study, a near-infrared (NIR)-based method was proposed to quantify the vitamin C content of citrus peels in a rapid way. The spectra of 249 citrus peels in the 912-1667 nm range were acquired, preprocessed, and then related to measured vitamin C values using the linear partial least squares (PLS) algorithm, indicating that normalization correction (NC) was more suitable for spectral preprocessing and NC-PLS model built with full NC spectra (375 wavelengths) showed a better performance in predicting vitamin C. To accelerate the predictive process, wavelength selection was conducted, and 15 optimal wavelengths were finally selected from NC spectra using the stepwise regression (SR) method, to predict vitamin C using the multiple linear regression (MLR) algorithm. The results showed that SR-NC-MLR model had the best predictive ability with correlation coefficients (r_P) of 0.949 and root mean square error (RMSE_P) of 14.814 mg/100 mg in prediction set, comparable to the NC-PLS model in predicting vitamin C. External validation was implemented using 40 independent citrus peels samples to validate the suitability of the SR-NC-MLR model, obtaining a good correlation (R² = 0.9558) between predicted and measured vitamin C contents. In conclusion, it was reasonable and feasible to achieve the rapid estimation of vitamin C in citrus peels using NIR spectra coupled with MLR algorithm.

Mediterranean Food Industry By-Products as a Novel Source of Phytochemicals with a Promising Role in Cancer Prevention

The Mediterranean diet is recognized as a sustainable dietary approach with beneficial health effects. This is highly relevant, although the production of typical Mediterranean food, i.e., olive oil or wine, processed tomatoes and pomegranate products, generates significant amounts of waste. Ideally, this waste should be disposed in an appropriate, eco-friendly way. A number of scientific papers were published recently showing that these by-products can be exploited as a valuable source of biologically active components with health benefits, including anticancer effects. In this review, accordingly, we elaborate on such phytochemicals recovered from the food waste generated during the processing of vegetables and fruits, typical of the Mediterranean diet, with a focus on substances with anticancer activity. The molecular mechanisms of these phytochemicals, which might be included in supporting treatment and prevention of various types of cancer, are presented. The use of bioactive components from food waste may improve the economic feasibility and sustainability of the food processing industry in the Mediterranean region and can provide a new strategy to approach prevention of cancer.

Study on Flavonoids and Bioactivity Features of Pericarp of Citrus reticulata "Chachi" at Different Harvest Periods

Dry mature pericarp of Citrus reticulata "Chachi" (PCR), Pericarpium Citri Reticulatae Chachiensis, is a traditional Chinese medicine that displays characteristics of different usage at different harvest times in clinical use. The corresponding changes in the bioactive components in PCR from different harvest times remain unclear. Therefore, in this study, broadly targeted metabolomics technology was used to compare the differences in bioactive components among pericarps of PCR, which are the raw material of PCR at different growth stages. In the results, 210 kinds of flavonoid metabolites were detected. The content of hesperidin in red PCR harvested in December was higher than that in Citri Reticulatae Pericarpium Viride (CRPV) and reddish PCR harvested from July to November. Furthermore, the content of nobiletin, tangeretin, and 3,3',4',5,6,7,8-heptamethoxyflavone in CRPV from July to September was higher than that in the PCR harvested at other times. In addition, the result of cluster analysis and PCA showed that CRPV harvested from July to September had an obvious grouping pattern with the reddish PCR and the red PCR harvested from October to December. Differential metabolites in six comparison groups (A1 vs. A6, A1 vs. A2, A2 vs. A3, A3 vs. A4, A4 vs. A5, A5 vs. A6) were 67, 48, 14, 51, 42, and 40, respectively. The common differential metabolite of four comparison groups was 3',4',7-trihydroxyflavone (A1 vs. A2, A2 vs. A3, A3 vs. A4, A4 vs. A5). All the flavonoid differential metabolites screened were enriched in 16 metabolic pathways. Moreover, the results of the evaluation of the total antioxidant capacity indicated that CRPV in August was a suitable raw material for the production of antioxidants. Through molecular docking, the content of potential anti-SARS-CoV-2 components in the PCR in October was higher than that in the PCR in other periods. These results further proved that PCR at different harvest times was endowed with different efficacy and usage due to the difference in the accumulation of bioactive components.

Regulatory effect of long-stranded non-coding RNA-CRNDE on neurodegeneration during retinal ischemia-reperfusion

Ischemia/reperfusion (I/R) injury is a common pathological mechanism involved in many ocular diseases. I/R is characterized by microvascular dysfunction and neurodegeneration. However, the mechanisms of neurodegeneration induced by I/R remain largely unknown. This study showed that the expression of long non-coding RNA-CRNDE was significantly upregulated after retinal ischemia-reperfusion (RIR). LncRNA-CRNDE knockdown alleviated retinal neurodegeneration induced by RIR injury, as shown by decreased reactive gliosis and reduced retinal cells loss. Furthermore, lncRNA-CRNDE knockdown directly regulated Müller cell function and indirectly affected RGC function in vitro. In addition, lncRNA-CRNDE knockdown led to a significant reduction in the release of several cytokines after RIR. This study suggests that lncRNA-CRNDE is a promising therapeutic target for RIR.

The new exploration of pure total flavonoids extracted from Citrus maxima (Burm.) Merr. as a new therapeutic agent to bring health benefits for people

The peel and fruit of Citrus varieties have been a raw material for some traditional Chinese medicine (TCM). Pure total flavonoids from Citrus maxima (Burm.) Merr. (PTFC), including naringin, hesperidin, narirutin, and neohesperidin, have been attracted increasing attention for their multiple clinical efficacies. Based on existing in vitro and in vivo research, this study systematically reviewed the biological functions of PTFC and its components in preventing or treating liver metabolic diseases, cardiovascular diseases, intestinal barrier dysfunction, as well as malignancies. PTFC and its components are capable of regulating glycolipid metabolism, blocking peroxidation and persistent inflammation, inhibiting tumor progression, protecting the integrity of intestinal barrier and positively regulating intestinal microbiota, while the differences in fruit cultivation system, picking standard, manufacturing methods, delivery system and individual intestinal microecology will have impact on the specific therapeutic effect. Thus, PTFC is a promising drug for the treatment of some chronic diseases, as well as continuous elaborate investigations are necessary to improve its effectiveness and bioavailability.

Prospects of ultrasonically extracted food bioactives in the field of non-invasive biomedical applications - A review

Foods incorporated with bioactive compounds, called nutraceuticals, can fight or prevent or alleviate diseases. The contribution of nutraceuticals or phytochemicals to non-invasive biomedical applications is increasing. Although there are many traditional methods for extracting bioactive compounds or secondary metabolites, these processes come with many disadvantages like lower yield, longer process time, high energy consumption, more usage of solvent, yielding low active principles with low efficacy against diseases, poor quality, poor mass transfer, higher extraction temperature, etc. However, nullifying all these disadvantages of a non-thermal technology, ultrasound has played a significant role in delivering them with higher yield and improved bio-efficacy. The physical and chemical effects of acoustic cavitation are the crux of the output. This review paper primarily discusses the ultrasound-assisted extraction (USAE) of bioactives in providing non-invasive prevention and cure to diseases and bodily dysfunctions in human and animal models. The outputs of non-invasive bioactive components in terms of yield and the clinical efficacy in either in vitro or in vitro conditions are discussed in detail. The non-invasive biomedical applications of USAE bioactives providing anticancer, antioxidant, cardiovascular health, antidiabetic, and antimicrobial benefits are analyzed in-depth and appraised. This review additionally highlights the improved performance of USAE compounds against conventionally extracted compounds. In addition, an exhaustive analysis is performed on the role and application of the food bioactives in vivo and in vitro systems, mainly for promoting these efficient USAE bioactives in non-invasive biomedical applications. Also, the review explores the recovery of bioactives from the less explored food sources like cactus pear fruit, ash gourd, sweet granadilla, basil, kokum, baobab, and the food processing industrial wastes like peel, pomace, propolis, wine residues, bran, etc., which is rare in literature.

Citrus maxima (Brum.) Merr. (Rutaceae): Bioactive Chemical Constituents and Pharmacological Activities

Citrus maxima (Burm). Merr. (family Rutaceae), commonly known as Pomelo, is an ethnomedicinally, pharmacologically, and phytochemically valued species. Various ethnomedicinal reports have revealed the use of C. maxima for cough, fever, asthma, diarrhea, ulcer, and diabetes and as a sedative. Numerous phytochemicals have been reported from C. maxima such as polyphenols, terpenoids, sterols, carotenoids, vitamins, and amino acids. The plant possesses significant bioactivities like antioxidant, antimicrobial, anti-inflammatory, analgesic, anticancer, antidiabetic, anti-Alzheimer's disease, insecticidal, anxiolytic, hepatoprotective, antimalarial, and antiobesity. Extensive research is necessary to explore the detailed mechanism of action of extracts and compounds to design effective medicines, herbal products, and functional foods.

Natural essential oil mix of sweet orange peel, cumin, and allspice elicits anti-inflammatory activity and pharmacological safety similar to non-steroidal anti-inflammatory drugs

An inflammation response occurs when the body reacts to exogenous and endo enous noxious stimuli, and it helps the body respond to infection and repair tissues, adapt to stress, and remove dead or damaged cells. Anti-inflammatory drugs such as non-steroidal anti-inflammatory drugs are traditionally used to treat inflammation; however, these drugs often cause negative side effects. For this reason, developing and establishing effective alternative medicines for treating many chronic diseases with underlying inflammation is critically dependent on the identification of new organic molecules and bioactive substances. Aromatic and volatile compounds found in essential oils isolated from Pimenta dioica (allspice), Cuminum cyminum (cumin), and Citrus sinensis (sweet orange) are a source of bioactive compounds. Allspice essential oil reduces ear inflammation more than 65% and the anti-inflammatory activity of allspice essential oil is enhanced when combined with sweet orange peel and cumin essential oils, resulting in the reduction of edema inflammation by more than 85%, similar to indomethacin. As an alternative to anti-inflammatory treatment, essential oil mix is pharmacologically safe as it is neither toxic nor mutagenic.

Protective Effects of Naringenin from Citrus sinensis (var. Valencia) Peels against CCl4-Induced Hepatic and Renal Injuries in Rats Assessed by Metabolomics, Histological and Biochemical Analyses

Citrus fruits are grown worldwide for their special nutritive and several health benefits. Among citrus bioactives, naringenin, a major flavanone, exhibits a potential hepatoprotective effect that is not fully elucidated. Herein, serum biochemical parameters and histopathological assays were used to estimate the hepatoprotective activity of naringenin, isolated from Citrus sinensis (var. Valencia) peels, in CCl4-induced injury in a rat model. Further, GC-MS-based untargeted metabolomics was used to characterize the potential metabolite biomarkers associated with its activity. Present results revealed that naringenin could ameliorate the increases in liver enzymes (ALT and AST) induced by CCl4 and attenuate the pathological changes in liver tissue. Naringenin decreased urea, creatinine and uric acid levels and improved the kidney tissue architecture, suggesting its role in treating renal disorders. In addition, naringenin increased the expression of the antiapoptoic cell marker, Bcl-2. Significant changes in serum metabolic profiling were noticed in the naringenin-treated group compared to the CCl4 group, exemplified by increases in palmitic acid, stearic acid, myristic acid and lauric acids and decrease levels of alanine, tryptophan, lactic acid, glucosamine and glucose in CCl4 model rats. The results suggested that naringenin's potential hepato- and renoprotective effects could be related to its ability to regulate fatty acids (FAs), amino acids and energy metabolism, which may become effective targets for liver and kidney toxicity management. In conclusion, the current study presents new insights into the hepato- and renoprotective mechanisms of naringenin against CCl4-induced toxicity.

The use of orange peel in the technology of drinks fermentation

Nutrition is one of the most important factors determining human health. Enrichment of food products with minerals, antioxidant compounds, and vitamins are relevant today. In this work, dry orange peel was used to enrich a fermented drink based on kvass wort with phenolic compounds and vitamin C. The following indicators were determined: the content of vitamin C, the amount of phenolic compounds and anthocyanins, the antioxidant activity of orange peel dried to a moisture content of 18%. The drink fermentation lasted 12 hours at 30 °C. Secondary fermentation was carried out for 48 hours. At this stage, orange peel was added in the amount of 10 g/l. During the experiment, the concentration of dry matter content, the acidity of the medium, and the content of ethyl alcohol were measured. Organoleptic indicators were determined during the tasting of the finished product. In the finished drink, the content of ethyl alcohol was 0.98%. It was found that the finished drink with peel contains 4 times more phenolic compounds and 1.5 times more vitamin C.

Headspace volatolome of peel flours from citrus fruits grown in Brazil

Citrus fruit peel comprises a pleasant mix of volatile compounds together with fibers, nutrients, and bioactive compounds. Therefore, it has great potential for use as a food ingredient. Studies evaluating the volatile composition of citrus peel flours are limited for most citruses. The goal of this study was to characterize, by HS-SPME/GC-MS, the volatile profile of citrus peel flours made from fruits commonly grown in Brazil. Two composite samples of ten types of citrus peel flours from consecutive harvests were evaluated. 69 volatile compounds were assigned, 49 in Tahiti acid lime, 49 in Sicilian lemon, 37 in Persian lime, 34 in Italian tangerine and oval kumquat, 33 in Valencia orange, 32 in Baia orange and round kumquat, 28 in Blood-of-Mombuca orange and 26 in Lima orange. 26 major compounds represented 93-99% of the total chromatogram peak area. Terpenic compounds were predominant in all samples, especially monoterpenes (about 48-97% of the total chromatogram peak area), while lower proportions of aldehydes (0.2-16.1%), monoterpene alcohols (0.4-11.8%) and esters (0.0-7.7%) were observed. Even though a few compounds like limonene, β-myrcene, linalool, α-pinene and valencene were detected in all citrus, volatile compounds followed specific patterns in the different citruses, with a clear distinction among them, especially between lemon flours and the remaining flours. The variety of volatile profiles and singular specific volatolomic signatures in citrus peels can be explored for different applications related to food flavoring and preservation, and promotion of good health. These aspects should be thoroughly investigated in future studies.

Phytowaste as nutraceuticals in boosting public health

The utilization of bioactive constituent of peels and seeds provide an effective, environment friendly and inexpensive therapy for different forms of human disease, and the production, improvement and documentation of novel nutraceuticals. This review systematically presents findings and further understanding of the reported benefits and therapeutic applications of peel and seed extracts on innovative cell culture and animal studies, as well as phased clinical human trial research. The extracts of seed and peels were reported to possess high quantities of bioactive substances with antioxidative, antidiabetic, hepatorenal protective, antithyroidal, anti-inflammatory, antibacterial, cardiovascular protective, neuro-protective effects, anticancer and wound healing activities. Therapeutic activities of the bioactive substances of peel and seed extracts include elevation of Superoxide dismutase (SOD), GSH-Px, t-GPx, Catalase and GST activities, with the suppression of MDA levels, hydroperoxide generation and lipid peroxidized products, the extracts also regulate inflammatory mediators and cytokines as they are reported to suppress the secretion of inflammatory cytokines, which include; IL-1β, PGE2, TGF-β and TNF-α and induces apoptosis and cell differentiation. This review revealed the therapeutic importance and best utilization of peels and seed extracts of fruits and vegetables.

Identification and Quantification of Polymethoxylated Flavonoids in Different Citrus Species Using UPLC-QTOF-MS/MS and HPLC-DAD

Many species from the genus Citrus are used in traditional medicine and contain polymethoxylated flavonoids. These compounds show anti-inflammatory and chemopreventive activities, among others, and therefore have a big potential to be developed as therapeutic agents or dietary supplements. Citrus species are different in their profile and yield of polymethoxylated flavonoids. Therefore, polymethoxylated flavonoids were identified and quantified in seven different Citrus species, including wild-type and commercially available species. All species were profiled using UPLC-QTOF-MS/MS analysis combined with mass spectral molecular networking. A total of 38 polymethoxylated flavonoids were detected and 8 of them were present in every species. As the yield of polymethoxylated flavonoids was different for each species, a generally applicable HPLC-diode array detection method was developed and validated according to the ICH guidelines to quantify the amount of nobiletin and the total amount of polymethoxylated flavonoids expressed as nobiletin. Analysis of the seven samples showed evidence that wild-type Citrus species (e.g., Citrus depressa) contain higher yields of polymethoxylated flavonoids compared to commercially available species (e.g., Citrus limon). Qualitative analysis revealed the broadest variety of different PMFs in C. depressa, Citrus reticulata, and Citrus reticulata × Citrus sinensis, which makes them interesting sources of polymethoxylated flavonoids for future development as therapeutic agents or dietary supplements.

Stratification of lung adenocarcinoma patients for d-limonene intervention based on the expression signature genes

Globally, lung cancer ranks as the most lethal malignant neoplasm. d-Limonene, a plant extract enriched with essential oils, has been reported to exert anti-cancer effects both in vitro and in vivo; however, its clinical effect on humans remains elusive. Therefore, the present study aimed to investigate the gene expression signature that would potentially stratify lung adenocarcinoma (LUAD) patients who may benefit from d-limonene intervention, thus facilitating the development of newer treatment strategies for LUAD. In total, 1877 significant differentially expressed genes (DEGs) were identified. These genes were mainly associated with the metabolism of terpenoids and polyketides, lipid metabolism, endocrine system, carbohydrate metabolism, and cell growth and death pathways. Three genes, including antioncogenes FZD3 and MTURN, and oncogene PRC1, which were regulated by d-limonene were identified based on survival analysis of TCGA-LUAD data and were validated by both in vitro and in vivo experiments. High-risk patients screened by the model exhibited a significantly poor prognosis. In conclusion, three gene expression signatures (FZD3, MTURN, and PRC1) were validated by both in vitro and in vivo experiments and identified to help stratify candidate lung adenocarcinoma patients who may benefit from d-limonene intervention. Although further studies are warranted, this study highlighted a potential strategy to improve the treatment outcomes of LUAD patients.

Antioxidant Activity and Healthy Benefits of Natural Pigments in Fruits: A Review

Natural pigments, including carotenoids, flavonoids and anthocyanidins, determine the attractive color of fruits. These natural pigments are essential secondary metabolites, which play multiple roles in the whole life cycle of plants and are characterized by powerful antioxidant activity. After decades of research and development, multiple benefits of these natural pigments to human health have been explored and recognized and have shown bright application prospects in food, medicine, cosmetics and other industries. In this paper, the research progress of natural fruit pigments in recent years was reviewed, including the structural characteristics and classification, distribution in fruits and analysis methods, biosynthetic process, antioxidant capacity and mechanism, bioaccessibility and bioavailability, and health benefits. Overall, this paper summarizes the recent advances in antioxidant activity and other biological functions of natural fruit pigments, which aims to provide guidance for future research.

Determination of etoxazole in different parts of citrus fruit and its potential dietary exposure risk assessment

In this study, the profile of etoxazole in whole citrus, peel and pulp samples collected from Chongqing, Guangdong and Anhui provinces was monitored and their dietary risk to human had also been assessed. The final residual levels and distributions of etoxazole in citrus samples were detected by using an ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). The results showed that final concentrations of etoxazole in whole citrus, peel, and pulp were ranged at 0.012-0.174, 0.010-0.637, and 0.010-0.011 mg kg^-1, respectively. The assessment of dietary risk suggested that chronic dietary risk of etoxazole in whole fruit and peel were 0.010-0.197% and 0.035-0.951%, respectively. Our findings indicated that the chronic risk of daily consumption of citrus fruit is acceptable at recommended dosage.

Anti-estrogenic and anti-aromatase activities of citrus peels major compounds in breast cancer

Estrogen signaling is crucial for breast cancer initiation and progression. Endocrine-based therapies comprising estrogen receptor (ER) modulators and aromatase inhibitors remain the mainstay of treatment. This study aimed at investigating the antitumor potential of the most potent compounds in citrus peels on breast cancer by exploring their anti-estrogenic and anti-aromatase activities. The ethanolic extract of different varieties of citrus peels along with eight isolated flavonoids were screened against estrogen-dependent breast cancer cell lines besides normal cells for evaluating their safety profile. Naringenin, naringin and quercetin demonstrated the lowest IC_50s and were therefore selected for further assays. In silico molecular modeling against ER and aromatase was performed for the three compounds. In vivo estrogenic and anti-estrogenic assays confirmed an anti-estrogenic activity for the isolates. Moreover, naringenin, naringin and quercetin demonstrated in vitro inhibitory potential against aromatase enzyme along with anticancer potential in vivo, as evidenced by decreased tumor volumes. Reduction in aromatase levels in solid tumors was also observed in treated groups. Overall, this study suggests an antitumor potential for naringenin, naringin and quercetin isolated from citrus peels in breast cancer via possible modulation of estrogen signaling and aromatase inhibition suggesting their use in pre- and post-menopausal breast cancer patients, respectively.

Insights into the chemical composition and bioactivities of citrus peel essential oils

Citrus peel (CP), a by-product of the citrus fruit processing, comprises nearly forty to fifty percent of the fruit portion. Interestingly, the essential oil (EO) is primarily concentrated in the peel portion of the citrus fruit. Extraction of CP essential oil (CPEO) is an effective way of utilizing the citrus fruit processing waste. The CPEO can be more efficiently recovered from CP waste by improving the efficiency of conventional extraction processes. The main components of CPEO include monoterpenes, sesquiterpenes and their oxygenated derivatives. Specifically, limonene is the major oil component identified in the peel of different citrus species. The health promoting biological activities of CPEO are functioning as antioxidant, anti-inflammatory, analgesic, antimicrobial and anticancer agents, thereby can be used as a source of functional components and preservatives for the development of nutritionally safe newer food products. This paper provides an in-depth knowledge about the chemical constituents and bioactivities of EOs extracted from peels of different citrus species.

Review of the nutritional composition, medicinal, phytochemical and pharmacological properties of Citrus reticulata Blanco (Rutaceae)

Citrus reticulata Blanco is a moderately-sized fruit tree widely used as herbal medicine worldwide. The nutritional composition, medicinal uses, phytochemistry and pharmacological properties of C. reticulata were critically reviewed in the current study. The literature linked to C. reticulata properties was obtained from multiple internet sources including Elsevier, Google Scholar, SciFinder, Web of Science, Pubmed, BMC, Science Direct, and Scopus. Ethnopharmacological research identified antioxidants such as vitamin C, carotenoids and phenolic compounds, also a source of sugars, organic acids, amino acids, pectins, minerals and volatile organic compounds as components of C. reticulata. As a medicinal plant, C. reticulata is used for the treatment of dyspepsia, gastro-intestinal distension, cough with profuse phlegm, hiccup and vomiting. The crude extracts of C. reticulata fruits have depicted anti-inflammatory, anticholesterolemic, analgesic, antiasthmatic, antiscorbutic, antiseptic, antitussive, carminative, expectorant, stomachic. With more people becoming nutrition-conscious, there has been an increase in the demand for the use of citrus fruits and their by-products as traditional medicines for conventional healthcare in developing countries.

Exploiting Citrus aurantium seeds and their secondary metabolites in the management of Alzheimer disease

Fruit by-products are considered nature’s golden gift for human health and a good starting point to discover new drugs depending on the fact that they contain millions of bio-active compounds that are responsible for therapeutic activities. In this context, the main goal of this study is to recycle Citrus aurantium (C. aurantium) seeds to produce pharmaceutical molecules to be used in the prevention of the progressive neurological damage associated with Alzheimer disease (AD). Donepezil (0.75 mg/kg), hesperidin (125 and 250 mg/kg) and limonoids (50 and 100 mg/kg) were used for treatment of rats for 2 weeks prior to concomitant administration of AlCl₃ for three successive weeks. Protection against cognitive deterioration was observed among study group with insignificant difference from normal control group and significant difference from positive control group in the Y-Maze test. On the other hand, treatment with both doses of hesperidin (125 and 250 mg/kg) and high dose of limonoids only (100 mg/kg) produced improvement in psychological state, observed by significant increase in ambulation frequency in comparison to positive control group, however it was not as frequent as normal group, as it was significantly less than normal group in the open field test. Regarding acetylcholine esterase (AChE) and beta-amyloid (β amyloid) levels, the effect of limonoids low dose was the best as it didn’t have a significant effect when compared to normal control, also hesperidin in both doses showed insignificant effects on β amyloid levels when compared to normal control group. Our results encourage the use of C. aurantium seeds which are wasted in huge amounts, as Alzheimer prophylactic food additives.

Phenolic composition, antioxidant potential and health benefits of citrus peel

Citrus peel (CP) forms around 40-50% of the total fruit mass but is generally thought to be a waste. However, it is a substantial source of naturally occurring health enhancing compounds, particularly phenolic compounds and carotenoids. Phenolic compounds in CP mainly comprise phenolic acids (primarily caffeic, p-coumaric, ferulic and sinapic acid), flavanones (generally naringin and hesperidin) and polymethoxylated flavones (notably nobiletin and tangeretin). It has also been noted that CP's contain more amounts of these compounds than corresponding edible parts of the fruits. Phenolic compounds present in CP act as antioxidants (by either donation of protons or electrons) and protect cells against free radical damage as well as help in reducing the risk of many chronic diseases. Owing to the more abundance of polyphenols in CP's, their antioxidant activity is also higher than other edible fruit parts. Therefore, peels from citrus fruits can be used as sources of functional compounds and preservatives for the development of newer food products, that are not only safe but also have health-promoting activities. The present review provides in-depth knowledge about the phenolic composition, antioxidant potential and health benefits of CP.

Valorization of byproducts from tropical fruits: Extraction methodologies, applications, environmental, and economic assessment: A review (Part 1: General overview of the byproducts, traditional biorefinery practices, and possible applications)

Tropical fruits represent one of the most important crops in the world. The continuously growing global market for the main tropical fruits is currently estimated at 84 million tons, of which approximately half is lost or wasted throughout the whole processing chain. Developing novel processes for the conversion of these byproducts into value-added products could provide a viable way to manage this waste problem, aiming at the same time to create a sustainable economic growth within a bio-economy perspective. Given the ever-increasing concern about sustainability, complete valorization through a bio-refinery approach, that is, zero waste concept, as well as the use of green techniques is therefore of utmost importance. This paper aims to report the status on the valorization of tropical fruit byproducts within a bio-refinery frame, via the application of traditional methodologies, and with specific attention to the extraction of phenolics and carotenoids as bioactive compounds. The different types of byproducts, and their content of bioactives is reviewed, with a special emphasis on the lesser-known tropical fruits. Moreover, the bioactivity of the different types of extracts and their possible application as a resource for different sectors (food, pharmaceutical, and environmental sciences) is discussed. Consequently, this review presents the concepts of tropical fruit biorefineries, and the potential applications of the isolated fractions.

Menopause-Associated Lipid Metabolic Disorders and Foods Beneficial for Postmenopausal Women

Menopause is clinically diagnosed as a condition when a woman has not menstruated for one year. During the menopausal transition period, there is an emergence of various lipid metabolic disorders due to hormonal changes, such as decreased levels of estrogens and increased levels of circulating androgens; these may lead to the development of metabolic syndromes including cardiovascular diseases and type 2 diabetes. Dysregulation of lipid metabolism affects the body fat mass, fat-free mass, fatty acid metabolism, and various aspects of energy metabolism, such as basal metabolic ratio, adiposity, and obesity. Moreover, menopause is also associated with alterations in the levels of various lipids circulating in the blood, such as lipoproteins, apolipoproteins, low-density lipoproteins (LDLs), high-density lipoproteins (HDL) and triacylglycerol (TG). Alterations in lipid metabolism and excessive adipose tissue play a key role in the synthesis of excess fatty acids, adipocytokines, proinflammatory cytokines, and reactive oxygen species, which cause lipid peroxidation and result in the development of insulin resistance, abdominal adiposity, and dyslipidemia. This review discusses dietary recommendations and beneficial compounds, such as vitamin D, omega-3 fatty acids, antioxidants, phytochemicals—and their food sources—to aid the management of abnormal lipid metabolism in postmenopausal women.

Bitter Orange (Citrus aurantium Linné) Improves Obesity by Regulating Adipogenesis and Thermogenesis through AMPK Activation

Obesity is a global health threat. Herein, we evaluated the underlying mechanism of anti-obese features of bitter orange (Citrus aurantium Linné, CA). Eight-week-administration of CA in high fat diet-induced obese C57BL/6 mice resulted in a significant decrease of body weight, adipose tissue weight and serum cholesterol. In further in vitro studies, we observed decreased lipid droplets in CA-treated 3T3-L1 adipocytes. Suppressed peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer binding protein alpha indicated CA-inhibited adipogenesis. Moreover, CA-treated primary cultured brown adipocytes displayed increased differentiation associated with elevation of thermogenic factors including uncoupling protein 1 and PPARγ coactivator 1 alpha as well. The effects of CA in both adipocytes were abolished in AMP-activated protein kinase alpha (AMPKα)-suppressed environments, suggesting the anti-adipogenic and pro-thermogenic actions of CA were dependent on AMPKα pathway. In conclusion, our results suggest CA as a potential anti-obese agent which regulates adipogenesis and thermogenesis via AMPKα.

Acrylamide Content of Experimental Flatbreads Prepared from Potato, Quinoa, and Wheat Flours with Added Fruit and Vegetable Peels and Mushroom Powders

Flatbreads are a major food consumed worldwide. To mitigate an undesirable safety aspect of flatbreads that might be associated with the potentially-toxic compound acrylamide, we recently developed recipes using a variety of grains that resulted in the production of low-acrylamide flatbreads. To further enhance the functionality of flatbreads, we have developed, in this work, new experimental flatbreads using potato, quinoa, and wheat flours supplemented with peel powders prepared from commercial nonorganic and organic fruits and vegetables (apples, cherry tomatoes, melons, oranges, pepino melons, sweet potato yams), potato peels, and mushroom powders (Lion’s Mane, Hericium erinaceus; Reishi, Ganoderma lucidum; and Turkey Tail, Trametes versicolor). These additives have all been reported to contain beneficial compositional and health properties. The results of fortification of the baked flatbreads showed either no effect or increases in acrylamide content by unknown mechanisms. Since the additives did not increase the acrylamide content of the quinoa flour flatbreads for the most part, such supplemented quinoa flatbreads have the potential to serve as a nutritional, gluten-free, low-acrylamide, health-promoting functional food. Mushroom powder-fortified wheat flatbreads with relatively low acrylamide content may also have health benefits.