Structural Studies of Mexican Husk Tomato (Physalis ixocarpa) Fruit Cutin.

Green tomato (Physalis ixocarpa) is a specie native to Mexico, and it is known as "tomatillo" or "husk tomato". The fruit contains vitamins, minerals, phenolic compounds, and steroidal lactones, presenting antimicrobial activity and antinarcotic effects. Therefore, it is not only used in traditional Mexican cuisine, but also in traditional medicine to relieve some discomforts such as fever, cough, and amygdalitis. However, it is a perishable fruit whose shelf life is very short. As a part of the peel, cuticle, and epicuticular waxes represent the most important part in plant protection, and the specific composition and structural characterization are significant to know how this protective biopolymer keeps quality characteristics in fresh fruits. P. ixocarpa cutin was obtained by enzymatic treatments (cellulase, hemicellulose, and pectinase) and different concentrations of TFA, and studied through Cross Polarization Magic Angle Spinning Nuclear Magnetic Resonance (CPMAS 13C NMR), Ultra-High Performance Liquid Chromatography coupled to Mass Spectrometry (UHPLC-MS), and was morphologically characterized by Confocal Laser Scanning Microscopy (CLSM) and Scanning Electron Microscopy (SEM). The main constituents identified under the basis of UHPLC-MS analysis were 9,10,18-trihydroxy-octadecanoic acid and 9,10-epoxy-18-hydroxy-octadecanoic acid with 44.7 and 37.5%, respectively. The C16 absence and low occurrence of phenolic compounds, besides the presence of glandular trichomes, which do not allow a continuous layer on the surface of the fruit, could be related to a lower shelf life compared with other common fruits such as tomato (Solanum lycopersicum).

Recovery of Naringin-Rich Flavonoid Extracts from Agroresidues with Anxiolytic- and Antidepressant-like Effects in Mice.

Citrus paradisi species belong to the Rutaceae family, and it is commonly known as grapefruit. Grapefruit consumption involves a large amount of waste that goes to landfills and produces significant pollution affecting the human health. To examine this phenomenon, we designed an efficient chemical method that recovers naringin-rich flavonoid extracts from the fresh waste of grapefruits, by using the solvent impregnation resin method (SIR) with XAD-4 amberlite and either methanol or water as elution systems. Additionally, we focused on evaluating these extracts' anxiolytic- and antidepressant-like effects in behavioral predictive paradigms in mice. According to direct Principal Component Analysis (PCA) by NMR, and Direct Injection Electrospray Ionization-Mass Spectrometry (DIESI-MS), methanol extracts obtained after resin treatment were free of coumarin compounds and evinced had a high content of naringin. Poncirin, phenylalanine, chrysin 5,7-dimethyl ether, 5,7-dimethoxy-4'-hydroxyflavanone, 2,3-dihydro-2-(4-hydroxyphenyl)-5,6,7,8-tetramethoxy-4H-1-benzopyran-4-one, tetrahydrocurcumin, corchoionoside C, 6'-coumaroyl-1'-O-[2-(3,4-dihydroxyphenyl) ethyl]-ß-D-glucopyranoside were also detected. Naringin-rich methanol extract caused a clear anxiolytic-like effect in the Elevated Plus Maze (EPM) and the Hole-Board (HBT) Tests, increasing oral doses of this extract did not produce a sedative effect. A single oral dose caused an antidepressant-like effect in the Tail Suspension Test (TST), while repeated administrations of the methanol extract elicited a robust antidepressant effect in the Forced Swimming Test (FST) in mice. Our evidence highlights the importance of bioprospecting studies of organic waste with therapeutic potentials, such as anxiety and depression disorders.

First Evidence of Gastroprotection by Schinus molle: Roles of Nitric Oxide, Prostaglandins, and Sulfhydryls Groups in Its Mechanism of Action.

Schinus molle is a plant traditionally used in Mexico to treat gastric disorders. However, no scientific evidence has been reported on its gastroprotective effect. The aim of the current contribution was to conduct a bioassay-guided study on S. molle to evaluate its gastroprotective activity in a model of Wistar rats given ethanol orally to induce gastric lesions. The hexane and dichloromethane extracts from the tested plant showed over 99% gastroprotection at a dose of 100 mg/kg. From the hexane extract, two of the three fractions (F1 and F2) afforded over 99% gastroprotection. The F1 fraction was subjected to column chromatography, which revealed a white solid. Based on the ESI-MS analysis, the two main compounds in this solid were identified. The predominant compound was probably a triterpene. This mixture of compounds furnished about 67% gastroprotection at a dose of 100 mg/kg. Pretreatment with L-NAME, indomethacin, and NEM was carried out to explore the possible involvement of nitric oxide, prostaglandins, and/or sulfhydryl groups, respectively, in the gastroprotective activity of the white solid. We found evidence for the participation of all three factors. No antisecretory activity was detected (tested by pylorus ligation). In conclusion, evidence is herein provided for the first time of the gastroprotective effect of S. molle.

Phenolic compounds profile by UPLC-ESI-MS in black beans and its distribution in the seed coat during storage.

Hard to cook phenomenon results from inadequate post-harvest storage of the bean associated with the microstructure and changes in seed color and texture. The aim of this study was to evaluate the physical and chemical properties, identify the phenolic compounds and their relationship with the black bean seed coat microstructure during 270 days at 30 °C and 70% r. h. The water absorption capacity decrease to 12.19% that induced changes in seed texture observed by increasing the hardness from 5.42 to 19.96 N. A total of 37 compounds were identified by UPLC-ESI-MS and the changes in phenolic profile during storage period contribute to the seed coat color saturation. The identification of flavonoids, hydroxybenzoic and hydroxycinnamic acids, as well as distribution of condensed tannins in the seed coat, the changes in physical properties evidenced by seed darkening and hardening contribute to the seed coat impermeability.

Gastroprotective activity of (E)-ethyl-12-cyclohexyl-4,5-dihydroxydodec-2-enoate, a compound isolated from Heliotropium indicum: role of nitric oxide, prostaglandins, and sulfhydryls in its mechanism of action.

CONTEXT: The gastroprotective effect of Heliotropium indicum L. (Boraginaceae), a plant traditionally used in Mexico to treat gastric ulcers, has been previously reported. However, no active compound was identified. OBJECTIVE: The current contribution aimed to isolate, through a bioassay-guided study, at least one compound from H. indicum with considerable gastroprotective activity, examine its effect on ethanol-induced gastric lesions in mice, and explore possible mechanisms of action. MATERIALS AND METHODS: Three extracts (hexane, dichloromethane, and methanol) were obtained from H. indicum leaves. Their 30 and 100 mg/kg doses were assessed on ethanol-induced gastric lesions in male CD1 mice. Since the dichloromethane extract was the most active, successive chromatographies were carried out leading to the identification of the most active compound. This compound (at 3-100 mg/kg) was compared to carbenoxolone (at 10-100 mg/kg) in biological evaluations in mice. Pre-treatments with indomethacin (10 mg/kg, s.c.), L-NAME (70 mg/kg, i.p.), and NEM (10 mg/kg, s.c.) were performed independently to determine the participation of prostaglandins, nitric oxide, and/or sulfhydryl groups, respectively, in the mechanism of action of the compound. RESULTS: (E)-Ethyl-12-cyclohexyl-4,5-dihydroxydodec-2-enoate, a compound isolated from H. indicum, afforded dose-dependent gastroprotective activity. The maximum effect was observed at 100 mg/kg (90.13 ± 3.08%), with an ED50 of 5.92 ± 2.48 mg/kg. Gastroprotection was not modified by pre-treatment with indomethacin, L-NAME, or NEM. CONCLUSIONS: (E)-Ethyl-12-cyclohexyl-4,5-dihydroxydodec-2-enoate, isolated from H. indicum, was found to produce a substantial gastroprotective effect. Prostaglandins, nitric oxide, and non-protein sulfhydryl groups are not involved in its mechanism of action.

Antioxidant and antihypertensive activity of Gouda cheese at different stages of ripening.

In Mexico, local ripened cheeses such as Chihuahua, Ranchero, and Cotija are produced, being consumed in great quantities together with imported cheeses. Proteolysis that takes place during ripening generates bioactive peptides; in this way the cheese acquires potential as a functional food. The ripening process of Gouda cheese was studied based on its bromatological and sensorial properties, bioactivity, and peptide profile. Ripened cheese met bromatological standard parameters and showed higher overall acceptability. After 90 days, bioactivity reached maximum values for radical scavenging (6.6%), ferric reducing power (11.2%), metal chelating effect (49%), and angiotensin I-converting enzyme inhibitory activity (66.2%). Eight peptides were identified, four from αS1-casein, f(1-9, 1-13, 1-14, and 25-36), and four from ß-casein, f(11-28, 60-63, 193-209, and 197-205). Ripening of Gouda cheese results in a product with functional potential due to the presence of peptides with biological activity. Additionally, the methodology proposed in this work could be used by the dairy industry to monitor the manufacturing process and ripening of other types of cheeses.

Antidepressant-like effects of a methanol extract of Leonotis nepetifolia in mice.

This study evaluated the antidepressant-like effects of a methanol extract of Leonotis nepetifolia in behavioural tests in mice. Our results showed that a single administration of the extract significantly reduced immobility behaviour in the tail suspension test, while three administrations were necessary to diminish immobility behaviour in the forced swimming test. A daily dose of the extract for 28 days improved body weight gain and significantly reduced corticosterone levels of mice exposed to chronic unpredictable mild stress. Metabolic profiling of the extract revealed that nepetaefolin, methoxynepataefolin, and 7-O-ß-glucoside luteolin were the main products. Acute and repeated administration of the extract produced antidepressant-like effects in animals subjected to chronic stress. Our results suggest the hypothalamus-hypophysis-adrenal axis participates in the antidepressant actions of the extract. These results show that alterations in behaviour elicited by stress can be prevented with L. nepetifolia treatment.

Cladodes: Chemical and structural properties, biological activity, and polyphenols profile.

The nopal cactus is an essential part of the Mexican diet and culture. The per capita consumption of young cladodes averages annually to 6.4 kg across the nation. In addition to contributing to the country's food culture, the nopal is considered a food with functional characteristics since, in addition to providing fiber, an important group of polyphenolic compounds is present, which has given cladodes to be considered a healthy food, for what they have been incorporated into the diet of Mexican people and many other countries worldwide. Research suggests that polyphenols from cladodes act as antioxidants and antidiabetics. This review studies the main phenolic components in cladodes and summarizes both conventional and novel methods to identify them.

Bean phenolic compound changes during processing: Chemical interactions and identification.

The common bean (Phaseolus vulgaris L.) represents one of the main crops for human consumption, due to its nutritional and functional qualities. Phenolic compounds have beneficial health effects, and beans are an essential source of these molecules, being found mainly in the seed coat and its color depends on the concentration and type of phenolic compounds present. The bean during storage and processing, such as cooking, germination, extrusion, and fermentation, undergoes physical, chemical, and structural changes that affect the bioavailability of its nutrients; these changes are related to the interactions between phenolic compounds and other components of the food matrix. This review provides information about the identification and quantification of phenolic compounds present in beans and the changes they undergo during processing. It also includes information on the interactions between the phenolic compounds and the components of the bean's cell wall and the analytical methods used to identify the interactions of phenolic compounds with macromolecules.

Calea zacatechichi Schltdl. (Compositae) produces anxiolytic- and antidepressant-like effects, and increases the hippocampal activity during REM sleep in rodents.

ETHNOPHARMACOLOGICAL RELEVANCE: Calea zacatechichi is a plant with an extensive popular and ritual use in Mexico. In healthy volunteers, it induces well-being and tranquility senses, and facilitates superficial stages of sleep. However, anxiolytic, and antidepressant-like effects and changes on the sleep-waking stages have not been explored. AIM: To determine anxiolytic and antidepressant-like effects of an aqueous extract of C. zacatechichi (CZ) in rodents and to analyze their effects on hippocampal activity in the rat sleep-waking cycle. MATERIAL AND METHODS: CZ anxiolytic- and antidepressant-like effects were evaluated in several mice and rat behavioral paradigms. CZ effects on temporal distribution of sleep were described, and hippocampus EEG frequency patterns were analyzed during the sleep-waking cycle; absolute and relative powers were analyzed during Rapid Eye Movements (REM) and non-REM sleep stages. CZ chemical analysis was performed by UPLC-ESI-MS. RESULTS: CZ produced specific and robust anxiolytic- and antidepressant-like effects in mice and rats, similar to those of prototypical drugs, at doses ranging from 0.5 to 50 mg/kg. CZ at 100 mg/kg produced visible mild sedative effects in rats, associated with a significant increase in Slow Wave Sleep episodes during a 6 h recording, and enhanced fast frequencies of hippocampus (gamma-band:31-50 Hz) during REM sleep. CONCLUSION: Results could support the well-being and tranquility senses reported by healthy consumers, and to explain the oneiric content during dreams and some improvements in cognitive processes described by consumers. Anxiolytic- and antidepressant-like effects of this species, reported for first time in this study could improve some aspects of mental health.

Avocado Creole Peel Ameliorates Metabolic Alterations Caused by a High Sucrose Fat Diet in a Wistar Rats Model.

High-sucrose high-fat diets are one of the causes of malnutrition, and may induce metabolic alterations such as dyslipidemia, insulin resistance, and adipogenesis. The objective of this work was to investigate the possible protective effect of traditionally edible avocado creole peel (Persea americana Mill var. drymifolia) when consuming a high-sucrose and fat diet (HSFD). The experimental animal model included 21 male Wistar rats divided in three groups: the control group received a standard diet of purina®, the HSFD group received a high fat diet plus 30% sucrose in drinking water, and finally the HSFD + AP group received the HSFD diet supplemented with 200 mg/kg of avocado peel for 14 weeks. It was observed that alterations included higher cholesterol, glucose, insulin, fatty acids and TNF-α levels as well as lower HDL, and adiponectin. The addition of avocado peel reverted some of these effects, resulting in normal values of triglicerides, insulin and adiponectin, while attenuated the levels of total cholesterol. Liver weight of the group added with avocado peel was similar to the control group. The neuronal density in the hippocampal areas CA1 and dentate gyrus DC were lower in the high glucose fat group, while the ingestion of the avocado peel showed a neuroprotective effect. The avocado creole ingestion reverted or attenuated most of the metabolic effects caused by a high-sucrose fat diet which was attributed to the compounds detected by HPLC-MS and GC-MS that included bioactive polyphenols such as flavanol quercetin, flavanone naringenin, flavan 3-ol catechin, cyanidin 3-glucoside, pelargonidin 3-glucoside, pelargonidin 3-rhamnoside, hydroxydelphinidin, eugenol and estragole.

Structural Studies of the Cutin from Two Apple Varieties: Golden Delicious and Red Delicious (Malus domestica).

The cuticle, a protective cuticular barrier present in almost all primary aerial plant organs, has a composition that varies between plant species. As a part of the apple peel, cuticle and epicuticular waxes have an important role in the skin appearance and quality characteristic in fresh fruits destined for human consumption. The specific composition and structural characteristics of cutin from two apple varieties, "golden delicious" and "red delicious", were obtained by enzymatic protocols and studied by means of cross polarization magic angle spinning nuclear magnetic resonance (CP-MAS 13C NMR), attenuated total reflection infrared spectroscopy (ATR-FTIR), and mass spectrometry, and were morphologically characterized by specialized microscopy techniques (atomic force microscopy (AFM), confocal laser scanning microscopy (CLMS), and scanning electron microscopy (SEM)). According to CP-MAS 13C NMR and ATR-FTIR analysis, cutins from both varieties are mainly composed of aliphatics and a small difference is shown between them. This was corroborated from the hydrolyzed cutins analysis by mass spectrometry, where 9,10,18-trihydroxy-octadecanoic acid; 10,20-Dihydroxy-icosanoic acid; 10,16-dihydroxy hexadecenoic acid (10,16-DHPA); 9,10-epoxy-12-octadecenoic acid; and 9,10-epoxy-18-hydroxy-12-octadecenoic acid were the main monomers isolated. The low presence of polysaccharides and phenolics in the cutins obtained could be related to the low elastic behavior of this biocomposite and the presence of cracks in the apple cutin's surface. These cracks have an average depth of 1.57 µm ± 0.57 in the golden apple, and 1.77 µm ± 0.64 in those found in the red apple. The results obtained in this work may facilitate a better understanding that mechanical properties of the apple fruit skin are mainly related to the specific aliphatic composition of cutin and help to much better investigate the formation of microcracks, an important symptom of russet formation.

Cutin from Solanum Myriacanthum Dunal and Solanum Aculeatissimum Jacq. as a Potential Raw Material for Biopolymers.

Plant cuticles have attracted attention because they can be used to produce hydrophobic films as models for novel biopolymers. Usually, cuticles are obtained from agroresidual waste. To find new renewable natural sources to design green and commercially available bioplastics, fruits of S. aculeatissimum and S. myriacanthum were analyzed. These fruits are not used for human or animal consumption, mainly because the fruit is composed of seeds. Fruit peels were object of enzymatic and chemical methods to get thick cutins in good yields (approximately 77% from dry weight), and they were studied by solid-state resonance techniques (CPMAS 13C NMR), attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), atomic force microscopy (AFM) and direct injection electrospray ionization mass spectrometry (DIESI-MS) analytical methods. The main component of S. aculeatissimum cutin is 10,16-dihydroxypalmitic acid (10,16-DHPA, 69.84%), while S. myriacanthum cutin besides of 10,16-DHPA (44.02%); another two C18 monomers: 9,10,18-trihydroxy-octadecanoic acid (24.03%) and 18-hydroxy-9S,10R-epoxy-octadecanoic acid (9.36%) are present. The hydrolyzed cutins were used to produce films demonstrating that both cutins could be a potential raw material for different biopolymers.

Aliphatic Diacidic Long-Chain C16 Polyesters from 10,16-Dihydroxyhexadecanoic Acid Obtained from Tomato Residual Wastes.

10,16-dihydroxyhexadecanoic acid obtained from agroresidual tomato waste, was oxidized to produce 7-oxohexadecanedioic acid in good yield (>70%) and purified without oxidation side products in one step. Polycondensation with 1,8-octanediol, yielded the polyester (poly(ω-carboxyl PA-co-OD)) with Mw = 2155.15 and Mn = 1637.27. The best enzymatic reaction conditions to get the polyester were using lipase CAL-B (%-by-wt relative to monomer) in toluene as a solvent for 1 h at 60 °C. The poly(ω-carboxyl PA-co-OD) was characterized by 1H- and 13C-NMR, mass spectrometry (MALDI-TOF) and the polyester film formed with a Langmuir-Blodgett Trough was analyzed by means of spectroscopic ellipsometry and atomic force microscopy.

Extraction and Identification of Anthocyanins in Corn Cob and Corn Husk from Cacahuacintle Maize.

Pigmented maize has been extensively studied due to its high anthocyanin content. This study has been focused mainly on kernel, although the whole plant of purple corn is a potential source of anthocyanins. First, general parameters of extraction (solvent system, solvent-to-solid ratio, number of extractions, and acid type) were established depending on the total anthocyanins content. Then, three extraction methods to access anthocyanins were compared: maceration extraction (ME), ultrasound-assisted extraction (UAE), and microwave-assisted extraction (MAE). Since the residual material still possessed an intense color, a further treatment was performed by application of enzymatic-assisted extraction (EAE). Three enzymatic cocktails (Xylanases, Celluclast, and Depol), pH, and temperature were evaluated to establish optimal reaction conditions. Subsequent analysis and identification of the anthocyanins obtained by four different extraction techniques were performed using HPLC and HPLC-mass spectrometry, respectively. The most efficient method was UAE using 20 min of ultrasound (100 W) preceded by sample treatment in the following conditions: ethanol/water/lactic acid mixture (80:19:1), two extractions, 1:10 solvent-to-solid ratio. As a result, anthocyanins from corn cob and corn husk were extracted at concentrations of 24.32 and 25.80 mg/gDW, respectively. No difference in the anthocyanins profile for samples extracted by three different methods was observed. However, an enhanced presence of cyanidin-3-(6''malonyl)glucoside was detected in the sample corresponding to the EAE method. Therefore, the Cahuacintle corn husk can be considered as a competitive source of anthocyanins with the available commercial sources. PRACTICAL APPLICATION: The by-products obtained from Cacahuacintle purple corn can be potentially used as natural colorants thanks to their anthocyanins content. In this work, we established the most efficient extraction method of anthocyanins from corn husk and corn cob, and demonstrated that their anthocyanins profile is comparable to other Peruvian purple corns, which are currently used as natural colorants. Therefore, the extraction procedure described in this study might be scaled-up in an industrial process to get access to anthocyanins from undervalued wastes.

Piper auritum Kunth (Piperaceae) improves the sexual performance of sluggish male rats through enhancing ejaculation.

ETHNOPHARMACOLOGICAL RELEVANCE: Piper auritum Kunth is employed as an aphrodisiac in the traditional medicine, but corroborative evidence for such effect is scarce. AIM OF THE STUDY: The pro-sexual effect of an aqueous extract of P. auritum and its possible mechanisms were analyzed in two paradigms of male sexual function. MATERIAL AND METHODS: Effects of an aqueous extract of P. auritum (PA, single administration) were investigated in the fictive ejaculation, and copulatory behavior paradigms in sexually sluggish male rats. WAY 100635 (antagonist of 5-HT1A receptors), atosiban (antagonist of oxytocinergic receptors), L-NAME (inhibitor of the nitric oxide synthase) and baclofen (antagonist of GABAB receptors) were used as pre-treatments in order to investigate the role of different neurotransmitter systems in PA actions. Chemical profile of PA was determined by Gases Chromatography and Ultra Performance Chromatography-Electrospray Ionization-Masses Spectrometry (UPLC-ESI-MS). RESULTS: In males with retarded ejaculation, PA stimulated ejaculatory behavior and recovered electromyographic activity of pelvic musculature participating in seminal emission and ejaculation. All pre-treatments blocked stimulating effects of PA on the fictive ejaculation; additionally WAY 100635 interfered with PA actions on ejaculatory behavior. Safrol, apigenin dimethylether, myristicin, vaccihein A, sakuranin and sakuranetin flavonoids, were main constituents of PA, with possible participation in its pro-sexual effects. CONCLUSIONS: Pro-sexual effects of P. auritum elicited at level of ejaculation were mediated by several neurotransmitter systems, among which serotonin and its 5-HT1A receptors play an important role. Present findings support P. auritum reputation as an aphrodisiac, with potential use in delayed ejaculation disorder.

The Timing of Melatonin Administration Is Crucial for Its Antidepressant-Like Effect in Mice.

Melatonin is synthesized by the pineal gland with a circadian rhythm in synchrony with the environmental light/dark cycle. A gradual increase in circulating levels of melatonin occur after lights off, reaching its maximum around the middle of the dark phase. Agonists of melatonin receptors have proved effectiveness as antidepressants in clinical trials. However, there is contradictory evidence about the potential antidepressant effect of melatonin itself. Herein we studied melatonin administration in mice at two zeitgeber times (ZT; ZT = 0 lights on; 12:12 L/D), one hour before the beginning (ZT11) and at the middle (ZT18) of the dark phase after either a single or a three-dose protocol. Behavioral despair was assessed through a forced-swimming test (FST) or a tail suspension test (TST), at ZT18.5. A single dose of 4 mg/kg melatonin at ZT11 was effective to reduce the immobility time in both tests. However, acute administration of melatonin at ZT18 was not effective in mice subjected to FST, and a higher dose (16 mg/kg) was required to reduce immobility time in the TST. A three-dose administration protocol of 16 mg/kg melatonin (ZT18, ZT11, and ZT18) significantly reduced immobility time in FST. Data indicate that the timely administration of melatonin could improve its antidepressant-like effect.

Lipase-Catalyzed Synthesis of Fatty Acid Esters of Trisaccharides.

Carbohydrate fatty acid esters have a broad spectrum of applications in the food, cosmetic, and pharmaceutical industries. The enzyme-catalyzed acylation is significantly more selective than the chemical process and is carried out at milder conditions. Compared with mono- and disaccharides, the acylation of trisaccharides has been less studied. However, trisaccharide esters display notable bioactive properties, probably due to the higher hydrophilicity of the sugar head group. In this chapter, we describe the acylation of two trisaccharides, maltotriose and 1-kestose, catalyzed by different immobilized lipases, using vinyl esters as acyl donors. To illustrate the potential of such compounds, the antitumor activity of 6″-O-palmitoyl-maltotriose is shown.

Esters of Quinoxaline 1`4-Di-N-oxide with Cytotoxic Activity on Tumor Cell Lines Based on NCI-60 Panel.

Quinoxalines display diverse and interesting pharmacological activities as antibacterial, antiviral, antiparasitic and anticancer agents. Particularly, their 1`4-di-N-oxide derivatives have proved to be cytotoxic agents that are active under hypoxic conditions as that of solid tumours. A new series of quinoxaline 1`4-di-N-oxide substitutes at 7-position with esters group were synthetized and characterized by infrared (IR), proton nuclear magnetic resonance (1H-NMR), spectroscopy, and elemental analysis. Seventeen derivatives (M1-M3, E1-E8, P1-P3 and DR1-DR3) were selected and evaluated for antitumor activities using the NCI-60 human tumor cell lines screen. Results showed that E7, P3 and E6 were the most active compounds against the cell lines tested. Substitutions at 7-position with esters group not necessarily affect the biological activity, but the nature of the esters group could exert an influence on the selectivity. Additionally, substitutions at 2-position influenced the cytotoxic activity of the compounds.

Comparative studies of cutins from lime (Citrus aurantifolia) and grapefruit (Citrus paradisi) after TFA hydrolysis.

Grapefruit and lime cutins were analyzed and compared in order to obtain information about their cutin architecture. This was performed using a sequential hydrolysis, first with trifluoroacetic acid to remove most of the polysaccharides present in the cutins, followed by an alkaline hydrolysis in order to obtain the main aliphatic compounds. Analysis by CPMAS 13C NMR and ATR FT-IR of the cutins after 2.0 M TFA revealed that grapefruit cutin has independent aliphatic and polysaccharide domains while in the lime cutin these components could be homogeneously distributed. These observations were in agreement with an AFM analysis of the cutins obtained in the hydrolysis reactions. The main aliphatic compounds were detected and characterized as 16-hydroxy-10-oxo-hexadecanoic acid and 10,16-dihydroxyhexadecanoic acid. These were present in grapefruit cutin at 35.80% and 21.86% and in lime cutin at 20.44% and 40.36% respectively.