Pollination systems in Pogonieae (Orchidaceae: Vanilloideae): A hypothesis of evolution among reward and rewardless flowers

The tribe Pogonieae of Vanilloideae (Orchidaceae) consists of six genera, including Pogoniopsis, a mycoheterotrophic taxon with morphological characteristics distinct from the remaining of the tribe. A hypothesis about the phylogeny of the tribe was inferred, involving all currently recognized genera, based on isolated and combined sequence data of 5.8S, 18S and 26S (nrDNA) regions using parsimony and Bayesian analyses. Phylogenetic analyses show that inclusion of Pogoniopsis turns the tribe Pogonieae paraphyletic. All analyses reveal that Pogoniopsis is closely related to members of Epidendroideae. The pantropical Vanilla is monophyletic if Dictyophyllaria is assumed as synonym of Vanilla. Members of Pogonieae are pollinated by several groups of solitary and social bees, two pollination systems being recognized: reward-producing and deceptive. The molecular phylogeny suggests that ancestrals related to Pogonieae gave rise to two evolutionary lines: a tropical one with reward production of flowers, and a predominantly temperate regions invading line with deceptive flowers. Reward-producing flowers characterize the South and Central American clade (=Cleistes), while deceptive pollination is prominent in the clade that includes North American-Asiatic taxa plus the Amazonian genus Duckeella. (C) 2012 Elsevier GmbH. All rights reserved.

Erysothrine, an alkaloid extracted from flowers of Erythrina mulungu Mart. ex Benth: Evaluating its anticonvulsant and anxiolytic potential

In this study, we isolated the alkaloid erysothrine from the hydroalcoholic extract of flowers from E. mulungu and screened for its anticonvulsant and anxiolytic actions based on neuroethological and neurochemical experiments. Our results showed that the administration of erysothrine inhibited seizures evoked by bicuculline, PTZ, NMDA and most remarkably, kainic acid. Also, erysothrine induced an increase in the number of entries but not in the time spent in the open arms of the EPM. However, we did not notice any alterations in the light-dark choice or in the open-field tests. In preliminary neurochemistry tests, we also showed that erysothrine (0.001-10 mu g/mL) did not alter the GABA or glutamate synaptossomal uptake and binding. Altogether, our results describe an alkaloid with anticonvulsant activity and mild anxiolytic activity that might be considered well tolerated as it does not alter the general behavior of the animals in the used doses. (C) 2012 Elsevier Inc. All rights reserved.