Studies into the phenolic patterns of different tissues of pineapple (Ananas comosus [L.] Merr.) infructescence by HPLC-DAD-ESI-MS (n) and GC-MS analysis

It Is Not All about Alkaloids-Overlooked Secondary Constituents in Roots and Rhizomes of Gelsemium sempervirens (L.) J.St.-Hil

Gelsemium sempervirens (L.) J.St.-Hil. is an evergreen shrub occurring naturally in North and Middle America. So far, more than 120 alkaloids have been identified in this plant in addition to steroids, coumarins and iridoids, and its use in traditional medicine has been traced back to these compound classes. However, a comprehensive phytochemical investigation of the plant with a special focus on further compound classes has not yet been performed. Therefore, the present study aimed at an extensive HPLC-MSn characterization of secondary metabolites and, for the first time, reports the occurrence of various depsides and phenolic glycerides in G. sempervirens roots and rhizomes, consisting of benzoic and cinnamic acid derivatives as well as dicarboxylic acids. Furthermore, mono- and disaccharides were assigned by GC-MS. Applying the Folin-Ciocalteu assay, the phenolic content of extracts obtained with different solvents was estimated to range from 30 to 50% calculated as chlorogenic acid equivalents per g dry weight and was related to the DPPH radical scavenging activity of the respective extracts. Upon lactic acid fermentation of aqueous G. sempervirens extracts, degradation of phenolic esters was observed going along with the formation of low-molecular volatile metabolites.

Solid-State Fermented Pineapple Peel: A Novel Food Ingredient with Antioxidant and Anti-Inflammatory Properties

It has been reported that pineapple (Ananas comosus) contains healthy nutrients and phytochemicals associated with antioxidant and anti-inflammatory capacities. However, a substantial amount of pineapple residue is produced due to a lack of valorization applications at the industrial scale, resulting in the loss of valuable nutrients. Solid-state fermentation (SSF) is proposed as an innovative strategy to enhance the release of bound phenolics from pineapple residues. In this work, the effects of SSF of pineapple peels with Lactobacillus plantarum, Lactobacillus rhamnosus, and Aspergillus oryzae on the release of phenolic compounds and their antioxidant and anti-inflammatory activities were evaluated, respectively. Pineapple peel extracts after SSF showed an increase in the release of phenolic compounds (248.11% with L. plantarum, 182% with A. oryzae, and 180.10% with L. rhamnosus), which led to an increase in the cellular antioxidant (81.94% with L. rhamnosus) and anti-inflammatory potential (nitric oxide inhibition of 62% with L. rhamnosus) compared to non-fermented extracts. Therefore, SSF of pineapple peels with L. plantarum, L. rhamnosus, and A. oryzae thrives as a new approach for the production of secondary metabolites with remarkable biological benefits, which can be the precursors for novel biofortified and nutraceutical-enriched foods that meet the needs of the most demanding and health-conscious consumers.

Changes in the chemical compositions and biological properties of kombucha beverages made from black teas and pineapple peels and cores

Several raw materials have been used as partial supplements or entire replacements for the main ingredients of kombucha to improve the biological properties of the resulting kombucha beverage. This study used pineapple peels and cores (PPC), byproducts of pineapple processing, as alternative raw materials instead of sugar for kombucha production. Kombuchas were produced from fusions of black tea and PPC at different ratios, and their chemical profiles and biological properties, including antioxidant and antimicrobial activities, were determined and compared with the control kombucha without PPC supplementation. The results showed that PPC contained high amounts of beneficial substances, including sugars, polyphenols, organic acids, vitamins, and minerals. An analysis of the microbial community in a kombucha SCOBY (Symbiotic Cultures of Bacteria and Yeasts) using next-generation sequencing revealed that Acetobacter and Komagataeibacter were the most predominant acetic acid bacteria. Furthermore, Dekkera and Bacillus were also the prominent yeast and bacteria in the kombucha SCOBY. A comparative analysis was performed for kombucha products fermented using black tea and a fusion of black tea and PPC, and the results revealed that the kombucha made from the black tea and PPC infusion exhibited a higher total phenolic content and antioxidant activity than the control kombucha. The antimicrobial properties of the kombucha products made from black tea and the PPC infusion were also greater than those of the control. Several volatile compounds that contributed to the flavor, aroma, and beneficial health properties, such as esters, carboxylic acids, phenols, alcohols, aldehydes, and ketones, were detected in kombucha products made from a fusion of black tea and PPC. This study shows that PPC exhibits high potential as a supplement to the raw material infusion used with black tea for functional kombucha production.

Assessment of metabolic, mineral, and cytotoxic profile in pineapple leaves of different commercial varieties: A new eco-friendly and inexpensive source of bioactive compounds

Pineapple is among the most produced and consumed fruits worldwide, and consequently, its agroindustrial production/processing generates high amounts of agricultural waste, which are routinely discarded. Thus, it is crucial to seek alternatives to reuse this agricultural waste that are in high availability. Therefore, this work aims to evaluate the chemical composition of a specific residue (leaves) of seven commercial varieties of pineapples, to attribute high added value uses, and to evaluate its potential as a source of secondary metabolites and minerals. Thereby, twenty-eight metabolites were annotated by UPLC-QTOF-MS^E, including amino acids, organic acids, and phenolic compounds. The following minerals were quantitatively assessed by ICP-OES: Zn (5.30-19.77 mg kg^-1), Cr, Cd, Mn (50.80-113.98 mg kg^-1), Cu (1.05-4.01 mg kg^-1), P (1030.77-6163.63 mg kg^-1) and Fe (9.06-70.17 mg kg^-1). In addition, Cr and Cd (toxic materials) present concentration levels below the limit of quantification of the analytical method (LOQ_Cr and LOQ_Cd = 0.02 mg kg^-1) for all samples. The multivariate analysis was conceived from the chemical profile, through the tools of PCA (principal component analysis) and HCA (hierarchical cluster analysis). The results show that pineapple leaves have similarities and differences concerning their chemical composition. In addition, the cytotoxicity assays of the extracts against tumor and non-tumor strains shows that the extracts were non-toxic. This fact can corroborate and enhance the prospection of new uses and applications of agroindustrial co-products from pineapple, enabling the evaluation and use in different types of industries, such as pharmacological, cosmetic, and food, in addition to the possibility of being a potential source of bioactive compounds.

In search of cytotoxic selectivity on cancer cells with biogenically synthesized Ag/AgCl nanoparticles

Green synthesis may be a useful approach to achieve selective cytotoxicity of silver nanoparticles on cancer cells and healthy cells. In this study, the concomitant biosynthesis of silver (Ag)/silver chloride (AgCl) nanoparticles from pineapple peel extracts and their behavior on the breast cancer cell line MCF-7 is shown. Bioreactions were monitored at different temperatures. Fourier-transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-vis), thermogravimetric analysis (TGA), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM) techniques were used to characterize nanoparticle development. The breast cancer cell line MCF-7 was used as a test model to study the cytotoxic behavior of Ag/AgCl nanoparticles and, as a counterpart, the nanoparticles were also tested on mononuclear cells. Ag/AgCl nanoparticles with spherical and triangular morphology were obtained. The size of the nanoparticles (10-70 nm) and the size distribution depended on the reaction temperature. A dose close to 20 µg/mL of Ag/AgCl nanoparticles considerably decreased the cell viability of the MCF-7 line. The best cytotoxicity effects on cancer cells were obtained with nanoparticles at 60 and 80 °C where cell viability was reduced up to 80% at a concentration of 50 µg/mL. A significant preference was observed in the cytotoxic effect of Ag/AgCl nanoparticles against cancer cells in comparison to monocytes.

Pineapple by-products as a source of bioactive compounds with potential for industrial food application

Pineapple is a tropical fruit consumed fresh or processed into various food products. However, the peel and crown of this fruit are not industrially exploited, thus generating tons of by-products that represent an economic and environmental concern. In order to promote the upcycling of these by-products, this work aimed to characterize the phenolic profile of its hydroethanolic extracts obtained from pineapple peel and crown leaves and to evaluate their in vitro bioactivity. The HPLC-DAD-ESI/MS analysis allowed the identification of 25 phenolic compounds, including phenolic acids and flavonoids. The antioxidant, cytotoxic, and antimicrobial activity assays highlighted the peel extract as the most promising and, therefore, it was incorporated into a traditional Portuguese pastry cake as a functional ingredient. The nutritional parameters of the developed food were not affected by the incorporation of the extract, but it promoted the antioxidant activity during its shelf-life. Overall, pineapple peel and crown appeared as promising by-products to be exploited by the food industry, which can be achieved through a circular economy approach.

Ohmic Heating Extraction at Different Times, Temperatures, Voltages, and Frequencies: A New Energy-Saving Technique for Pineapple Core Valorization

Pineapple core is considered a processing by-product. This study proposed and evaluated an ohmic heating extraction-based valorization platform to obtain value-added bioactive compounds from pineapple core and studied the effects of four important processing parameters. In this sense, a Taguchi design (L16(4)4) was used to assess the effects of temperature (70, 80, 90, and 100 °C), time (15, 30, 45, and 60 min), voltage (110, 160, 210, and 260 V), and frequency (60, 340, 620, and 900 Hz) on heating rate, come-up time, energy consumption, system performance efficiency, total phenolic compounds (TPC), DPPH, and ABTS. Finally, a side-by-side comparison of optimized ohmic heating (OOH) and conventional extraction was performed, and chemical composition was compared by ultra-performance liquid chromatography equipped with photodiode array detection-mass (UPLC-DAD-ESI-MS-MS). According to the results, increasing temperatures enhanced system performance efficiency but negatively affected TPC and antioxidant values above 90 ℃. Similarly, prolonging the extraction (>30 min) decreased TPC. Further, increasing voltage (from 110 to 260 V) shortened the come-up time (from 35.75 to 5.16 min) and increased the heating rate (from 2.71 to 18.80 °C/min−1). The optimal conditions were 30 min of extraction at 80 °C, 160 V, and 900 Hz. Verification of the optimal conditions revealed that OOH yielded an extract with valuable bioactive compounds and saved 50% of the time and 80% of energy compared to the conventional treatment. The UPLC-DAD-ESI-MS-MS showed that there were similarities between the chemical profiles of the extracts obtained by conventional and OOH methods, while the concentration of major compounds varied depending on the extraction method. This information can help achieve sustainable development goals (SDGs) by maximizing the yield and minimizing energy and time consumption.

Immunomodulatory effect of metabolites from digested and fermented fractions from irradiated pineapple (Annanas comosus L.) snack-bars

Phenolic compounds (PC), can modulate the immune response. UV-C irradiation, commonly used as a minimal processing method in fresh-foods to reduce the microbial load, increase shelf-life, provide a minimal processing and facilitate the release of PC. This study aimed to evaluate the effect of intestinal (IF) and fermented (FF) fractions of non-irradiated (NIPB) and irradiated (IPB) pineapple snack-bars on the production of nitric oxide (NO), interleukin 6 (IL-6), cyclooxygenase 2 (COX-2), and tumor necrosis factor-alpha (TNF-α) in mice macrophages. IF of NIPB and IPB exerted an immunomodulatory effect by promoting the production of NO (26 pg/mL) in both treatments, COX-2 (438 and 399 pg/mL), and TNF-α (778 and 802 pg/mL) for NIPB and IPB respectively. The TNF-α increased in IF of NIPB and IPB approximately 371 %, and in FF, only increased 132 %. The NO production was not different between IF and FF. COX-2 production was higher in FF.

Nutritionally Enhanced Probioticated Whole Pineapple Juice

Nutritionally enhanced probioticated whole pineapple juice (WPJ, comprising juice of pineapple pulp and peel) beverages were produced by fermentation of WPJ with the probiotic bacterium Lactobacillus plantarum WU-P19. The 12 h fermented juice contained between 2.1 × 109 and 3.7 × 109 live cells of the probiotic per milliliter, depending on the beverage formulation. The beverage had a pH of around 4.1 and a lactic acid content of ~12.8 g L−1. It had a total sugar (glucose, sucrose, fructose, maltose) content of ~100.2 g L−1. During fermentation, some of the initial glucose and fructose were consumed by the probiotic, but sucrose and maltose were not consumed. The original WPJ was free of vitamin B12, but fermentation enhanced vitamin B12 content (~19.5 mg L−1). In addition, fermentation enhanced the concentrations of vitamins B2, B3, and B6, but the bacterium consumed some of the vitamin B1 originally present. From a nutritional perspective, the final probioticated beverage was a good source of vitamin B12, vitamin C and vitamin B6. In addition, it contained nutritionally useful levels of vitamins B1, B2, and B3. The calorific value of the final beverage was 56.94 kcal per 100 mL. The product was stable during 21-day refrigerated (4 °C) storage.

Chemical Composition Profiling and Biological Activities of Phenolic Compounds in Eleven Red Sorghums

The profiles of soluble and insoluble phenolic compounds in 11 commercial red sorghums (B11, B12, B13, B14, J124, J127, J138, J140, J142, J152, and J158) were investigated using ultraperformance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF-MS) analysis. A total of 48 phenolic compounds including 35 phenolic acids and their derivatives, 12 flavonoids, and 1 proanthocyanidin were identified, and 8 phenolic compounds were reported for the first time in sorghums. Four major 3-deoxyanthocyanidins were also quantified, with their soluble forms accounting for 99.75-99.87% of the total contents. Pearson's correlation analyses indicated that 3-deoxyanthocyanidins significantly contributed to the antioxidant capacities of the red sorghums and that 5-methoxy-luteolinidin showed the strongest correlation. Besides, the soluble phenolic fraction of B13 dose-dependently inhibited the proliferation of Caco-2 cells and the secretion of IL-1β and NO in RAW264.7 macrophages, which might be attributed to its relatively high total phenolic (TPC), flavonoid (TFC), and proanthocyanidin content (TPAC) values and radical scavenging capacities.

Optimization of Natural Antioxidants Extraction from Pineapple Peel and Their Stabilization by Spray Drying

Pineapple peel still contains an important amount of phenolic compounds and vitamins with valuable antioxidant activity. In this way, the aim of this study was the recovery of the bioactive compounds from pineapple peel using environmentally friendly and low-cost techniques, envisaging their application in food products. From the solid-liquid extraction conditions tested, the one delivering an extract with higher total phenolic content and antioxidant capacity was a single extraction step with a solvent-pineapple peel ratio of 1:1 (w/w) for 25 min at ambient temperature, using ethanol-water (80-20%) as a solvent. The resulting extract revealed a total phenolic content value of 11.10 ± 0.01 mg gallic acid equivalent (GAE)/g dry extract, antioxidant activity of 91.79 ± 1.98 µmol Trolox/g dry extract by the DPPH method, and 174.50 ± 9.98 µmol Trolox/g dry extract by the FRAP method. The antioxidant rich extract was subjected to stabilization by the spray drying process at 150 °C of inlet air temperature using maltodextrin (5% w/w) as an encapsulating agent. The results showed that the antioxidant capacity of the encapsulated compounds was maintained after encapsulation. The loaded microparticles obtained, which consist of a bioactive powder, present a great potential to be incorporated in food products or to produce bioactive packaging systems.

Cytotoxic Fractions from Hechtia glomerata Extracts and p-Coumaric Acid as MAPK Inhibitors

Preliminary bioassay-guided fractionation was performed to identify cytotoxic compounds from Hechtia glomerata, a plant that is used in Mexican ethnomedicine. Organic and aqueous extracts were prepared from H. glomerata’s leaves and evaluated against two cancer cell lines. The CHCl₃/MeOH (1:1) active extract was fractionated, and the resulting fractions were assayed against prostate adenocarcinoma PC3 and breast adenocarcinoma MCF7 cell lines. Active fraction 4 was further analyzed by high-performance liquid chromatography–quadrupole time-of-flight–mass spectrometry analysis to identify its active constituents. Among the compounds that were responsible for the cytotoxic effects of this fraction were flavonoids, phenolic acids, and aromatic compounds, of which p-coumaric acid (p-CA) and its derivatives were abundant. To understand the mechanisms that underlie p-CA cytotoxicity, a microarray assay was performed on PC3 cells that were treated or not with this compound. The results showed that mitogen-activated protein kinases (MAPKs) that regulate many cancer-related pathways were targeted by p-CA, which could be related to the reported effects of reactive oxygen species (ROS). A molecular docking study of p-CA showed that this phenolic acid targeted these protein active sites (MAPK8 and Serine/Threonine protein kinase 3) at the same binding site as their inhibitors. Thus, we hypothesize that p-CA produces ROS, directly affects the MAPK signaling pathway, and consequently causes apoptosis, among other effects. Additionally, p-CA could be used as a platform for the design of new MAPK inhibitors and re-sensitizing agents for resistant cancers.

Phytochemical Composition and Antioxidant Activity of Portulaca oleracea: Influence of the Steaming Cooking Process

In this work, we compared the phenolic composition and antioxidant capacity of methanolic extracts of raw and steamed aerial parts of Portulaca oleracea L. Two new cyclo-dopa amides were identified, named oleraceins X and Y, along with six known ones (oleraceins A, B, C, N, J, and U). Compounds identification and quantification were done by high-performance liquid chromatography with diode array and mass spectrometry detections. The most abundant compounds were phenolic alkaloids (oleraceins), and the main quantified compounds were isocitric and citric acids, with concentrations of 500–550 and 440–600 mg/100 g dried extract, respectively. The study of both the influence of the steaming process in Portulaca oleracea L. and total phenolic content and radical scavenging assays (ABTS^·+ and DPPH) were also carried out. The total individual phenolic content of raw Portulaca decreased from 1380 mg/100 g DE to 1140 mg/100 g DE after the steaming process. The antioxidant capacity in ABTS and DPPH assays decreased approximately 50 and 40%, respectively, after samples were cooked by steaming. The raw extracts presented the highest concentration of bioactive compounds, as well as higher antioxidant and radical scavenging values.

Non-thermal Processing of Pineapple (Ananas comosus [L.] Merr.) Juice Using Continuous Pressure Change Technology (PCT): Effects on Physical Traits, Microbial Loads, Enzyme Activities, and Phytochemical Composition

A comprehensive study using continuous pressure change technology (PCT) for the non-thermal processing of fresh pineapple juice on pilot scale was conducted (1 L/min, 50 MPa, argon, 3 min, <35 °C). The immediate effects of a single and a twofold PCT treatment on the most important quality parameters were examined and compared with those of fresh and thermally pasteurised (90 °C) juices. In comparison to the fresh juice, both PCT-treated samples exhibited slightly brighter and less yellowish colour (CIE L*a*b*). A significant reduction in the mean particle size resulted in diminished centrifugable pulp contents and enhanced cloud stability. Moreover, a slightly improved microbial quality (−0.9 to −1.2 log10 CFU/mL) in terms of total aerobic and yeast and mould counts was attained. Noteworthy, PCT retained a high bromelain activity (−3 to −15% reduction) and efficiently inactivated polyphenol oxidase. Water-soluble vitamins, phenolic compounds, and all further constituents assessed were mostly preserved. However, the high residual peroxidase activity (−10 to −23%) and microbial loads are likely to affect juice quality during storage. In contrast, thermal pasteurisation ensured a complete reduction in both microbial counts (−4.4 to −4.5 log10 CFU/mL) and effective inactivation of peroxidase. However, bromelain activity was strongly affected (−83%) by heat treatment, and colour was darkened and even less yellowish. Overall, this study highlighted the potential of PCT for the production of fresh-like pineapple juices; however, its current limitations were revealed as well.

Antimicrobial, antioxidant, volatile and phenolic profiles of cabbage-stalk and pineapple-crown flour revealed by GC-MS and UPLC-MSE

Unconventional parts of vegetables represent a rich source of health-promoting phytochemicals. The phenolic profile of cabbage-stalk flour (CSF), pineapple-crown flour (PCF), and their essential oils were characterized via UPLC-ESI-QTOF-MS^E and GC-FID/MS. Antimicrobial activity was tested against five strains, and antioxidant activities were determined in free and bound extracts. Globally, 177 phenolics were tentatively identified in PCF (major p-coumaric acid, ferulic acid, and 4-hydroxybenzaldehyde) and 56 in CSF (major chlorogenicacid, quercetin 3-O-glucuronide, and p-coumaric acid). PCF exhibited a distinguished profile (lignans, stilbenes) and antioxidant capacity, especially in bound extracts (1.3 g GAE.100 g^-1; 0.6 g catechin eq.100 g^-1; DPPH: 244.7; ABTS: 467.8; FRAP: 762.6 µg TE.g^-1, ORAC: 40.9 mg TE.g^-1). The main classes of volatile compounds were fatty acids, their esters, and terpenes in CSF (30) and PCF (41). A comprehensive metabolomic approach revealed CSF and PCF as a promising source of PC, showing great antioxidant and discrete antimicrobial activities.

Application of Edible Alginate Films with Pineapple Peel Active Compounds on Beef Meat Preservation

Alginate-based edible films containing natural antioxidants from pineapple peel were applied in the microbial spoilage control, color preservation, and barrier to lipid oxidation of beef steaks under storage at 4 °C for five days. Different stabilization methods of pineapple peel compounds were used before incorporation into alginate films, including extracted compounds with an hydroalcoholic solvent encapsulated in microparticles, microparticles produced by spray-drying pineapple peel juice, and particles obtained by milling freeze dried pineapple peel. Bioactive films exhibited higher antioxidant activity (between 0.15 µmol to 0.35 µmol FeSO4.7H2O/g dried film) than the alginate film without these compounds (0.02 µmol FeSO4.7H2O/g dried film). Results showed that control films without active compounds had no significant effect on decreasing the microbial load of aerobic mesophilic and Pseudomonas spp., while the films containing encapsulated hydroalcoholic extract showed a significant inhibitory effect on microbial growth of meat at two days of storage. Alginate films containing peel encapsulated extract were effective for maintaining the color hue and intensity of red beef meat samples. Pineapple peel antioxidants have the potential to retard lipid oxidation in meat samples, and the possibility of incorporation of a higher amount of pineapple peel bioactive compounds in the films should be investigated.

Study on Three Sarcocapnos Species as Potential Sources of Bioactive Compounds: Relation between Phenolic Content and Bioactivity by Multivariate Analysis

In this work, we report the phenolic composition and bioactivity of the aerial parts of three species of Sarcocapnos (S. enneaphylla, S. pulcherrima, and S. saetabensis) to study their potential as sources of bioactive compounds to revalorize them and contribute to the conservation of these plant species. Samples were collected in different locations in the province of Jaén (southeast of Spain), and qualitative and quantitative analyses of phenolic compounds were performed by high-performance liquid chromatography with diode array and mass spectrometry detection. S. enneaphylla presented the highest concentration of phenolic compounds (58 mg/g DE). The most abundant compound in S. enneaphylla and S. saetabensis was rutin (35 mg/g DE and 11.7 mg/g DE, respectively), whereas isorhamnetin-O-rutinoside was dominant in S. pulcherrima (11.5 mg/g DE). Several assays were performed to evaluate the potential bioactivity of the three species of Sarcocapnos. These assays included antioxidant and radical scavenging (ABTS and DPPH), reducing power (CUPRAC and FRAP), phosphomolybdenum and metal chelating, and enzyme inhibitory activity (acetylcholinesterase, amylase, butyrylcholinesterase, glucosidase, and tyrosinase). In general, all methanolic extracts presented the highest phenolic and flavonoid contents, as well as the highest radical scavenging, antioxidant, and enzyme inhibitory properties. This relationship between phenolics and bioactivity was confirmed by multivariate analysis.

Glutathionyl-S-chlorogenic acid is present in fruit of Vaccinium species, potato tubers and apple juice

A hydroxycinnamate-like component was identified in highbush blueberry (Vaccinium corymbosum) fruit, which had identical UV and mass spectrometric properties to an S-linked glutathionyl conjugate of chlorogenic acid synthesized using a peroxidase-catalyzed reaction. The conjugate was present in fruits from all highbush blueberry genotypes grown in one season, reaching 7-20% of the relative abundance of 5-caffeoylquininc acid. It was enriched, along with anthocyanins, by fractionation on solid phase cation-exchange units. Mining of pre-existing LC-MS data confirmed that this conjugate was ubiquitous in highbush blueberries, but also present in other Vaccinium species. Similar data mining identified this conjugate in potato tubers with enrichment in peel tissues. In addition, the conjugate was also present in commercial apple juice and was stable to pasteurization and storage. Although glutathionyl conjugates of hydroxycinnamic acids have been noted previously, this is the first report of glutathionyl conjugates of chlorogenic acids in commonly-eaten fruits and vegetables.

Microencapsulation of Pineapple Peel Extract by Spray Drying Using Maltodextrin, Inulin, and Arabic Gum as Wall Matrices

A pineapple peel hydroalcoholic extract rich in phenolic compounds, was stabilized by microencapsulation using spray drying technology, with maltodextrin, inulin, and arabic gum as wall materials. The influence of the type of wall material and drying temperature (150 and 190 °C) on the particles properties was studied. The particles presented a spherical shape with a diameter ranging from approximately 1.3 to 18.2 µm, the exception being the ones with inulin that showed a large degree of agglomeration. All powders produced presented an intermediate cohesiveness and a fair to good flowability according to Carr index and Hausner ratio, which envisages suitable handling properties at an industrial scale. The microencapsulation processes using maltodextrin and arabic gum at 150 °C were the ones that showed higher maintenance of the antioxidant activity of compounds present in the extract before encapsulation during spray drying. In addition, the microparticles obtained were quite efficient in stabilizing the encapsulated phenolic compounds, as their antioxidant activity did not change significantly during six months of storage at 5 °C.

Effect of Pulsed Light Treatment on Natural Microbiota, Enzyme Activity, and Phytochemical Composition of Pineapple (Ananas comosus [L.] Merr.) juice

The effect of pulsed light (PL) on numerous important quality characteristics of pineapple juice was studied and compared with untreated and thermally pasteurised samples. The laboratory scale PL batch system used was operated with each three different voltages (1.8, 2.1, and 2.4 kV) and numbers of pulses (47, 94, and 187). Treatments with 2.4 kV and either 94 or 187 pulses (757/1479 J·cm−2) resulted in a 5-log reduction in aerobic mesophiles and the yeast and mould counts. Peroxidase was more resistant to PL than polyphenol oxidase, whereas the bromelain activity was completely retained in all PL-treated juices. Colour and antioxidant capacity were minimally affected, while vitamin C, genuine pineapple furanones, and phenolic compounds declined. In contrast, thermal pasteurisation was more detrimental to colour, antioxidant capacity, and vitamin C content, but resulted in a superior inactivation of microorganisms and enzymes and retention of phenolic compounds. Principal component analysis (PCA) permitted the differentiation of fresh, thermally pasteurised, and all PL-treated juices. PCA on the basis of the individual juice constituents additionally arranged the latter juices according to the number of pulses and voltage levels applied, particularly promoted by the oxidation of ascorbic to dehydroascorbic acid. In conclusion, PL treatment represents a promising new alternative to conventional thermal preservation techniques, whereby the inactivation of deteriorative enzymes may be further optimised.

Diversity and Toxigenicity of Fungi that Cause Pineapple Fruitlet Core Rot

The identity of the fungi responsible for fruitlet core rot (FCR) disease in pineapple has been the subject of investigation for some time. This study describes the diversity and toxigenic potential of fungal species causing FCR in La Reunion, an island in the Indian Ocean. One-hundred-and-fifty fungal isolates were obtained from infected and healthy fruitlets on Reunion Island and exclusively correspond to two genera of fungi: Fusarium and Talaromyces. The genus Fusarium made up 79% of the isolates, including 108 F. ananatum, 10 F. oxysporum, and one F. proliferatum. The genus Talaromyces accounted for 21% of the isolated fungi, which were all Talaromyces stollii. As the isolated fungal strains are potentially mycotoxigenic, identification and quantification of mycotoxins were carried out on naturally or artificially infected diseased fruits and under in vitro cultures of potential toxigenic isolates. Fumonisins B₁ and B₂ (FB₁-FB₂) and beauvericin (BEA) were found in infected fruitlets of pineapple and in the culture media of Fusarium species. Regarding the induction of mycotoxin in vitro, F.proliferatum produced 182 mg kg⁻¹ of FB₁ and F. oxysporum produced 192 mg kg⁻¹ of BEA. These results provide a better understanding of the causal agents of FCR and their potential risk to pineapple consumers.

Chemical characterization, computational analysis and biological views on Daphne gnidioides Jaub. & Spach extracts: Can a new raw material be provided for biopharmaceutical applications?

The scientific world tends to turn to natural products such as medicinal and aromatic plants because of the inadequacy of commercially available synthetic drugs as antibiotics or anticancer, and their adverse effects on healthy tissues. One of these plants is Daphne gnidioides Jaub. & Spach, which belongs to the Thymelaeaceae family, and there is no data in the literature on its biological activity. This study is aimed to elucidate the chemical profiles and in vitro anticancer, antibacterial and DNA protection and enzyme inhibitory properties of methanol extracts of root, stem, and leaf of D. gnidioides Jaub. & Spach. Polyphenolic components of the extracts were characterized by HPLC-MS/MS. The highest phenolic content was detected in the leaf extract (TIPC = 43.5 ± 0.5 mg/g DE), followed by stem (TIPC = 27.3 ± 0.7 mg/g DE) and root (TIPC = 18.3 ± 0.2 mg/g DE) extracts. Vicenin-2 and 3-O-p-coumaroyl-5-O-caffeoylquinic acid were the main identified compounds in leaf and both root and stem extracts, respectively. The extracts did not show any protective effect on DNA against experimental Fenton's reagent. The minimum inhibitory concentration and the minimum bactericidal concentration values for the root and leaf extracts against tested bacterial strains ranged from 31.25 to 500 μg/mL. After 48 h interaction of the cancer cell lines with the extracts, only the stem extract had significant cytotoxicity on HeLa cells (IC50 = 86.16 μg/mL). No remarkable activity of the extracts, which was tested against MDA-MB-231, was detected (IC50 > 1000 μg/mL). These data showed that D. gnidioides Jaub. & Spach stem extract inhibited the survival of HeLa cells in a time-dependent manner. After the treatment of IC50 concentration of stem extract with HeLa cells, an increase in LC3-II autophagic gene expression was detected. Also, the extracts exhibited significant tyrosinase inhibitory effects which were confirmed by molecular docking. To sum up, the tested extracts could be used as a starting point for the development of new multifunctional drugs.

GC-MS Based Metabolite Profiling to Monitor Ripening-Specific Metabolites in Pineapple (Ananas comosus)

Pineapple is one of the most cultivated tropical, non-climacteric fruits in the world due to its high market value and production volume. Since non-climacteric fruits do not ripen after harvest, the ripening stage at the time of harvest is an important factor that determines sensory quality and shelf life. The objective of this research was to investigate metabolite changes in the pineapple ripening process by metabolite profiling approach. Pineapple (Queen variety) samples from Indonesia were subjected to GC-MS analysis. A total of 56, 47, and 54 metabolites were annotated from the crown, flesh, and peel parts, respectively. From the principal component analysis (PCA) plot, separation of samples based on ripening stages from C0-C2 (early ripening stages) and C3-C4 (late ripening stages) was observed for flesh and peel parts, whereas no clear separation was seen for the crown part. Furthermore, orthogonal projection to latent structures (OPLS) analysis suggested metabolites that were associated with the ripening stages in flesh and peel parts of pineapple. This study indicated potentially important metabolites that are correlated to the ripening of pineapple that would provide a basis for further study on pineapple ripening process.

Anti-Melanogenic Effect of Ethanolic Extract of Sorghum bicolor on IBMX-Induced Melanogenesis in B16/F10 Melanoma Cells

To evaluate possibility as a skin whitening agent of Sorghum bicolor (S. bicolor), its antioxidant activity and anti-melanogenic effect on 3-isobutyl-1-methylxanthine (IBMX)-induced melanogenesis in B16/F10 melanoma cells were investigated. The result of total phenolic contents (TPC) indicated that 60% ethanol extract of S. bicolor (ESB) has the highest contents than other ethanol extracts. Antioxidant activity was evaluated using the 2,2'-azino-bis-(3-ethylbenzothiazolin-6-sulfonic acid) diammonium salt (ABTS)/1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging activities and malondialdehyde (MDA) inhibitory effect. These results showed ESB has significant antioxidant activities. Inhibitory effect against tyrosinase was also assessed using L-tyrosine (IC₅₀ value = 89.25 μg/mL) and 3,4-dihydroxy-L-phenylalanine (L-DOPA) as substrates. In addition, ESB treatment effectively inhibited melanin production in IBMX-induced B16/F10 melanoma cells. To confirm the mechanism on anti-melanogenic effect of ESB, we examined melanogenesis-related proteins. ESB downregulated melanogenesis by decreasing expression of microphthalmia-associated transcription factor (MITF), tyrosinase and tyrosinase-related protein (TRP)-1. Finally, 9-hydroxyoctadecadienoic acid (9-HODE), 1,3-O-dicaffeoylglycerol and tricin as the main compounds of ESB were analyzed using the ultra-performance liquid chromatography-ion mobility separation-quadrupole time of flight/tandem mass spectrometry (UPLC-IMS-QTOF/MS²). These findings suggest that ESB may have physiological potential to be used skin whitening material.

Potentially Bioactive Metabolites from Pineapple Waste Extracts and Their Antioxidant and α-Glucosidase Inhibitory Activities by 1H NMR

Pineapple (Ananas comosus) waste is a promising source of metabolites for therapeutics, functional foods, and cosmeceutical applications. This study strives to characterize the complete metabolite profiles of a variety of MD2 pineapple waste extracts. Metabolomics strategies were utilized to identify bioactive metabolites of this variety prepared with different solvent ratios. Each pineapple waste extract was first screened for total phenolic content, 2,2-diphenyl-1-picrylhydrazyl free radical scavenging, nitric oxide scavenging, and α-glucosidase inhibitory activities. The highest TPC was found in all samples of the peel, crown, and core extracted using a 50% ethanol ratio, even though the results were fairly significant than those obtained for other ethanol ratios. Additionally, crown extracted with a 100% ethanol ratio demonstrated the highest potency in DPPH and NO scavenging activity, with IC₅₀ values of 296.31 and 338.52 µg/mL, respectively. Peel extracted with 100% ethanol exhibited the highest α-glucosidase inhibitory activity with an IC₅₀ value of 92.95 µg/mL. Then, the extracts were analyzed and the data from ¹H NMR were processed using multivariate data analysis. A partial least squares and correlogram plot suggested that 3-methylglutaric acid, threonine, valine, and α-linolenic acid were the main contributors to the antioxidant activities, whereas epicatechin was responsible for the α-glucosidase inhibitory activity. Relative quantification further supported that 100% crown extract was among the extracts that possessed the most abundant potential metabolites. The present study demonstrated that the crown and peel parts of MD2 pineapple extracted with 100% ethanol are potentially natural sources of antioxidants and α-glucosidase inhibitors, respectively.

(Poly)phenols, Carotenoids, and Tocochromanols in Corn (Zea mays L.) Kernels As Affected by Phosphate Fertilization and Sowing Time

Corn (Zea mays L.) growth and development is often limited by the availability of phosphate. We thus hypothesized that phosphate fertilization may increase the contents of (poly)phenols, carotenoids, and tocochromanols (vitamin E) in corn grains. Corn plants cultivated on a soil fertilized with 44 kg phosphorus/ha were compared to plants grown on soil with low plant-available phosphate (1.6 mg CAL-P/100 g of soil), each sown early (April) and late (May) in a randomized field experiment. HPLC-DAD-(HR)-ESI-MSⁿ revealed 19 soluble and 10 insoluble (poly)phenols, comprising phenolic acids, phenolic amines, diferulic, and triferulic acids in corn grains. Contents of individual (poly)phenols, carotenoids, and tocochromanols in whole grains were significantly (p < 0.05) increased by sowing time, but not by phosphate fertilization. In conclusion, low phosphate availability did not impair the biosynthesis of (poly)phenols, carotenoids, and tocochromanols in corn grains.

Hechtia glomerata Zucc: Phytochemistry and Activity of Its Extracts and Major Constituents Against Resistant Bacteria

Hechtia glomerata Zucc. is used both as a source of food and in ethnomedicine to treat various diseases derived from bacterial infections such as bronchitis, laryngitis, nephritis, whooping cough, urethritis, and sepsis. There are no previous reports about its chemistry and biological activities. Therefore, the aims of this study were to identify components from organic and aqueous extracts of H. glomerata and test the extracts and major isolate compounds against resistant bacteria. Hexane, CHCl₃/MeOH, and aqueous extracts were prepared and analyzed by different chromatographic techniques. Structural elucidation was carried out by NMR spectroscopy and X-ray diffraction. The antibacterial activities of extracts, phytochemicals, and semisynthetic derivatives against resistant bacteria were determined by the broth micro-dilution method. From the hexane extract nonacosane (1), hexatriacontanyl stearate (2), hexacosanol (3), oleic acid (4), and β-sitosterol (5) were isolated and characterized. From the CHCl₃/MeOH extract, p-coumaric acid (6), margaric acid (7), caffeic acid (8), daucosterol (9), and potassium chloride (10) were isolated and characterized. A total of 58 volatile compounds were identified by GC-MS from the hexane extract and two solids were isolated from the CHCl₃/MeOH extract. The UPLC-QTOF-MS analysis of the aqueous extract allowed the identification of 55 polar compounds. Hexane and aqueous extracts showed antibacterial activity against ESBL Escherichia coli, and three strains of Klebsiella pneumoniae ESBL, NDM-1 +, and OXA-48 with MIC values of 500 µg/mL. The CHCl₃/MeOH extract was devoid of activity. The activity of phytocompounds and their semisynthetic derivatives toward resistant bacteria was weak. The most active compound was β-sitosterol acetate, with a MIC value of 100 µg/mL against carbapenem-resistant A. baumannii. This is the first report of the secondary metabolites of H. glomerata Zucc. and the activity of its extracts and major pure compounds against resistant bacterial strains.

Polyphenolic profile and antioxidant activity of meristem and leaves from "chagual" (Puya chilensis Mol.), a salad from central Chile

The Bromeliaceae Puya chilensis Mol. is a native monocotyledonous food plant that can be found in central Chile. It is traditionally known as chagual. The tender basal part of the leaves, just starting from the meristem, are consumed as a salad. The aim of this work was to describe the phenolic content and composition of the meristem and leaves of chagual, as well as their antioxidant capacity and inhibitory activity against metabolic syndrome-associated enzymes. Samples of chagual, including two cultivated and three wild growing plants, were analyzed and compared for composition and bioactivity. From the phenolic enriched extract of the plant (PEE), 26 compounds were tentatively identified by HPLC-DAD-ESI-MSⁿ, including 12 hydroxycinnamic acids and 14 flavonoids. The main compounds were identified as diferuloyl hexaric acid isomers and 5-p-Coumaroylquinic acid. The compounds were quantified in both meristem and leaves. The PEE content was up to ten times higher in the meristem than in the leaves, ranging from 0.18 to 124.08 mg/g PEE. The samples inhibited α-glucosidase, but did not show effect on α-amylase and pancreatic lipase. This is the first report on the polyphenol composition and bioactivity of the edible components of the chagual food plant.

Metabolomics-guided investigations of unintended effects of the expression of the hydroxycinnamoyl quinate hydroxycinnamoyltransferase (hqt1) gene from Cynara cardunculus var. scolymus in Nicotiana tabacum cell cultures

Chlorogenic acids (CGAs) are phenolic compounds biosynthesized in the phenylpropanoid pathway, with hydroxycinnamoyl quinate hydroxycinnamoyltransferase (HQT) as the key enzyme. Variation of CGAs has been noted in different plants, with globe artichoke (Cynara cardunculus var. scolymus L.) producing high amounts and a diverse spectrum of CGAs in its leaves. In the current study, the effect of overexpression of the hqt1 transgene from globe artichoke in tobacco was evaluated at the metabolome level. Here, metabolomic approaches based on ultra-high performance liquid chromatography coupled to mass spectrometry, together with chemometric models such as principal component analysis and orthogonal partial least square discriminant analysis, were employed to evaluate altered metabolic changes due to hqt1 overexpression. CGA profiles (caffeoylquinic acids: 3-CQA, 4-CQA and 5-CQA; p-coumaroylquinic acids: 4-pCoQA and 5-pCoQA; and 4,5-di-caffeoylquinic acid) of transgenic tobacco cell cultures were detected at lower concentrations than in the wild type. Interestingly, the cells were found to rather accumulate, as an unintended effect, abscisic acid - and benzoic acid derivatives. The results suggest that insertion of hqt1 in tobacco, and overexpression in undifferentiated cells, led to rechannelling of the phenylpropanoid pathway to accumulate benzoic acids. These findings proved to be contrary to the results shown elsewhere in leaf tissues, thus indicating differential metabolic control and regulation in the undifferentiated cell culture system.

Characterization of bioactive compounds of Annona cherimola L. leaves using a combined approach based on HPLC-ESI-TOF-MS and NMR

Annona cherimola Mill. (cherimoya) has widely been used as food crop. The leaves of this tree possess several health benefits, which are, in general, attributed mainly to its bioactive composition. However, literature concerning a comprehensive characterization based on a combined approach, which consists of nuclear magnetic resonance (NMR) and high-performance liquid chromatography coupled with time-of-flight mass spectrometry (HPLC-TOF-MS), from these leaves is scarce. Thus, the aim of this work was to study the polar profile of full extracts of cherimoya leaves by using these tools. Thus, a total of 77 compounds have been characterized, 12 of which were identified by both techniques. Briefly, 23 compounds were classified as amino acids, organic acids, carbohydrates, cholines, phenolic acid derivatives, and flavonoids by NMR, while 66 metabolites were divided into sugars, amino acids, phenolic acids and derivatives, flavonoids, phenylpropanoids, and other polar compounds by HPLC-TOF-MS. It is worth mentioning that different solvent mixtures were tested and the total phenolic content in the extracts quantified (TPC via HPLC-TOF-MS). The tendency observed was EtOH/water 80/20 (v/v) (17.0 ± 0.2 mg TPC/g leaf dry weight (d.w.)) ≥ acetone/water 70/30 (v/v) (16.1 ± 0.7 mg TPC/g leaf d.w.) > EtOH/water 70/30 (v/v) (14.0 ± 0.3 mg TPC/g leaf d.w.) > acetone/water 80/20 (v/v) (13.5 ± 0.4 mg TPC/g leaf d.w.). Importantly, flavonoids derivatives were between 63 and 76% of the TPC in those extracts. Major compounds were sucrose, glucose (α and β), and proline, and chlorogenic acid and rutin for NMR and HPLC-TOF-MS, respectively. Graphical abstract The combined use of LC-HRMS and NMR is a potential synergic combination for a comprehensive metabolite composition of cherimoya leaves.

Chemical profile of pineapple cv. Vitória in different maturation stages using electrospray ionization mass spectrometry

BACKGROUND

Pineapple is the fruit of Ananas comosus var. comosus plant, being cultivated in tropical areas and has high energy content and nutritional value. Herein, 30 samples of pineapple cv. Vitória were analyzed as a function of the maturation stage (0-5) and their physico-chemical parameters monitored. In addition, negative-ion mode electrospray ionization mass spectrometry [ESI(-)FT-ICR MS] was used to identify and semi-quantify primary and secondary metabolites present in the crude and phenolic extracts of pineapple, respectively.

RESULTS

Physico-chemical tests show an increase in the total soluble solids (TSS) values and in the TSS/total titratable acidity ratio as a function of the maturity stage, where a maximum value was observed in stage 3 (¾ of the fruit is yellow, which corresponds to the color of the fruit peel). ESI(-)FT-ICR MS analysis for crude extracts showed the presence mainly of sugars as primary metabolites present in deprotonated molecule form ([M - H]^- and [2 M - H]^- ions) whereas, for phenolic fractions, 11 compounds were detected, being the most abundant in the third stage of maturation. This behavior was confirmed by quantitative analysis of total polyphenols.

CONCLUSION

ESI-FT-ICR MS was efficient in identifying primary (carbohydrates and organic acids) and secondary metabolites (13 phenolic compounds) presents in the crude and phenolic extract of the samples, respectively. © 2017 Society of Chemical Industry.

Highlighting mass spectrometric fragmentation differences and similarities between hydroxycinnamoyl-quinic acids and hydroxycinnamoyl-isocitric acids

Background

Plants contain a myriad of metabolites which exhibit diverse biological activities. However, in-depth analyses of these natural products with current analytical platforms remains an undisputed challenge due to the multidimensional chemo-diversity of these molecules, amplified by both isomerization and conjugation. In this study, we looked at molecules such as hydroxyl-cinnamic acids (HCAs), which are known to exist as positional and geometrical isomers conjugated to different organic acids namely quinic- and isocitric acid.

Objective

The study aimed at providing a more defined distinction between HCA conjugates from Amaranthus viridis and Moringa oleifera, using mass spectrometry (MS) approaches.

Methods

Here, we used a UHPLC–MS/MS targeted approach to analyze isobaric HCA conjugates extracted from the aforementioned plants.

Results

Mass spectrometry results showed similar precursor ions and fragmentation pattern; however, distinct differences were seen with ions at m/z 155 and m/z 111 which are associated with isocitric acid conjugates.

Conclusion

Our results highlight subtle differences between these two classes of compounds based on the MS fingerprints, enabling confidence differentiation of the compounds. Thus, these findings provide a template reference for accurate and confident annotation of such compounds in other plants.

Electronic supplementary material

The online version of this article (doi:10.1186/s13065-017-0262-8) contains supplementary material, which is available to authorized users.

Indigenous leafy vegetables of Eastern Africa - A source of extraordinary secondary plant metabolites

Indigenous African leafy vegetables vary enormously in their secondary plant metabolites whereat genus and the species have a great impact. In African nightshade (Solanum scabrum), spiderplant (Cleome gynandra), amaranth (Amaranthus cruentus), cowpea (Vigna unguiculata), Ethiopian kale (Brassica carinata) and common kale (Brassica oleracea) the specific secondary metabolite profile was elucidated and gained detailed data about carotenoids, chlorophylls, glucosinolates and phenolic compounds all having an appropriate contribution to health beneficial properties of indigenous African leafy vegetables. Exemplarily, various quercetin glycosides such as quercetin-3-rutinoside occur in high concentrations in African nightshade, spiderplant, and amaranth between ~1400-3300μg/g DW. Additionally the extraordinary hydroxycinnamic acid derivatives such as glucaric isomers and isocitric acid isomers are found especially in amaranth (up to ~1250μg/g DW) and spiderplant (up to 120μg/g DW). Carotenoids concentrations are high in amaranth (up to101.7μg/g DW) and spiderplants (up to 64.7μg/g DW) showing high concentrations of β-carotene, the pro-vitamin A. In contrast to the ubiquitous occurring phenolics and carotenoids, glucosinolates are only present in the Brassicales species Ethiopian kale, common kale and spiderplant characterized by diverse glucosinolate profiles. Generally, the consumption of a variety of these indigenous African leafy vegetables can be recommended to contribute to different benefits such as antioxidant activity, increase pro-vitamin A and anticancerogenic compounds in a healthy diet.

Side Streams of Plant Food Processing As a Source of Valuable Compounds: Selected Examples

Industrial processing of plant-derived raw materials generates enormous amounts of by-products. On one hand, these by-products constitute a serious disposal issue because they often emerge seasonally and are prone to microbial decay. On the other hand, they are an abundant source of valuable compounds, in particular secondary plant metabolites and cell wall materials, which may be recovered and used to functionalize foods and replace synthetic additives with ingredients of natural origin. This review covers 150 references and presents select studies performed between 2001 and 2016 on the recovery, characterization, and application of valuable constituents from grape pomace, apple pomace, potato peels, tomato pomace, carrot pomace, onion peels, by-products of citrus, mango, banana, and pineapple processing, side streams of olive oil production, and cereal by-products. The criteria used were economic importance, amounts generated, relevance of side streams as a source of valuable compounds, and reviews already published. Despite a plethora of studies carried out on the utilization of side streams, relatively few processes have yet found industrial application.