Speeding drug discovery targeting RNAs: An iterative "RNA selection-compounds screening cycle" for exploring RNA-small molecule pairs.

RNA is an emerging target of next-generation drug development. Recently, new small molecules targeting RNAs were discovered by several pharmaceutical companies. Methods have been reported to identify small molecules targeting a specific RNA sequence and structural motif, however, because of diverse sequence and structural motifs potentially present in the druggable functional RNAs, large sets of structure-activity relationships (SARs) information of small molecule - RNA interactions will be required for the acceleration and efficient startup of the discovery programs toward unprecedented RNA targets. Here we describe our iterative RNA selection and compounds screening to accumulate rich information about small molecules - RNA interaction. The RNAs that selectively bind to the initial molecular target, compound 1 from our in-house chemical library (JT-library), was isolated using in vitro selection technique from a hairpin-structured RNA library mimicking precursor microRNA (pre-miRNA). Then, we engineered pre-let-7f-2 to create its mutant that can bind to compound 1 by embedding the in vitro selected RNA motif for compound 1 in the hairpin loop region. The obtained mutant pre-let-7f-2-loop-mt was used as a target for screening 316 analogs of compound 1. A surface plasmon resonance (SPR) -based screening was performed against pre-let-7f-2-loop-mt-immobilized sensor surface and we obtained four compounds that can bind to the RNA. Among these four compounds, three compounds showed higher affinity to pre-let-7f-2-loop-mt than the parental compound 1, which suggests the feasibility of our strategy for gathering the SAR information on small molecule - RNA interactions. We demonstrated only one cycle of RNA selection and compounds screening in the present study, but can continue this cycle with the selected molecule to gain new RNAs and even new RNA motifs and gather much SAR information with improved accuracy.

[Effects of Piper longum L. on chills in Japanese young women: time-dependent changes in skin surface temperature and its recovery rate following the exposure to mild cold stress].

Chills can lead to problems such as insomnia, mental fatigue, and unstable emotions. Increasing evidence shows that young women, as well as menopausal women, suffer from chills. The present study investigated the effect of Piper longum L. on chills in young women. Participants with (n = 16) and without (n = 16) chills were sampled randomly from female university students using reported discriminative criteria (Yamada et al, 2007). Each participant was randomly assigned to low- (15 mg) and high-dose (30 mg) P. longum groups. We determined the severity of complaints related to chills, physical parameters (body mass index, body fat ratio, and blood pressure), the peripheral circulation dynamics using a laser tissue blood flow-meter, and the skin surface temperature in the fingers using a thermograph. Mild cold stress was applied 10 min after taking a capsule containing P. longum or a dextrin placebo. Then, a thermograph was recorded every minute for 11 min. Piper longum significantly facilitated the recovery of skin surface temperature at either low or high dosages in participants with chills. In subjects without chills, neither high- nor low-dosage of P. longum had an effect. Our findings have important implications for the utility of P. longum in women with chills.

Kohki tea protects the rabbit bladder from ischemia/reperfusion-induced contractile dysfunction.

OBJECTIVES: Results of several studies indicated that ischemia/reperfusion is an etiological factor in obstructive bladder dysfunction. Kohki tea pretreatment was shown to reduce the dysfunctions induced by partial outlet obstruction in rabbits. The current study was designed to determine if pretreatment of rabbits with Kohki tea could prevent the contractile dysfunctions induced by bilateral ischemia followed by reperfusion. METHODS: New Zealand white rabbits were separated into several groups; one half of each group was pretreated by oral gavage for 3 weeks with Kohki tea and the other half was treated with vehicle (water). Experimental groups were subjected to bilateral ischemia for either 1 or 3 h followed by reperfusion for either 1 h or 1 week (4 groups). The results from the experimental groups were compared to the groups of rabbits receiving sham operations. RESULTS: Under all experimental conditions, Kohki tea significantly reduced the contractile dysfunctions induced by ischemia and ischemia followed by reperfusion. CONCLUSIONS: This data is consistent with the concept that Kohki tea acts by protecting the bladder smooth muscle and mucosa from cellular damage caused by ischemia/reperfusion.

Hepatoprotective effect of sesquiterpenes in turmeric.

Hepatoprotective effect of turmeric together with its sesquiterpenes and curcuminoids fractions were examined on D-galactosamine induced liver injury in rats. All the diets individually contained the turmeric extract, the curcuminoids fraction, and the sesquiterpenes fraction suppressed the increase of LDH, ALT, and AST levels caused by D-GalN treatment. Since few anti-oxidative activities are expected in the sesquiterpenes fraction, it is presumed that hepatoprotective mechanism of sesquiterpenes in turmeric is different from that of curuminoids.

Hepatoprotective activity of tocha, the stems and leaves of Ampelopsis grossedentata, and ampelopsin.

Hepatoprotective effect of the leaves and stems of Ampelopsis grossedentata together with its main constituent, ampelopsin, were examined on D-galactosamine induced liver injury in rats. The diet containing 50% ethanolic extract (1%) and ampelopsin (0.1%) markedly suppressed the increase of LDH, ALT, AST, alpha-tocopherol levels and GSG/GSSH caused by GalN treatment. These results suggested that ampelopsin from Tocha acted to prevent the oxidative stress in vivo that may have been due to active oxygen species formed by a macrophage by the action of GalN.

Antioxidative components of Psoralea corylifolia (Leguminosae).

A meroterpene and four flavonoids were isolated from the seeds of Psoralea corylifolia as antioxidative components. Their structures were elucidated by spectral data and identified as bakuchiol (1), bavachinin (2), bavachin (3), isobavachin (4) and isobavachalcone (5). In particular, meroterpene 1 and flavonoids 4 and 5 showed broad antioxidative activities in rat liver microsomes and mitochondria. They inhibited NADPH-, ascorbate-, t-BuOOH- and CCl(4)-induced lipid peroxidation in microsomes. They also prevented NADH-dependent and ascorbate-induced mitochondrial lipid peroxidation. Bakuchiol (1) was the most potent antioxidant in microsomes and the inhibition of oxygen consumption induced by lipid peroxidation was time-dependent. Furthermore, bakuchiol (1) protected human red blood cells against oxidative haemolysis. These phenolic compounds in P. corylifolia were shown to be effective in protecting biological membranes against various oxidative stresses.

Effect of oral Kohki tea on bladder dysfunction induced by severe partial outlet obstruction.

PURPOSE: Extracts of the leaves of Engelhardtia chrysolepis, a subtropical plant that grows wild in southern China, have been used medicinally in east Asia for hundreds of years. A standard extract named Kohki tea (Maruzen Pharmaceuticals, Onomichi City, Japan) is sold over the counter in Japan as a sweet tea shown to confer many beneficial effects on general health and well-being. The tea contains strong antioxidants, including several dihydroflavonol glycosides. The results of previous studies show that natural products with antioxidant activities provide protective effects on the bladder of rabbits with partial outlet obstruction. We determined in vivo and in vitro whether oral pretreatment of rabbits with Kohki tea protects the bladder from dysfunction induced by partial outlet obstruction. MATERIALS AND METHODS: A total of 28 New Zealand White rabbits were separated into 4 groups of 7 each. Rabbits in groups 1 and 2 were treated by gavage with 100 mg./kg. Kohki tea daily in distilled water, while those in groups 3 and 4 were given distilled water. After 4 weeks of daily oral administration each rabbit was sedated, the bladder was catheterized and cystometry was performed at a filling rate of 1 ml. per minute. At the completion of cystometry the rabbits were immediately anesthetized. Moderate outlet obstruction was created in groups 1 and 3, and sham surgery was performed in groups 2 and 4. Treatment was continued for an additional 4 weeks, when each rabbit was sedated and cystometry was repeated. After cystometry the bladder was exposed through a midline incision, excised, weighed and 4 strips of bladder body were cut for contractility studies. The balance of the bladder was separated between smooth muscle and mucosa by blunt dissection, frozen in liquid nitrogen and stored at -70C for biochemical analyses. RESULTS: Partial outlet obstruction stimulated similar increases in the bladder weight of all obstructed rabbits. Partial outlet obstruction resulted in a significant decrease in bladder compliance in all obstructed animals. However, the bladder of obstructed rabbits given Kohki tea were significantly more compliant than those given water. Voiding pressures in the control group and the obstructed group given distilled water were approximately equal, while obstructed rabbits given Kohki tea showed significantly higher maximal voiding pressure. The contractile responses to all forms of stimulation were reduced by obstruction to a significantly greater degree in the rabbits not given tea than in those given tea. Sarcoplasmic reticulum Ca2+-adenosine triphosphatase enzyme activity of the bladder was significantly reduced in obstructed rabbits given vehicle but activity was not reduced in obstructed rabbits given Kohki tea. CONCLUSIONS: Kohki tea had a significant protective effect on bladder function, contractile responses and bladder biochemistry in rabbits with moderate to severe partial outlet obstruction.