Affinity gel synthesis from the p-aminobenzoic acid derivative 4-amino-2-methylbenzoic acid and purification of polyphenol oxidase from various plant sources.

The polyphenol oxidase (PPO) enzyme, which causes enzymatic browning, has been repeatedly purified from fruit and vegetables by affinity chromatography. In the present research, Sepharose 4B-l-tyrosine-4-amino-2-methylbenzoic acid, a novel affinity gel for the purification of the PPO enzyme with high efficiency, was synthesized. Additionally, Sepharose 4B-l-tyrosine-p-aminobenzoic acid affinity gel, known in the literature, was also synthesized, and 9.02, 16.57, and 28.13 purification folds were obtained for the PPO enzymes of potato, mushroom, and eggplant by the reference gel. The PPO enzymes of potato, mushroom, and eggplant were purified 41.17, 64.47, and 56.78-fold from the new 4-amino-2-methylbenzoic acid gel. Following their isolation from the new affinity column, the assessment of PPO enzyme purity involved the utilization of SDS-PAGE. According to the results from SDS-PAGE and native PAGE, the molecular weight of each enzyme was 50 kDa. Then, the inhibition effects of naringin, morin hydrate, esculin hydrate, homovanillic acid, vanillic acid, phloridzin dihydrate, and p-coumaric acid phenolic compounds on purified potato, mushroom, and eggplant PPO enzyme were investigated. Among the tested phenolic compounds, morin hydrate was determined to be the most potent inhibitor on the potato (Ki: 0.07 ± 0.03 µM), mushroom (Ki: 0.7 ± 0.3 µM), and eggplant (Ki: 4.8 ± 1.2 µM) PPO enzymes. The studies found that the weakest inhibitor was homovanillic acid for the potato (Ki: 1112 ± 324 µM), mushroom (Ki: 567 ± 81 µM), and eggplant (Ki: 2016.7 ± 805.6 µM) PPO enzymes. Kinetic assays indicated that morin hydrate was a remarkable inhibitor on PPO.

Antioxidant pectins from eggplant (Solanum melongena) fruit exocarp, calyx and flesh isolated through high-power ultrasound and sodium carbonate.

Dried and milled eggplant fruit peel and calyces (PC) and mesocarp, placenta and core (Mes) were utilized as natural sources of valuable chemicals. Pectins were extracted with 0.1 M Na2CO3 (1 h; 23 °C). A high-power ultrasound (US) pretreatment (10 min net time; 12.76 W/cm2 power intensity) in 10:200 (g/mL) powder:water ratio led to the lowest solvent and energy consumptions after the subsequent 0.1 M Na2CO3 stirring, permitting the highest recoveries of uronic acid (UA) from PC and Mes (80.25 and 93.8 %, respectively). Homogalacturonans (>65 % w/w UA) of low degree of methylesterification, of acetylation, and 90,214-138,184 Da molecular weights with low polydispersity (≈1.32-1.40) were obtained. They included released ferulate (≈3.5 mg/100 g) esterified pectins. Antioxidants (caffeoylquinic acid, putrescine and spermidine derivatives, ß-carotene, lutein) gave additional technological value to their thickening effect as pectins protected tryptophan, tyrosine, alkyl side chains and sulfhydryl of skim milk proteins from UV-C photo-oxidation.

Domestic cooking methods affect the stability and bioaccessibility of dark purple eggplant (Solanum melongena) phenolic compounds.

Eggplant is an important component of the Mediterranean Diet, which becomes edible after cooking. This study determined the fate of dark purple eggplant phenolic compounds after baking, boiling, frying, grilling and digestion. Thirty-seven phenolic compounds were identified and quantified in raw eggplant. Frying determined a 74% increase in total hydroxycinnamic acids whereas a decrease was observed after boiling (27%), grilling (51%), and baking (60%). After digestion, 45%, 33% and 22% of total phenolic compounds resulted bioaccessible in baked, grilled and fried dark purple eggplant. Fried eggplant displayed the highest amount of phenolic compounds (751.46 mg/100 g) after digestion. The cooking methods differently affected the release of individual phenolic compounds. Baking and grilling resulted in higher amount of bioaccessible caffeoylquinic acids whereas frying in di-caffeoylquinic acids and hydroxycinnamic acid-amides. A careful design of the cooking method may be pivotal to modulate the release of specific phenolic compounds.

Chemical Composition Analysis, Antioxidant, and Antibacterial Activities of Eggplant Leaves.

Agricultural by-products represent one of the biggest pollutants for the environment, therefore, investigating new sources for the extraction of bioactive compounds is a topic of great interest for the entire scientific community. This work is aimed at studying the chemical composition (pigments, phenolics, volatile compounds) and biological activities (antioxidant and antimicrobial properties) of young and mature leaves of five eggplant cultivars (Solanum melongena L.) grown in Tunisia (Tizona, A1014, Nawel, A336, and Mirval). Pigment analysis showed no statistical variations between the two types of leaves, whereas higher levels of anthocyanins were recorded in young leaves of three out of five cultivars (24.7-52.8 mg 100 g-1 ). Total phenolic compounds (966.5-2072.6 mg 100 g-1 ) and o-diphenols (343.9-741.2 mg 100 g-1 ) contents varied significantly according to leaf age and cultivar. However, no statistically significant variation between young and mature leaves was found in flavonols and tannins content. As for volatile profiles, 62 constituents were characterized with non-terpene derivatives (52.0-61.6 %) and apocarotenes (19.9-35.6 %) as major chemical classes. Regarding the antioxidant activity, methanol extracts of Tizona cultivar mature leaves displayed important antiradical properties using DPPH, ABTS, and phosphomolybdenum assays (IC50 0.1, 0.2 and 0.01 mg mL-1 , respectively). With regards to reducing power determination, the most active extract was obtained from mature A1014 leaves. Further, young Mirval leaves proved to be significantly active from a bactericidal point of view against Candida albicans and Staphylococcus aureus of 3.1 mg mL-1 and 0.2 mg mL-1 MBC, respectively. In conclusion, eggplant leaves are a noteworthy source of antioxidant and antimicrobial compounds with potential use in the pharmaceutical, the cosmetics and the food industries.

Fluorescence spectroscopy and molecular modeling of anthocyanins binding to bovine lactoferrin peptides.

This work was aimed to obtain lactoferrin peptides, with anthocyanins-binding capabilities, by using eggplant peels extract as a source of anthocyanins. The chromatographic analysis of the extract evidenced the presence of five individual anthocyanins, with delfinidin-3-rutinoside being identified as the predominant. 20 small peptides were identified, from which four are containing Trp at C-terminal. By estimating the thermodynamic parameters, van der Waals and hydrogen bonding were found to have important roles in binding of anthocyanins to LF and LF-derived peptides. In order to complement the experimental results, the in silico methods were further employed to add single molecule level details on the potential interactions between different peptides and the main anthocyanins from eggplant peels. The docking tests indicated that the Trp containing peptides can bind, with different affinities either delphynidine-3-glycoside or delphynidine-3-rutinoside, therefore explaining the fluorescence quenching results. Our results have indicated a mechanism for the interactions between anthocyanins and LF and its small molecular weight peptides, whereas providing insights for formulating ingredients and foods with enhanced bioactives-binding properties.

Sesquiterpenoids with diverse carbon skeletons from the sepals of Solanum melongena L.

Eight new sesquiterpenoids named melongenaterpenes M-T (1-8), together with nine known compounds (9-17), were isolated from the 70% ethanol extract of the sepals of Solanum melongena L. The structures of all isolated compounds were elucidated based on 1D and 2D NMR spectra and a comprehensive comparison of their spectroscopic and physical data with values from the published literatures. Meanwhile, the cytotoxicity of all the isolated compounds was evaluated on the three human cancer lines of Hela, Ishikawa and MGC-803 by CCK8 assay, respectively.

Terpenes and lignans from the roots of Solanum melongena L.

Phytochemical investigation of the roots of Solanum melongena L. resulted in the isolation of ten terpenes and sixteen lignans, including a new triterpene saponin, officinoterpenoside E (1) and twenty-five known compounds (2-26). All compounds were firstly isolated from S. melongena except 2, 13, 21, 22. The structures of these compounds were determined by 1 D and 2 D NMR spectra referring to the literatures, together with high-resolution mass spectrometric analysis. All compounds were evaluated for the cytotoxicity against three cancer cell lines (HepG2, Hela, and MCF-7) in vitro. The results showed that compounds 1, 6, 20, 25 and 26 exhibited moderate cytotoxicity against HepG2, Hela and MCF-7 cells with IC50 values in the range of 16.8 ± 1.7 to 29.1 ± 1.9 µM. Therefore, these terpenoids and lignans may have potential biological activity, and also seemed to be of great chemotaxonomic value for S. melongena.

Emulsification of oil-in-water emulsions with eggplant (Solanum melongena L.).

HYPOTHESIS: Eggplant is rich in polysaccharides. The mechanically homogenized eggplant flesh pulp (EFP) is expected to emulsify and stabilize o/w emulsions. The adsorption and network structure of the polysaccharides are hypothesized to contribute to the stability of emulsions. EXPERIMENTS: Creaming index (CI) and droplet size distribution were observed to evaluate the stabilities of EFP emulsions at different EFP concentrations (0.50, 0.75, 1.00, 1.25 and 1.50% w/v). Optical and fluorescence microscopy, confocal laser scanning microscopy and cryogenic scanning electron microscopy were conducted to observe the emulsification properties of the EFP-stabilized emulsions. In addition, rheological measurements were performed to reveal the EFP emulsions' rheological behaviours. FINDINGS: The prepared oil-in-water emulsion emulsified by EFP remained stable at an EFP concentration of 1.50%. Rheological analysis illustrated that the emulsions had typical shear-thinning property and gel-like nature. The emulsification mechanisms were explained by the formation of an interfacial film adhered to the oil droplets and the coherent three-dimensional network formed by filament and sheet-like polysaccharide strands in the continuous phase. This finding may define a new kind of natural and dietary emulsifier for emulsion-based food, beverage, and pharmaceutical products.

Spectrophotometric and Smartphone-Assisted Determination of Phenolic Compounds Using Crude Eggplant Extract.

In order to develop a simple, reliable and low cost enzymatic method for the determination of phenolic compounds we studied polyphenol oxidase activity of crude eggplant (S. melongena) extract using 13 phenolic compounds. Catechol, caffeic and chlorogenic acids, and L-DOPA have been rapidly oxidized with the formation of colored products. Monophenolic compounds have been oxidized at a much slower speed. Ferulic acid, quercetin, rutin, and dihydroquercetin have been found to inhibit polyphenol oxidase activity of crude eggplant extract. The influence of pH, temperature, crude eggplant extract amount, and 3-methyl-2-benzothiazolinone hydrazone (MBTH) concentration on the oxidation of catechol, caffeic acid, chlorogenic acid, and L-DOPA has been investigated spectrophotometrically. Michaelis constants values decrease by a factor of 2 to 3 in the presence of MBTH. Spectrophotometric (cuvette and microplate variants) and smartphone-assisted procedures for phenolic compounds determination have been proposed. Average saturation values (HSV color model) of the images of the microplate wells have been chosen as the analytical signal for smartphone-assisted procedure. LOD values for catechol, caffeic acid, chlorogenic acid, and L-DOPA equaled 5.1, 6.3, 5.8 and 30.0 µM (cuvette procedure), 12.2, 13.2, 13.2 and 80.4 µM (microplate procedure), and 23.5, 26.4, 20.8 and 120.6 µM (smartphone procedure). All the variants have been successfully applied for fast (4-5 min) and simple TPC determination in plant derived products and L-DOPA determination in model biological fluids. The values found with smartphone procedure are in good agreement with both spectrophotometric procedures values and reference values. Using crude eggplant extract- mediated reactions combined with smartphone camera detection has allowed creating low-cost, reliable and environmentally friendly analytical method for the determination of phenolic compounds.

Melongenaterpenes A-L, Vetispirane-Type Sesquiterpenoids from the Roots of Solanum melongena.

Melongenaterpenes A-L (1-12), 12 new sesquiterpenoids with rare spiro[4.5]decane skeletons, were isolated from the roots of Solanum melongena. Their 2D structures and relative configurations were determined based on NMR and HRESIMS data. The absolute configuration of melongenaterpene A (1) was defined by X-ray crystallographic analysis. The absolute configurations of the remaining compounds were determined by comparison of their NMR data with 1 and consideration of the biosynthetic pathway. This is the first report of the crystal structure of a vetispirane-type sesquiterpenoid. None of the compounds exhibited cytotoxic activity against the three human cancer cell lines HepG2, HeLa, and MCF-7.

Chlorogenic acid-rich Solanum melongena extract has protective potential against rotenone-induced neurotoxicity in PC-12 cells.

Neurodegenerative diseases are major threats to human health. Here, through fluorescence, colorimetric, immunoblotting, spectroscopy, and laser scanning confocal microscopic techniques, we investigated the neuroprotective properties of chlorogenic acid-rich Solanum melongena extracts (SM extract) in rotenone-induced PC-12 cell death. The results showed that rotenone caused apoptosis to PC-12 cells by elevating Bax/Bcl-2 ratio and increasing caspase-3 activity. Rotenone also increased ROS in cells while suppressing SOD and catalase activities. This resulted in the depletion of ATP in cells by blocking mitochondria complex I activity. Pretreatment of the cells with SM extract at concentrations of 100, 250, and 500 µg/ml before incubation for 24 hr with rotenone significantly prevented apoptosis, decreased ROS, and increased ATP production in the cells. SM extract upregulated SOD and catalase activities in the cells. These results unveil evidence that SM extract content neuroprotective properties that can be exploited to prevent and treat neurodegenerative diseases. PRACTICAL APPLICATIONS: Solanum melongena eggplant is a popular ingredient in many traditional recipes and is well known in Asia for its medicinal benefits. Despite numerous scientific reports of the potential health benefits of this plant, reports on its effects in neurodegenerative diseases is still lacking. This pilot study demonstrates that S. melongena eggplant can protect against neurotoxicity in neurodegenerative diseases. The results of this research serves as a base for further research on eggplant that will result in its usage on a larger scale as functional food materials.

Phenolic distribution, antioxidant activity, and enzyme inhibitory properties of eggplant (Solanum aethiopicum) cultivated in two different locations within Nigeria.

Solanum aethiopicum is commonly cultivated in Nigeria for its nutritional and medicinal properties. Although, information on the possible effect of location on the biological activities of S. aethiopicum has not been reported, however, present research work investigated the phenolic contents and distribution, antioxidative properties, and enzyme inhibitory activities of S. aethiopicum collected from two locations in Nigeria. HPLC phenolic profile, polyphenol contents, free radical scavenging activities, and inhibitory effect of eggplant extracts on carbohydrate metabolizing enzymes were carried out. Significant variations were observed in the phenolic profile, polyphenol contents, antioxidant activities, and enzymes inhibitory properties of the extracts from different locations. In most of the analyses carried out, extract of eggplant fruit collected from Uyo (UEF) showed higher activities than the one obtained from Ibadan (IEF). Thus, findings from this study revealed that geographical location may influence the phenolic contents, antioxidant, and enzymes inhibitory properties of eggplant fruits. PRACTICAL APPLICATIONS: The geographical location of a particular place determines the nature and biological activities of plants cultivated in the area. Hence, we presented the effect of location on the phenolic profile, antioxidant, and enzyme inhibitory properties of eggplant fruit (S. aethiopicum) cultivated in two different locations in Nigeria. However, data generated in this study showed the effect of location on phenolic composition and biological activities of eggplant fruit cultivated in Nigeria.

Bioactive glycoalkaloides isolated from Solanum melongena fruit peels with potential anticancer properties against hepatocellular carcinoma cells.

Hepatocellular carcinoma (HCC) is progressively increasing tumor with lack of accurate prognosis and inadequate systemic treatment approaches. Solanum sp. (such as Solanum melongena) is a folk herb which is reported to possess anticancer properties. In a continuity for our interest in pursuing the anticancer activity of compounds isolated from the fruit peels of Solanum melongena, the HPLC profiling and ESI-MS assessment for the methanolic extract evidenced the presence of bioactive glycoalkaloids (solasonine, solasodine and solamargine). These glycoalkaloids were isolated, purified and proved to possess in vitro cytotoxicity against human liver cancer cell lines (Huh7 and HepG2). Herein, we investigated the potential mechanism of action of these compounds using DNA content flow-cytometry and apoptosis/necrosis differential anaylsis using annexin-V/FITC staining. Solasonine, solasodine and solamargine inducd significant antiproliferative effect against liver cancer cells (Huh7 and HepG2) which was attributed to cell cycle arrest at S-phase. Solamargine, solasodine and solasonine induced significant apoptosis in Huh7 cells. Only solamargine-induced cell cycle arrest, was reflected as apoptotic cell killing effect against HepG2 cells. In conclusion, glycoalkaloids derived from Solanum melongena and particularly, solamargine are promising antiproliferative agents with potential anticancer effects.

Eggplant fruits protect against DNA damage and mutations.

Eggplant belongs to the Solanaceae family, and it has an important antioxidant capability that has been shown to counteract oxidation, which is harmful to health and many diseases. In this present study, we evaluated the antigenotoxic effects of six eggplants ((Solanum aculeatissimum Jacq. 'Ma-khuea-lueang'; ML), (Solanum aculeatissimum Jacq. 'Ma-khuea-pro'; MP), (Solanum aculeatissimum Jacq. 'Ma-khuea-sawoei'; MS), (Solanum melongena Linn. 'Ma-khuea-khai-tao'; MKT), (Solanum melongena Linn. 'Ma-khuea-muang klom'; MM) and (Solanum torvum Sw. 'Ma-khuea-phuang'; MPH)) against urethane-induced somatic mutation and recombination test (SMART) in Drosophila melanogaster and hydrogen peroxide-induced oxidative DNA damage in human lymphocytes. First, we determined all of the eggplant extracts of their antioxidant properties including radical scavenging activities, reducing antioxidant power and total phenolic contents, surprisingly ML extract showed the highest level of activity. In SMART, larvae were fed with each lyophilized eggplant. The results revealed that no sample was mutagenic. Interestingly, we found that all six eggplants had a potent inhibitory effect against urethane-induced mutagenicity. Moreover, the protective effect of each eggplant extract against oxidative DNA damage in human lymphocytes was investigated using the single-cell gel electrophoresis (comet) assay. The treatment cells with six eggplant extracts prevented DNA human lymphocytes in response to hydrogen peroxide, especially ML extract exhibited higher an inhibition percentage than other samples. This study demonstrated that these eggplants seem to be safe for consumption and their extracts could protect against DNA damage. Thus, these eggplants have the potential to provide health benefits associated with prevention or reduced risk of developing chronic diseases, such as cancer.

A Polyphenol Rich Extract from Solanum melongena L. DR2 Peel Exhibits Antioxidant Properties and Anti-Herpes Simplex Virus Type 1 Activity In Vitro.

DR2B and DR2C extracts, obtained by ethanolic maceration of peel from commercially and physiologically ripe aubergine berries, were studied for the antioxidative cytoprotective properties and anti-HSV-1 activity, in line with the evidence that several antioxidants can impair viral replication by maintaining reducing conditions in host cells. The antioxidative cytoprotective effects against tBOOH-induced damage were assessed in Caco2 cells, while antiviral activity was studied in Vero cells; polyphenolic fingerprints were characterized by integrated phytochemical methods. Results highlighted different compositions of the extracts, with chlorogenic acid and delphinidin-3-rutinoside as the major constituents; other peculiar phytochemicals were also identified. Both samples reduced reactive oxygen species (ROS) production and exhibited scavenging and chelating properties. DR2C partly counteracted the tBOOH-induced cytotoxicity, with a remarkable lowering of lactate metabolism under both normoxia and hypoxia; interestingly, it increased intracellular GSH levels. Furthermore, DR2C inhibited the HSV-1 replication when added for 24 h after viral adsorption, as also confirmed by the reduction of many viral proteins' expression. Since DR2C was able to reduce NOX4 expression during HSV-1 infection, its antiviral activity may be correlated to its antioxidant properties. Although further studies are needed to better characterize DR2C activity, the results suggest this extract as a promising new anti-HSV-1 agent.

Implication of the Significance of Dietary Compatibility: Based on the Antioxidant and Anti-Inflammatory Interactions with Different Ratios of Hydrophilic and Lipophilic Antioxidants among Four Daily Agricultural Crops.

The hydrophilic extracts of eggplant peel (HEEP) and purple sweet potato (HEPP) and lipophilic extracts of tomato (LET) and carrot (LEC) were mixed in different ratios to assess the significance of the compatibility of aliments, based on their antioxidant and anti-inflammatory interactions in H9c2 cells. The results indicated that groups of some combinational extracts (HEPP-HEEP F1/10, LEC-HEEP F3/10, LEC-HEPP F3/10) showed stronger synergistic antioxidant and anti-inflammatory effects than individual groups. For example, the glutathione peroxidase (GPx) activity of the LEC-HEEP (F3/10) group (86.71 ± 1.88) was higher than that in the HEEP (79.97 ± 1.68) and LEC (77.31 ± 1.85) groups. The level of reactive oxygen species (ROS) was 30.37 ± 0.25 in the LEC-HEEP (F3/10) group while the levels were 34.34 ± 0.36 and 46.23 ± 0.51 in the HEEP and LEC groups, respectively. And the level of malondialdehyde (MDA) was 1.82 ± 0.24 in the LEC-HEEP (F3/10) group while the levels were 2.48 ± 0.13 and 3.01 ± 0.24 in the HEEP and LEC groups, respectively. The expressions of inflammatory mediators (IL-1ß, IL-6, IL-8) and cell adhesion molecules (VCAM-1, ICAM-1) showed similar tendencies. However, some groups (LET-LEC F5/10, LET-LEC F9/10, LET-HEPP F7/10) showed antagonistic effects based on these indicators. The principal component analysis showed that samples could be defined by two principal components: PC1, the main phenolic acids and flavonoids; PC2, carotenoids. Moreover, phenolics and anthoyanins were in the majority in synergistic groups, and carotenoids were in the majority in antagonistic groups. These results indicated that there exist synergistic or antagonistic interactions of aliments on antioxidation and anti-inflammation, which implied the significance of food compatibility.

Nutritional value and antioxidant content of seed-containing and seedless eggplant fruits of two cultivars grown under protected cultivation during autumn-winter and spring-summer.

BACKGROUND: Due to their low carbohydrate and high antioxidant content, eggplants are beneficial for the human diet. At <15 °C, pollen production and fertility are reduced and plant-growth regulators may be used to set seedless fruit. Because only the agronomic effects of hormone are well-documented, we investigated the composition and metabolism during the development/maturation of seed-containing and seedless fruits of two cultivars grown over two seasons. RESULTS: The respiration rate of both seedless and seed-containing fruit decreased with development and maturation. In seedless fruit, starch content decreased at market maturity, whereas in seed-containing fruit starch increased. Respiration and starch were higher in spring-summer than in autumn-winter. Disaccharides were highest at market maturity, with sucrose generally higher in seed-containing fruit; monosaccharides were variable and protein content was reduced in seedless fruit. Phenols closely correlated with antioxidant activity and decreased with development; at market maturity in spring-summer phenols were higher in seedless fruit (Tsakoniki) or unaffected (Emi). Polyphenol oxidase and peroxidase activities were mostly higher in seed-containing fruit, but browning was higher in seedless fruit. CONCLUSIONS: Notwithstanding reduced protein and increased browning, seedless fruit at market maturity presented less starch, hence fewer calories, and more antioxidants (phenols) for the human diet than the corresponding seed-containing fruit. © 2017 Society of Chemical Industry.

Effects of Grilling on Total Polyphenol Content and Antioxidant Capacity of Eggplant (Solanum melongena L.).

Cooking can change the polyphenol contents of eggplant. This study elucidated the effects of grilling on total polyphenol content (TPC), antioxidant capacity, and the inner structures of eggplant. After identical hollowing, cylindrical eggplant samples were prepared and were then grilled until their center temperatures (CT) respectively reached 50, 65, 75, 85, and 95 °C. Chemical assays and observations of the inner structures clarified that TPC and 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity decreased as CT increased when CT was below 65 °C. Results also showed that TPC and DPPH radical scavenging activity increased as CT increased when CT was between 65 °C and 95 °C. For CT 65 °C, the samples retained polyphenol oxidase (PPO) activity up to 40% of the raw state activity. The 3 grilled eggplant models, chlorogenic acid, chlorogenic acid-sugar and chlorogenic acid-amino acid model, yielded results showing that phenol functional groups on chlorogenic acid were thermally stable and that phenol functional groups on chlorogenic acid reacted neither with sugar nor with amino acids. Results show that PPO activity is a primary reason for the decrease of the 2 indices. Optical microscopic and scanning electron microscopic observations revealed collapsed cells and inter-tissue cracks around the surface area for CT 85 and 95 °C. Scanning electron microscopic observations clarified that intercellular bonds for CT 85 and 95 °C became thinner than those for CT 75 °C around the middle area. The phenomena explained above are reasons for the increase of TPC and DPPH radical scavenging activity.

Insights in the Fruit Flesh Browning Mechanisms in Solanum melongena Genetic Lines with Opposite Postcut Behavior.

Color, taste, flavor, nutritional value, and shelf life are important factors determining quality and healthiness of food and vegetables. These factors are strongly affected by browning processes, occurring after fruit or vegetable cutting. Characterization of ten eggplant genotypes for chlorogenic acid (CGA) content, total phenols (TP), polyphenoloxidase (PPO) activity, and browning tendency corroborated a lack of significant correlations between biochemical factors and fruit flesh browning. Further in-depth molecular and biochemical analyses of two divergent eggplant genetic lines, AM199 (high browning) and AM086 (low browning), within 30 min from cutting, highlighted differences in the physiological mechanisms underlying the browning process. qRT-PCR analysis revealed distinct activation mechanisms of CGA biosynthetic and PPO genes in the two genetic lines. Metabolic data on CGA, sugars, and ascorbic acid contents confirmed that their different browning tendency matched with different metabolic responses to cutting. Our findings suggest that the complex mechanism of flesh browning in the two eggplant genetic lines might be mediated by multiple specific factors.

Dioscin Derived from Solanum melongena L. "Usukawamarunasu" Attenuates α-MSH-Induced Melanogenesis in B16 Murine Melanoma Cells via Downregulation of Phospho-CREB and MITF.

This study aimed to chemically isolate and explore an antimelanogenesis inducer in extracts of Solanum melongena L. "Usukawamarunasu" eggplant. We successfully identified dioscin ([25R]-Spirost-5-en-3ß-yl) 2-O-(6-deoxy-α-L-mannopyranosyl) - 4-O-(6-deoxy-α-L-mannopyranosyl)-ß-D-glucopyranoside] in the plant, and examined the effects of α-melanocyte-stimulating hormone (MSH)-induced melanogenesis in B16 murine melanoma cells by this plant-derived dioscin. Immunoblot analysis suggested that dioscin reduced the expression of tyrosinase, tyrosinase-related protein-1 (TRP-1), and TRP-2, resulting in inhibition of intracellular production of melanin. In addition, dioscin caused reduction of phosphorylated cAMP-responsive element binding protein 1 transcription factors (CREB), which led to a reduction of microphthalmia-related transcription factor (MITF) in α-MSH-stimulated cells, but did not affect phosphorylation of extracellular signal-regulated kinase. Furthermore, dioscin significantly downregulated the expression of tyrosinase, TRP-1, and TRP-2, which led to the reduction of α-MSH-induced melanogenesis in B16 cells. These results suggest that dioscin may decrease the level of MITF via inhibition of phosphorylation of CREB in α-MSH-induced melanogenesis in B16 cells.