Africanized Bee Venom (Apis mellifera Linnaeus): Neuroprotective Effects in a Parkinson's Disease Mouse Model Induced by 6-hydroxydopamine.

This study evaluated the neuroprotective effects of the Africanized bee venom (BV) and its mechanisms of action after 6-hydroxydopamine-(6-OHDA)-induced lesion in a mice model. Prior to BV treatment, mice received intrastriatal microinjections of 6-OHDA (no induced dopaminergic neuronal death) or ascorbate saline (as a control). BV was administered subcutaneously at different dosages (0.01, 0.05 or 0.1 mg·Kg-1) once every two days over a period of 3 weeks. The open field test was carried out, together with the immunohistochemical and histopathological analysis. The chemical composition of BV was also assessed, identifying the highest concentrations of apamin, phospholipase A2 and melittin. In the behavioral evaluation, the BV (0.1 mg·Kg-1) counteracted the 6-OHDA-induced decrease in crossings and rearing. 6-OHDA caused loss of dopaminergic cell bodies in the substantia nigra pars compacta and fibers in striatum (STR). Mice that received 0.01 mg·Kg-1 showed significant increase in the mean survival of dopaminergic cell bodies. Increased astrocytic infiltration occurred in the STR of 6-OHDA injected mice, differently from those of the groups treated with BV. The results suggested that Africanized BV has neuroprotective activity in an animal model of Parkinson's disease.

γ-Terpinene complexed with ß-cyclodextrin attenuates spinal neuroactivity in animals with cancer pain by Ca2+ channel block.

OBJECTIVES: Considering that γ-terpinene (γ-TPN) is a monoterpene found in Cannabis oil, with high lipophilicity and limited pharmacokinetics, our objective was to evaluate whether its complexation in ß-cyclodextrin (γ-TPN/ß-CD) could improve its physicochemical properties and action on cancer pain, as well as verify the mechanisms of action involved. METHODS: The γ-TPN/ß-CD was prepared and submitted to physicochemical characterization. Animals with sarcoma 180 were treated (vehicle, γ-TPN 50 mg/kg, γ-TPN/ß-CD 5 mg/kg or morphine) and assessed for hyperalgesia, TNF-α and IL-1ß levels, iNOS and c-Fos activity. The effects of γ-TPN on calcium channels were studied by patch-clamp and molecular docking. RESULTS: ß-CD improved the physicochemical properties and prolonged the anti-hyperalgesic effect of γ-TPN. This compound also reduced the levels of IL-1ß, TNF-α and iNOS in the tumour, and c-Fos protein in the spinal cord. In addition, it reduced Ca2+ current, presenting favourable chemical interactions with different voltage-dependent calcium channels. CONCLUSION: These results indicate that the complexation of γ-TPN into ß-CD increases its stability and time effect, reducing spinal neuroactivity and inflammation by blocking calcium channels.

Development of a New Formulation Based on In Situ Photopolymerized Polymer for the Treatment of Spinal Cord Injury.

Spinal Cord Injury (SCI) promotes a cascade of inflammatory events that are responsible for neuronal death and glial scar formation at the site of the injury, hindering tissue neuroregeneration. Among the main approaches for the treatment of SCI, the use of biomaterials, especially gelatin methacryloyl (GelMA), has been proposed because it is biocompatible, has excellent mechanical properties, favoring cell adhesion and proliferation. In addition, it can act as a carrier of anti-inflammatory drugs, preventing the formation of glial scars. The present work presents the development and in situ application of a light-curing formulation based on GelMA containing a natural extract rich in anti-inflammatory, antioxidant and neuroprotective substances (hydroalcoholic extract of red propolis-HERP) in an experimental model of SCI in rats. The formulations were prepared and characterized by time of UV exposition, FTIR, swelling and degradation. The hydrogels containing 1 mg/mL of HERP were obtained by the exposure to UV radiation of 2 µL of the formulation for 60 s. The locomotor evaluation of the animals was performed by the scale (BBB) and demonstrated that after 3 and 7 days of the injury, the GelMA-HERP group (BBB = 5 and 7) presented greater recovery compared to the GelMA group (BBB = 4 and 5). Regarding the inflammatory process, using histomorphological techniques, there was an inflammation reduction in the groups treated with GelMA and GelMA-HERP, with decreases of cavitation in the injury site. Therefore, it is possible to conclude that the use of GelMA and GelMA-HERP hydrogel formulations is a promising strategy for the treatment of SCI when applied in situ, as soon as possible after the injury, improving the clinical and inflammatory conditions of the treated animals.

Involvement of nuclear factor κB and descending pain pathways in the anti-hyperalgesic effect of ß-citronellol, a food ingredient, complexed in ß-cyclodextrin in a model of complex regional pain syndrome - Type 1.

Complex regional pain syndrome type 1 (CRPS-1) is a painful syndrome without effective treatment. In order to explore possible new treatments, we used an animal model of CRPS-1 to examine the effects of ß-Citronellol (ßCT), a monoterpene found in a variety of plants that has been shown to have analgesic effects. We aimed to assess its effects alone, and complexed with ß-cyclodextrin (ßCD), which has been previously used to enhance the effects of a number of medicines. The ßCT-ßCD was characterized physiochemically using high performance liquid chromatography (HPLC) and differential scanning calorimetry (DSC) and shown to have 80% efficiency. In the animal model, Swiss mice were treated with ßCT, ßCT-ßCD, vehicle, pregabalin or sham and evaluated for hyperalgesia and motor coordination. Inflammatory mediators were measured by Western blot or ELISA and the descending pain pathway by immunofluorescence. ßCT was shown to have an anti-hyperalgesic effect (without affecting motor coordination) that reduced inflammatory mediators and activated the descending pain pathway, and these effects were increased with complexation in ßCD. Our results showed ßCT-ßCD to be a promising treatment for CRPS-1.

COVID-19 Mortality and Case-Fatality Rates in Sergipe State, Northeast Brazil, From April to June 2020.

Information on how coronavirus disease 2019 (COVID-19) mortality is related to population characteristics in low- and middle-income countries is still limited. We described the deaths from COVID-19 in Sergipe state, Northeast Brazil, from April 2 to June 27, 2020. For this purpose, we conducted a study composed of (i) a case series study of all deaths due to COVID-19 and (ii) a population-based study to verify the behavior of the mortality and case-fatality rates (CFR) related to COVID-19. Data from 605 deaths due to COVID-19 were used to describe the characteristics of individuals with the disease, as well as the differences in gender, age, and comorbidities. Additionally, population data were extracted to estimate the mortality and CFR by population stratum. We also performed an adjusted CFR analysis including a time lag of 14 days between the onset of symptoms and reporting deaths. Of the 605 patients included in this study, 321 (53.1%) were males and the median age was 67.0 years. Most patients (n = 447, 73.9%) who died from COVID-19 had at least one pre-existing clinical condition. The mortality rate was 29.3 deaths per 100,000 inhabitants and the crude CRF was 2.6% (95% CI 2.4-2.8). CFR was higher in males (3.1%, 95% CI 2.8-3.4; p < 0.001) and people aged ≥60 years (14.2%, 95% CI 13.0-15.6; p = 0.042). About 25% of patients died during the first 24-h post-hospital admission. The adjusted CFR for a 14-day time lag was ~2-fold higher than the crude CFR over the study period.

HPLC-DAD-UV analysis, anti-inflammatory and anti-neuropathic effects of methanolic extract of Sideritis bilgeriana (lamiaceae) by NF-κB, TNF-α, IL-1ß and IL-6 involvement.

Medicinal plants remain an invaluable source for therapeutics of diseases that affect humanity. Sideritis bilgeriana (Lamiaceae) is medicinal plant used in Turkey folk medicine to reduce inflammation and pain, but few studies scientific corroborates its medicinal use so creating a gap between popular use and scientific evidence. Thus, we aimed to evaluate the pharmacological effects of the methanolic extract of S. bilgeriana (MESB) in rodents nociception models and also performed its phytochemical analysis. Firstly, a screening was carried out that enabled the identification of the presence of phenolic compounds and flavonoids. In view of this, a chromatographic method by HPLC-DAD-UV was developed that made it possible to identify chlorogenic acid and its quantification in MESB. MESB-treated mice (MESB 50, 100 and 200 mg/kg, p.o.) reduced mechanical hyperalgesia and myeloperoxidase activity (p < 0.01), and also showed a reduced pain behavior in capsaicin test. In the carrageenan-induced pleurisy test, MESB (100 mg/kg p.o.) significantly reduced the leukocyte (polymorphonuclear) count in the pleural cavity and equally decreased the TNF-α and IL-1ß levels (p < 0.001). In the PSNL model, mechanical hyperalgesia was reduced on the first evaluation day and during the 7 days of evaluation compared to the vehicle group (p < 0.001). Thermal hyperalgesia was also reduced 1 h after treatment compared to the vehicle group (p < 0.001) and reversed the loss of force initially displayed by the animals, thus inferring an analgesic effect in the muscle strength test. Analysis of the marrow of these animals showed a decrease in the level of pro-inflammatory cytokine IL-6 (p < 0.001) and factor NF-κB, in relation to the control group (p < 0.05). Moreover, the MESB treatment produced no noticeable side effects, no disturb in motor performance and no signs of gastric or hepatic injury. Together, the results suggests that MESB could be useful to management of inflammation and neuropathic pain mainly by the management of pro-inflammatory mediators (NF-κB, TNF-α, IL-1ß and IL-6), so reinforcing its use in popular medicine and corroborating the need for further chemical and pharmacological studies for the species.

Reduced cutaneous inflammation associated with antioxidant action after topical application of the aqueous extract of Annona muricata leaves.

Annona muricata L. is used in folk medicine for treatment of diseases related to inflammatory and oxidative processes. This study investigated the effect of the aqueous extract of A. muricata leaves (AEAM) on TPA-induced ear inflammation and antioxidant capacity, both in vitro and in vivo. The in vitro antioxidant capacity of AEAM was measured by the 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing/antioxidant power (FRAP) and lipoperoxidation assays. Cytotoxicity and reactive oxygen species (ROS) release were evaluated in the L929 fibroblasts. Swiss mice were submitted to TPA application and were topically treated with AEAM (0.3, 1 or 3 mg/ear). After 6 h, inflammatory and oxidative parameters were evaluated. Quercetin 3-glucoside, rutin, chlorogenic acid, catechin and gallic acid were identified in AEAM. It also presented antioxidant activity in all in vitro assays used. Incubation with AEAM did not cause cell cytotoxicity but reduced ROS release from fibroblasts. Compared with the control group, treatment with AEAM significantly reduced ear oedema and mieloperoxidase activity in inflamed ears, as well as histological parameters of inflammation. These results were associated with the reduction of total hydroperoxides and modulation of catalase, but not superoxide dismutase activity. These findings show the anti-inflammatory effect of AEAM is associated with antioxidant capacity.

Anti-Inflammatory Activity of Limonene in the Prevention and Control of Injuries in the Respiratory System: A Systematic Review.

INTRODUCTION: The pulmonary inflammatory response results from exposure to injurious factors and is associated with oxidative stress, which intensifies the pathological reaction. In this context, limonene, a monoterpene found in citrus fruits, can be a therapeutic alternative for the treatment of this pathology, as it presents known anti-inflammatory and antioxidant actions. OBJECTIVE: The purpose of this article is to provide an overview of the anti-inflammatory activity of limonene and its capacity to prevent and control respiratory system injuries. SEARCH STRATEGY: A comprehensive literature search of the Cochrane, Scopus, MEDLINE-PubMed, Web of Science, and Lilacs databases was performed using the keywords: "limonene", "lung", "pulmonary", "airway", "trachea", "lung injury", "respiratory system", "respiratory tract diseases". SELECTION CRITERIA: Studies on the use of limonene in disorders of the respiratory system, published until August 2019, were included. Those that did not use limonene alone or treated lesions in different systems other than the respiratory system, without targeting its anti-inflammatory action were excluded. In addition, review articles, meta-analyses, abstracts, conference papers, editorials/letters and case reports were also excluded. RESULTS: Of the 561 articles found, 64 were in the Cochrane database, 235 in Scopus, 99 in Web of science, 150 in PubMed and 13 in Lilacs. After completing the systematic steps, 25 articles were selected for full reading, after which 7 papers remained in the review. An article was added after a manual literature search, resulting in a total of 8 papers. There was a high level of agreement on inclusion/exclusion among the researchers who examined the papers (Kappa index > 88%). CONCLUSION: Limonene has effective anti-inflammatory activity in both preventing and controlling respiratory system injuries.

Effects of the solid lipid nanoparticle of carvacrol on rodents with lung injury from smoke inhalation.

The aim of this present study was to evaluate the effect of solid lipid nanoparticles (SLN) containing carvacrol over the lung damage of airway smoke inhalation. The study was conducted with 30 rats subjected to smoke inhalation and divided into 5 groups such as, normal control, negative control, oxygen group, SLN alone, and SLN+CARV group. The animals were sacrificed 24 h after the induction of inhalation injury further, the tissues of larynx, trachea, and lungs were collected for the histological, hematological, myeloperoxidase, and malondialdehyde analysis. The obtained results showed that treatment with CARV+SLN minimized the inhalation injury, since it reduced malondialdehyde significantly, when compared to the negative control group and minimized the histological changes which proves the absence of pulmonary emphysema and exudate in laryngeal and tracheal lumen in the CARV+SLN-treated group. Meanwhile, the presence of lesion with chronic characteristics was observed in the negative control and oxygen groups. It is suggested that the SLN containing carvacrol minimized oxidative stress and histological damages generated from smoke inhalation in rodents.

Naringenin complexed with hydroxypropyl-ß-cyclodextrin improves the sciatic nerve regeneration through inhibition of p75NTR and JNK pathway.

Peripheral nerve injuries are common conditions that often lead to dysfunctions. Although much knowledge exists on the several factors that mediate the complex biological process involved in peripheral nerve regeneration, there is a lack of effective treatments that ensure full functional recovery. Naringenin (NA) is the most abundant flavanone found in citrus fruits and it has promising neuroprotective, anti-inflammatory and antioxidant effects. This study aimed to enhance peripheral nerve regeneration using an inclusion complex containing NA and hydroxypropyl-ß-cyclodextrin (HPßCD), named NA/HPßCD. A mouse sciatic nerve crush model was used to evaluate the effects of NA/HPßCD on nerve regeneration. Sensory and motor parameters, hyperalgesic behavior and the sciatic functional index (SFI), respectively, improved with NA treatment. Western blot analysis revealed that the levels of p75NTR ICD and p75NTR full length as well phospho-JNK/total JNK ratios were preserved by NA treatment. In addition, NA treatment was able to decrease levels of caspase 3. The concentrations of TNF-α and IL-1ß were decreased in the lumbar spine, on the other hand there was an increase in IL-10. NA/HPßCD presented a better overall morphological profile but it was not able to increase the number of myelinated fibers. Thus, NA was able to enhance nerve regeneration, and NA/HPßCD decreased effective drug doses while maintaining the effect of the pure drug, demonstrating the advantage of using the complex over the pure compound.

Involvement of the PKA pathway and inhibition of voltage gated Ca2+ channels in antihyperalgesic activity of Lippia grata/ß-cyclodextrin.

Neuropathic pain (NP) is a difficult condition to treat because of the modest efficacy of available drugs. New treatments are required. In the study we aimed to investigate the effects of the essential oil from Lippia grata alone or complexed in ß-cyclodextrin (LG or LG-ßCD) on persistent inflammatory and neuropathic pain in a mouse model. We also investigated Ca2+ currents in rat dorsal root ganglion (DRG) neurons. Male Swiss mice were treated with LG or LG/ß-CD (24 mg/kg, i.g.) and their effect was evaluated using an acute inflammatory pleurisy model and nociception triggered by intraplantar injection of an agonist of the TRPs channels. We also tested their effect in chronic pain models: injection of Freund's Complete Adjuvant and partial sciatic nerve ligation (PSNL). In the pleurisy model, LG reduced the number of leukocytes and the levels of TNF-α and IL-1ß. It also inhibited cinnamaldehyde and menthol-induced nociceptive behavior. The pain threshold in mechanical and thermal hyperalgesia was increased and paw edema was decreased in models of inflammatory and neuropathic pain. PSNL increased inflammatory protein contents and LG and LG-ßCD restored the protein contents of TNF-α, NF-κB, and PKA, but not IL-1ß and IL-10. LG inhibited voltage gated Ca2+ channels from DRG neurons. Our results suggested that LG or LG-ßCD produce anti-hyperalgesic effect in chronic pain models through reductions in TNF-α levels and PKA, and inhibited voltage-gated calcium channels and may be innovative therapeutic agents for the management of NP.

Anti-hyperalgesic and anti-inflammatory effects of citral with ß-cyclodextrin and hydroxypropyl-ß-cyclodextrin inclusion complexes in animal models.

Citral (CIT) is a monoterpene formed by the geranial and neral stereoisomers. CIT is the major compound of Cymbopogon citratus essential oil, commonly known as "lemongrass", and has demonstrated potential antihyperalgesic, anti-nociceptive and anti-inflammatory effects. However, CIT shows high volatility, low solubility in water and consequent low bioavailability, which limits its use. Therefore, the aim of this study was to evaluate cell viability, anti-hyperalgesic and anti-inflammatory effects of inclusion complexes of CIT on ß-cyclodextrin (ß-CD) and hydroxypropyl-ß-cyclodextrin (HP-ß-CD). Initially, physical mixture (PM) and freeze-dried inclusion (FD) complexes of CIT/ß-CD and CIT/HP-ß-CD were obtained in the molar ratio (1:1). The samples were characterized by DSC, TG/DTG, FT-IR, XRD, SEM and the complexation efficiency were performed by HPLC. Cell viability assay was performed by rezasurin reduction technique in J774 macrophages cell line. The motor activity through rota rod apparatus, mechanical hyperalgesia and pleurisy induced by carrageenan were evaluated in mice. The complexation of CIT was evidenced with ß-CD and HP-ß-CD by the characterization techniques analyzed. The complexation efficiency of CIT/ß-CD and CIT/HP-ß-CD were 78.6% and 71.7%, respectively. The CIT, CIT/ß-CD and CIT/HP-ß-CD showed cell viability in macrophages and did not interfere in the motor activity of mice. Besides that, the samples demonstrated antihyperalgesic and anti-inflammatory activity due to the reduction in total leukocytes and TNF-α levels. However, CIT/ß-CD has better pharmacological effects among the three samples evaluated. Therefore, CIT/ß-CD has potential for the development of products to treat inflammatory and pain reactions.

Carvacrol/ß-cyclodextrin inclusion complex inhibits cell proliferation and migration of prostate cancer cells.

Carvacrol, a phenolic monoterpene derived from thyme oil has gained wide interest recently because of its anticancer activities. To improve the solubility of carvacrol, the formation of inclusion complexes with ß-cyclodextrin was performed by ultrasound and freeze-drying methods and characterized using thermal analysis, FTIR, XRD, SEM, NMR and HPLC analysis. From these results, carvacrol was successfully complexed within ß-cyclodextrin cavity. Moreover, HPLC analysis demonstrated a higher entrapment efficiency for freeze-drying method (81.20 ±â€¯0.52%) in contrast to ultrasound method (34.02 ±â€¯0.67%). Hence, freeze-drying inclusion complex was evaluated for its antiproliferative effect and cytotoxicity against prostate cancer cell line (PC3) in vitro. Further, freeze-drying complex led to a dose-dependent inhibition in tumor cell growth in 2D and 3D cell culture systems. Altogether, the inclusion of carvacrol in ß-cyclodextrin led to the formation of stable complexes with potent antiproliferative effects against PC3 cells, in vitro. Such an improved cytotoxic effect can be attributed to the enhanced the aqueous solubility and bioavailability of carvacrol by effective complexation in ß-cyclodextrin.

Molecular mechanism underlying orofacial antinociceptive activity of Vanillosmopsis arborea Baker (Asteraceae) essential oil complexed with ß-cyclodextrin.

BACKGROUND: Vanillosmopsis arborea Baker has recognized economic value owing to the high content of (-)-α-bisabolol (BISA) in the essential oil of its stem (EOVA). The antinociceptive effect of EVOA has already been demonstrated, and ß-cyclodextrin (ßCD) is known to improve the analgesic effect of various substances. PURPOSE: Thus, we aimed to evaluate the orofacial antinociceptive effect of a complex containing EOVA-ßCD in rodents. METHODS: EOVA was obtained by simple hydrodistillation, and the essential oil was complexed with ßCD. The animals (n = 6/group) were treated orally with EOVA-ßCD (10 or 50 mg/kg), or vehicle (control), and subjected to cutaneous orofacial nociception (formalin, capsaicin, acidic saline or glutamate), corneal (hypertonic saline) or temporomandibular (formalin) tests. The expression of FOS protein was analyzed in the spinal cord. Molecular docking was performed using the 5-HT3 and M2 receptors and BISA. RESULTS: The oral administration of EOVA-ßCD reduced nociceptive behaviour. Moreover, EOVA-ßCD decreased FOS expression. The molecular docking study indicates that BISA interacts with 5-HT3 and M2 receptors, indicating the potential mechanism of action of the tested compound. CONCLUSIONS: Our results indicate that EOVA-ßCD possesses orofacial antinociceptive effect, indicating that this complex can be used in analgesic drug development.

The inclusion complex of carvacrol and ß-cyclodextrin reduces acute skeletal muscle inflammation and nociception in rats.

BACKGROUND: Skeletal muscle inflammation is strongly associated with pain and may impair regeneration and functional recovery after injury. Since anti-inflammatory and antinociceptive effects have been described for the inclusion complex of carvacrol and ß-cyclodextrin (ßCD-carvacrol), this study investigated the effects of ßCD-carvacrol in a model of acute skeletal muscle inflammation. METHODS: Muscle injury was induced in male Wistar rats by injection of 3% carrageenan in the gastrocnemius muscle. Rats were orally pretreated with saline (vehicle) or ßCD-carvacrol (20, 40, 80 and 180 mg/kg) one hour before administration of carrageenan. RESULTS: The injection of carrageenan in the gastrocnemius muscle increased tissue myeloperoxidase (MPO) activity (p < 0.001), edema (p < 0.001) and the levels of tumoral necrosis factor (TNF)-α, interleukin (IL)-1ß, IL-6, macrophage inflammatory protein (MIP-2), but not IL-10 levels. Also, it increased mechanical hyperalgesia and decreased the grip force of animals. Pretreatment with ßCD-carvacrol (80 or 160 mg/kg) significantly decreased muscle MPO activity and edema 24 h after injury in comparison to vehicle-pretreated group. Animals pretreated with ßCD-carvacrol (160 mg/kg) presented significantly lower levels of IL-1ß, IL-6 and MIP-2 and higher levels of IL-10 six hours after induction and lower levels of TNF-α and MIP-2 after 24 h when compared to the vehicle group. Pretreatment with ßCD-carvacrol also reduced mechanical hyperalgesia and limited the decrease of grip force (80 or 160 mg/kg; p < 0.001) 6 and 24 h after injury. CONCLUSION: These results show that ßCD-carvacrol reduces inflammation and nociception in a model of acute injury to skeletal muscles.

New drugs or alternative therapy to blurring the symptoms of fibromyalgia-a patent review.

INTRODUCTION: Fibromyalgia (FM) is a musculoskeletal condition characterized by chronic widespread pain, tenderness and often accompanied by other comorbid conditions such as depression, anxiety, chronic fatigue, among others. Now, we aimed to survey the recent patents describing new drugs or alternative therapy for FM. Areas covered: This review covers the therapeutic patents published between 2010 and 2017 from specialized search databases (WIPO, DERWENT, INPI, ESPANET and USPTO) that report the discovery of new drugs or pharmacologic alternative for the treatment of FM. Expert opinion: New therapeutic substances have been proposed in the last seven years. At least as it has been found in our survey, most are still in the pre-clinical phase of the study, and its clinical applicability is unclear. However, other therapeutic approaches were found in patents such as well-established drugs in the market in combination or drug repositioning that combines the 'new analgesic' effects with the old side effects. Hence, it is a safe approach for pharmaceutical market, but poorer to patients who need a radical innovation. So, there is the emerging need for further studies on the safety and efficacy of such therapeutic measures and the search for improvement of side effects, as well as the development of new drugs that are unorthodox for different FM symptoms.

Inclusion complex between ß-cyclodextrin and hecogenin acetate produces superior analgesic effect in animal models for orofacial pain.

Hecogenin acetate (HA) is a steroidal sapogenin-acetylated with pharmacological properties which have already been described in the literature such as, anti-inflammatory, anti-hyperalgesic and antinociceptive, but it has low solubility in aqueous media. Therefore, in an attempt to overcome this, we set out to create inclusion complexes between HA and b-cyclodextrin (b-CD) and evaluate the antinociceptive effects in the orofacial nociception in mice. The complexes were prepared using different methods in the molar ratios 1:1 and 1:2 and characterized physicochemically. The results of the physicochemical characterization elucidated inclusion complexes formation between b-CD and HA by freeze drying method in the molar ratio 1:2, which obtained a complexation efficiency of 92% and produced superior analgesic effect in animal models for orofacial pain at a lower dose when compared to HA alone.

D-limonene exhibits superior antihyperalgesic effects in a ß-cyclodextrin-complexed form in chronic musculoskeletal pain reducing Fos protein expression on spinal cord in mice.

Chronic musculoskeletal pain is one of the main symptoms found in Fibromyalgia with unclear etiology and limited pharmacological treatment. The aim of this study was to complex LIM in ß-cyclodextrin (LIM-ßCD) and then evaluate its antihyperalgesic effect in an animal model of chronic musculoskeletal pain. Differential scanning calorimetry and scanning electron microscopy was used for the characterization of the inclusion complex. Male Swiss mice were used for experimental procedures where mechanical hyperalgesia, thermal hyperalgesia, muscular strength, Fos immunofluorescence was studied after induction of hyperalgesia. Mechanism of action was also investigated through tail flick test and capsaicin-induced nociception. Endothermic events and morphological changes showed that the slurry complex method was the best method for the complexation. After induction of hyperalgesia, the oral administration of LIM-ßCD (50mg/kg) significantly increased the paw withdrawal threshold compared to uncomplexed limonene. Fos immunofluorescence showed that both compounds significantly decreased the number of Fos-positive cells in the dorsal horn. In nociceptive tests, FLU was able to reverse the antinociceptive effect of LIM-ßCD. After intraplantar administration of capsaicin, LIM was able to significantly decrease time to lick. LIM-ßCD has antihyperalgesic action superior to its uncomplexed form, with possible action in the dorsal horn of the spinal cord. These results suggest the possible applicability of LIM, uncomplexed or complexed with ßCD, in conditions such as FM and neuropathic pain, for which there are currently only limited pharmacological options.

Anti-hyperalgesic effect of Lippia grata leaf essential oil complexed with ß-cyclodextrin in a chronic musculoskeletal pain animal model: Complemented with a molecular docking and antioxidant screening.

BACKGROUND: Due to its unclear pathophysiology, the pharmacological treatment of fibromyalgia is a challenge for researchers. Studies using medicinal plants, such as those from the genus Lippia, complexed with cyclodextrins (CDs) have shown innovative results. OBJECTIVE: The present research intended to evaluate the effect of an inclusion complex containing ß-cyclodextrin (ßCD) inclusion complex with Lippia grata (LG) essential oil in a chronic musculoskeletal pain model, its central activity and its possible interaction with neurotransmitters involved in pain. METHODS: After acid saline-induced chronic muscle pain, male mice were evaluated for primary and secondary hyperalgesia and muscle strength. Moreover, an antagonist assay was performed to assess the possible involvement of the opioidergic, serotonergic and noradrenergic pathways. In addition, Fos protein in the spinal cord was assessed, and a docking study and antioxidant assays were performed. RESULTS: The treatment with LG-ßCD, especially in the dose of 24mg/kg, was able to significantly decrease (p<0.05) the paw withdrawal and muscle threshold. Furthermore, LG-ßCD was shown to affect the opioidergic and serotonergic pathways. There were no significant changes in muscle strength. Fos protein immunofluorescence showed a significant decrease in expression in the dorsal horn of the spinal cord. The main compounds of LG showed through the docking study interaction energies with the alpha-adrenergic and µOpioid receptors. In all antioxidant assays, LG exhibited stronger antioxidant activities than LG-ßCD. CONCLUSION: This study suggested that LG-ßCD could be considered as a valuable source for designing new drugs in the treatment of chronic pain, especially musculoskeletal pain.