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.

Metabolomic Analysis of Phytochemical Compounds from Agricultural Residues of Eggplant (Solanum melongena L.).

The eggplant is a fruit rich in natural products and produced worldwide. However, its cultivation generates a large amount of scarcely used agricultural residues with poor chemical characterization. This study aimed to identify and quantify the metabolome and determine the composition of select phytochemicals and the overall antioxidant capacity of various anatomical parts of the plant. The plant's root, leaf, stem, and fruit were analyzed by quantitative mass spectrometry-based untargeted metabolomics and chemoinformatics, and phytochemicals were quantified by spectrophotometric analysis. Moreover, we determined the total antioxidant capacity of the distinct plant parts to infer a possible biological effect of the plant's metabolites. Various secondary metabolites were identified as terpenes, phenolic compounds, alkaloids, and saponins, distributed throughout the plant. The leaf and fruit presented the highest concentration of phenolic compounds, flavonoids, anthocyanins, and alkaloids, accompanied by the highest antioxidant capacity. Although the stem and root showed the lowest abundance of secondary metabolites, they provided around 20% of such compounds compared with the leaf and fruit. Overall, our study improved the understanding of the eggplant metabolome and concluded that the plant is rich in secondary metabolites, some with antioxidant properties, and shows potential nutraceutical and biopharmaceutical applications.

Identification of Novel Iso-Esculeoside B from Tomato Fruits and LC-MS/MS-Based Food Screening for Major Dietary Steroidal Alkaloids Focused on Esculeosides.

Plants from the Solanaceae family are known to be sources of several nutritionally relevant steroidal glycoalkaloids (SGAs). With the aim of quantitatively investigating the occurrence of the main SGA from tomatoes, eggplants, and potatoes in various food samples and evaluating their relevance in the human diet, a rapid single-step extraction liquid chromatography-tandem mass spectrometry method was developed. Over the course of isolating several commercially unavailable SGAs from tomato products to use them as reference standards, a previously unknown derivative was detected, structurally characterized, and identified as a novel isomer of esculeoside B-1 and B-2. After validation of the method, 36 food items exclusively derived from Solanaceae plants were analyzed for their SGA contents and a specific occurrence of each alkaloid in tomato, eggplant, or potato products was revealed. This is the first study reporting quantitative data on the occurrence of esculeoside A, B-1, B-2, and iso-esculeoside B in tomato products obtained by using appropriate reference compounds rather than applying a semi-quantitative approach based on α-tomatine as a reference. Some of the analyzed tomato products contained the esculeosides in concentrations of >500 mg/kg, clearly indicating their relevance in the human diet and the need of investigating their potential bioactivities in the future.

Degradation Kinetics of Anthocyanins from Purple Eggplant in a Fortified Food Model System during Microwave and Frying Treatments.

A model food system was designed with dietary fiber and crude anthocyanins from purple eggplant peel to explore the degradation mechanism of anthocyanins during microwave and frying treatments. Our results found that delphinidin-3-O-rutinoside was either hydrolyzed into delphinidin or condensed with p-coumaric acid to form p-coumaroyl-delphinidin-3-O-glucoside. Delphinidin was cleaved into gallic acid and phloroglucinaldehyde, which might be further oxidized into pyrogallol and phloroglucinol, respectively. The total anthocyanin degradation followed the first-order kinetics in fried and microwaved solid matrix samples as well as microwaved liquid matrix samples. However, the total anthocyanin degradation followed the second-order kinetics in the heated liquid matrix samples at the frying temperature. The brown/polymeric color index, which negatively correlated with the anthocyanin content, increased faster in the liquid matrix samples than in the solid matrix samples. Compared with frying treatment, a higher rate of anthocyanin degradation in solution was observed under microwave treatment. However, anthocyanins were subject to much more damage under frying treatment than microwave treatment in a solid food system.

From nutrition to medicine: Assessing hemorrhoid healing activity of Solanum melongena L. via in vivo experimental models and its major chemicals.

ETHNOPHARMACOLOGICAL RELEVANCE: Solanum melongena L. (eggplant) is used for treatment of rheumatism, beriberi, itching, toothache, bleeding, asthma, bronchitis, cholera, neuralgia and hemorrhoids in traditional medicine (Turkish, Chinese, and Indian). Hemorrhoids from these diseases, are common illness in all over the world, which are treated with various approaches including ethnobotanicals. AIM OF THE STUDY: This study aimed to evaluate the anti-hemorrhoidal activity of eggplant, an edible plant, which is commonly utilized around the world. MATERIALS & METHODS: In vivo anti-hemorrhoidal activity of the methanolic extract prepared from eggplant was evaluated by experimental hemorrhoid model, subsequently histological and biochemical analysis. Hemorrhoid, which was induced by applying croton oil to the anal area of the rats. Furthermore, the extract was screened for anti-inflammatory activity which is based on the inhibition of acetic acid-induced increase in capillary permeability. The healing potential was comparatively assessed with a reference Pilex® tablet and cream. Phytochemical analysis performed by HPLC. The amount of the major phenolic compound (chlorogenic acid) in extract was found by using HPLC method. RESULTS: Histological and biochemical analysis demonstrated that eggplant extract is highly effective against hemorrhoid in comparison to the controls and the commercial preparation. In addition, the methanolic extract demonstrated significant inhibitory effect on acetic acid-induced increase in capillary permeability. The phytochemical studies identified major compound as chlorogenic acid (2.86%) by liquid chromatography. CONCLUSION: The eggplant calyxes, not edible, are easy to reach, by products/vast from the food sources. This is the first scientific evidence revealing that the eggplant extract has significant anti-hemorrhoidal and anti-inflammatory activity.

Horticultural Plant Residues as New Source for Lignocellulose Nanofibers Isolation: Application on the Recycling Paperboard Process.

Horticultural plant residues (tomato, pepper, and eggplant) were identified as new sources for lignocellulose nanofibers (LCNF). Cellulosic pulp was obtained from the different plant residues using an environmentally friendly process, energy-sustainable, simple, and with low-chemical reagent consumption. The chemical composition of the obtained pulps was analyzed in order to study its influence in the nanofibrillation process. Cellulosic fibers were subjected to two different pretreatments, mechanical and TEMPO(2,2,6,6-Tetramethyl-piperidin-1-oxyl)-mediated oxidation, followed by high-pressure homogenization to produce different lignocellulose nanofibers. Then, LCNF were deeply characterized in terms of nanofibrillation yield, cationic demand, carboxyl content, morphology, crystallinity, and thermal stability. The suitability of each raw material to produce lignocellulose nanofibers was analyzed from the point of view of each pretreatment. TEMPO-mediated oxidation was identified as a more effective pretreatment to produce LCNF, however, it produces a decrease in the thermal stability of the LCNF. The different LCNF were added as reinforcing agent on recycled paperboard and compared with the improving produced by the industrial mechanical beating. The analysis of the papersheets' mechanical properties shows that the addition of LCNF as a reinforcing agent in the paperboard recycling process is a viable alternative to mechanical beating, achieving greater reinforcing effect and increasing the products' life cycles.

Ionic liquid-modified countercurrent chromatographic isolation of high-purity delphinidin-3-rutinoside from eggplant peel.

Delphinidin-3-rutinoside, a high-value of anthocyanin, was isolated and purified by ionic liquid (IL)-modified countercurrent chromatography (CCC) from waste peel of eggplant (Solanum melongena), one of the most common vegetables consumed all around the world. Different conventional CCC and IL-CCC solvent systems were evaluated in respect of partition coefficient (K), separation factor (α), and stationary phase retention factor (Sf ) to separate polar target and other components. Basic solvent system, kind of ILs, and amount of ILs were systematically optimized by totally K-targeted strategy, which drastically reduced the experimental effort. Finally, a novel CCC two-phase solvent system (methyl tert-butyl ether-butanol-acetonitrile-1% trifluoroacetic acid water-1-butyl-3-methylimidazolium hexafluorophosphate ([C4 MIM][PF6 ]) [2:4:1:5:0.2; v/v/v/v/v]) was successfully established and applied. The baseline separation of target fraction was obtained in one cycle process. The purity of delphinidin-3-rutinoside was over 99%. Moreover, the distribution behavior of different kinds of ILs in biphasic solvent system and the removal method of ILs were explored. The results showed that hydrophobic IL significantly improved the partition of polar anthocyanin in organic solvent system, thereby the separation resolution and stationary phase retention through introducing intermolecular forces. This IL-modified CCC strategy may be applied for the separation of other anthocyanins from variety of natural food resources and waste.

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.

Value-Added Lager Beer Enriched with Eggplant (Solanum melongena L.) Peel Extract.

Manufacturing beer with a high biological value requires identifying new methods for increasing the health-enhancing compounds level. The aim of this study was to increase the biological value of beer by adding antioxidant-rich eggplant (Solanum melongena L.) peel extract (EPE). The total phenolic content (TPC), total flavonoid content (TFC), and total monomeric anthocyanin content (TMA) were determined. Moreover, the antioxidant activity was evaluated by different radical scavenging assays. The addition of different levels of EPE resulted in a significant increase of TPC and TFC of beer samples from 0.426 to 0.631 mg GAE/mL, and from 0.065 to 0.171 mg CE/mL, respectively. The EPE-supplemented beer samples developed a reddish color because of the presence of anthocyanin pigments. The TMA content of beer varied from 0.011 to 0.083 mg D3G/mL with the level of added EPE. The HPLC analysis indicated that the anthocyanins prevailing in the eggplant peels were delphinidin-3-rutinoside, delphininidin-3-glucoside and delphinidin-3-rutinoside-5-glucoside. The radical scavenging assays indicated a linear increase of the antioxidant activity following EPE addition, without altering the physicochemical parameters of the beer. These results are promising for using the EPE as a functional ingredient for beer production.

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.

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.

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.

Application of gum Arabic and maltodextrin for encapsulation of eggplant peel extract as a natural antioxidant and color source.

Our aim was to produce an encapsulated powder loaded with eggplant peel extract as a natural source of color and antioxidants through gum Arabic and maltodextrin. The effect of spray drying inlet temperature (140-170°C) and various carriers (maltodextrin, gum Arabic, and their combination) on powder production yield, physical properties, flowability, color, total phenolic content (TPC), antioxidant activity, infrared spectroscopy (FTIR), microstructure and particle size were investigated. Our results revealed that physicochemical properties of powders were influenced by the carrier type and inlet temperature. Obtained powders by maltodextrin at 170°C showed the highest TPC (5.2mg/g), DPPH (73.4%), ABTS (90.5%), TEAC (2. 5mM), hydroxyl radicals scavenging activity (79.1%) and reducing power (1.2 Abs700) among all samples. FTIR spectroscopy indicated that the extract was encapsulated by the carriers. Microstructure evaluation of powders showed some hollow particles with matrix-type structures. Sensory evaluation indicated that addition of encapsulated eggplant extract into the formulation of gummy candy improved its color and overall acceptability.

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.

Physicochemical, Functional, and Nutraceutical Properties of Eggplant Flours Obtained by Different Drying Methods.

The importance of consuming functional foods has led the food industry to look for alternative sources of ingredients of natural origin. Eggplants are a type of vegetable that is valued for its content in phytochemical compounds and it is due to the fact that this research is conducted towards the development of eggplant flour as a proposal to be used as a functional ingredient in the food industry. In this study, the eggplant fruits were divided into four groups, based on the drying method and the equipment used: Minced, drying oven (T1); sliced, drying oven (T2); sliced and frozen, drying tunnel (T3); and sliced, drying tunnel (T4). All the eggplant flours showed the same trend regarding their antioxidant capacity and phenolic content in the order T2 > T4 > T1 > T3. The freezing of eggplant was found to have a negative effect on functional and antioxidant properties. With respect to their nutritional composition, the flours did not change in their crude fiber, protein, and fat contents. In general terms, the T2 flour is a potential ingredient for the preparation of foods with functional properties since it is rich in phenolic compounds and antioxidants.

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.

New steroidal saponins from the roots of Solanum melongena L.

Phytochemical investigation of the roots of Solanum melongena L. resulted in the isolation of six new steroidal saponins, including five new cholestane saponins (1-5) and one new steroidal alkaloid (6), along with one new natural product (7) and three know steroids (8-10). The structures of all isolated compounds were determined by 1D and 2D NMR experiments and by comparison of their spectroscopic and physical data with literature values. The inhibitory activities on nitric oxide (NO) production stimulated by lipopolysaccharide (LPS) in a RAW 264.7 cell line were assayed for all the isolated compounds. Compounds 1, 2 and 4-9 exhibited moderate inhibition of NO production with IC50 values ranging from 12.6 to 59.5 µM.

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.