Anticonvulsive and neuroprotective effects of aqueous and methanolic extracts of Anacyclus pyrethrum root in kainic acid-induced-status epilepticus in mice.

PURPOSE: Epilepsy is a chronic neurological disorder characterized by spontaneous and recurrent seizures. The currently available synthetic antiepileptic drugs have a limited efficacy and are associated with a wide range of side effects. In Ayurveda, Anacyclus pyrethrum root (APR) has been used as a traditional antiepileptic remedy. The aim of the present study is to evaluate the anticonvulsive and neuroprotective effects of aqueous and methanol extracts of Anacyclus pyrethrum root (AEAPR and MEAPR) on experimental model of status epilepticus (SE). METHODS: Twenty four male mice were divided into four groups. The control and KA groups had free access to tap water for 5 days before the intraperitoneal injection of distillated water or kainic acid (KA; 30 mg/kg), respectively. In the treated groups, mice received extracts solutions MEAPR and AEAPR in drinking water at the concentration of 5 g/l for 5 days. At the fifth day, animals received intraperitoneal injection of KA. The behavioral changes latency of seizures, the number of wet dog shakes (WDS) and the mortality were observed over 6 h. Thereafter, the mice were sacrificed for immunohistochemical studies. RESULTS: Pretreatment with MEAPR and AEAPR decreases significantly the frequency of WDS (32.5% and 43.9%, p < 0.01; respectively), and increases considerably the latent period (77.9% and 91.9%, p<0.01; respectively) between the injection of the KA and the appearance of the SE as compared to the KA group. The duration and severity of seizure in the MEAPR or AEAPR-pretreated groups were significantly lower (p < 0.01 and p < 0.05 or p < 0.01; respectively) than those in the KA group. These behavioral results were confirmed by the immunohistochemical study at the level of the hippocampus, in which the c-FOS and GFAP expression of both MEAPR and AEAPR-treated animals largely reduced (p < 0.001) the number of labelled cells with respect to the group, which received the KA alone. CONCLUSION: Our results showed that the MEAPR and AEAPR have anticonvulsive effect and putative neuroprotective effect against seizures induced by KA. Further studies are required to identify its active ingredients responsible for the observed effects.

Defense of pyrethrum flowers: repelling herbivores and recruiting carnivores by producing aphid alarm pheromone.

(E)-ß-Farnesene (EßF) is the predominant constituent of the alarm pheromone of most aphid pest species. Moreover, natural enemies of aphids use EßF to locate their aphid prey. Some plant species emit EßF, potentially as a defense against aphids, but field demonstrations are lacking. Here, we present field and laboratory studies of flower defense showing that ladybird beetles are predominantly attracted to young stage-2 pyrethrum flowers that emitted the highest and purest levels of EßF. By contrast, aphids were repelled by EßF emitted by S2 pyrethrum flowers. Although peach aphids can adapt to pyrethrum plants in the laboratory, aphids were not recorded in the field. Pyrethrum's (E)-ß-farnesene synthase (EbFS) gene is strongly expressed in inner cortex tissue surrounding the vascular system of the aphid-preferred flower receptacle and peduncle, leading to elongated cells filled with EßF. Aphids that probe these tissues during settlement encounter and ingest plant EßF, as evidenced by the release in honeydew. These EßF concentrations in honeydew induce aphid alarm responses, suggesting an extra layer of this defense. Collectively, our data elucidate a defensive mimicry in pyrethrum flowers: the developmentally regulated and tissue-specific EßF accumulation and emission both prevents attack by aphids and recruits aphid predators as bodyguards.