Humberto Hugo Nunes de Andrade's research while affiliated with Universidade Federal da Paraíba and other places

Due to the complex nature of pain and the participation of physical, cognitive, psychological and behavioral aspects, pain management has several approaches. The use of medicinal plants in developing countries is quite expressive. Seeking new options for the treatment of emerging or debilitating diseases. Therefore, the present study seeks to elucidate the effects of the monoterpene, citronellal, differentiating its activity by isomers (R)-(+) and (S)-(-) citronellal. The study used several methods to evaluate the effects of citronellal isomers on motor coordination, nociceptive response, and the involvement of opioid, glutamatergic, and transient receptor pathways. The methods included rota-rod, hot-plate, and formalin tests, as well as the use of specific inhibitors and agonists. Data were analyzed using inferential statistics with a 95% confidence level. Both isomers did not significantly affect the motor coordination of the studied animals. The isomer (S)-(-) citronellal showed better results in relation to its structural counterpart, managing to have an antinociceptive effect in the formalin and hot plate tests with a lower concentration (100 mg/kg) and presenting fewer side effects, however, the this study was not able to elucidate the mechanism of action of this isomer despite having activity in studies with substances that act on specific targets such as glutamate and capsaicin, its activity was not reversed with the use of antagonists for pathways related to nociception. While the (R)-(+) citronellal isomer, despite showing total activity only at a concentration of 150 mg/kg, was able to determine its mechanism of action related to the opioid pathway by reversing its activity by the antagonist naloxone, being this is a pathway already correlated with nociception control treatments, however, it is also related to some unwanted side effects. In this way, new studies are sought to elucidate the mechanism related to the isomer (S)-(-) citronellal and a possibility of use in other areas related to the treatment of pain or inflammation.

Introduction: Alzheimer's and Parkinson's are neurodegenerative disorders that affect a great number of people around the world, seriously compromising the quality of life of individuals, due to motor and cognitive damage. In these diseases, pharmacological treatment is used only to alleviate symptoms. This emphasizes the need to discover alternative molecules for use in prevention. Objective: Using Molecular Docking, this review aimed to evaluate the anti-Alzheimer's and anti- Parkinson's activity of linalool and citronellal, as well as their derivatives. Methodology: Before performing Molecular Docking simulations, the compounds' pharmacokinetic characteristics were evaluated. For Molecular Docking, 7 chemical compounds derived from citron- ellal, and 10 compounds derived from linalool, and molecular targets involved in Alzheimer's and Parkinson's pathophysiology were selected. Results: According to the Lipinski rules, the compounds under study presented good oral absorption and bioavailability. For toxicity, some tissue irritability was observed. For Parkinson-related targets, the citronellal and linalool derived compounds revealed excellent energetic affinity for α-Synuclein, Adenosine Receptors, Monoamine Oxidase (MAO), and Dopamine D1 receptor proteins. For Alzheimer disease targets, only linalool and its derivatives presented promise against BACE enzyme activity. Conclusion: The compounds studied presented high probability of modulatory activity against the dis- ease targets under study, and are potential candidates for future drugs.

Epilepsy is a chronic neurological disorder affecting 1-2% of world population, and one-third of patients are refractory to pharmacological treatment. This fact has stimulated research for new antiepileptic drugs and natural products have been an important source. trans-Anethole (TAN) is a phenylpropanoid, component of some essential oils, extracted from plants, and its effects have been little studied. Therefore, this study is aimed at investigating the TAN effect in classic seizure models and evaluate the electroencephalographic (EEG) profile of animals treated with this substance. For this, Swiss male mice (Mus musculus) were used, and the lethal dose was evaluated and subsequently submitted to the test maximal electroshock (MES), the pentylenetetrazole- (PTZ) induced seizure test, and the EEG profile. Initially, the LD50 for TAN was estimated in 1000 mg/kg (i.p.) dose and there was no sign of acute toxicity or death. In the MES test, TAN 300, i.p. ( 12.00 ± 2.9 s) and 400 mg/kg, i.p. ( 9.00 ± 4.4 s) doses was able to decrease tonic seizures duration induced by electric discharge (0.5 mA, 150 pulses/s, for 0.5 s). In the PTZ test (75 mg/kg, i.p.), TAN 400 mg/kg, i.p. increased the latency to myoclonic jerks (80.0 (56.0–134.0)), the latency totonic-clonic seizures (900.0 (861.0–900.0) and decrease seizure duration (0.0 (0.0–10.0)). No deaths were found in this groups compared to vehicle. EEG analysis showed an amplitude decrease of waves (ratio of baseline) in TAN 300 ( 1.82 ± 0.23 ) and 400 mg/kg ( 1.06 ± 0.16 ) groups. In this way, TAN at 400 mg/kg was able to inhibit and/or attenuate seizures by increasing the time for the onset of spasms and convulsions, as reducing the duration of seizures. The EEG profile corroborate with this results showing a reduction in the amplitude of waves compared to the PTZ group. Thus, TAN showed an anticonvulsant effect in all experimental models performed, behavioral and electroencephalographic.

Ethnopharmacological relevance The Waltheria viscosissima A. St.- Hil (Malvaceae) is also known as ‘Malva branca’, has been reported as ethnopharmacologically useful plant containing antinociceptive and anti-inflammatory properties, but scientific evidence is absent. Aim of the study: Elucidate the antinociceptive, anti-inflammatory and antioxidant activity of the crude ethanol extract (EEBWa.v) and alkaloid fraction (FAWa.v) of aerial parts of the W. viscosissima in healthy mice with induced inflammation. Materials and methods EEBWa.v and FAWa.v (50, 100 and 200 mg/kg) and morphine (10 mg/kg) were used in vivo tests of chemical nociception induced by acetic acid (0.6%; 10 mg/kg) and formalin (2.5%) in Swiss male mice. Acute inflammation was induced by carrageenan (1%) in vivo tests and there were several groups tested. The control (inflammation induced without treatment) and the groups treated with EEBWa.v (100 mg/kg), FAWa.v (100 mg/kg) and dexamethasone (2 mg/kg). After this procedure, the animals were euthanized and the peritoneal fluid was collected to evaluate cell migration and redox balance (malondialdehyde - MDA and Total Antioxidant Capacity - TAC). Results The morphine, EEBWa.v (50 and 100 mg/kg) and FAWa.v (100 mg/kg) significantly reduced the number of abdominal writhes compared to the control group. FAWa.v (100 mg/kg) was superior to FAWa.v (200 mg/kg). In the formalin-induced nociception model (neurogenic phase) EEBWa.v (50 and 200 mg/kg) significantly reduced the number of paw licks. In the inflammatory phase with peripheral action, FAWa.v (100 mg/kg) was superior to EEBWa.v (200 mg/kg). EEBWa.v and FAWa.v (100 mg/kg) proved to be significant for the next experiments. Both samples showed reduction in cell migration, as well as those treated with dexamethasone, in animals with inflammation induced by carrageenan, compared to the untreated group. The redox balance (TAC and MDA) revealed that only EEBWa.v (100 mg/kg) had higher antioxidant potential than the untreated group and the dexamethasone group, p < 0.005 and p < 0.001, respectively. FAWa.v (100 mg/kg) did not show antioxidant activity superior to EEBWa.v. It was also detected that EEBWa.v and FAWa.v (100 mg/kg) failed to inhibit lipid peroxidation. Conclusions The W. viscosissima stimulates pain control, which can be mediated by both central and peripheral action. These bioactive compounds showed promising and potential to replace standard medicines. This bioactive effect is statistically similar to morphine and dexamethasone, standard medicines on the market, but with the advantage of antioxidant activity.

Objective: To evaluate the antinociceptive activity of perillyl acetate in mice and in silico simulations. Methods: The vehicle, perillyl acetate (100, 150 and/or 200 mg/ kg, i.p.), diazepam (2 mg/kg, i.p.) or morphine (6 mg/kg, i.p.) was administered to mice, respectively. Rotarod test, acetic acid-induced abdominal writhing, formalin-induced nociception, hot plate test, and tail-flick test were performed. Opioid receptors-involvement in perillyl acetate antinociceptive effect was also investigated. Results: Perillyl acetate did not affect the motor coordination of mice. However, it reduced the number of acetic acid-induced abdominal twitches and licking times in the formalin test. There was an increase of latency time in the tail-flick test of 30 and 60 minutes. Pretreatment with naloxone reversed the antinociceptive effect of perillyl acetate (200 mg/kg). In silico analysis demonstrated that perillyl acetate could bind to μ-opioid receptors. Conclusions: Perillyl acetate has antinociceptive effect at the spinal level in animal nociception models, without affecting the locomotor integrity and possibly through μ-opioid receptors. In silico studies have suggested that perillyl acetate can act as a μ-opioid receptor agonist.

Hydroxycitronellal (HC) is a monoterpene present in essential oils of aromatic plants of different species, obtained from semisynthesis of citronellal, and is widely used as a fragrance in cosmetics. The objective of this work was to evaluate the possible anxiolytic-like activity of HC and its possible mechanism of action using in vivo and in silico methodologies. Swiss male mice (Mus musculus) were treated with HC (12.5, 25, and 50 mg/kg, i.p.) and subjected to the rota rod, elevated plus maze, and open field tests. No significant impairments were observed in the rota rod tests for the motor activity of the animals treated with HC at 12.5, 25, and 50 mg/kg, i.p., indicating no myo-relaxing or sedative effects. In the elevated plus maze, HC (in the three doses) induced significant increases in the percentage of entries (respectively, 34.8%, 33.8%, and 38.6%) and in the length of stay (respectively, 49.9%, 56.1%, and 57.0%) in the open arms of the EPM, as well as the number of crossings in the open field tests. The mechanism of action of the compound’s anxiolytic-like activity can be attributed to the involvement of GABAA receptors, and this interaction was observed in in vivo and in silico studies. For HC, the results suggest anxiolytic-like effects, possibly via modulation of the GABAergic system. The use of natural products to treat anxiety can become an alternative to existing synthetic products.

Objetivo: Investigar a substância GA-4, quanto a ser um potente candidato a antidepressivo, além de identificar seu possível mecanismo de ação através de docking. Métodos: Foram realizados ensaios psicofarmacológicos in vivo, devidamente autorizado pelo Comitê de ética no uso de animais, utilizando camundongos Swiss, sendo através de testes do campo aberto nas doses de 50, 100 e 200 mg/Kg, analisando os parâmetros: Rearing, Grooming, Número de cruzamentos, micções e bolos fecais. Além do teste do nado forçado, sendo avaliado o tempo de imobilidade dos animais nas mesmas doses do teste de campo aberto. A modelagem molecular foi realizada através de programas computacionais. Resultados: Os resultados mostraram que a substância GA-4 apresenta atividade antidepressiva, tendo em vista que reduziu o tempo de imobilidade no teste do nado forçado e não alterou a atividade locomotora no teste de campo aberto. No estudo de docking, a substância GA-4 teve afinidade com o receptor α2- adrenérgico e se ligou no mesmo sítio de ativação da ioimbina, mostrando ser um possível antagonista dos receptores α2- adrenérgico Conclusão: Diante dos resultados obtidos, podemos concluir que a substância GA-4 é um potencial candidato a medicamento antidepressor. Possivelmente por antagonizar os receptores α2- adrenérgico.

Cinnamic alcohol, cinnamic aldehyde, and cinnamic acid are compounds commonly found in the volatile oil of barks of species in the genus Cinnamomum spp. Schaeff., Lauraceae, popularly known as cinnamon. Cinnamon has been used for millennia for both food and medicinal purposes. The present study reviews the main pharmacological studies on cinnamic alcohol and its derivatives, in order to stress out that cinnamon is a natural product, enriched with compounds endowed of important pharmacological effects that can be benefic to the human health. As a literature review using a qualitative approach, covering articles published between 1970 and 2020, the databases consulted were Pubmed, Web of Science, Science Direct, and Scopus. The following descriptors were searched: “cinnamon,” “cinnamic alcohol,” “cinnamyl alcohol,” “cinnamaldehyde,” “cinnamic aldehyde,” “cinnamic acid,” and “benzoate.” We selected 32 articles studying non-clinical pharmacological aspects of cinnamic alcohol and its derivatives, with emphasis on their central nervous system activities and anti-inflammatory, antioxidant, and antimicrobial potential. In conclusion, the present review demonstrates non-clinical evidence for cinnamic alcohol and its derivatives as bioactive compounds with pharmacological importance, yet we note the lack of clinical studies.Graphical abstract

Lippia pedunculosa Hayek (EOLp) presents tripanocid and amebicid effects. However essential oil needs to be further studied in experimental models of analgesia and inflammation once the prevalence of pain in the population generates great suffering and disability and the drugs most often used have undesirable side effects. We also evaluated whether the inclusion complex formulation EOLp/β-cyclodextrin (β-CD) was able to improve the antinociceptive activity of the EOLp alone. Data were evaluated by analysis ofvariance (ANOVA), followed by Tukey’s test. Differences were considered significant if p<0.05. EOLp presented better antinociceptive effect when compared to the EOLp/β-CD inclusion complex. Thus, cyclodextrins appear not to be efficient for essential oilswith peroxide substances. However, in peritonitis, EOLp reduced total leucocyte migration and IL-1β levels in the peritoneal fluid, which confirmed its anti-inflammatory effect. The observed effects suggest that EOLp is the best promising option for the treatment of inflammation and pain-related disorders.

Anxiety in the world population has increased significantly; the problem has encouraged studies regarding innovative alternatives for treatment. Research with Citrus aurantium L. essential oil (CEO) has revealed positive results with anxiolytic effects in both animals and humans. However, certain limitations affect its storage and preservation, its efficiency in therapy, and determination of adequate posologies. The potential use of cyclodextrins as drug carriers has been successfully explored. This study aims to assess the anxiolytic potential of a CEO/2-hydroxypropyl-β-cyclodextrin (HP-β-CD) inclusion complex. Preparation of the inclusion complex was performed using the Alpha 1-2 LDplus lyophilizer. To allow formation, and avoid loss of volatiles to the atmosphere, Limonene (LIM), the main compound in CEO, together with HPβ-CD in a molar ratio of (1: 1M) was dispersed in ethanol for 36 hours using a laboratory shaker at room temperature (25°C). Non-clinical murine pharmacological tests were performed for anxiety assessment in experimental and control groups. To assess anxiety and motor impairment, the animals were evaluated using the elevated plus maze, open field, and rota-rod tests. Satisfactory results of the anxiolytic effect of the OEC complexed in HP-β-CD were observed, with the indication of an potentiation of the effect with doses lower than 500 mg/kg and 250 mg/kg complexed, suggesting improvement in the anxiolytic properties of the OEC.