New fraternine analogues: Evaluation of the antiparkinsonian effect in the model of Parkinson's disease.

Venom-derived peptides are important sources for the development of new therapeutic molecules, especially due to their broad pharmacological activity. Previously, our research group identified a novel natural peptide, named fraternine, with promising effects for the treatment of Parkinson's disease. In the present paper, we synthesized three peptides bioinspired in fraternine: fra-10, fra-14, and fra-24. They were tested in the 6-OHDA-induced model of parkinsonism, quantifying motor coordination, levels of TH+ neurons in the substantia nigra pars compacta (SN), and inflammation mediators TNF-α, IL-6, and IL-1ß in the cortex. Peptides fra-14 and fra-10 improved the motor coordination in relation to 6-OHDA lesioned animals. However, most of the peptides were toxic in the doses applied. All three peptides reduced the intensity of the lesion induced rotations in the apomorphine test. Fra-24 higher dose increased the number of TH+ neurons in SN and reduced the concentration of TNF-α in the cortex of 6-OHDA lesioned mice. Overall, only the peptide fra-24 presented a neuroprotection effect on dopaminergic neurons of SN and a reduction of cytokine TNF-α levels, making it worthy of consideration for the treatment of PD.

Pathophysiological effects caused by the venom of the social wasp Synoeca surinama.

Envenomation by wasp stings is a public health preoccupation, and signals after stings have variable effects depending on the number of attacks and individual sensitivities. Even with the high rate of wasp sting cases, the study of phatophysiological effects of the envenomation is still very incipient. In this context, early and accurate assessment of this prognostic can aid in the reduction of the symptomatology and complete remission of the later symptoms. Then, the present study evaluated the toxicological effects caused by envenomation produced by Synoeca surinama, a wasp easily found in Neotropical regions. In vivo tests comprised the evaluation of LD50 (OECD 423), nociception, edema, myotoxic lesion and hemorrhage induction, in vitro tests were realized to evaluate hemolysis, contractile and coagulation alteration. The envenomation effects observed were dose- and time-dependent; the LD50 observed for S. surinama was 178 µg/kg, approximately 17 times more lethal than that of the honeybee. Moreover, a potent algesic and oedema effect, and weak hemorrhagic signal were observed after injection of the venom wasp. Assays in vitro showed that this venom is able to prolong the clotting time of plasma and to increase creatine kinase levels. Our results demonstrated that this venom induced serious local and systemic effects in mammals and, so, to avoid permanent damage to the patient, health professionals should carefully investigate each accident. Moreover, due to its high occurrence in Neotropical regions, ecological management, particularly in areas with free access of children and elderly, should be performed.