Polymethoxyflavones from Nicotiana plumbaginifolia (Solanaceae) exert antinociceptive and neuropharmacological effects in mice.

Polymethoxylavones (PMFs)are known to exhibit significant anti-inflammatory and neuroprotective properties. Nicotiana plumbaginifolia, an annual Bangladeshi herb, is rich in polymethoxyflavones that possess significant analgesic and anxiolytic activities. The present study aimed to determine the antinociceptive and neuropharmacological activities of polyoxygenated flavonoids namely- 3,3',5,6,7,8-hexamethoxy-4',5'-methylenedioxyflavone (1), 3,3',4',5',5,6,7,8-octamethoxyflavone (exoticin) (2), 6,7,4',5'-dimethylenedioxy-3,5,3'-trimethoxyflavone (3) and 3,3’,4’,5,5’,8-hexamethoxy-6,7-methylenedioxyflavone(4), isolated and identified from N. plumbaginifolia. Antinociceptive activity was assessed using the acetic-acid induced writhing, hot plate, tail immersion, formalin and carrageenan-induced paw edema tests, whereas neuropharmacological effects were evaluated in the hole cross, open field and elevated plus maze test. Oral treatment of compounds 1, 3 and 4 (12.5-25 mg/kg b.w.) exhibited dose-dependent and significant (p< 0.01) antinociceptive activity in the acetic-acid, formalin, carrageenan and thermal (hot plate)-induced pain models. The association of ATP-sensitive K+ channel and opioid systems in their antinociceptive effect was obvious from the antagonist effect of glibenclamide and naloxone respectively. These findings suggested central and peripheral antinociceptive activities of the compounds. Compound 1, 3 and 4 (12.5 mg/kg b.w.) demonstrated significant (p< 0.05) anxiolytic-like activity in the elevated plus-maze test, while the involvement of GABAA receptor in the action of compound 3 and 4 was evident from the reversal effects of flumazenil. In addition, compounds 1 and 4 (12.5-25 mg/kg b.w) exhibited anxiolytic activity without altering the locomotor responses. The present study suggested that the polymethoxyflavones (1-4) from N. Plumbaginifoliacould be considered as suitable candidates for the development of analgesic and anxiolytic agents

Loss-of-Function Mutations in Three Homoeologous PHYTOCLOCK 1 Genes in Common Wheat Are Associated with the Extra-Early Flowering Phenotype.

Triticum aestivum L. cv 'Chogokuwase' is an extra-early flowering common wheat cultivar that is insensitive to photoperiod conferred by the photoperiod insensitive alleles at the Photoperiod-B1 (Ppd-B1) and Ppd-D1loci, and does not require vernalization for flowering. This reduced vernalization requirement is likely due to the spring habitat allele Vrn-D1 at the VERNALIZATION-D1 locus. Genotypes of the Ppd-1 loci that determine photoperiod sensitivity do not fully explain the insensitivity to photoperiod seen in 'Chogokuwase'. We detected altered expression patterns of clock and clock-output genes including Ppd-1 in 'Chogokuwase' that were similar to those in an einkorn wheat mutant that lacks the clock-gene homologue, wheat PHYTOCLOCK 1 (WPCL1). Presumptive loss-of-function mutations in all WPCL1 homoeologous genes were found in 'Chogokuwase' and 'Geurumil', one of the parental cultivars. Segregation analysis of the two intervarietal F2 populations revealed that all the examined F2 plants that headed as early as 'Chogokuwase' had the loss-of-function wpcl1 alleles at all three homoeoloci. Some F2 plants carrying the wpcl1 alleles at three homoeoloci headed later than 'Chogokuwase', suggesting the presence of other loci influencing heading date. Flowering repressor Vrn-2 was up-regulated in 'Chogokuwase' and 'Geurumil' that had the triple recessive wpcl1 alleles. An elevated transcript abundance of Vrn-2 could explain the observation that 'Geurumil' and some F2 plants carrying the three recessive wpcl1 homeoealleles headed later than 'Chogokuwase'. In spite of the up-regulation of Vrn-2, 'Chogokuwase' may have headed earlier due to unidentified earliness genes. Our observations indicated that loss-of-function mutations in the clock gene wpcl1 are necessary but are not sufficient to explain the extra-early heading of 'Chogokuwase'

Melatonin suppression during a simulated night shift in medium intensity light is increased by 10-minute breaks in dim light and decreased by 10-minute breaks in bright light

Exposure to light at night results in disruption of endogenous circadian rhythmicity and/or suppression of pineal melatonin, which can consequently lead to acute or chronic adverse health problems. In the present study, we investigated whether exposure to very dim light or very bright light for a short duration influences melatonin suppression, subjective sleepiness, and performance during exposure to constant moderately bright light. Twenty-four healthy male university students were divided into two experimental groups: Half of them (mean age: 20.0 +/- 0.9 years) participated in an experiment for short-duration (10 min) light conditions of medium intensity light (430 lx, medium breaks) vs. very dim light (< 1 lx, dim breaks) and the other half (mean age: 21.3 +/- 2.5 years) participated in an experiment for short-duration light conditions of medium intensity light (430 lx, medium breaks) vs. very bright light (4700 lx, bright breaks). Each simulated night shift consisting of 5 sets (each including 50-minute night work and 10-minute break) was performed from 01:00 to 06:00 h. The subjects were exposed to medium intensity light (550 lx) during the night work. Each 10-minute break was conducted every hour from 02:00 to 06:00 h. Salivary melatonin concentrations were measured, subjective sleepiness was assessed, the psychomotor vigilance task was performed at hourly intervals from 21:00 h until the end of the experiment. Compared to melatonin suppression between 04:00 and 06:00 h in the condition of medium breaks, the condition of dim breaks significantly promoted melatonin suppression and the condition of bright breaks significantly diminished melatonin suppression. However, there was no remarkable effect of either dim breaks or bright breaks on subjective sleepiness and performance of the psychomotor vigilance task. Our findings suggest that periodic exposure to light for short durations during exposure to a constant light environment affects the sensitivity of pineal melatonin to constant light depending on the difference between light intensities in the two light conditions (i.e., short light exposure vs. constant light exposure). Also, our findings indicate that exposure to light of various intensities at night could be a factor influencing the light-induced melatonin suppression in real night work settings

Heading dates of ‘Chogokuwase’ and the parental cultivars in the field.

<p>Heading dates of ‘Chogokuwase’ and the parental cultivars in the field.</p

Frequency distribution of days to heading in the 114 F₂ plants from a segregating population growing under SD conditions with a vernalization treatment.

<p>The F₂ population was derived from a cross between ‘Chogokuwase’ and ‘Norin 61’. White boxes indicate the plants with homozygous <i>wpcl1</i> alleles at three homoeoloci. Black boxes show the plants having one or more functional <i>WPCL1</i> homoeoalleles. Arrows indicate days to heading in ‘Chogokuwase’ and ‘Norin 61’, respectively.</p

Gene expression patterns of <i>VRN-1</i> and <i>WFT</i> in ‘Chogokuwase’ and its parental cultivars.

<p>Expression levels were measured in the second (2L), third (3L) and fourth (4L) leaf stages of ‘Chogokuwase’ (blue), ‘Minaminokomugi’ (red), and ‘Geurumil’ (yellow) under V0-LD, V21-LD and V0-SD conditions. X- and Y-axis indicate days after 21 days-vernalization and relative transcript abundances, respectively. Transcript abundance was measured relative to the abundance of <i>Actin</i> gene transcripts. Bars on each observation indicate standard errors.</p

Gene expression patterns of <i>Vrn-1</i> and <i>Vrn-2</i> (<i>ZCCT1</i> and <i>ZCTT2</i>) under SD conditions in ‘Chogokuwase’ and the parental cultivars.

<p>White and black boxes indicate light and dark periods, respectively. Two-week-old seedlings were sampled at 3h intervals over 24h. Means ± standard deviations were calculated from data in three technical repeated experiments. Relative transcript abundance was calculated using the <i>Actin</i> gene as an internal control.</p

Mutations in <i>WPCL1</i> homoeologues.

<p>(a) A 142 bp deletion was detected in <i>WPCL-B1</i> of ‘Chogokuwase’ and ‘Geurumil’. The start codon is shown in bold letters in the nucleotide sequence alignment. (b) Comparison of the amino acid sequence of the Myb domain between functional (gene names shown in uppercase letters) and loss-of-function (gene names shown in lowercase letters) <i>WPCL1</i> homoeologues. The gray box indicates the SHAQKYF motif.</p

Relationship between days to heading and genotypes of <i>WPCL1</i> and <i>Vrn-1</i> loci in an F₂ population derived from ‘Geurumil’ and ‘Minaminokomugi’.

<p>(a) Comparison of days to heading between genotypes of <i>WPCL1</i> homoeoloci in the 489 F₂ plants. Days to heading indicate the number of days after April 1. Arrows show the heading date in ‘Chogokuwase’ (C), ‘Geurumil’ (G) and ‘Minaminokomugi’ (M), respectively. White boxes indicate the plants carrying homozygous <i>wpcl1</i> alleles at three homoeoloci. Black boxes show the plants carrying functional <i>WPCL-B1</i> and<i>/</i>or <i>WPCL-D1</i> alleles. (b) A subset of the segregating population having the triple recessive <i>wpcl1</i> alleles. Comparison of days to heading between genotypes of the <i>Vrn-D1</i> locus in 25 F₂ plants with three loss-of-function <i>wpcl1</i> homoeoalleles.</p

Relationship between days to heading and genotypes of the <i>WPCL1</i> and <i>Vrn-2</i> loci in the recombinant inbred lines of einkorn wheat.

<p>The days to heading in 89 recombinant inbred lines derived from a cross between <i>T</i>. <i>monococcum</i> mutants and <i>T</i>. <i>boeoticum</i> were compared. The parental <i>monococcum</i> accession lacks <i>WPCL1</i> and <i>Vrn-2</i>, whereas the <i>boeoticum</i> accession has <i>WPCL1</i> and <i>Vrn</i>-2. Arrows indicate days to heading of the parental <i>T</i>. <i>monococcum</i> (KT3-5) and <i>T</i>. <i>boeoticum</i> (KT1-1) accessions, respectively.</p