Lavandula angustifolia mill. (Lamiaceae) ethanol extract and its main constituents as promising agents for the treatment of metabolic disorders: chemical profile, in vitro biological studies, and molecular docking.

Lavandula angustifolia Mill. (lavender) is one of the most used medicinal plants. Herein, we chemically characterised and investigated the antioxidant properties and the capability to inhibit key enzymes for the treatment of type 2 diabetes (TD2) and obesity such as pancreatic lipase, α-glucosidase, and α-amylase of the ethanolic extract of two lavender samples (La1 and La2) from southern Italy. Both extracts significantly inhibited α-glucosidase, while La1 inhibited α-amylase and lipase more effectively than La2. To investigate whether these properties could be due to a direct interaction of the main constituents of the extracts with the targeted enzymes, molecular docking studies have been performed. As a result, the selected compounds were able to interact with the key residues of the binding site of the three proteins, thus supporting biological data. Current findings indicate the new potential of lavender ethanolic extract for the development of novel agents for T2D and obesity.

Antibacterial activity and chemical characterization of almond (Prunus dulcis L.) peel extract.

In this study, almond skin of Prunus dulcis L. variety Casteltermini was characterised for its chemical composition and for the inhibitory activity towards food associated microorganisms belonging to pathogenic (Salmonella Enteritidis, Staphylococcus aureus, Escherichia coli and Listeria monocytgenes), spoilage (Pseudomonas poae and Brochotrix thermospacta) and useful (Levilactobacillus brevis and Saccharomyces cerevisiae) groups. The n-hexane extract of P. dulcis skin, investigated by GC-MS, evidenced linoleic, palmitic, and oleic acids as the main abundant compounds. Staphylococcus aureus ATCC 33862 growth was strongly limited by n-hexane extract and the minimum inhibition concentration (MIC) was 25.5 mg/mL. These results highlight the potential of almond by-products as food bio-preservatives as well as pharmaceutical products.

Production of High-Quality Red Fruit Juices by Athermal Membrane Processes.

Membrane-based processes are increasingly used to clarify and concentrate thermo-sensitive fruit juices and plant extracts as alternatives to conventional processes. This work aimed to evaluate the quality of red fruit juices clarified and concentrated by an integrated membrane process with special regard to the preservation of valuable compounds. A red fruit juice obtained from a blend of pomegranate, cactus pear, and red orange juices of Sicilian origin was clarified by microfiltration (MF) and then pre-concentrated up to 33 °Brix by nanofiltration (NF). The pre-concentrated juice was finally concentrated by osmotic distillation (OD) up to 50 and 60 °Brix. Samples of clarified, pre-concentrated, and concentrated juice were analyzed for their physico-chemical composition and in terms of the antioxidant activity and inhibitory activity against α-amylase and lipase. The results clearly confirmed the assumption of a mild fruit juice processing method, allowing us to preserve the original nutritional and functional properties of the fresh juice. In particular, the OD retentate at 60 °Brix resulted the most active sample against pancreatic lipase and α-amylase inhibitory activity with IC50 values of 44.36 and 214.65 µg/mL, respectively.

Advances on Natural Abietane, Labdane and Clerodane Diterpenes as Anti-Cancer Agents: Sources and Mechanisms of Action.

Extensive research over the past decades has identified numerous phytochemicals that could represent an important source of anti-cancer compounds. There is an immediate need for less toxic and more effective preventive and therapeutic strategies for the treatment of cancer. Natural compounds are considered suitable candidates for the development of new anti-cancer drugs due to their pleiotropic actions on target events with multiple manners. This comprehensive review highlighted the most relevant findings achieved in the screening of phytochemicals for anticancer drug development, particularly focused on a promising class of phytochemicals such as diterpenes with abietane, clerodane, and labdane skeleton. The chemical structure of these compounds, their main natural sources, and mechanisms of action were critically discussed.

An Overview of Traditional Uses, Phytochemical Compositions and Biological Activities of Edible Fruits of European and Asian Cornus Species.

Cornus species are widely distributed in central and southern Europe, east Africa, southwest Asia, and America. Several species are known for edible fruits, especially Cornus mas and Cornus officinalis. These delicious fruits, characterized by their remarkable nutritional and biological values, are widely used in traditional medicine. In contrast to the other edible Cornus species, C. mas and C. officinalis are the most studied for which little information is available on the main phytochemicals and their biological activities. Fruits are characterised by several classes of secondary metabolites, such as flavonoids, phenolic acids, lignans, anthocyanins, tannins, triterpenoids, and iridoids. The available phytochemical data show that the different classes of metabolites have not been systematically studied. However, these edible species are all worthy of interest because similarities have been found. Thus, this review describes the traditional uses of Cornus species common in Europe and Asia, a detailed classification of the bioactive compounds that characterize the fruits, and their beneficial health effects. Cornus species are a rich source of phytochemicals with nutritional and functional properties that justify the growing interest in these berries, not only for applications in the food industry but also useful for their medicinal properties.

Evaluation of Selected Quality Parameters of "Agristigna" Monovarietal Extra Virgin Olive Oil and Its Apple Vinegar-Based Dressing during Storage.

This study aimed to investigate the quality parameters and the oxidative stability (180 days of storage) of a water-oil emulsion formulated with Calabrian (Italy) monovarietal Agristigna extra virgin olive oil and apple vinegar. The best extra virgin olive oil/apple vinegar ratio was found to be 85/15 (v/v) and lecithin (2% w/v) was the best additive to reach proper stability and viscosity over time. An increase of lightness parameters was evidenced in both products in a storage time-dependent manner. During storage, both oil and dressing showed a free acidity level beyond the accepted limit for extra virgin olive oil, whereas a slight increase of the peroxide value was observed only for Glasoil at the end of the observation time without affecting sensory attributes. A general decrease of phytochemicals was observed for extra virgin olive oil and Glasoil, with different reduction trends and degrees depending on the chemical class. A lower stability of Glasoil during shelf-life was confirmed by the worsening of the rheological features and by the polyunsaturated fatty acids reduction (up to -21.71%) with a corresponding increase of the monounsaturated fatty acids/polyunsaturated fatty acids ratio (about +25.69%).

Almond (Prunus dulcis cv. Casteltermini) Skin Confectionery By-Products: New Opportunity for the Development of a Functional Blackberry (Rubus ulmifolius Schott) Jam.

This work proposes for the first time a model for reusing almond (Prunus dulcis cv. Casteltermini from Sicily, Southern Italy) skin to formulate a new functional blackberry (Rubus ulmifolius Schott) jam. For this purpose, blackberries were analysed fresh and as jam, traditionally prepared with a minimum fruit amount of 80%. Different percentages of almond skin (20, 15, and 10% w/w) were added to jam. The phytochemical profile of enriched jam was investigated by LC-ESI/LTQOrbitrap/MS analyses. Anthocyanins, hydrolysable tannins, and triterpenoids were identified in a blackberry extract, while proanthocyanidins, flavonoids, and oxylipins were identified in an almond extract. The n-hexane extract of P. dulcis skin, investigated by GC-MS, evidenced linoleic, palmitic, and oleic acids as the main abundant compounds. Samples were investigated for their antioxidant activity using DPPH, ABTS, ß-carotene, and FRAP tests. The hypoglycaemic and hypolipidemic effects were studied by α-amylase, α-glucosidase, and lipase inhibitory assays. In order to evaluate the effect of thermal process on enriched jam bioactivity, pasteurisation was applied. An increase in activities for all samples was observed, in particular for jam enriched with 20% w/w of almond skin. Based on obtained data, and supported by sensory analysis, we propose enriched jam as a promising source of compounds useful for preventing diseases associated with oxidative stress.

Concentration of Bioactive Phenolic Compounds in Olive Mill Wastewater by Direct Contact Membrane Distillation.

Olive mill wastewater (OMW), generated as a by-product of olive oil production, is considered one of the most polluting effluents produced by the agro-food industry, due to its high concentration of organic matter and nutrients. However, OMW is rich in several polyphenols, representing compounds with remarkable biological properties. This study aimed to analyze the chemical profile as well as the antioxidant and anti-obesity properties of concentrated fractions obtained from microfiltered OMW treated by direct contact membrane distillation (DCMD). Ultra-high performance liquid chromatography (UHPLC) analyses were applied to quantify some phenols selected as phytochemical markers. Moreover, α-Amylase, α-glucosidase, and lipase inhibitory activity were investigated together with the antioxidant activity by means of assays, namely ß-carotene bleaching, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic) acid (ABTS) diammonium salts, 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, and Ferric Reducing Activity Power (FRAP) tests. MD retentate-which has content of about five times greater of hydroxytyrosol and verbascoside and about 7 times greater of oleuropein than the feed-was more active as an antioxidant in all applied assays. Of interest is the result obtained in the DPPH test (an inhibitory concentration 50% (IC50) of 9.8 µg/mL in comparison to the feed (IC50 of 97.2 µg/mL)) and in the ABTS assay (an IC50 of 0.4 µg/mL in comparison to the feed (IC50 of 1.2 µg/mL)).

New Insights into the Antioxidant and Anti-Inflammatory Effects of Italian Salvia officinalis Leaf and Flower Extracts in Lipopolysaccharide and Tumor-Mediated Inflammation Models.

This work aimed to investigate and compare the in vitro antioxidant and anti-inflammatory effects of Salvia officinalis L. (sage) from Italy, with the aim of raising its current knowledge in this field. Leaves and flowers (S1-S8), harvested in two areas of Southern Italy, were extracted with methanol as a solvent by maceration or ultrasound-assisted extraction. Sage extracts, analysed by high pressure liquid chromatography-diode-array detection-electrospray ionization-quadrupole-mass spectroscopy (HPLC-DAD-ESI-Q-MS), exerted a promising antioxidant activity investigated using ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), and ß-carotene bleaching tests, and elicited a significant decrease in reactive oxygen species (ROS) production in lipopolysaccharide (LPS)-stimulated RAW 264.7 murine macrophages. The anti-inflammatory activity was analysed in the same in vitro model. All the extracts did not affect cell viability although they showed anti-inflammatory activity, as they induced a decrease in nitrite levels that was greater than 50%, when employed at 50 µg/mL. Furthermore, they elicited a decrease in nitrite levels, as well as a decline in pro-inflammatory cytokine expression. The NF-κB transcription factor proved to be involved in the mechanisms that underlie such effects. Interestingly, sage extracts were able to interfere with the inflammatory activity induced by breast cancer cell-conditioned media (nitrite levels were significantly decreased, p < 0.05; p < 0.01), highlighting for the first time the important role of S. officinalis in controlling inflammation processes related to neoplastic progression.

LC-ESI/HRMS analysis of glucosinolates, oxylipins and phenols in Italian rocket salad (Diplotaxis erucoides subsp. erucoides (L.) DC.) and evaluation of its healthy potential.

BACKGROUND: This study investigated the chemical profile and biological activity of Diplotaxis erucoides subsp. erucoides (L.) DC. (Brassicaceae) collected in Sicily (Italy). RESULTS: Liquid chromatography coupled with electrospray ionization and high-resolution mass spectrometry (LC-ESI/HRMS) analysis of the ethanol extract revealed the presence of 42 compounds - glucosinolates, hydroxycinnamic acids, flavonoids, and oxylipins. The extract was tested for its antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic) acid (ABTS), ferric reducing ability power (FRAP), and ß-carotene bleaching tests. Promising protection from lipid peroxidation was observed after 30 min of incubation in a ß-carotene bleaching test (IC50 of 3.32 µg mL-1 ). The inhibition of carbohydrates-hydrolyzing enzymes resulted in IC50 values of 85.18 and 92.36 µg mL-1 for α-amylase and α-glucosidase, respectively. Significant inhibition against lipase enzyme was observed (IC50 of 61.27 µg mL-1 ). CONCLUSION: Diplotaxis erucoides can be considered a potential source of antioxidant, hypoglycemic, and hypolipidemic bioactives. © 2021 Society of Chemical Industry.

In vitro and in vivo studies of Cucurbita pepo L. flowers: chemical profile and bioactivity.

Edible flowers consumption has increased in recent years due to their rich content of healthy phytochemicals. The aim of this study was to analyse the chemical profile of Cucurbita pepo L. flowers, and to explore their antioxidant and hypoglycaemic properties. Moreover, in order to assess in vivo effects, biochemical analysis, Reactive Oxygen Metabolites (d-ROMs) and Biological Antioxidant Potential (BAP) tests were performed on mice serum. High Performance Liquid Chromatography-Diode Array Detection (HPLC-DAD) analyses revealed the presence of (+)-catechin, (-)-epicatechin, rutin, and syringic acid as main constituents. 2,2'-Azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and Ferric Reducing Antioxidant Power (FRAP) tests showed interesting results. The extract exhibited the strongest inhibitory effect on α-glucosidase (IC50 of 144.77 µg/mL). In vivo results confirmed the hypoglycaemic effects, also affecting lipid metabolism but did not revealed benefits on ROS production. These results may add some information supporting the use of C. pepo flowers as functional foods and/or nutraceuticals.

In vitro anti-proliferative and anti-bacterial properties of new C7 benzoate derivatives of pinocembrin.

In the present work, the in vitro anti-proliferative and anti-bacterial activities of three semi-synthetic benzoate pinocembrin derivatives, isolated from the aerial parts of Glycyrrhiza glabra L., were investigated. As occurs in most natural compounds, the bioavailability of pinocembrin is very poor, therefore it should be improved by chemical strategies aimed to prolong its shelf life and, consequently, its activity. On this basis, three benzoate derivatives of pinocembrin (a1-a3) were synthesised and assayed in order to ascertain their biological value. Among them, compound a1 showed the highest anti-proliferative activity on a wide panel of cancer cell lines, as well as low toxic effects on non-malignant breast cells. The calculated IC50 values in HeLa and SKBR3 cells were 8.5 and 12.7 µM, respectively. Briefly, a1 treatment increased ROS levels, induced mitochondrial membrane damage leading to necrotic death of HeLa cells. Moreover, a1 displayed a promising anti-bacterial activity.

The Effect of Blanching on Phytochemical Content and Bioactivity of Hypochaeris and Hyoseris Species (Asteraceae), Vegetables Traditionally Used in Southern Italy.

The impact of blanching on the phytochemical content and bioactivity of Hypochaeris laevigata (HL), Hypochaeris radicata (HR), Hyoseris radiata (HRA), and Hyoseris lucida subsp. taurina (HT) leaves was studied and compared to fresh plant materials and residual blanching water. For this purpose, total phenols, flavonoids, carotenoids, and chlorophyll contents were quantified. The antioxidant effect was investigated by using different in vitro tests (ß-carotene, ferric reducing ability power (FRAP), 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH), whereas the potential inhibitory activity of key enzymes linked to obesity was screened against lipase, α-amylase, and α-glucosidase. Generally, the phytochemical content followed the trend: fresh > blanching water > blanched samples. The same trend was observed in the antioxidant activity independently of the applied test as well as in the inhibition of lipase and carbohydrates-hydrolysing enzymes. In particular, fresh Hypochaeris laevigata (HL1) showed the lowest inhibitory concentration 50% (IC50) values of 31.3 and 42.7 µg/mL, against α-glucosidase and α-amylase, respectively, whereas fresh Hyoseris radiata (HRA1) showed the most promising hypolipidemic activity (IC50 value of 39.8 µg/mL). Collectively, these results support the health effect of these wild plants and demonstrated that blanching water should be reused in food preparation since it is a good source of bioactive compounds and its consumption should be recommended in order to increase the uptake of micronutrients.

Chemical Profile, Antioxidant, Anti-Inflammatory, and Anti-Cancer Effects of Italian Salvia rosmarinus Spenn. Methanol Leaves Extracts.

In this study, we evaluated and compared the chemical composition, the antioxidant, anti-inflammatory, and anti-proliferative effects of four methanol extracts (R1-R4), of Salvia rosmarinus Spenn. in two different sites of Southern Italy obtained by maceration or ultrasound-assisted extraction. Extracts of S. rosmarinus collected on the Ionian coast are indicated with the abbreviations R1 (maceration) and R2 (ultrasound-assisted extraction). Extracts of S. rosmarinus collected on the Tyrrhenian coast are indicated with the abbreviations R3 (maceration) and R4 (ultrasound-assisted extraction). The chemical composition was analyzed using High Pressure liquid chromatography-Diod-Array detection-Electrospray ionization-Quadrupole-Mass Spectroscopy (HPLC-DAD-ESI-Q-MS). The antioxidant activity was analyzed by 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) 2,2-diphenyl-1-picrylhydrazyl (DPPH), ß-carotene bleaching, and Ferric Reducing Antioxidant Power (FRAP) assays. Antioxidant features were also assessed in lipopolysaccharide (LPS)-stimulated RAW-264.7 murine macrophages, evaluating Reactive Oxygen Species (ROS) production; in the same experimental model, the anti-inflammatory activity of the extracts was investigated. Interestingly, all extracts displayed antioxidant and anti-inflammatory properties. They exhibited significative nitrite production inhibitory activity, whith IC50 values ranging from 3.46 to 5.53 µg/mL, without impairing cell viability. The anti-inflammatory activity was also investigated by Western Blotting and immunofluorescence assay, highlighting the R3 and R4 extracts ability to reduce NF-κB translocation, as well as to disrupt the MAPKs signaling pathway. Extracts exhibited both potential anti-proliferative activity on breast cancer cells, inducing apoptosis, without affecting non-tumorigenic cells, and the ability to inhibit MDA-MB-231 cells' motility. Finally, the rosemary extracts treatment significantly reduced the power of conditioned media, from MCF-7 or MDA-MB-231 cells to induce nitrite production on RAW 264.7 cells, confirming their promising anti-inflammatory activity.

Ferulago nodosa Subsp. geniculata (Guss.) Troia & Raimondo from Sicily (Italy): Isolation of Essential Oil and Evaluation of Its Bioactivity.

Ferulago nodosa (L.) Boiss. (Apiaceae) is a species occurring in the Balkan-Tyrrhenian area. The object of the present study is Sicilian F. nodosa subsp. geniculata (Guss.) Troia & Raimondo, classified as an endemic F. nodosa subspecies. Aerial parts of this plant species were subjected to hydrodistillation to obtain an essential oil. A total of 93 compounds were identified with 2,3,6-trimethyl benzaldehyde (19.0%), spathulenol (9.0%), (E)-caryophyllene (5.4%), and caryophyllene oxide (5.4%) as the main components. The biological activities of F. nodosa essential oil were also investigated. This oil showed an interesting antioxidant potential in a 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) test (IC50 of 14.05 µg/mL). Additionally, hypoglycemic and antilipidemic effects were evaluated. Lipase enzyme was inhibited with an IC50 value of 41.99 µg/mL. Obtained data demonstrated that F. nodosa could be considered a promising source of bioactive compounds useful for the treatment and management of obesity.

Olive Mill Wastewater Polyphenol-Enriched Fractions by Integrated Membrane Process: A Promising Source of Antioxidant, Hypolipidemic and Hypoglycaemic Compounds.

The valorisation of food wastes is a challenging opportunity for the green, sustainable, and competitive development of industry. The recovery of phenols contributes to the sustainability of olive waste sector, reducing its environmental impact and promoting the development of innovative formulations of interest for pharmaceutical, nutraceutical, and cosmeceutical applications. In this work, olive mill wastewater was treated through a combination of microfiltration (MF), nanofiltration (NF), and reverse osmosis (RO) in a sequential design to produce polyphenol-enriched fractions that have been investigated for their chemical profile using ultra-high-performance liquid chromatography (UHPLC), and their potential antioxidant, hypolipidemic, and hypoglycaemic activities. RO retentate exhibited the highest content of hydroxytyrosol, tyrosol, oleuropein, verbascoside, vanillic acid, and luteolin. In particular, a content of hydroxytyrosol of 1522.2 mg/L, about five times higher than the MF feed, was found. RO retentate was the most active extract in all in vitro tests. Interestingly, this fraction showed a 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic) acid (ABTS) radicals scavenging activity with an IC50 value of 6.9 µg/mL and a potential inhibition of lipid peroxidation evaluated by the ß-carotene bleaching test with IC50 values of 25.1 µg/mL after 30 min of incubation. Moreover, RO retentate inhibited α-amylase and α-glucosidase with IC50 values of 65.3 and 66.2 µg/mL, respectively.

Ceiba speciosa (A. St.-Hil.) Seeds Oil: Fatty Acids Profiling by GC-MS and NMR and Bioactivity.

This study aimed to evaluate the chemical composition by gas chromatography-mass spectrometry (GC-MS) and Nuclear Magnetic Resonance (NMR) analyses, the antioxidant activities evaluated by different in vitro assays namely 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), Ferric Reducing Ability Power (FRAP), and ß-carotene bleaching tests, and the inhibitory effects of enzymes linked to obesity (lipase, α-amylase, and α-glucosidase) of fixed seed oil of Ceiba speciosa (A. St.-Hil.). Fourteen compounds were identified. Linoleic acid (28.22%) was the most abundant followed by palmitic acid (19.56%). Malvalic acid (16.15%), sterculic acid (11.11%), and dihydrosterculic acid (2.74%) were also detected. C. speciosa fixed oil exerted a promising ABTS radicals scavenging activity with an IC50 value of 10.21 µg/mL, whereas an IC50 of 77.44 µg/mL against DPPH+ radicals was found. C. speciosa fixed oil inhibited lipase with an IC50 value of 127.57 µg/mL. The present investigation confirmed the functional properties of C. speciosa fixed oil, and proposes its use as valuable source of bioactive constituents.

High-Performance Liquid Chromatography/Electrospray Ionization Tandem Mass Spectrometry (HPLC-ESI-MSn) Analysis and Bioactivity Useful for Prevention of "Diabesity" of Allium commutatum Guss.

This study aimed at evaluating and comparing the chemical profile obtained by HPLC-ESI-MSn analysis, the inhibitory activity of enzymes linked to obesity (α-amylase, α-glucosidase, and lipase) and the antioxidant properties (DPPH, ABTS, FRAP, and ß-carotene bleaching tests) of ethanol extracts of bulbs (BE) and aerial parts (APE) from Allium commutatum Guss. (known in Italy as "aglio delle isole"). The chemical profile revealed alliin as the main abundant compound with values of 31.5 and 38.8 mg/g extract for BE and APE, respectively. APE is rich also in quercetin (38.5 mg/g extract) and luteolin (31.8 mg/g extract). Bulbs extract exhibited the highest activity as inhibitor of enzymes linked to obesity. Except for DPPH test, APE showed the highest antioxidant potential with IC50 of 7.6 and 56.6 µg/mL in ABTS and ß-carotene bleaching test after 60 min of incubation, respectively. In conclusion, the present investigation revealed A. commutatum bulbs and aerial parts as a promising source of inhibitors of enzyme linked to the obesity and of antioxidant compounds.

Flower and Leaf Extracts of Sambucus nigra L.: Application of Membrane Processes to Obtain Fractions with Antioxidant and Antityrosinase Properties.

This study aimed at evaluating and comparing the chemical profile as well as the antityrosinase and antioxidant activities of ethanol (EtOH) and methanol (MeOH) extracts of Sambucus nigra L. (Adoxaceae) flowers and leaves in order to discover new candidates for food additives and cosmetic and pharmaceutical products. For this purpose, a novel lower-melting-point ethylene-chlorotrifluoroethylene (LMP ECTFE) nanofiltration (NF) membrane was employed in order to produce the concentrated fractions of S. nigra. Floral extracts were richer in phytochemicals in comparison to the leaf extracts. The High-performance liquid chromatography (HPLC) profile revealed rutin, quercetin, protocateuchic acid, 3,5-dicaffeoylquinic acid, and neochlorogenic acid as the most abundant compounds. Ferric reducing antioxidant power (FRAP), 2,2'-diphenil-1-picrylhydrazil (DPPH) radical scavenging, and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) tests were used to investigate the antioxidant properties. NF retentate fractions of floral ethanol extracts exerted the highest tyrosinase inhibitory activity with an IC50 of 53.9 µg/mL and the highest ABTS radical scavenging activity (IC50 of 46.4 µg/mL). In conclusion, the present investigation revealed the potential benefits of NF application in S. nigra extracts processing, suggesting the use of retentate fractions as a promising source for antioxidant and tyrosinase inhibitory compounds which could pave the way for future applications.

Cytotoxicity of cucurbitacin E from Citrullus colocynthis against multidrug-resistant cancer cells.

BACKGROUND: Cucurbitacin E (CuE) is an oxygenated tetracyclic triterpenoid isolated from the fruits of Citrullus colocynthis (L.) Schrad. PURPOSE: This study outlines CuE's cytotoxic activity against drug-resistant tumor cell lines. Three members of ABC transporters superfamily, P-glycoprotein (P-gp), breast cancer resistance protein (BCRP) and ABCB5 were investigated, whose overexpression in tumors is tightly linked to multidrug resistance. Further factors of drug resistance studied were the tumor suppressor TP53 and the epidermal growth factor receptor (EGFR). METHODS: Cytotoxicity assays (resazurin assays) were used to investigate the activity of Citrullus colocynthis and CuE towards multidrug resistant cancer cells. Molecular docking (In silico) has been carried out to explore the CuE's mode of binding to ABC transporters (P-gp, BCRP and ABCB5). The visualization of doxorubicin uptake was done by a Spinning Disc Confocal Microscope. The assessment of proteins expression was done by western blotting analysis. COMPARE and hierarchical cluster analyses were applied to identify, which genes correlate with sensitivity or resistance to cucurbitacins (CuA, CuB, CuE, CuD, CuI, and CuK). RESULTS: Multidrug-resistant cells overexpressing P-gp or BCRP were cross-resistant to CuE. By contrast, TP53 knock-out cells were sensitive to CuE. Remarkably, resistant cells transfected with oncogenic ΔEGFR or ABCB5 were hypersensitive (collateral sensitive) to CuE. In silico analyses demonstrated that CuE is a substrate for P-gp and BCRP. Immunoblot analyses highlighted that CuE targeted EGFR and silenced its downstream signaling cascades. The most striking result that emerged from the doxorubicin uptake by ABCB5 overexpressing cells is that CuE is an effective inhibitor for ABCB5 transporter when compared with verapamil. The COMPARE analyses of transcriptome-wide expression profiles of tumor cell lines of the NCI identified common genes involved in cell cycle regulation, cellular adhesion and intracellular communication for different cucurbitacins. CONCLUSION: CuE represents a potential therapeutic candidate for the treatment of certain types of refractory tumors. To best of our knowledge, this is the first time to identify CuE and verapamil as inhibitors for ABCB5 transporter.