Advanced precursors in marine biosynthetic study. Part 3: The biosynthesis of dichloroimines in the tropical marine sponge Stylotella aurantium

The biosynthetic origins of the dichloroimine group in the stylotellanes A and B 1,2 have been investigated by incorporation of [C-14]-labeled farnesyl isocyanide 7 and farnesyl isothiocyanate 3 into the sponge Stylotella aurantium. (C) 2002 Elsevier Science Ltd. All rights reserled.

Biosynthetic pathways to dichloroimines; precursor incorporation studies on terpene metabolites in the tropical marine sponge Stylotella aurantium

The biosynthetic origin of the dichloroimine functional group in the marine sponge terpene metabolites stylotellanes A ( 3) and B ( 4) was probed by the use of [C-14]-labelled precursor experiments. Incubation of the sponge Stylotella aurantium with [C-14]-labelled cyanide or thiocyanate resulted in radioactive terpenes in which the radiolabel was shown by hydrolytic chemical degradation to be associated specifically with the dichloroimine carbons. Additionally, label from both precursors was incorporated into farnesyl isothiocyanate ( 2). A time course experiment with [ 14C]cyanide revealed that the specific activity for farnesyl isothiocyanate decreases over time, but increases for stylotellane B ( 4), consistent with the rapid formation of farnesyl isothiocyanate ( 2) from inorganic precursors followed by a slower conversion to stylotellane B ( 4). The advanced precursors farnesyl isothiocyanate ( 2) and farnesyl isocyanide ( 5) were supplied to S. aurantium, and shown to be incorporated efficiently into stylotellane A ( 3) and B ( 4). Feeding of [C-14]-farnesyl isothiocyanate ( 2) resulted in a higher incorporation of label than with [C-14]-farnesyl isocyanide ( 5). Farnesyl isocyanide was incorporated into farnesyl isothiocyanate in agreement with labelling studies in other marine sponges. Both farnesyl isocyanide and isothiocyanate were further incorporated into axinyssamide A ( 11) as well as the cyclized dichloroimines (12)-(14), ( 16) that represent more advanced biosynthetic products of this pathway. These results identify the likely biosynthetic pathway leading to the major metabolites of S. aurantium.

Marine isocyanides and related natural products structure, biosynthesis and ecology

This review highlights structural and biosynthetic work on a group of nitrogen-functionalised terpenes that are almost exclusively found in marine invertebrates and the animals that feed on them. The chemical functionality reviewed includes isocyanides, isothiocyanates, formamides, thiocyanates, isocyanates, and dichloroimines. The literature through mid 2003 is reviewed and there are 143 citations.

Optimizing the formation of in vitro sponge primmorphs from the Chinese sponge Stylotella agminata (Ridley)

The establishment and optimization of in vitro primmorph formation from a Chinese sponge, Stylotella agminata (Ridley), collected from the South China Sea, were investigated. Our aims were to identify the key factors affecting primmorph formation in this species and to optimize the technique for developing an in vitro primmorph culture system. The size of dissociated cells from S. agminata is relatively small, in the range between 5 and 10 mum. Round-shaped primmorphs of less than 100 gm were formed 3 days after transferring the dissociated cells into seawater containing Ca2+ and Mg2+. The effect of various cell dissociation conditions, inoculum. cell density, concentration of antibiotics, pH, and temperature was further investigated upon the formation of primmorphs. The time required for primmorph formation, primmorph size distribution, and the proliferating capability were microscopically documented. Healthy sponge S. agminata, inoculum. cell density and culture temperature play a critical role for the successful formation of primmorphs and that the microbial contamination will have to be controlled. (C) 2002 Elsevier Science B.V. All rights reserved.

Variabilidade genómica de Citrus tristeza virus e transformação genética de Citrus aurantium L. com vista à obtenção de resistência

Tese de dout., Biologia, Faculdade de Engenharia de Recursos Naturais, Univ. do Algarve, 2003

Regeneración in vitro de naranja agrio (Citrus aurantium Linn)

Tesis (Maestría en Ciencias con Especialidad en Química de Productos Naturales) UANL

Anxiolytic and sedative effects of extracts and essential oil from Citrus aurantium L.

Citrus aurantium L. is commonly used as an alternative treatment for insomnia, anxiety and epilepsy. Essential oil from peel (EOP) and hydroethanolic (70% w/v) extract (HE) from leaves were obtained. Hexanic (HF), dichloromethanic (DF) and final aqueous (AF) fractions were obtained from HE by successive partitions. Swiss male mice (35-45 g) were treated orally with 0.5 or 1.0 g/kg of these preparations 30 min before the experiments for the evaluation of the sedative/hypnotic activity (sleeping time induced by sodium pentobarbital-SPB: 40 mg/kg, i.p.), anxiolytic activity (elevated plus maze-EPM) and anticonvulsant activity (induced by pentylenetetrazole-PTZ: 85 mg/kg, se or by maximal electroshock-MES: 50 mA, 0.11s, corneal). The results showed that EOP (0.5 g/kg) increased the latency period of tonic seizures in both convulsing experimental models. This effect was not dose-dependent. Treatment with 1.0 g/kg increased the sleeping time induced by barbiturates and the time spent in the open arms of the EPM. Specific tests indicated that the preparation, in both doses used, did not promote deficits in general activity or motor coordination. HF and DF fractions (1.0 g/kg) did not interfere in the epileptic seizures, but were able to enhance the sleeping time induced by barbiturates. The results obtained with EOP in the anxiety model, and with EOP, HF and DF in the sedation model, are in accord with the ethnopharmacological use of Citrus aurantium L., which could be useful in primary medical care, after toxicological investigation.

Effects of the essential oil from Citrus aurantium L. in experimental anxiety models in mice

Citrus aurantium L. is popularly used to treat anxiety, among other indications suggesting central nervous system action. Previous studies showed anxiolytic effect in the essential oil from peel in mice evaluated on the elevated plus maze [Carvalho-Freitas, M.I.R., Costa, M., 2002. Anxiolytic and sedative effects of extracts and essential oil from Citrus aurantium L. Biological and Pharmaceutical Bulletin 25, 1629-1633.]. In order to better characterize the activity of the essential oil, it was evaluated in two other experimental models: the light-dark box and the marble-burying test, respectively related to generalized anxiety disorder and to obsessive compulsive disorder. Mice were treated acutely by oral route 30 min (single dose) or once a day for 15 days (repeated doses) before experimental procedures. In light-dark box test, single treatment with essential oil augmented the time spent by mice in the light chamber and the number of transitions between the two compartments. There were no observed alterations in the parameters evaluated in light-dark box after repeated treatment. Otherwise, single and repeated treatments with essential oil were able to suppress marble-burying behavior. At effective doses in the behavioral tests, mice showed no impairment on rotarod procedure after both single and repeated treatments with essential oil, denoting absence of motor deficit. Results observed in marble-burying test, related to obsessive compulsive disorder, appear more consistent than those observed in light-dark box. (c) 2005 Elsevier B.V. All rights reserved.

Effect of Citrus aurantium l. essential oil on muscle regeneration in mdx mice

Duchenne muscular dystrophy (DMD) is a severe X-linked recessive disorder characterized by the progressive loss of muscular strength. Mdx mutant mice show a marked deficiency in dystrophin, which was related to muscle membrane stability. The aim of this study was to verify the possible protective anti-inflammatory effect of citrus oil on mdx muscle fibers. Thus, adult male and female mdx mice (014/06-CEEA) were divided into control and citrus-treated. After 60 days of treatment, one ml of blood was collected for creatine kinase (CK) test. Diaphragm, sternomastoideus, anterior tibial and gastrocnemius muscles were removed and processed according to histological routine methods. The observed alterations indicate a direct effect of citrus. Recent studies have improved the diagnosis of muscular diseases but with no definitions of efficient treatments. Intervention with several therapies is important to many patients presenting muscular dystrophy, which enables them to live longer and be more active, while there is no development of gene therapies.

Effects of limonene and essential oil from Citrus aurantium on gastric mucosa: Role of prostaglandins and gastric mucus secretion

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)