Elucidation of Degradation Behavior of Barbiturates in Artificial Gastric Juice: Study on Degradability of Drugs in Stomach (V).

The gastric stability of eight barbiturates (BARs) (barbital, primidone, allobarbital, phenobarbital, cyclobarbital, pentobarbital, secobarbital, and thiobutabarbital (TBB)) was examined in artificial gastric juice using LC/UV detection. Among the eight BARs, only TBB was degraded at higher temperatures. Furthermore, the degradation product of TBB was isolated, structurally analyzed, and finally identified as 5-butan-2-yl-5-ethyl-1,3-diazinane-2,4,6-trione, also known as butabarbital.

Elucidation of Degradation Behavior of Nitrazepam, a Benzodiazepine Drug, under Basic Conditions: Study on Degradability of Drugs in Stomach (IV).

This study investigates the stability of nitrazepam (NZP), a benzodiazepine drug, under basic conditions, since alkaline putrefactive amines and ammonia are produced once bodies are left to decompose for a long period postmortem after a murder involving NZP or an accidental overdose of NZP. The degradation of NZP in an aqueous alkaline solution was investigated by LC/photodiode array detector (PDA) where the NZP degradation product was isolated and purified by solid-phase extraction using Oasis MCX, and its chemical structure was determined by LC/time-of-flight (TOF)-MS, NMR spectroscopy, and single-crystal X-ray crystallography. The results revealed that NZP was immediately degraded under basic conditions with 2-amino-5-nitrobenzophenone being an intermediate which further degraded to provide 2-hydroxy-5-nitrobenzophenone as the final degradation product.

Possible mechanism for improving the endogenous immune system through the blockade of peripheral μ-opioid receptors by treatment with naldemedine.

Background: It has been considered that activation of peripheral μ-opioid receptors (MORs) induces side effects of opioids. In this study, we investigated the possible improvement of the immune system in tumour-bearing mice by systemic administration of the peripheral MOR antagonist naldemedine.

Methods: The inhibitory effect of naldemedine on MOR-mediated signalling was tested by cAMP inhibition and β-arrestin recruitment assays using cultured cells.

Further investigation of the rapid-onset and short-duration action of the G protein-biased μ-ligand oliceridine.

TRV130 (oliceridine), a G protein-biased ligand for μ-opioid receptor, has recently been synthesized. It is considered to have strong antinociceptive effects and only minor adverse effects. However, whether or not oliceridine actually exhibits an ideal pharmacological profile as an analgesic has not yet been fully clarified in animal studies.

[Overview of 43 Years of Studies on Asymmetric Synthesis].

Our investigations of various aspects of organic chemistry over the past 43 years are reviewed in this paper. The following subjects are discussed: 1) the diastereoselective addition reaction to chiral imines and oxazolidines of organometallic reagents and its applications and 2) the reaction and synthesis of fluorine-containing compounds.

Usefulness for the combination of G-protein- and β-arrestin-biased ligands of μ-opioid receptors: Prevention of antinociceptive tolerance.

Background: µ-Opioid receptor internalization is considered to be critically linked to antinociceptive tolerance. Although µ-opioid receptor agonists have been administered simultaneously with other drugs to control pain, little information is available regarding opioid–opioid interactions. Therefore, the present study was designed to further investigate the utility of a new G protein-biased ligand for µ-opioid receptors, TRV130, which has an antinociceptive effect without β-arrestin-dependent µ-opioid receptor internalization, and its combination with fentanyl using µ-opioid receptor-expressing cells and mice.

Development of κ Opioid Receptor Agonists by Focusing on Phenyl Substituents of 4-Dimethylamino-3-phenylpiperidine Derivatives: Structure-Activity Relationship Study of Matrine Type Alkaloids.

A series of new κ opioid receptor (KOR) agonists were developed from the lead compound 4-dimethylamino-1-pentanoylpiperidine (3), a matrine-type alkaloid. Derivatives of 3 were synthesized with a variety of phenyl substituents and evaluated for their antinociceptive effects. Additionally, their selectivity for an opioid receptor was investigated for cis-4c and d, and trans-4g, all of which had high activity exerted through the KOR.

Design and Synthesis of a Piperidinone Scaffold as an Analgesic through Kappa-Opioid Receptor: Structure-Activity Relationship Study of Matrine Alkaloids.

The matrine-type alkaloid 4-dimethylamino-1-pentanoylpiperidine (3a) has an antinociceptive effect through its impact on the κ-opioid receptor (KOR). Derivatives of 3a were synthesized by altering its amide and tertiary amine groups, and were evaluated for their antinociceptive effects. The results indicated that the distance between these groups on 3a was optimal for the antinociceptive effect.

Narcolepsy-like sleep disturbance in orexin knockout mice are normalized by the 5-HT1A receptor agonist 8-OH-DPAT.

Rationale: Orexin knockout (KO) mice exhibit a phenotype that is similar to human narcolepsy, and monoamine-related compounds, such as psychostimulants and 5-HT uptake inhibitors, have been used for the treatment of narcoleptic disorders. However, little information is available regarding the pathophysiological features of orexin KO mice, particularly with respect to their narcoleptic-like disorder and how it is affected by monoamine-related compounds.

Objectives: The present study was designed to investigate both the nature of the neuronal changes in orexin KO mice and the therapeutic effects of monoamine-related compounds on the sleep disorder in orexin KO mice.

Effect of p-aminophenols on tyrosinase activity.

Tyrosinase is involved in the synthesis of melanin in the skin and hair as well as neuromelanin in the brain. This rate limiting enzyme catalyzes two critical steps (reactions) in melanogenesis; the hydroxylation of tyrosine to form DOPA and the subsequent oxidation of DOPA into dopaquinone. Several new aminophenol derivatives have been synthesized based on structure-activity relationship studies of N-(4-hydroxyphenyl)retinamide (1), a derivative of retinoic acid.

Differential substitution for the discriminative stimulus effects of 3,4-methylenedioxymethamphetamine and methylphenidate in rats.

Previous studies have demonstrated that methylphenidate, MDMA (3,4-methylenedioxymethamphetamine), and other psychostimulants exert stimulant-like subjective effects in humans. Furthermore, MDMA and methylphenidate substitute for the discriminative stimulus effects of psychostimulants, such as amphetamine and cocaine, in animals, which suggests that MDMA and methylphenidate may produce similar discriminative stimulus effects in rats. However, there is no evidence regarding the similarities between the discriminative stimulus effects of MDMA and methylphenidate.

A combination of liposomal sunitinib plus liposomal irinotecan and liposome co-loaded with two drugs enhanced antitumor activity in PC12-bearing mouse.

Pheochromocytomas are highly angiogenic neuroendocrine tumors. The side effects of treatment with cytotoxic agents frequently outweigh the benefits. Neuroendocrine tumors are highly angiogenic, dependent on vascular endothelial growth factor and receptor (VEGFR) activation.

Efficient microwave-assisted prenylation of pinostrobin and biological evaluation of its derivatives as antitumor agents.

Pinostrobin (5-hydroxy-7-methoxyflavanone) obtained in relatively large amounts from fingerroot (Boesenbergia pandurata) was converted to its C-6 and C-8 prenylated derivatives. The Mitsunobu reaction, europium(III)-catalyzed Claisen-Cope rearrangement, and Claisen reaction coupled with cross-metathesis were used as the key steps. Using a sealed-vessel microwave reactor, the Mitsunobu and Claisen/Cope reactions occurred smoothly with short reaction times and in satisfactory yields.

Concise total synthesis of (-)-deoxocuscohygrine and (-)-dihydrocuscohygrine.

The concise enantioselective total synthesis of C(2)-asymmetrical (-)-deoxocuscohygrine and (-)-dihydrocuscohygrine are described. Double-diastereoselective additions of normal Grignard reagent to bis(1,3-oxazolidine) have been deployed to construct chiral diamine fragments as a key step.

Changes in the rewarding effects induced by tramadol and its active metabolite M1 after sciatic nerve injury in mice.

Introduction: The present study was designed to investigate the rewarding effects induced by tramadol and its active metabolite O-desmethyltramadol (M1) under a neuropathic pain-like state.

Results: In opioid receptor binding and G protein activation, we confirmed that M1, but not tramadol, showed mu-opioid receptor (MOR) agonistic activity. Furthermore, we found that the subcutaneous (s.

Hydroxyethylated cationic cholesterol derivatives in liposome vectors promote gene expression in the lung.

Three cationic cholesterol derivatives (CCDs), which differ in their types of amine and bear a hydroxyethyl group at the amine group, were synthesized and formulated into liposomes and nanoparticles as gene delivery vectors. In vitro transfection into A549 cells proved that liposomes formulated with CCDs and dioleoylphosphatidylethanolamine (DOPE) of 1/2 molar ratio were more effective than the corresponding nanoparticles with CCDs and Tween 80 at charge ratios (+/-) of 1/2, 3/1 and 5/1. Among the liposomal formulations, non-hydroxyethylated CCDs were more effective than hydroxyethylated ones in vitro.

p-Dodecylaminophenol derived from the synthetic retinoid, fenretinide: antitumor efficacy in vitro and in vivo against human prostate cancer and mechanism of action.

Fenretinide, N-(4-hydroxyphenyl)retinamide (4-HPR) is an aminophenol-containing synthetic retinoid derivative of all-trans-retinoic acid, which is a potent chemopreventive and antiproliferative agent against various cancers. Clinical studies of 4-HPR have shown side effects consisting of night blindness and ocular toxicity. To maintain potent anticancer activity without side effects, p-dodecylaminophenol (p-DDAP) was designed based on structure-activity relationships of 4-HPR.

Lack of development of behavioral sensitization to methylphenidate in mice: correlation with reversible astrocytic activation.

Methamphetamine is a powerfully addictive psychostimulant that dramatically affects the mammalian central nervous system. Methylphenidate has been shown to have psychostimulus effects similar to methamphetamine. In the present study, we compared several effects of methylphenidate to those of methamphetamine.

Potent anticancer activities of novel aminophenol analogues against various cancer cell lines.

Novel aminophenol analogues were synthesized based on the structure of fenretinide (N-(4-hydroxyphenyl)retinamide, 5), which is a potent anticancer agent. Our findings showed that the anticancer activities of 5 were due to the side chain attached to the aminophenol moiety. A p-octylaminophenol (p-OAP) provided the most potent anticancer activity among p-alkylaminophenols examined.

Hypoglycemic effects of multiflorine derivatives in normal mice.

(-)-Multiflorine isolated from leguminous plants produces a hypoglycemic effect when administered to mice with streptozotocin-induced diabetes. (-)-Multiflorine has an enaminone-type conjugation on the A ring, which is unusual in lupine alkaloids. Proceeding on the assumption that the A-B ring is responsible for the hypoglycemic effect, several compounds bearing the quinolizidin-2-one ring system were synthesized, and their hypoglycemic effects were examined.

Antioxidant and anticancer activities of novel p-alkylaminophenols and p-acylaminophenols (aminophenol analogues).

Novel compounds were designed based on fenretinide, N-(4-hydroxyphenyl)retinamide (2), which is a synthetic amide of all-trans-retinoic acid (1) that is a potent antioxidant and anticancer agent. Our recent findings indicated that antioxidant and anticancer activities were due to p-methylaminophenol moiety (8) in 2, and that p-octylaminophenol (7), which has an elongated alkyl chain, was more potent than 8. This finding lets us to investigate whether compounds containing alkyl or acyl chains linked to an aminophenol residue as long as 2 and 1, would show activities greater than 2.

Implication of the descending dynorphinergic neuron projecting to the spinal cord in the (+)-matrine- and (+)-allomatrine-induced antinociceptive effects.

We previously reported that either (+)-matrine (matridin-15-one) or (+)-allomatrine (the C-6 epimer of matrine)-induced antinociceptive effect was attenuated by s.c. pretreatment with a kappa-opioid receptor (KOR) antagonist nor-binaltorphimine (nor-BNI), indicating the critical role of KORs in antinociceptive effects induced by these alkaloids.

Effect of 1-O-ethyl-3-butylcyclohexanol on the skin permeation of drugs with different physicochemical characteristics.

The effects of 1-O-ethyl-3-butylcyclohexanol (OEBC) on the in vitro skin permeation of ten model drugs with different physicochemical properties across excised rat skin were evaluated. The results showed that the addition of OEBC significantly improved the in vitro skin permeation of the model drugs compared with the control (without OEBC). To clarify the promoting mechanism of OEBC, a multiple regression analysis was employed.

[Structure activity relation study of matrine-type alkaloids. Part III].

6-Acyldecahydro [1,6]naphthyridines were synthesized as derivatives of matrine-type and allomatrine-type alkaloids, and the structure-activity relations were examined by the acetic acid-induced abdominal contraction test. All synthesized derivatives produced the antinociception in mice. The antinociceptive potencies of 15a-c and 16a-c were lower than those of 17a-c, 18a-c, 19a-c and 20a-c.