Synergistic larvicidal and repellent effects of essential oils of three Origanum species on Rhipicephalus annulatus tick.

Ticks are of great economic importance worldwide, both because they represent major obstacles to livestock productivity and because of their ability to transmit diseases to humans and animals. Although synthetic acaricides are the most common method for tick control, their overuse has led to the development of resistance as well as unacceptable residual levels in animal products and in the environment in general. There is therefore an urgent need to identify alternative treatments. Among such alternative approaches for tick control is plant essential oil (EO) therapy. In the present study, we investigated the synergistic effect of EOs of three oregano species-Origanum onites, O. majorana and O. minutiflorum-against Rhipicephalus annulatus larvae. Gas chromatography-mass spectrometry profiles of the three EOs revealed that carvacrol was their major component, with a concentration of 86.2% in O. majorana, 79.1% in O. minutiflorum and 77.4% in O. onites. The results of larvicidal assays revealed that the doses that lead to the death of 50% of the ticks (LC50) were 22.99, 25.08 and 27.06 µL/mL for O. majorana, O. minutiflorum and O. onites EOs, respectively, whereas the doses that lead to the death of 99% (LC99) were 41.26, 43.62 and 48.96 µL/mL. In addition, the LC50 and LC99 of the three oils combined was lower (viz., 4.01 and 6.97 µL/mL) than that of each oil alone. The tested EOs were also able to repel larvae of R. annulatus to varying degrees, with O. onites oil exhibiting the greatest repellent effect, as shown by the lowest RC50 dose, followed by O. minutiflorum and O. majorana. Interestingly, this means that the oil that was least effective in killing the larvae was the most effective in repelling them. The calculated synergistic factor of any combination was higher than 1 which means that combinations have a synergistic effect. In conclusion, the combination of all three oils showed higher toxic and repellent activities than either oil separately or combinations of any two oils, suggesting synergistic effects with low doses. Further studies including field trials and the establishment of the mode of action and side effects are urgently needed to expand on these findings, and other tick stages such as adults should also be tested.

Anticoccidial and Antioxidant Activities of Moringa oleifera Leaf Extract on Murine Intestinal Eimeriosis.

BACKGROUND: Coccidiosis is an intestinal disease caused by protozoan parasites of the genus Eimeria and responsible for considerable economic loss in the livestock and poultry industries. Resistance to the current anticoccidial drugs is now a major challenge to efforts to control the disease, and this has stimulated the search for new compounds as alternative treatments. In this context, plant extracts have emerged as an alternative and complementary approach to control coccidiosis. In the present study, an ethanol extract of Moringa oleifera leaves was screened for its anticoccidial activity against Eimeria papillata infection in mice. METHODS: To this end, albino mice were allocated into three groups: the first group was the non-infected control; the second and third groups were infected with 103 E. papillata oocysts. Of these, the second group was kept as an infected control; while the third group was gavaged with 100 µl of moringa leaf extract (MLE) at a dose of 400 mg MLE/kg, once daily, for five days. RESULTS: MLE significantly suppressed oocyst excretion in faeces, and histological study of the jejunum showed a significant decrease in the number of parasitic stages, with significant improvement in the numbers of goblet cells. Furthermore, the expression of MUC2 gene was upregulated in the treated mice compared with infected, which further supports the anticoccidial potential of MLE. Moreover, our study evidenced that MLE reduced oxidative damage by decreasing TBARS and iNOS expression, and increasing the GSH and GPX levels. Also, treatment with MLE promoted the expression of Bcl-2 and ultimately, inhibited the apoptosis of host cells in the treated mice. CONCLUSION: Our data indicate that MLE has anticoccidial, anti-oxidant and anti-apoptotic activities in mice infected with Eimeria papillata.

In vivo assessment of the antimalarial and spleen-protective activities of the Saudi propolis methanolic extract.

Antimalarial drug resistance is the main therapeutic challenge to the control of the disease, making the search for new compounds as alternative treatments of central importance. Propolis has a long history of medicinal use due to its antifungal, antibacterial and antiprotozoal properties. The present study therefore aimed to evaluate the antimalarial activity of the Saudi propolis methanolic extract against Plasmodium chabaudi infection in mice. To this end, albino mice were divided into five groups: the first group was the normal control; the second, third, fourth and fifth groups were infected intraperitoneally with 106 P. chabaudi-parasitized erythrocytes. The last three groups of mice were gavaged with 100 µl of propolis extract (PE) at a dose of 25, 50 and 100 mg PE/kg, respectively, once daily for 7 days. PE significantly suppressed the parasitaemia and showed significant efficacy in ameliorating anaemic conditions in P. chabaudi-infected mice in a dose-dependent manner. Histological investigation of the spleen tissue of treated and untreated mice further supports the antimalarial potential of PE. In addition, our study proved that Saudi PE reduced oxidative damage by decreasing the malondialdehyde (MDA) and increasing the catalase (CAT) activity and the glutathione (GSH) levels. Also, Saudi PE increased the level of some pro-inflammatory cytokines such as IFN-γ, TNF-α, GM-CSF and G-CSF, with the most effective dose being 100 mg PE/kg. In conclusion, PE showed antimalarial and antioxidant activities and provided protection against spleen tissue damage in P. chabaudi-infected mice.

In Vitro Scolicidal Effects of Salvadora persica Root Extract against Protoscolices of Echinococcus granulosus.

It has been known that Arak, Salvadora persica, has a number of medicinal properties. We tried to investigate in vitro scolicidal effect of root extracts of this plant against protoscolices from hydatid cysts of Echinococcus granulosus. Protoscolices were aseptically collected from sheep livers containing hydatid cysts. S. persica root extract was used in 10, 30, and 50 mg/ml concentration for 10, 20, and 30 min. The viability of protoscolices was ascertained by 0.1% eosin staining. Scolicidal activity of S. persica extract at a concentration of 10 mg/ml was 36.3%, 50.3%, and 70.8% after 10, 20, and 30 min of exposure, respectively. The scolicidal effect of this extract at a concentration of 30 mg/ml was 52.9%, 86.7%, and 100% after 10, 20, and 30 min of exposure, respectively. S. persica extract at a concentration of 50 mg/ml, meanwhile, killed 81.4%, 100%, and 100% of protoscolices after 10, 20, and 30 min, respectively. Also, the cytotoxic potential of S. persica was assessed on human liver cells (HepG2) using trypan blue exclusion test. No cytotoxic effect was observed on HepG2 cell line. The present study confirmed for the first time that the ethanolic extract of S. persica has high scolicidal power in vitro. However, in vivo effect of this material remains to be studied for treatment of echinococcosis in humans and herbivorous animals.

Dietary selenium affects intestinal development of Eimeria papillata in mice.

Here, we investigated the effect of the trace element selenium (Se) on course and outcome of Eimeria-paplllata-induced coccidiosis in mice. Male mice were fed on Se-adequate (0.15 ppm), Se-deficient, and Se-high diets (1.0 ppm) for 6 weeks. Mice were orally infected with 1,000 oocysts. The prepatent period lasts for 3 days, but the course of infections varied. At Se-adequate diet, the maximum fecal output of oocysts amounted to 68,300 ooccysts/g feces on day 5 p.i.. However, fecal shedding of oocysts was accelerated in mice on Se-deficient diet and occurred already on day 4 p.i.. By contrast, maximal shedding is impaired in mice on high-Se diet, which takes place on day 5 p.i., but with a decreased output of only 7,300 oocysts/g feces. Light microscopy reveals that all developmental stages are affected: meronts, micro- and macrogamonts, and developing oocysts are increased in comparison with mice fed on selenium-adequate diet. At high Se, the number of parasitic stages in the jejunum is substantially higher than at Se-deficient diet. Se does not affect the number of jejunal Alcian blue-stained goblet cells. Se deficiency increased the number of apoptotic cells in the jejunum. Substantially increased histological injury scores reveal more injuries in jejunum tissue infected by E. papillata. Our data indicate that high dietary Se exerts potential anticoccidial activity. This may be taken advantage of in control measures towards Eimeriosis as a feed additive, potentially alleviating the need for concomitantly utilized anti-coccidial drugs in the feed.

Differential miRNA expression in the mouse jejunum during garlic treatment of Eimeria papillata infections.

Accumulating evidence indicates a critical role of microRNAs (miRNAs) in the outcome of diseases. Here, we investigate the effect of garlic on the intestinal miRNA signature of male Balb/c mice during infections with Eimeria papillata. Garlic decreases the intracellular development as evidenced by a lowered fecal output of E. papillata oocysts from 3,150 ± 410 to approximately 1,750 ± 390 oocysts per gram feces on day 4 postinoculation. This anti-coccidial activity of garlic is associated with an inhibition of the E. papillata-induced increases of interferon gamma, inducible nitric oxide synthase, nitrite/nitrate, and malondialdehyde and decrease in glutathione. Moreover, garlic downregulates the E. papillata-induced increases in the expression of the miRNAs miR-1959, miR-203, and miR-21, and it upregulates the expression of the 11 miRNA species miR-142-5P, miR-15A, miR-10A, miR-29B, miR-1902, miR-125A-5P, let-7E, miR-148A, miR-130A, miR-10B, and miR-93, respectively, as revealed by miRXplore microarray technology. Real-time PCR confirms these effects of garlic in the jejunum of E. papillata-infected mice. Our data indicate that the anti-coccidial activity of garlic is associated with specific changes in the miRNA signature of the mouse jejunum, the target site of E. papillata. These changes may reflect an involvement of miRNAs in garlic-activated pathways to reduce and/or to repair E. papillata-induced tissue injuries.