Phyto-Courier, a Silicon Particle-Based Nano-biostimulant: Evidence from Cannabis sativa Exposed to Salinity.

peer reviewedGlobal warming and sea level rise are serious threats to agriculture. The negative effects caused by severe salinity include discoloration and reduced surface of the leaves, as well as wilting due to an impaired uptake of water from the soil by roots. Nanotechnology is emerging as a valuable ally in agriculture: several studies have indeed already proven the role of silicon nanoparticles in ameliorating the conditions of plants subjected to (a) biotic stressors. Here, we introduce the concept of phyto-courier: hydrolyzable nanoparticles of porous silicon, stabilized with the nonreducing saccharide trehalose and containing different combinations of lipids and/or amino acids, were used as vehicle for the delivery of the bioactive compound quercetin to the leaves of salt-stressed hemp (Cannabis sativa L., Santhica 27). Hemp was used as a representative model of an economically important crop with multiple uses. Quercetin is an antioxidant known to scavenge reactive oxygen species in cells. Four different silicon-based formulations were administered via spraying in order to investigate their ability to improve the plant's stress response, thereby acting as nano-biostimulants. We show that two formulations proved to be effective at decreasing stress symptoms by modulating the amount of soluble sugars and the expression of genes that are markers of stress-response in hemp. The study proves the suitability of the phyto-courier technology for agricultural applications aimed at crop protection

Physical methods for enhancing oral mucosal delivery: Sonophoresis, iontophoresis and electroporation methods

The need for more rapid onset of action and improved absorption of medications has resulted in great development of drug delivery technologies. Transmucosal drug delivery offers a convenient route of administration for a variety of clinical indications. Unfortunately, the wide variability in structure of the oral mucosal tissues could constitute a key factor in drug penetration and absorption. To circumvent this obstacle and to increase the drug flux through the mucosal membranes, different approaches to permeation enhancement are used. This chapter describes the most significant aspects of the physical techniques widely used such as sonophoresis, iontophoresis, and electroporation. These physical methods are extensively used to enhance drug permeation through the skin, nevertheless, they have some infrequent applications on the mucosae of the oral cavity despite are very promising. In the future, these methods could be further developed and improved

Acetaldehyde operant self-administration in rats: focus on D2-receptor activation.

Acetaldehyde (ACD), ethanol first metabolite, is rewarding in rodents and humans; it induces “place preference”, is self-administer directly in the VTA, orally in an operant/conflict paradigm and increases DA neurons’ firing. This research aims at investigating DA2-receptor role in the reinstatement of acetaldehyde operant-drinking behaviour, following induction, maintenance and abstinence in the rat. Male Wistar rats are trained to orally self-administer ACD solution (3.2% v/v) or water, in an operant chamber under a FR1. Afterwards animals undergo cyclic periods of deprivation and relapse to ACD. The effect ofD2-receptor activation by quinpirole (0.03mg/kg,i.p.) on operant ACD self-administration is tested during relapse sessions. Rats show a peak-and-drop drinking pattern that reaches regular and higher values in the last training days. Quinpirole administration produces lever press reduction in ACD group when compared to basal intake(p<0.001) and to vehicle (p<0.05;p<0.001), while when treatment is suspended, rats reinstate lever presses for ACD. ACD incentive properties involve dopamine neurotransmission: D2-receptor activation is able to reduce reinstatement of operant drinking behaviour for ACD, following periods of abstinence, probably acting at a pre-synaptic level, thus reducing DA release in mesolimbic areas. These findings further support ACD pivotal role in ethanol central effects

New prospective in treatment of Parkinson’s disease: Studies on permeation of ropinirole through buccal mucosa

The aptitude of Ropinirole to permeate the buccal tissue was tested using porcine mucosa mounted on Franz-type diffusion cells as ex vivo model. Drug permeation was also evaluated in presence of various penetration enhancers and in iontophoretic conditions. Ropinirole, widely used in treatment of motor fluctuations of Parkinson’s Disease, passes the buccal mucosa. Flux and permeability coefficient values suggested that the membrane does not appear a limiting step to the drug absorption. Nevertheless, an initial lag time is observed but the input rate can be modulated by permeation enhancement using Limonene or by application of electric fields. Absorption improvement was accompanied by the important reduction of the lag time; at once the time required to reach the steady state plasma concentration was drastically decreased. On the basis of these results we could assume that clinical application of Ropinirole by buccal delivery is feasibl

N-valproyl-aminoacids as new potential antiepileptic drugs: Synthesis, characterization and in vitro studies on stability

Epilepsy, affecting at least 50 million persons worldwide, is one of the most common neurological disorders. Despite the significant advances in understanding epileptogenic mechanisms and in counteracting their pathological consequences, this clinical condition still has to be faced of treating more effectively the symptoms (epileptic seizures) and of preventing their unfavourable evolution. So far, research has been unsuccessful involved in developing effective antiepileptic drugs (AEDs) capable of preventing the development of the pathogenic process, set in motion by different etiological factors, that leads ultimately to chronic epilepsies. 1,2 So, a substantial need remains to develop new AEDs with better safety, less toxicity, and higher efficacy. 3,4 Valproic acid, VPA, is one of the four most widely prescribed AEDs. Besides its wide use in both generalized and partial epilepsies, VPA has also gained widespread use in recent years for the treatment of bipolar disorders, neuropathic pain and for prophylactic treatment of migraine. 5,6 However the use of VPA is limited by two rare but potentially life-threatening side effects, hepatotoxicity, induced from the formation of metabolite(s) with a terminal double bond, specifically 4-ene-VPA,7 and teratogenicity, associated with the parent compound itself.8 In a previous work we reported the synthesis of aminoacidic ester derivatives of VPA as resulted of chemical conjugation of VPA with esters of essential neutral minoacids, with the aim of modifying the physicochemical properties relevant to bioavailability, such as solubility or lipophilicity, improving the efficacy and reducing unwanted side or toxic effects of VPA. 9 We had reported also the synthesis of N-valproyl-L-tryptophan, that has shown adequate physicochemical characteristics to permeate biological membranes and antiepileptic activity at lower concentration than VPA. 10,11 In this paper, we focused our research on synthesis and characterization of new aminoacidic compounds with potential antiepileptic activity: N-Valproyl-L-Leucine (ValLeu), N-Valproyl-L-methionine (ValMet) and N-Valproyl- L-Histidine (ValHist). The conjugation could consent to obtain VPA derivatives, lacking of structural characteristics usually implicated on VPA teratogenicity, and avoiding formation of possible hepatoto metabolites. The aminoacidic derivatives of VPA was successfully obtained covalent linking carboxyl group of drug with aminic group of L- aminoacids, by synthesis involving two main steps. The first step, described in our previous work 9 was modified by adding DMAP as further coupling agent together with DCC. The structures of obtained compounds were assigned on the basis of respective analytical data-sets, FT-IR, MS and 1H and 13 C-NMR spectral data. Since the drug lipophilicity is an important factor conditioning brain uptake, the apparent partition coefficient (P app) could be used as simple descriptor of ability to cross the BBB: values of log P app within -0.2 to 1.3 have been described as optimal for cerebral transport; on the other hand higher values than these could reduce the rate of transport inside the membrane.12,13 Apparent partition coefficient ( Papp) of ValLeu, ValMet and ValHist were determined in n-octanol/phosphate buffer pH 7.4 solution and expressed as Log Papp.The determined Log Papp resulted -0.11,- 1,02 and -1,61 respectively. The Log D pH7.4 values indicate that ValLeu, ValMet are adequate to cross biological membranes and in particular BBB barrier while ValHist value is too low, probably due to the fact that was obtained as hydrochloride. Compared to others drug administration routes, the oral one emains the most preferred as it implies ease of administration as well as high patient compliance. However, the transit through the gastrointestinal tract could constitute a limiting step to bioavailability as a consequence of degradation correlated to the environmental pH. In view of a possible administration of ValLeu, ValMet and ValHist by oral route, studies on their chemical stability were performed in simulated gastro-intestinal buffer (37°C, pH 1.2 to 8.0) and monitored by HPLC analysis. The experiments demonstrated that ValLeu, ValMet and ValHist remained unchanged up to 24 h, and did not produce degradation products orpotential metabolites. This behaviour indicates high stability at pH conditions of gastro-intestinal tract. Since compounds containing amide functional group could be susceptible of hydrolysis by plasma and/or cerebral enzymes, our experiments were focused on the evaluation of stability of ValLeu, ValMet and ValHist in these biological environments. Otherwise, plasma stability of drug candidates plays an important role in drug discovery and development; it is essential for maintaining acceptable drug concentration and half-life in order to achieve desirable pharmacological effects. 14 Experimental data highlighted that ValLeu, ValMet and ValHist remained unmodified up to 24 h in plasma environment. In rat brain homogenate ValLeu, ValMet and ValHist did not undergo cleavage after 24 h, indicating that synthetized compounds have also good stability to cerebral enzyme

N-valplroyl-aminoacids as new potential antiepileptic drugs: synthesis, characterization and in vitro studies on stability

Epilepsy, affecting at least 50 million persons worldwide, is one of the most common neurological disorders. Despite the significant advances in understanding epileptogenic mechanisms and in counteracting their pathological consequences, this clinical condition still has to be faced of treating more effectively the symptoms (epileptic seizures) and of preventing their unfavourable evolution. So far, research has been unsuccessful involved in developing effective antiepileptic drugs (AEDs) capable of preventing the development of the pathogenic process, set in motion by different etiological factors, that leads ultimately to chronic epilepsies .[1, 2] So, a substantial need remains to develop new AEDs with better safety, less toxicity, and higher efficacy [3, 4]. Valproic acid, VPA, is one of the four most widely prescribed AEDs. Besides its wide use in both generalized and partial epilepsies, VPA has also gained widespread use in recent years for the treatment of bipolar disorders, neuropathic pain and for prophylactic treatment of migraine. [5,6] However the use of VPA is limited by two rare but potentially life-threatening side effects, hepatotoxicity, induced from the formation of metabolite(s) with a terminal double bond, specifically 4-ene-VPA, [7] and teratogenicity, associated with the parent compound itself [8]. In a previous work we reported the synthesis of aminoacidic ester derivatives of VPA as resulted of chemical conjugation of VPA with esters of essential neutral aminoacids, with the aim of modifying the physicochemical properties relevant to bioavailability, such as solubility or lipophilicity, improving the efficacy and reducing unwanted side or toxic effects of VPA [9]. We had reported also the synthesis of N-valproyl-L-tryptophan, that has shown adequate physicochemical characteristics to permeate biological membranes and antiepileptic activity at lower concentration than VPA. [10,11] In this paper, we focused our research on synthesis and characterization of new aminoacidic compounds with potential antiepileptic activity: N-Valproyl-L-Leucine (ValLeu), N-Valproyl-L-methionine (ValMet) and N-Valproyl-L-Histidine (ValHist). The conjugation could consent to obtain VPA derivatives, lacking of structural characteristics usually implicated on VPA teratogenicity, and avoiding formation of possible hepatotoxic metabolites. The aminoacidic derivatives of VPA was successfully obtained covalent linking carboxyl group of drug with aminic group of L-aminoacids, by synthesis involving two main steps. The first step, described in our previous work [9] was modified by adding DMAP as further coupling agent together with DCC. The structures of obtained compounds were assigned on the basis of respective analytical data-sets, FT-IR, MS and 1H and 13C-NMR spectral data. Since the drug lipophilicity is an important factor conditioning brain uptake, the apparent partition coefficient (Papp) could be used as simple descriptor of ability to cross the BBB: values of log Papp within -0.2 to 1.3 have been described as optimal for cerebral transport; on the other hand higher values than these could reduce the rate of transport inside the membrane [12, 13]. Apparent partition coefficient (Papp) of ValLeu, ValMet and ValHist were determined in n-octanol /phosphate buffer pH 7.4 solution and expressed as Log Papp. The determined Log Papp resulted -0.11,- 1,02 and -1,61 respectively. The Log DpH7.4 values indicate that ValLeu, ValMet are adequate to cross biological membranes and in particular BBB barrier while ValHist value is too low, probably due to the fact that was obtained as hydrochloride. Compared to others drug administration routes, the oral one remains the most preferred as it implies ease of administration as well as high patient compliance. However, the transit through the gastrointestinal tract could constitute a limiting step to bioavailability as a consequence of degradation correlated to the environmental pH. In view of a possible administration of ValLeu, ValMet and ValHist by oral route, studies on their chemical stability were performed in simulated gastro-intestinal buffer (37°C, pH 1.2 to 8.0) and monitored by HPLC analysis. The experiments demonstrated that ValLeu, ValMet and ValHist remained unchanged up to 24 h, and didn’t produce degradation products or potential metabolites. This behaviour indicates high stability at pH conditions of gastro-intestinal tract. Since compounds containing amide functional group could be susceptible of hydrolysis by plasma and/or cerebral enzymes, our experiments were focused on the evaluation of stability of ValLeu, ValMet and ValHist in these biological environments. Otherwise, plasma stability of drug candidates plays an important role in drug discovery and development; it is essential for maintaining acceptable drug concentration and half-life in order to achieve desirable pharmacological effects [14]. Experimental data highlighted that ValLeu, ValMet and ValHist remained unmodified up to 24 h in plasma environment. In rat brain homogenate ValLeu, ValMet and ValHist didn’t undergo cleavage after 24 h, indicating that synthetized compounds have also good stability to cerebral enzymes. References [1] Arroyo S, Brodie MJ, Avanzini G, Baumgartner C, Chiron C, Dulac O, French JA, Serratosa JM Is refractory epilepsy preventable? Epilepsia, (2002) 43, 437–444. [2] Walker MC, White HS, Sander JWAS. Disease modification in partial epilepsy. Brain, (2002) 125, 1937–1950 [3] Bialer M, Yagen B, Valproic Acid: Second Generation, Neurotherapeutics (2007) 4, 130-137 [4] Shimshoni J A, Bialer M, Yagen B, Synthesis and anticonvulsant activity of aromatictetramethylcyclopropanecarboxamide derivatives, Bioorg. Med. Chem. (2008) 16, 6297-6305. [5] Lennkh C, Simhandl C, Current aspects of valproate in bipolar disorder, Int Clin Psychopharmacol. (2000) 15, 1-11. [6] Guidotti A, Dong E, Kundakovic M, Satta R, Grayson DR, Costa E Characterization of the action of antipsychotic subtypes on valproate-induced chromatin remodelling, Trends Pharmacol. Sci. (2008) 30, 55–60., 7]. [7] Silva MFB, Aires CC, Luis PB, Ruiter JP, Ijlst L, Duran M, et al. Valproic acid metabolism and its effects on mitochondrial fatty acid oxidation: a review. J Inherit Metab Dis (2008). 31, 205-216 [8] Bojic U, Ehlers K, Ellerbeck U, Bacon CL, O’driscoll E, O’connell C, Berezin V, Kawa A, Lepekhin E, Bock E, Regan CM, Nau H. Studies on the teratogen pharmacophore of Valproic acid analogues: Evidence of interactions at a hydrophobic centre, Eur. J. Pharmacol. (1998) 354 289–299. [9] Giannola LI; Lamartina L; De Caro V. Synthesis and characterization of aminoacidic pro-drugs of valproic acid. Pharmazie (1998) 53, 829-834. [10] De Caro V, Giandalia G, Siragusa MG, Lamartina L, Friscia S, Sardo P, Carletti F, Rizzo V, Ferraro G, Giannola LI. N-Valproyl-L-Tryptophan for CNS-targeting: synthesis, characterization and efficacy in vitro studies of a new potential antiepileptic drug, Med. Chem. (2011) 7, 9-17. [11] Sardo P, Rizzo V, Friscia S, Carletti F, De Caro V, Scaturro AL, Giandalia G, Giannola LI, Ferraro G Inhibitory effects of N-valproyl-L-tryptophan on high potassium, low calcium and low magnesium-induced CA1 hippocampal epileptiform bursting activity in rat brain slices, J Neural Transm. (2012) 119, 1249–1259. [12] Trojnar MK; Weirzchowska-Cioch E, Krzyzanowski M; Jargiello M, Czuzczwar SJ. New generation of valproic acid. Pol. J. Pharmacol., (2004) 56, 283–288. [13] Gimenez F, Fernandez C, Mabondzo A. Transport of HIV protease inhibitors through the bloodbrain barrier and interactions with the efflux proteins, P-glycoprotein and multidrug resistance proteins. J. Acquir. Immune Defic. Syndr. (2004) 36, 649-658 [14] Di L, Kerns EH, HongY, Chen H. Development and application of high throughput plasma stability assay for drug discovery. Int. J. Pharm., (2005) 297, 110–11

Design, synthesis and preliminary evaluation of dopamine-amino acid conjugates as potential D1 dopaminergic modulators

The dopamine-amino acid conjugate DA-Phen was firstly designed to obtain a useful prodrug for the therapy of Parkinson's disease, but experimental evidence shows that it effectively interacts with D1 dopamine receptors (D1DRs), leading to an enhancement in cognitive flexibility and to the development of adaptive strategies in aversive mazes, together with a decrease in despair-like behavior. In this paper, homology modelling, molecular dynamics, and site mapping of D1 receptor were carried out with the aim of further performing docking studies on other dopamine conjugates compared with D1 agonists, in the attempt to identify new compounds with potential dopaminergic activity. Two new conjugates (DA-Trp 2C, and DA-Leu 3C) have been identified as the most promising candidates, and consequently synthesized. Preliminary evaluation in terms of distribution coefficient (DpH7.4), stability in rat brain homogenate, and in human plasma confirmed that DA-Trp (2C), and DA-Leu (3C) could be considered as very valuable candidates for further in&nbsp;vivo studies as new dopaminergic drugs

Modulation of alcohol consumption using an operant self-administration paradigm: effects of a new dopamine aminoacidic conjugate, Phenylalanine-β(3,4dihydroxyphenyl)-etilamide.

Rewarding and reinforcing properties of alcohol have been shown to be mediated by activation of the mesolimbic dopaminergic system. Experimental evidences suggest that mesolimbic dopamine system is hypofunctional in addicted brain; further, reduced dopaminergic activity outlasts somatic signs of withdrawal and may drive craving and relapse. Boosting strategy on dopaminergic neurons could represent a valid therapy. Effects of pharmacological manipulation of brain Dopaminergic receptors by a new dopamine conjugate, Phenylalanine-β(3,4dihydroxyphenyl)-etilamide (DA-Phen), on operant behaviour and on both acute and prolonged withdrawal symptoms during ethanol abstinence have been evaluated. Male Wistar rats were tested in an operant conditioning task: they were subjected to Habituation (Ethanol 5%), Training (Ethanol 20%), and Extinction sessions. Then, three cycles of Deprivation/Relapse were performed. Rats were administered with DA-Phen (0.03mmol/kg i.p) during abstinence, or during relapse, 2h prior the operant task session. Locomotor activity and anxiety-like behaviour during withdrawal were also evaluated. Da-Phen, administered during abstinence phase, or during relapse, was able to reduce alcoholic intake pattern by 50% from the second day of operant conditioning task (p<0.001). DA-Phen induced significant differences in chronically alcohol-treated rats both on total distance travelled (p<0.001) and percentage of time on centre (p<0.05) in the Open Field, and percentage of open time (p<0.001), entries (p<0.05) and head dippings (p<0.001) in the Elevated plus Maze. Results suggest that DA-Phen can reduce ethanol intake by attenuating ethanol rewarding value and/or elevating endogenous dopaminergic activity, as well as the behavioural signs of withdrawal