Evaluation of the antinociceptive activity of extracts of Sonchus oleraceus L. in mice

Ethnopharmacological relevance

Sonchus oleraceus L. has been used to relieve pain in Brazilian folk medicine.

Aim of the study

Sonchus oleraceus L. has been used to relieve pain in Brazilian folk medicine. This study was conducted to establish the antinociceptive properties of hydroethanolic and dichloromethane extracts from aerial parts of Sonchus oleraceus in mice using chemical and thermal models of nociception.

Materials and methods

The formalin, hot plate, and tail immersion tests as well as acetic acid-induced writhing were used to investigate the antinociceptive activity in mice.

Results

Given orally, the extracts at test doses of 30–300 mg/kg, produced significant inhibitions on chemical nociception induced by intraperitoneal acetic acid and subplantar formalin since decreased the number of writhing episodes and the time licking. Treatment with the extracts in the same doses produced a significant increase of the reaction time in tail immersion and in the hot plate test. The extracts administered at 300 mg/kg, p.o. had a stronger antinociceptive effect than indomethacin (5 mg/kg, p.o.) and morphine (10 mg/kg, p.o.).

Conclusion

The extracts of Sonchus oleraceus markedly demonstrated antinociceptive action in mice, which supports previous claims of its traditional use.     

trans‐resveratrol alone and hydroxystilbenes of rhubarb (Rheum rhaponticum L.) root reduce liver damage induced by chronic ethanol administration: a comparative study in mice

The hepatoprotective effects and pharmacokinetics of trans‐resveratrol and hydroxystilbenes of the garden rhubarb (Rheum rhaponticum L., R. rhaponticum) root ethanol extract were studied. Ethanol was administered to male BALB/c mice for 35 days in an inhalation chamber. During this time vehicle, trans‐resveratrol (20 mg/kg per day) or R. rhaponticum extract was intraperitoneally (i.p.) administered and mice were sacrificed for the collection of liver and blood. In an additional experiment, the level of parent compounds and metabolites was estimated in the blood after acute i.p. administration of trans‐resveratrol or R. rhaponticum extract. The levels of hydroxystilbenes, their metabolites and fatty acid oxy‐metabolites (oxylipins) were studied by LC‐tandem DAD‐MS/MS. Ethanol induced hepatotoxicity, as evidenced by histological changes and accumulation of oxylipins in the blood. Both trans‐resveratrol and R. rhaponticum extract reduced the extent of these changes. The pharmacokinetics of trans‐resveratrol was characterized by a rapid removal from the blood and metabolism to sulfates and glucuronides. After the administration of R. rhaponticum extract, in addition to trans‐resveratrol glucoside and its metabolites, several other hydroxystilbenes were found. Inhibition of oxidation of polyunsaturated fatty acids is proposed as a basis of the hepatoprotective effect of both trans‐resveratrol and R. rhaponticum extract. Copyright © 2008 John Wiley & Sons, Ltd.     

PDNF, a human parasite-derived mimic of neurotrophic factors, prevents caspase activation, free radical formation, and death of dopaminergic cells exposed to the Parkinsonism-inducing neurotoxin MPP+

The neuraminidase/trans-sialidase of Trypanosoma cruzi, the agent of Chagas' disease, promotes differentiation and survival of growth factor-deprived neuronal and glial cells. To gain further insights into the possible neuroprotection of this parasite-derived counterpart of neurotrophic factors (PDNF), we sought to determine whether it mimics growth factors in a cellular model of neurodegenerative diseases. Ascertaining cell viability by morphology, vital dye exclusion, mitochondrial reducing function, and absence of DNA fragmentation, we show here that PDNF rescues from death two dopaminergic neuronal cell lines and one differentiated immortalized mesencephalic neurons exposed to the neurotoxin 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP) and its toxic metabolite, 1-methyl-4-phenylpyridinium (MPP+), both widely used in models of Parkinson's disease. We further show that PDNF promoted survival at concentrations comparable to bona fide growth factors in a MAPK/Erk activation-dependent manner. PDNF also strongly suppresses the overproduction of MPTP-induced reactive oxygen species (ROS), and the activation of both initiator caspase-9 and effector caspase-3. This down-regulation of ROS and caspases explains, at least in part, the PDNF-induced salvaging of the dopaminergic cells from the Parkinsonism-promoting toxin, confirming the novel and striking functional mimicry by the trypanosome neuraminidase of host growth factors in a cellular model of neurodegeneration.     

Influence of atmospheric versus reduced oxygen concentration on development of human blastocysts in vitro: a prospective study on sibling oocytes

Numerous studies show the beneficial effect of reduced oxygen on the culture of animal embryos in vitro. However, few similar studies have been carried out in humans, and the conclusions from these were contradictory. Using sibling human oocytes, a prospective study was carried out to analyse the effect of 5 and 20% oxygen on prolonged development of embryos. The outcomes measured were fertilization rate and proportion of morphologically optimal embryos, blastocysts and optimal blastocysts developing on day 5. The results were analysed separately for the group of IVF (n = 988 oocytes) and ICSI (n = 928 oocytes) cycles. It was found that low oxygen did not influence fertilization, but in comparison with 20% oxygen, it resulted in a significantly higher proportion of embryos being optimal on day 3 after IVF (59 versus 43.2%; P < 0.001) as well as after ICSI cycles (51.2 versus 28.5%; P < 0.001). In both methods, the lower oxygen concentration improved the blastulation rate (73.2 versus 63.1%; P < 0.05 and 67.4 versus 54.7%; P < 0.001) and increased the proportion of embryos reaching the stage of expanded blastocyst with normal inner cell mass on day 5 (31.1 versus 14.6%; P < 0.001 and 18.9 versus 11.4%; P < 0.01). The ratio of successful embryo development to optimal blastocyst stage on day 5 of culture, calculated for two oxygen concentrations, was 2.1 for IVF and 1.7 for ICSI, in favour of lower oxygen tension.