Transition of aromatic volatile and transcriptome profiles during melon fruit ripening.

Melon (Cucumis melo L.) is an important diploid crop with a wide variety of flavors due to its distinct aromatic volatile organic compounds (VOC). To understand the development of VOC profiles during fruit development, we performed metabolomic and transcriptomic analysis of two cantaloupe varieties over the course of fruit development. A total of 130 metabolites were detected in fruit samples, and 449014207 reads were mapped to the melon genome. A total of 4469 differentially expressed genes in fruits were identified and used to visualize the transition of VOC and transcriptomic profiles during the fruit development. A shift of VOC profiles in both varieties was observed from early-fruit profiles enriched in C5-C8 lipid-derived VOCs to late-fruit profiles abundant in C9 lipid-derived VOCs, apocarotenoids, and esters. The shift coincided with the expression of specific isoforms of lipid and carotenoid metabolizing enzymes as well as transcription factors involved in fruit ripening, metabolite regulation, and hormone signaling.

Citrus limonoids induce apoptosis and inhibit the proliferation of pancreatic cancer cells.

In our recent study, we demonstrated that certain limonoids isolated from citrus seeds induced apoptosis in human pancreatic (Panc-28) cells. In this study, limonin, nomilin and limonexic acid (LNA) were investigated for understanding the possible mode of cytotoxicity in cultured pancreatic cancer (Panc-28) cells. All three limonoids inhibited Panc-28 cell proliferation, with IC50 values less than 50 µM after 72 h of incubation. The induction of apoptosis was confirmed through the cleavage of caspase-3, decreased mitochondrial membrane potential, and expression of apoptosis-related proteins. The Bax/Bcl2 expression ratio was increased up to 11-fold in cells pre-treated with 60 µM limonoids for 48 h. Apart from this, the limonoids also induced the expression of p21, and exhibited anti-inflammatory activity through decreasing the expression of cox-2, NF-κB and IL-6. Based on these results, we were interested in understanding the possible mode of inhibition by LNA, which exhibited the highest activity. The treatment of Panc-28 cells resulted in dose- and time-dependent induction of apoptosis-inducible proteins. In addition, treatment with 60 µM LNA resulted in the activation of Akt-associated signals to induce apoptosis, and the same was confirmed by the effects of the compounds on pAkt, p53, VEGF and caspase proteins. The results of this study demonstrated the cytotoxicity of limonoids to human pancreatic cancer cells through the modulation of genes involved in proliferation and survival.

Frequent asymptomatic infection with tobacco ringspot virus on melon fruit.

Melon is one of the most popular fruits worldwide and has been bred into various cultivars. RNA-sequencing using healthy melon fruit was performed to determine differences in gene expression among cultivars. Unexpected RNA-seq results revealed that viruses asymptomatically infected fruits at a high frequency (16 of 21 fruits examined were infected) and that viral transcripts highly accumulated in comparison with host transcripts (15 %-75 % of total reads). Their nucleotide sequences and phylogenetic analyses indicated that more than 10 novel isolates of tobacco ringspot virus (TRSV) were found in melon fruits. Asymptomatic infection with TRSV on melon fruits was confirmed by both immunoblot and RT-PCR analyses. Numerous isolates of TRSV generated and maintained in melon fields, and this is likely due to their asymptomatic infections. This TRSV melon isolate infected Nicotiana benthamiana plants with stunting and yellowing symptoms. This is the first report of frequent and asymptomatic infection of TRSV in consumable melon fruits.

Hormonal and metabolites responses in Fusarium wilt-susceptible and -resistant watermelon plants during plant-pathogen interactions.

BACKGROUND: Fusarium oxysporum f. sp. niveum (FON) causes Fusarium wilt in watermelon. Several disease-resistant watermelon varieties have been developed to combat Fusarium wilt. However, the key metabolites that mount defense responses in these watermelon varieties are unknown. Herein, we analyzed hormones, melatonin, phenolic acids, and amino acid profiles in the leaf tissue of FON zero (0)-resistant (PI-296341, Calhoun Grey, and Charleston Grey) and -susceptible (Sugar Baby) watermelon varieties before and after infection. RESULTS: We found that jasmonic acid-isoleucine (JA-Ile) and methyl jasmonate (MeJA) were selectively accumulated in one or more studied resistant varieties upon infection. However, indole-3-acetic acid (IAA) was only observed in the FON 0 inoculated plants of all varieties on the 16th day of post-inoculation. The melatonin content of PI-296341 decreased upon infection. Conversely, melatonin was only detected in the FON 0 inoculated plants of Sugar Baby and Charleston Grey varieties. On the 16th day of post-inoculation, the lysine content in resistant varieties was significantly reduced, whereas it was found to be elevated in the susceptible variety. CONCLUSIONS: Taken together, Me-JA, JA-Ile, melatonin, and lysine may have crucial roles in developing defense responses against the FON 0 pathogen, and IAA can be a biomarker of FON 0 infection in watermelon plants.

A sensitive HPLC-FLD method combined with multivariate analysis for the determination of amino acids in l-citrulline rich vegetables.

The proposed analytical method reports the separation and quantification of 21 amino acids including l-citrulline from fresh vegetables and commercial juices using a C8 column. Optimal separation conditions for amino acids analysis were obtained with 20 mM sodium acetate (solvent A) and water with organic modifier acetonitrile and methanol (solvent B; 18/50/32 V/V). The ideal pH and column temperature were found to be 5.40 and 35 °C, respectively. The LOD and LOQ values were obtained in the range of 0.02-0.19 ng/mL and 0.04-0.39 ng/mL for all amino acids respectively. Relative standard deviations (RSD) of intraday and interday analysis were found to be <2.7% and 7.9%, respectively. The recovery of amino acids were found be satisfactory for all the tested crops. The developed method was successfully used for the quantification of amino acids in six fresh vegetable juices including watermelon, cucumber, celery, calabaza squash, zucchini squash, yellow squash and commercial juices. Multivariate analysis was used to determine the significant differences in the amino acids profiles. l-citrulline content was highest in fresh watermelon juice (716.57 ± 24.80 µg/mL) and commercial watermelon lime juice (826.48 ± 34.48 µg/mL). The optimized analytical method is rapid, sensitive, accurate and reproducible for analysis of free amino acids including l-citrulline from different vegetable juices and other food products. To the best of our knowledge, this is the first report to separate OPA derivatives of amino acids using C8 column from watermelon, cucumber, zucchini squash, yellow squash, calabaza squash, and celery in a HPLC-FLD system.

In vitro and in silico elucidation of antidiabetic and anti-inflammatory activities of bioactive compounds from Momordica charantia L.

Bitter melon (Momordica charantia) has been used to manage diabetes and related conditions in various parts of the world. In the present study, ten compounds were isolated from acetone and methanol extracts of bitter melon. The chemical structures of compounds were unambiguously elucidated by 1D, 2D NMR, and high-resolution mass spectra. Identified compounds 1-7 exhibited significant inhibition of α-amylase and moderate inhibition of α-glucosidase activities. Momordicoside G and gentisic acid 5-O-ß-d-xyloside showed the highest inhibition of α-amylase (70.5%), and α-glucosidase (56.4%), respectively. Furthermore, molecular docking studies of isolated compounds 1-7 were able to bind to the active sites of both enzymes. Additionally, the isolated compounds 1-7 significantly attenuated lipopolysaccharide (LPS)-induced inflammation, downregulating the expression of pro-inflammatory markers NF-κB, INOS, IL-6, IL-1ß, TNF-α, and Cox-2 in murine macrophage RAW 264.7 cells. One phenolic derivative, gentisic acid 5-O-ß-d-xyloside, was isolated and identified for the first time from bitter melon, and significantly suppressed the expression of Cox-2 and IL-6 compared to the LPS-treated group. α-Amylase and α-glucosidase are targets of anti-diabetes drugs, our findings suggest that compounds purified from bitter melon may have potential to use as functional food ingredients for the prevention of type 2 diabetes and related inflammatory conditions.

Metabolite profiling and in vitro biological activities of two commercial bitter melon (Momordica charantia Linn.) cultivars.

The current study was designed to characterize the metabolite profile and bioactivity of two commercial bitter melon (Momordica charantia Linn.) genotypes. UPLC-high resolution mass spectrometry (HRMS) was used to identify 15 phenolic and 46 triterpenoids in various bitter melon extracts. Total phenolic levels were the highest (57.28 ±â€¯1.02) in methanolic extract of the inner tissue of Indian Green cultivar, which also correlated to the highest DPPH radical scavenging activity (30.48 ±â€¯2.49 ascorbic acid equivalents (mg of AAE)/g of FD). In addition, highest levels of total saponins were observed in chloroform extract of the Chinese bitter melon pericarp (75.73 mg ±â€¯4.67 diosgenin equivalents (DE)/g of FD). Differential inhibition of α-amylase and α-glucosidase activity was observed in response to polarity of extract, cultivar and tissue type. These results suggest that consumption of whole bitter melon may have potential health benefits to manage diabetes.

Cucurbitane-type compounds from Momordica charantia: Isolation, in vitro antidiabetic, anti-inflammatory activities and in silico modeling approaches.

Momordica charantia L., commonly known as bitter melon, belongs to the Cucurbitaceae family. Various in vitro and in vivo studies have indicated that extracts of bitter melons have anti-diabetic properties. However, very little is known about the specific purified compounds responsible for these antidiabetic properties. In the present study, 3ß,7ß,25-trihydroxycucurbita-5,23(E)-dien-19-al, charantal, charantoside XI, and 25ξ-isopropenylchole-5, 6-ene-3-O-d-glucopyranoside were isolated from bitter melon fruit. The structures of the purified compounds were elucidated by HR-ESIMS, 1D, and 2D NMR experiments. All compounds exhibited significant inhibition of α-amylase and α-glucosidase comparable to acarbose. Molecular docking studies demonstrated that purified compounds were able to bind to the active sites of proteins. Additionally, the purified compounds showed significant anti-inflammatory activity, downregulating the expression of NF-κB, iNOS, IL-6, IL-1ß, TNF-α, and Cox-2 in lipopolysaccharide-activated macrophage RAW 264.7 cells. Our findings suggest that the purified compounds have potential anti-diabetic and anti-inflammatory activities and therefore hold promise for the development of plant-based management for diabetic and inflammatory conditions.

Metabolomic studies of volatiles from tomatoes grown in net-house and open-field conditions.

In the present study, the influence of production systems (net-house and open-field) on volatile profiles of three Texas A&M University (TAMU) and five commercial tomato varieties was investigated. Forty metabolites were determined using headspace solid phase microextraction (HS-SPME) equipped with gas chromatography and mass spectrometry (GC-MS). The data was evaluated by multivariate analyses to discriminate the effects of genotype and production system, and to identify potential biomarker(s). The levels of hexanal, p-cymene, and (E)-2-hexenal from TAMU varieties were distinct from those of commercial tomato varieties. Similarly, 16 metabolites were considerably affected by the production systems, and majority of these volatiles were significantly higher in the net-house-grown tomatoes. Multivariate analysis also allowed identifying geranylacetone and d-limonene as potential biomarkers to classify tomatoes according to production systems. These findings underline the importance of the selection of variety and production system to preserve or improve desirable aroma traits in tomatoes.

An optimized solvent extraction and characterization of unidentified flavonoid glucuronide derivatives from spinach by UHPLC-HR-QTOF-MS.

A rapid, sensitive analytical method using ultra-high-pressure liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-HR-QTOF-MS) was developed for the identification and quantification of flavonoids from spinach. The extraction efficiency of flavonoids was evaluated by different solvents such as acetone, ethanol, methanol, acetone: water (70:30), ethanol: water (70:30) and methanol: water (70:30). Flavonoid identification was achieved by UV spectra, high resolution accurate mass and their fragmentation pattern. The precursor and product ions were recorded by both broadband collision ion dissociation (bbCID) and multiple reaction monitoring (MRM) techniques. Different collision energies (5, 10, 15, 20, 40, and 70 eV) were optimized to obtain the mass spectra of flavonoids in positive and negative ionization modes. For the first time, five minor flavonoid glucuronide derivatives were identified in spinach. MRM and bbCID provided glucuronide fingerprint ions at m/z 175.0278 and m/z 113.0257 respectively in negative ionization mode. The quantification of identified flavonoids was achieved by 5,3',4'-trihydroxy-3-methoxy-6:7-methylen-dioxyflavone-4'-ß-D-glucuronide which was purified by semi-preparatory HPLC. The purity of the isolated compound was confirmed by NMR analysis. The identified 5,3',4'-trihydroxy-3-methoxy-6:7-methylen-dioxyflavone-4'-ß-D-(2'-O-feurloyl-glucuronide) was the prominent flavonoid and the level was significantly higher in the acetone fraction (2.95 ±â€¯0.16 µg/g FW). This study demonstrates the systematic identification of potential bioactive compounds especially glucuronide derivatives from spinach.

Identification and Quantification of Phytochemicals, Antioxidant Activity, and Bile Acid-Binding Capacity of Garnet Stem Dandelion (Taraxacum officinale).

Dandelion (Taraxacum officinale) var. Garnet Stem was harvested from Texas and New Jersey for identification, quantification of phytochemicals, measurement of free radical scavenging activity, and bile acid binding capacity. The red midrib and petioles were extracted with methanol or ethanol and with or without water in combination with four different acids such as formic, hydrochloric, acetic, and citric acid. LC-ESI-HR-QTOF-MS was used to identify four anthocyanins including cyanidin-3-glucoside, cyanidin-3-(6-malonyl)-glucoside (A-1), cyanidin-3-(6-malonyl)-glucoside (A-2), and peonidin-3-(malonyl)-glucoside for the 1st time. In New Jersey samples, vitamin C and ß-carotene were highest in the leaf blades versus whole leaf and petioles. Samples from Texas had highest amount of lutein, violaxanthin, and chlorophyll a and b in leaf blades versus whole leaf and petioles. Maximum DPPH free scavenging activity was found in MeOH: water: acid (80:19:1) and the combination of FA with EtOH: water: acid (80:19:1) demonstrated the higher level of total phenolic. Among six bile acids, sodium chenodeoxycholate was bound maximum in both Texas and New Jersey samples. This is the first report of anthocyanin identification from the midvein and petiole of Garnet Stem dandelion and results suggested that the phytochemicals and nutrients are highest in the leaf but may vary the amount depending on harvest location. PRACTICAL APPLICATION: Four anthocyanins in the red midrib and petioles of Garnet Stem could be a potential source for antioxidants and can be used as a source of natural food color.

Storage Stability of Dietary Nitrate and Phenolic Compounds in Beetroot (Beta vulgaris) and Arugula (Eruca sativa) Juices.

Nitrate and polyphenols from the diet may enhance the production and bioavailability of nitric oxide, a radical signaling molecule critical for cardiovascular health. Understanding the stability of these bioactives in beetroot and arugula juices is important for their functions. In this study, the stability of nitrate and phenolics in beetroot and arugula juices was measured for 32 days at different temperatures (25, 4, -20, and -80 °C). The levels of nitrate were measured by reversed-phase HPLC and initial levels were found to be 4965.34 ± 72.69 µg/mL for beetroot and 6310.20 ± 24.79 µg/mL for arugula. Interestingly, nitrate degradation started within 24 hr at 25 °C and after 4 days at 4 °C. At -20 °C and -80 °C, nitrate levels remained stable for one month. Total phenolics and free radical scavenging activity varied significantly during storage conditions. Beetroot juice at 25 °C, significant decrease in total phenolics and antioxidant activity was observed, whereas at 4, -20 and -80 °C, the levels remained relatively stable. By contrast, arugula juice at 25 and 4 °C, an increase in total phenolics and antioxidant activity were observed after one month. Furthermore, UPLC-HR-QTOF-MS analysis demonstrated that flavonoid glucosides were converted to their aglycones and lower phenolics, resulting in higher total phenolics and antioxidant activity during storage. In conclusion, beetroot and arugula juices required frozen conditions for long-term storage to prevent degradation of nitrate and to maintain their nutritional value. PRACTICAL APPLICATION: Beetroot and arugula juices have health-beneficial compounds such as nitrate and phenolics. Understanding the proper storage conditions can allow consumers to make informed choices that can help fresh juices to maintain their health promoting properties.

Production system influences volatile biomarkers in tomato.

INTRODUCTION: In recent years, growers have used various production types, including high-tunnel systems, to increase the yield of tomatoes (Lycopersicon esculentum). However, the effect of high-tunnel cultivation, in comparison to conventional open-field production, on aroma and flavor volatiles is not fully understood. OBJECTIVES: To optimize the extraction and quantification conditions for the analysis of tomato volatiles using headspace solid phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS), and study the effect of production systems on volatile profiles using metabolomics approach. METHODS: The HS-SPME conditions were optimized for extraction and GC-MS was used to quantify the volatiles from four tomato varieties grown in open-field and high-tunnel systems. Univariate and multivariate analyses were performed to identify the influence of production system on tomato volatiles. RESULTS AND CONCLUSIONS: The extraction of 2 g tomato samples at 60 °C for 45 min using divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fiber gave the maximum amounts of volatiles. This optimized method was used to identify and quantify 41 volatiles from four tomato varieties. The levels of ß-damascenone were higher in the high-tunnel tomatoes and geranylacetone was higher in open-field tomatoes. These two volatile compounds could be considered as biomarkers for tomatoes grown in high-tunnel and open-field production systems. This study is the first report comparing volatiles in tomatoes grown in high-tunnel and open-field conditions, and our results confirmed that there is a critical need to adopt biomarker-specific production systems to improve the nutritional and organoleptic properties of tomatoes.

Optimized method for the quantification of pyruvic acid in onions by microplate reader and confirmation by high resolution mass spectra.

The present study describes the rapid microplate method to determine pyruvic acid content in different varieties of onions. Onion juice was treated with 2,4-dinitrophenylhydrazine to obtain hydrazone, which was further treated with potassium hydroxide to get stable colored complex. The stability of potassium complex was enhanced up to two hours and the structures of hydrazones were confirmed by LC-MS for the first time. The developed method was optimized by testing different bases, acids with varying concentrations of dinitrophenyl hydrazine to get stable color and results were comparable to developed method. Repeatability and precision showed <9% relative standard deviation. Moreover, sweet onion juice was stored for four weeks at different temperatures for the stability; the pyruvate remained stable at all temperatures except at 25°C. Thus, the developed method has good potential to determine of pungency in large number of onions in a short time using minimal amount of reagents.

Rapid ultra-high-performance liquid chromatography/quadrupole time-of-flight tandem mass spectrometry and selected reaction monitoring strategy for the identification and quantification of minor spinacetin derivatives in spinach.

RATIONALE: Spinach is green leafy vegetable which is a rich source of flavonoids, phenolic acids, carotenoids, and vitamins A, C and E. It contains unique flavonoids which have significant anticarcinogenic, antiinflammatory and free radical scavenging activities. The present study reports the systematic identification and quantification of novel flavonoids by ultra-high-performance liquid chromatography with quadrupole time-of-flight tandem mass spectrometry (UHPLC/HR-QTOFMS). METHODS: An ultrasonication technique was used for the extraction of flavonoids from spinach. A rapid and reliable analytical method was established for the identification of flavonoids from methanolic extract. Flavonoids were characterized by their ultraviolet (UV) spectra, high-resolution accurate masses and MS/MS fragmentation pathways obtained using electrospray ionization (ESI). Furthermore, precursor ions from the intact molecule, and the resulting product ions, were monitored by selected reaction monitoring (SRM) with different collision energies in positive and negative ion mode. RESULTS: For the first time, five minor spinacetin derivatives were identified under optimized SRM and broadband collision-induced dissociation (+bbCID) conditions. Fragmentation pathways were proposed for spectra obtained in ESI positive ion mode. The use of HR-QTOFMS and SRM allowed us to differentiate between molecules with the same nominal mass. The identified spinacetin derivatives were found to be acylated with ferulic and coumaric acids. CONCLUSIONS: UHPLC interfaced with HR-QTOFMS in combination with SRM provides a rapid, reliable and highly sensitive method for the identification of flavonoids, and potentially other bioactive compounds, in a complex matrix.

Citrus nomilin down-regulates TNF-α-induced proliferation of aortic smooth muscle cells via apoptosis and inhibition of IκB.

Nomilin is a bitter compound present in citrus and has been demonstrated as useful for various disease preventions through anti-proliferative, anti-inflammatory, and pro-apoptotic activities. Although in vitro disease models have shown that certain limonoids in the p38 mitogen-activated protein kinase signal cascade, the downstream signaling pathways remain unclear. In this study, the effects of nomilin on the proliferation and apoptotic pathways of human aortic smooth muscle cells (HASMCs) that forms the basis of progression of atherosclerotic diseases and restenosis was tested for the first time. The cellular uptake level and stability of nomilin were determined by high-performance liquid chromatography and high-resolution mass spectra. Pretreatment of HASMCs with nomilin stimulated extrinsic caspase-8, intrinsic caspase-9, and apoptotic caspase-3 and resulted in significant inhibition of TNF-α-induced proliferation. Additionally, results showed a decreased ratio of anti-apoptotic Bcl-2 protein to pro-apoptotic Bax (Bcl2/Bax), indicating mitochondrial dysfunction consistent with apoptosis. Furthermore, nomilin significantly decreased the phosphorylation of IκBα, an inhibitor of NF-κB and subsequently, reduced the downstream inflammatory signaling in TNF-α treated HASMCs. Our findings indicate that the anti-proliferative activity of nomilin on TNF-α-induced HASMCs results from apoptosis through a mitochondrial-dependent pathway and suppression of inflammatory signaling mediated through NF-κB.

A metabolomics approach to identify and quantify the phytochemicals in watermelons by quantitative (1)HNMR.

Watermelon (Citrullus vulgaris) contains many health-promoting compounds, such as ascorbic acid, carotenoids, phenolic acids and amino acids including l-citrulline, arginine, and glutathione. Reported HPLC method for quantification of l-citrulline and sugars in watermelon involves, time-consuming sample preparation, post-column color development and detection with fluorescence and refractive index detectors. The present study describes development of a method to identify and quantify amino acids and sugars simultaneously from watermelon samples using quantitative proton NMR. Lyophilized watermelon samples (30-50mg) were extracted with deuterium oxide (D2O) by sonication and the centrifuged extract was directly used for quantification and identification with (1)HNMR. An external coaxial insert containing a 65µL of 0.012% 3-(trimethylsilyl) propionic-(2,2,3,3-d4) acid sodium salt (TSP-d4) in D2O was used as a quantitative reference. The levels of l-citrulline and sugars were measured in less than 6min. This rapid quantitation method was validated for specificity, linearity, accuracy, precision, reproducibility, and robustness. The limit of detection for l-citrulline was 38µg/mL and the limit of quantification was 71µg/mL; for sugars, the limits were 59-94µg/mL and 120µg/mL, respectively. This method can be used widely for confirmation and rapid quantitation of multiple compounds in large number of biological or breeding samples for routine analysis.

Polymethoxyflavones Isolated from the Peel of Miaray Mandarin (Citrus miaray) Have Biofilm Inhibitory Activity in Vibrio harveyi.

Citrus fruits are a good source of bioactive compounds with numerous beneficial biological activities. In the present study, fruits of the unexplored Miaray mandarin were used for the isolation of 10 bioactive compounds. Dried peels were sequentially extracted with hexane and chloroform in a Soxhlet-type apparatus for 8 h. The extracts were concentrated under vacuum and separated by flash chromatography to obtain nine polymethoxyflavones and a limonoid. The purity of each compound was analyzed by high-performance liquid chromatography (HPLC), and the compounds were identified by spectral analysis using MALDI-TOF-MS and NMR. The isolated compounds were identified as 5-hydroxy-3,7,3',4'-tetramethoxyflavone, 5,6,7,8,4'-pentamethoxyflavone (tangeretin), 3,5,6,7,8,3',4'-heptamethoxyflavone, 5,6,7,8,3',4'-hexamethoxyflavone (nobiletin), 3,5,7,8,3',4'-hexamethoxyflavone, 3,5,7,3',4'-pentamethoxyflavone (pentamethylquercetin), 5,7,4'-trimethoxyflavone, 5,7,8,4'-tetramethoxyflavone, 5,7,8,3',4'-pentamethoxyflavone, and limonin. These compounds were further tested for their ability to inhibit cell-cell signaling and biofilm formation in Vibrio harveyi. Among the evaluated polymethoxyflavones, 3,5,6,7,8,3',4'-heptamethoxyflavone and 3,5,7,8,3',4'-hexamethoxyflavone inhibited autoinducer-mediated cell-cell signaling and biofilm formation. These results suggest that Miaray mandarin fruits are a good source of polymethoxyflavones. This is the first report on the isolation of bioactive compounds from Miaray mandarin and evaluation of their biofilm inhibitory activity as well as isolation of pentamethylquercetin from the Citrus genus.

Ethylene degreening modulates health promoting phytochemicals in Rio Red grapefruit.

In the current study, we examined the effects of postharvest degreening and storage on phytochemicals in Rio Red grapefruit. Grapefruits were degreened with 3.5 µl/l of ethylene at 21 °C and 80% relative humidity for 72 h, while non-degreened fruits were used as the control. Furthermore, the grapefruits were stored at 11 °C for 3 weeks and then at 21 °C for 2 weeks. Degreening improved the peel colour of the grapefruit without affecting total soluble solids or acidity of the juice. Degreened fruits had significantly more ascorbic acid after 35 days of storage. Degreening had no significant effect on the levels of carotenoids, limonoids and flavonoids as compared to the non-degreened fruits, after 35 days of storage. However, after 7 days, degreened fruits had more limonin and flavonoids and less furocoumarin, namely 6',7'-dihydroxybergamottin. Overall, ethylene treatment had a significant effect on the phytochemical contents of Rio Red grapefruit, especially after 7 days of storage.