Determination of phenolic acids and flavonoids of apple and pear by high-performance liquid chromatography

Strawberry Achenes Are an Important Source of Bioactive Compounds for Human Health

Strawberries are highly appreciated for their taste, nutritional value and antioxidant compounds, mainly phenolics. Fruit antioxidants derive from achenes and flesh, but achene contribution to the total fruit antioxidant capacity and to the bioaccessibility after intake is still unknown. In this work, the content of total phenolic compounds, flavonoids, anthocyanins and antioxidant capacity (TEAC, FRAP and DPPH) of achenes and flesh were compared in non-digested as well as in gastric and intestinal extracts after in vitro digestion. Results showed that, despite strawberry achenes represent a small fraction of the fruit, their contribution to total fruit antioxidant content was more than 41% and accounted for 81% of antioxidant capacity (TEAC). Achenes have higher quantity and different quality of antioxidants in non-digested and digested extracts. Antioxidant release was higher in the in vitro gastric digested extracts, but digestion conditions did not only affect quantity but quality, resulting in differences in antioxidant capacity and highlighting the importance of simulating physiological-like extraction conditions for assessing fruit antioxidant properties on human health. These results give new insights into the use of strawberry achenes as a source of bioactive compounds to be considered in strawberry breeding programs for improving human health.

Comparison of different drying methods on Chinese ginger (Zingiber officinale Roscoe): Changes in volatiles, chemical profile, antioxidant properties, and microstructure

Nowadays, food industry is facing challenges in preserving better quality of fruit and vegetable products after processing. Recently, many attentions have been drawn to ginger rhizome processing due to its numerous health promoting properties. In our study, ginger rhizome slices were subjected to air-drying (AD), freeze drying (FD), infrared drying (IR), microwave drying (MD) and intermittent microwave & convective drying (IM&CD). Quality attributes of the dried samples were compared in terms of volatile compounds, 6, 8, 10-gingerols, 6-shogaol, antioxidant activities and microstructure. Results showed that AD and IR were good drying methods to preserve volatiles. FD, IR and IM&CD led to higher retention of gingerols, TPC, TFC and better antioxidant activities. However, FD and IR had relative high energy consumption and drying time. Therefore, considering about the quality retention and energy consumption, IM&CD would be very promising for thermo sensitive material.

Fruit Intake and Abdominal Aortic Calcification in Elderly Women: A Prospective Cohort Study

Cardiovascular disease (CVD) is the leading cause of death worldwide. There is a consistent inverse relationship between fruit intake with CVD events and mortality in cross-sectional and prospective observational studies, but the relationship of fruit intake with measurements of atherosclerosis in humans is less clear. Nutritional effects on abdominal aortic calcification (AAC), a marker for subclinical intimal and medial atherosclerotic vascular disease, have not been studied previously. The aim of this study was to examine the cross-sectional relationship of total and individual fruit (apple, pear, orange and other citrus, and banana) intake with AAC, scored between 0 and 24. The current study assessed baseline data for a cohort of 1052 women over 70 years of age who completed both a food frequency questionnaire assessing fruit intake, and underwent AAC measurement using dual energy X-ray absorptiometry. AAC scores were significantly negatively correlated with total fruit and apple intakes (p < 0.05), but not with pear, orange or banana intakes (p > 0.25). In multivariable-adjusted logistic regression, each standard deviation (SD; 50 g/day) increase in apple intake was associated with a 24% lower odds of having severe AAC (AAC score >5) (odd ratio OR): 0.76 (0.62, 0.93), p = 0.009). Total and other individual fruit intake were not associated with increased odds of having severe AAC. Apple but not total or other fruit intake is independently negatively associated with AAC in older women.

Injection-port derivatization coupled to GC-MS/MS for the analysis of glycosylated and non-glycosylated polyphenols in fruit samples

Polyphenols, including glycosylated polyphenols, were analyzed via a procedure based on injection-port derivatization coupled to gas chromatography-tandem mass spectrometry (GC-MS/MS). The polyphenols in lyophilized fruit samples were extracted with an acidified MeOH mixture assisted by ultrasound. Samples were dried under vacuum, and carbonyl groups were protected with methoxylamine. Free hydroxyl groups were subsequently silylated in-port. Mass fragmentations of 17 polyphenol and glycosylated polyphenol standards were examined using Multiple Reaction Monitoring (MRM) as the acquisition mode. Furthermore, in-port derivatization was optimized in terms of optimal injection port temperature, derivatization time and sample: N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA) volume ratio. A C18 solid-phase-extraction clean-up method was used to reduce matrix effects and injection liner degradation. Using this clean-up method, recoveries for samples spiked at 1 and 10μg/g ranged from 52% to 98%, depending on the chemical compound. Finally, the method was applied to real fruit samples containing the target compounds. The complete chromatographic runtime was 15min, which is faster than reported for recent HPLC methods able to analyze similar compounds.

Potential Prophylactic Properties of Apple and Characterization of Potent Bioactive from cv. "Granny Smith" Displaying Strong Antimutagenicity in Models Including Human Lymphoblast TK6(+/-) Cell Line

Potential prophylactic attributes in terms of antimutagenicity, antioxidant, and radioprotective properties were evaluated for 8 common apple cultivars namely "Fuji," "Golden Delicious," "Granny Smith," "Ambri Kashmiri," "Kinnaur," "Red Delicious," "Royal Gala," and "Shimla," where cultivar based significant variation was observed. Cv. "Granny Smith" displayed significantly higher and broad spectrum antimutagenicity in Escherichia coli rpoB based rifampicin resistance (Rif(R) ) assay, whereas, "Ambri Kashmiri," "Royal Gala," and "Shimla" showed lower antimutagenicity. Cultivars "Ambri Kashmiri," "Kinnaur," and "Red Delicious" exhibited strong antioxidant activity than cv. "Granny Smith" as assayed by radical scavenging, reducing potential and radioprotective property assays. The antioxidant and radioprotective properties were found to be better correlated than antimutagenicity. Suppression of error-prone DNA repair pathway (such as E. coli SOS response) was found to be one of the possible mechanisms contributing to its antimutagenicity. Phenolic extract of "Granny Smithˮ showing higher antimutagenicity was HPLC purified and the bioactive fraction (tR 35.4 min) contributing maximally (∼80%) to the observed antimutagenicity was identified as procyanidin dimer (PD) by ESI-MS/MS. The above observed antimutagenicity in bacterial assay system was well reproduced in Thymidine Kinase Mutation (TKM) assay performed using human lymphoblast cell line (TK6(+/-) ) cell line making the findings more prophylactically relevant.

Altered Phenylpropanoid Metabolism in the Maize Lc-Expressed Sweet Potato (Ipomoea batatas) Affects Storage Root Development

There is no direct evidence of the effect of lignin metabolism on early storage root development in sweet potato. In this study, we found that heterologous expression of the maize leaf color (Lc) gene in sweet potato increased anthocyanin pigment accumulation in the whole plant and resulted in reduced size with an increased length/width ratio, low yield and less starch content in the early storage roots. RT-PCR analysis revealed dramatic up-regulation of the genes involved in the lignin biosynthesis pathway in developing storage roots, leading to greater lignin content in the Lc transgenic lines, compared to the wild type. This was also evidenced by the enhanced lignification of vascular cells in the early storage roots. Furthermore, increased expression of the β-amylase gene in leaves and storage roots also accelerated starch degradation and increased the sugar use efficiency, providing more energy and carbohydrate sources for lignin biosynthesis in the Lc transgenic sweet potato. Lesser starch accumulation was observed in the developing storage roots at the initiation stage in the Lc plants. Our study provides experimental evidence of the basic carbohydrate metabolism underlying the development of storage roots, which is the transformation of lignin biosynthesis to starch biosynthesis.

An electrochemical biosensing platform based on 1-formylpyrene functionalized reduced graphene oxide for sensitive determination of phenol

A novel electrochemical biosensing platform is proposed. New tyrosinase-based biosensor can be used to detect phenols.

Economical and environmentally-friendly approaches for usage of onion (Allium cepa L.) waste

General anatomy and different layers in onion.

Quercetin and the mitochondria: A mechanistic view

Quercetin is an important flavonoid that is ubiquitously present in the diet in a variety of fruits and vegetables. It has been traditionally viewed as a potent antioxidant and anti-inflammatory molecule. However, recent studies have suggested that quercetin may exert its beneficial effects independent of its free radical-scavenging properties. Attention has been placed on the effect of quercetin on an array of mitochondrial processes. Quercetin is now recognized as a phytochemical that can modulate pathways associated with mitochondrial biogenesis, mitochondrial membrane potential, oxidative respiration and ATP anabolism, intra-mitochondrial redox status, and subsequently, mitochondria-induced apoptosis. The present review evaluates recent evidence on the ability of quercetin to interact with the abovementioned pathways, and critically analyses how, such interactions can exert protection against mitochondrial damage in response to toxicity induced by several exogenously and endogenously-produced cellular stressors, and oxidative stress in particular.

Impact of dehydration of purslane on retention of bioactive molecules and antioxidant activity

Purslane (Portulaca oleracea L.) has several health benefits, such as it reduces risk of CVD, obesity and diabetes. The objective of the study was to investigate the effect of different drying on retention of bioactive molecules, such as omega-3 fatty acids, total phenolic content and antiradical activity of purslane. Five different dehydration methods including microwave (100 MW, 5 min), tray, vacuum, low temperature low humidity, infrared were used at 55-60 °C for 5-7 h for dehydration of purslane. Three solvents, viz. water, ethanol and methanol were used for extraction of bioactive molecules from purslane. Total polyphenol content, antiradical activity and rehydration ratio of the bioactive molecules were determined. Results revealed that total PUFA, α-linolenic acid (ALA), total polyphenol content and antiradical activity were found to retain in the dried purslane in the range of (47.9-59.9 %), (42.5-50 %), (188-408GAE/100 g) and (33.0-88.8 mg/100 g) respectively. The highest values of ALA, total polyphenol content and antiradical activity were found to obtain in the vacuum dried sample. Rehydration ratio was found in the range of 3.2-4.3 and vacuum dried purslane showed maximum rehydration. It could be concluded that vacuum dehydration of purslane is an effective method for retention of bioactive molecules and good rehydration behaviour of dried purslane.

Functional identification of organic cation transporter 1 as an atenolol transporter sensitive to flavonoids

Atenolol, a β1-adrenergic receptor blocker, is administered orally and its intestinal absorption has recently been indicated to be mediated by carrier protein and reduced markedly by ingestion of some fruit juices, such as apple and orange juices. This could be postulated to be a problem arising from the interaction of some components of fruit juices with atenolol at a transporter involved in its intestinal uptake, but the responsible transporter and its interacting components have not been identified yet. In an attempt to examine that possibility, we could successfully find that human organic cation transporter 1 (OCT1/SLC22A1), which is suggested to be expressed at the brush border membrane of enterocytes, is highly capable of transporting atenolol. In this attempt, OCT1 was stably expressed in Madin-Darby canine kidney II cells and the specific uptake of atenolol by the transporter was found to be saturable, conforming to the Michaelis-Menten kinetics with the maximum transport rate (V_max) of 4.00 nmol/min/mg protein and the Michaelis constant (K_m) of 3.08 mM. Furthermore, the OCT1-specific uptake was found to be inhibited by various flavonoids, including those contained in fruit juices that have been suggested to interfere with intestinal atenolol absorption. Particularly, phloretin and quercetin, which are major components of apple juice, were potent in inhibiting OCT1-mediated atenolol transport with the inhibition constants of 38.0 and 48.0 µM, respectively. It is also notable that the inhibition by these flavonoids was of the noncompetitive type. These results indicate that OCT1 is an atenolol transporter that may be involved in intestinal atenolol uptake and sensitive to fruit juices, although its physiological and clinical relevance remains to be further examined.

•

We explored an atenolol transporter from among the cation or anion transporters.

•

OCT1 expressed on apical side in enterocytes has transport activity of atenolol.

•

Transport of atenolol by OCT1 is inhibited by flavonoids.

•

Phloretin and quercetin noncompetitively inhibit OCT1-mediated atenolol transport.

Phytochemical Characterization of Chinese Bayberry (Myrica rubra Sieb. et Zucc.) of 17 Cultivars and Their Antioxidant Properties

In order to fully understand the variations of fruit quality-related phytochemical composition in Chinese bayberry (Myrica rubra Sieb. et Zucc.), mature fruit of 17 cultivars from Zhejiang and Jiangsu provinces was used for the investigation of fruit quality attributes, including fruit color, soluble sugars, organic acids, total phenolics, flavonoids, antioxidant capacity, etc. Sucrose was the main soluble sugar, while citric acid was the main organic acid in bayberry fruit. The content of total phenolics and total flavonoids were positively correlated with 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) antioxidant activity and 2,2ʹ-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging activity. Five anthocyanidins, i.e., delphinidin–hexoside (Dp–Hex), cyanidin-3–O-galactoside (C-3–Gal), cyanidin-3–O-glucoside (C-3–Glu), pelargonidin-3–O-glucoside (Pg-3–Glu) and peonidin-3-O-glucoside (Pn-3–Glu), and seven flavonols compounds, i.e., myricetin-3-O-rhamnoside (M-3–Rha), myricetin deoxyhexoside–gallate (M-DH–G), quercetin-3-O-galactoside (Q-3–Gal), quercetin-3–O-glucoside (Q-3–Glu), quercetin-3–O-rhamnoside (Q-3–Rha), kaempferol-3–O-galactoside (K-3–Gal) and kaempferol-3–O-glucoside (K-3–Glu), were identified and characterized among the cultivars. The significant differences in phytochemical compositions among cultivars reflect the diversity in bayberry germplasm, and cultivars of good flavor and/or rich in various health-promoting phytochemicals are good candidates for future genetic breeding of bayberry fruit of high quality. In conclusion, our results may provide important information for further breeding or industrial utilization of different bayberry resources.

Identification of proanthocyanidins from litchi (Litchi chinensis Sonn.) pulp by LC-ESI-Q-TOF-MS and their antioxidant activity

Content of total proanthocyanidins as well as total phenolics, flavonoids, antioxidant activities were evaluated for litchi (Litchi chinensis Sonn.) pulp of 32 cultivars. One cultivar, Hemaoli, showed the highest total proanthocyanidins and total phenolics, and DPPH or ABTS radical scavenging activities. ESI-MS and NMR analysis of the Hemaoli pulp crude extracts (HPCE) showed that procyandins composed of (epi)catechin unites with degree of polymerization (DP) of 2–6 were dominant proanthocyanidins in HPCE. After the HPCE was fractionated by a Sephadex LH-20 column, 32 procyanidins were identified by LC-ESI-Q-TOF-MS in litchi pulp for the first time. Quantification of individual procyanidin in HPCE indicated that epicatechin, procyanidin B2, procyanidin C1 and A-type procyanidin trimer were the main procyanidins. The radical scavenging activities of different fractions of HPCE as well as six procyanidins standards were evaluated by both DPPH and ABTS assays. HPCE fractions showed similar antioxidant activities with those of Vc and six individual procyanidins, the IC₅₀ of which ranged from 1.88 ± 0.01 to 2.82 ± 0.10 μg/ml for DPPH assay, and from 1.52 ± 0.17 to 2.71 ± 0.15 μg/ml for ABTS assay. Such results indicate that litchi cultivars rich in proanthocyanidins are good resources of dietary antioxidants and have the potential to contribute to human health.

Polyphenols as active ingredients for cosmetic products

Polyphenols are secondary plant metabolites with antioxidant, anti-inflammatory and anti-microbial activity. They are ubiquitously distributed in the plant kingdom; high amounts contain, for example, green tea and grape seeds. Polyphenolic extracts are attractive ingredients for cosmetics and pharmacy due to their beneficial biological properties. This review summarizes the effects of polyphenols in the context of anti-ageing activity. We have explored in vitro studies, which investigate antioxidant activity, inhibition of dermal proteases and photoprotective activity, mostly studied using dermal fibroblasts or epidermal keratinocytes cell lines. Possible negative effects of polyphenols were also discussed. Further, some physicochemical aspects, namely the possible interactions with emulsifiers and the influence of the cosmetic formulation on the skin delivery, were reported. Finally, few clinical studies, which cover the anti-ageing action of polyphenols on the skin after topical application, were reviewed.

Recovery potential of cold press byproducts obtained from the edible oil industry: physicochemical, bioactive, and antimicrobial properties

Physicochemical, bioactive, and antimicrobial properties of different cold press edible oil byproducts (almond (AOB), walnut (WOB), pomegranate (POB), and grape (GOB)) were investigated. Oil, protein, and crude fiber content of the byproducts were found between 4.82 and 12.57%, between 9.38 and 49.05%, and between 5.87 and 45.83%, respectively. GOB had very high crude fiber content; therefore, it may have potential for use as a new dietary fiber source in the food industry. As GOB, POB, and WOB oils were rich in polyunsaturated fatty acids, AOB was rich in monounsaturated fatty acids. Oil byproducts were also found to be rich in dietary mineral contents, especially potassium, calcium, phosphorus, and magnesium. WOB had highest total phenolic (802 ppm), flavonoid (216 ppm), and total hydrolyzed tannin (2185 ppm) contents among the other byproducts. Volatile compounds of all the byproducts are mainly composed of terpenes in concentration of approximately 95%. Limonene was the dominant volatile compound in all of the byproducts. Almond and pomegranate byproduct extracts showed antibacterial activity depending on their concentration, whereas those of walnut and grape byproducts showed no antibacterial activity against any pathogenic bacteria tested. According to the results of the present study, walnut, almond, pomegranate, and grape seed oil byproducts possess valuable properties that can be taken into consideration for improvement of nutritional and functional properties of many food products.

Acute anti-hyperglycaemic effects of an unripe apple preparation containing phlorizin in healthy volunteers: a preliminary study

BACKGROUND

The health-promoting properties of apples are directly related to the biologically active compounds that they contain, such as polyphenols. The objective of this study was to prepare a low-sugar, fibre- and phlorizin-enriched powder from unripe apples and to gain insight regarding its anti-hyperglycaemic activity in healthy volunteers.

RESULTS

The unripe apples (Malus domestica Borkh.) were collected 30 days after the full bloom day; blanched and pressed to obtain apple pomace which was then processed with a food cutter, oven-dried and milled to prepare apple powder. The concentrations of total sugars, water-soluble pectin and phlorizin in the apple preparation were 153.44 ± 2.46, 27.73 ± 0.51 and 12.61 ± 0.15 g kg(-1), respectively. Acute ingestion of the apple preparation improved glucose metabolism in the oral glucose tolerance test (OGTT) in six healthy volunteers by reducing the postprandial glucose response at 15 to 30 min by approximately two-fold (P < 0.05) and by increasing urinary glucose excretion during the 2- to 4-h interval of the OGTT by five-fold (P < 0.05).

CONCLUSION

The results obtained indicate that the dried and powdered pomace of unripe apples can be used as a health-promoting natural product for the reduction of postprandial glycaemia and to improve the health of patients with diabetes.

Improvement of Analytical Methods for the Determination of Polyphenolic Bioactive Compounds in Berry Fruits

Berry fruits contain high levels of different phytochemicals, most of which are phenolic molecules. Fruits of the same cultivar from different locations and different harvest years have different chemical compositions, particularly related to polyphenols. The difference may be due to specific climatic conditions, the type of soil in which the plants grow, and the stresses to which the plants were subjected because these phytochemicals are produced as a defense mechanism through a secondary metabolic process. For this reason, it is important to establish simple and reliable procedure to determine polyphenolic compounds in berry fruits considering the increasing attention on these compounds for different potential uses. In order to choose and to improve the most adequate analytical procedure for the determination of the polyphenolic substances in berry fruits, different methods were applied and compared on samples of elderberry and blackberry.

Ingredients in fruit juices interact with dasatinib through inhibition of BCRP: a new mechanism of beverage-drug interaction

Small molecule tyrosine kinase inhibitors (TKIs) are a group of highly novel and target-specific anticancer drugs. Recently, most TKIs are found to be substrates of P-glycoprotein (P-gp) and Breast Cancer Resistance Protein (BCRP). However, little information is available regarding the Pgp- or BCRP-mediated interaction of TKIs with coadministered drugs/food/beverage. Our objective was to evaluate the effect of the major ingredients of grapefruit juice (GFJ), orange juice (OJ), apple juice (AJ), and green tea on P-gp and BCRP-mediated dasatinib efflux. Among the 14 ingredients screened, only tangeretin and nobiletin moderately inhibited P-gp-mediated dasatinib efflux. In contrast, four ingredients in GFJ [i.e., bergamottin, 6',7'-dihydroxybergamottin (DHB), quercetin, and kaempferol], two ingredients in OJ (tangeretin and nobiletin), and one ingredient in AJ (i.e., hesperetin) greatly inhibited BCRP-mediated dasatinib efflux at the concentration of 50 μM (p < 0.001). Further concentration-dependent studies revealed that bergamottin, DHB, tangeretin, and nobiletin are potent BCRP inhibitors, with IC₅₀ values 3.19, 5.2, 1.19, and 1.04 μM, respectively. Further in vivo investigations are warranted to evaluate the BCRP-mediated FJ-TKI interaction. Literature reports only documented the modulatory effect of FJ and green tea on CYP3A, P-gp, and OATP. Our novel finding that FJ ingredients strongly inhibit BCRP may represent a new mechanism of beverage-drug interaction.

Direct Identification and Characterization of Phenolic Compounds from Crude Extracts of Buds and Internodes of Grapevine (Vitis vinifera cv Merlot)

The crude methanol extracts of latent buds and internodes Vitis vinifera L. cv. Merlot were used for the determination of phenolic compounds by a combination of reverse phase HPLC with diode array detection (HPLC-DAD) and mass spectrometry (LC-MS). This method allowed the identification of 9 phenolic compounds without purification or fractionation. These 9 compounds were divided into three groups: procyanidins, flavonols and stilbenes. Detection by HPLC-DAD at different wave lengths of 280 nm to 320 nm, allowed the estimation of concentrations of those compounds. This method permitted, for the first time, both characterization and quantification of polyphenolic compounds in buds of grapevine. Comparison with the results obtained in internodes showed that quercetin, resveratrol tetramer and ε-viniferin had similar levels in buds and internodes while six other compounds identified had higher levels in buds.

Evolution of polyphenols and organic acids during the fermentation of apple cider

BACKGROUND

Polyphenols and organic acids are important constitutes in the cider because they greatly contribute to organoleptic quality. The determination of their changes is important for monitoring the fermentation process for purposes of quality control. In this study, the evolution of polyphenols and organic acids was monitored throughout the cider fermentation process. The samples were taken periodically and the polyphenols and organic acids contents were determined using HPLC methods.

RESULTS

The contents of polyphenols and organic acids were in constant change. After fermentation, the content of (+)-catechin, (-)-epicatechin, chlorogenic acid, cinnamic acid, p-coumaric acid, gallic acid, caffeic acid, ferulic acid, rutin and phloridzin decreased by different degrees, while protocatechuic acid increased after fermentation. The content of organic acids was also affected by fermentation. Malic acid, lactic acid, quinic acid, pyruvic acid and citric acid showed different levels of increase, but succinic acid content decreased.

CONCLUSIONS

The contents of polyphenols and organic acids were affected by fermentation. Their changing profiles during fermentation process were dependent on the type of phenolic compounds and organic acids studied.

Evaluation of physicochemical properties and intestinal permeability of six dietary polyphenols in human intestinal colon adenocarcinoma Caco-2 cells

Phenolic compounds are common ingredients in many dietary supplements and functional foods. However, data concerning physicochemical properties and permeability of polyphenols on the intestinal epithelial cells are scarce. The aims of this study were to determine the experimental partition coefficient (Log P), and parallel artificial membrane permeability assay (PAMPA), to characterize the bi-directional transport of six phenolic compounds viz. caffeic acid, chrysin, gallic acid, quercetin, resveratrol and rutin in Caco-2 cells. The experimental Log P values of six polyphenols were correlated (R (2) = 0.92) well with the calculated Log P values. The apparent permeability (P app) range of all polyphenols in PAMPA for the apical (AP) to basolateral (BL) was 1.18 ± 0.05 × 10(-6) to 5.90 ± 0.16 × 10(-6) cm/s. The apparent Caco-2 permeability (P app) range for the AP-BL was 0.96 ± 0.03 × 10(-6) to 3.80 ± 0.45 × 10(-6) cm/s. The efflux ratio of P app (BL → AP) to P app (AP → BL) for all phenolics was <2, suggesting greater permeability in the absorptive direction. Six compounds exhibited strong correlations between Log P and PAMPA/Caco-2 cell monolayer permeation data. Dietary six polyphenols were poorly absorbed through PAMPA and Caco-2 cells, and their transepithelial transports were mainly by passive diffusion.

Characterisation of phenolic compounds in processed fibres from the juice industry

The content of phenolic compounds was determined in nine industrially processed fibres derived from the juice industry. Apple, peach, and pear as non-citrus fruit fibres were examined, as well as orange peel and flesh, tangerine peel and flesh, and lemon flesh as citrus fruit fibres, and carrot as vegetable fibre. The extractable phenolic profile of all fibres was obtained by UPLC-PDA-FLR-MS/MS. Forty phenolic compounds were identified and their concentrations determined. In addition, bound phenolic acids and proanthocyanidins were measured in solid residues in order to determine the phenolic compounds remaining. Also, to allow the comparison of the profiles and contents in the fresh fruit and fibres, we analysed extractable and bound phenolic compounds in lyophilized peel and pulp from fresh fruit. The profile and phenolic content of the fibres was similar to that of the fresh fruit, except for flavan-3-ols, which registered lower values.

Flavonoid compositions and antioxidant activity of calamondin extracts prepared using different solvents

Calamondin has been demonstrated to exhibit antioxidant function and tyrosinase inhibitory activity, which might be attributed to its flavonoid compounds. To improve their application, the flavonoid compositions and antioxidant activity of calamondin extracts, prepared by different solvents, were investigated. The results showed that total phenolic and flavonoid contents of extracts from peel of calamondin were higher than that from pulp, except the flavonoid content in hot water extract. The flavonoids found in extracts of calamondin were 3′, 5′-di-C-β-glucopyranosylphloretin (DGPP), naringin, hesperidin, nobiletin, tangeretin, and diosmin. DGPP exhibited the highest quantity, while naringin and hesperidin were the other two major flavonoids. The content of DGPP in hot water extract of peel was higher than in extracts of organic solvents, however, the contents of nobiletin and tangeretin were found only in extracts of organic solvents. The highest levels of total flavonoids and DGPP were obtained in hot water extract from peel at 90°C. The extracts of hot water and ethyl acetate showed higher 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging potency than that of ethanol and methanol. A positive relationship existed between total phenolic contents and DPPH scavenging potency (p < 0.01), while total flavonoid compositions also showed correlation (p < 0.05). Thus, DGPP, naringin, and hesperidin might contribute to antioxidant activity. Collectively, the hot water extract of calamondin peel might have potential for health food and cosmetic applications due to its good antioxidant activity and high level of DGPP.

Analysis of phenolic acids of Jerusalem artichoke (Helianthus tuberosus L.) responding to salt-stress by liquid chromatography/tandem mass spectrometry

Plant phenolics can have applications in pharmaceutical and other industries. To identify and quantify the phenolic compounds in Helianthus tuberosus leaves, qualitative analysis was performed by a reversed phase high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) and quantitative analysis by HPLC. Ten chlorogenic acids (CGAs) were identified (3-o-caffeoylquinic acid, two isomers of caffeoylquinic acid, caffeic acid, p-coumaroyl-quinic acid, feruloylquinic acid, 3,4-dicaffeoyquinic acid, 3,5-dicaffeoylquinic acid, 1,5-dicaffeoylquinic acid, and 4,5-dicaffeoylquinic acid) by comparing their retention times, UV-Vis absorption spectra, and MS/MS spectra with standards. In addition, four other phenolic compounds, including caffeoyl glucopyranose, isorhamnetin glucoside, kaempferol glucuronide, and kaempferol-3-o-glucoside, were tentatively identified in Helianthus tuberosus leaves for the first time. The 3-o-caffeoylquinic acid (7.752 mg/g DW), 4,5-dicaffeoylquinic acid (5.633 mg/g DW), and 3,5-dicaffeoylquinic acid (4.900 mg/g DW) were the major phenolic compounds in leaves of Helianthus tuberosus cultivar NanYu in maturity. The variations in phenolic concentrations and proportions in Helianthus tuberosus leaves were influenced by genotype and plant growth stage. Cultivar NanYu had the highest concentration of phenolic compounds, in particular 3-o-caffeoylquinic acid and 4,5-dicaffeoylquinic acid compared with the other genotypes (wild accession and QingYu). Considering various growth stages, the concentration of total phenolics in cultivar NanYu was higher at flowering stage (5.270 mg/g DW) than at budding and tuber swelling stages. Cultivar NanYu of Helianthus tuberosus is a potential source of natural phenolics that may play an important role in the development of pharmaceuticals.