Ligustilide covalently binds to Cys703 in the pre-S1 helix of TRPA1, blocking the opening of channel and relieving pain in rats with acute soft tissue injury.

ETHNOPHARMACOLOGICAL RELEVANCE: The natural anodyne Ligustilide (Lig), derived from Angelica sinensis (Oliv.) Diels and Ligusticum chuanxiong Hort., has been traditionally employed for its analgesic properties in the treatment of dysmenorrhea and migraine, and rheumatoid arthritis pain. Despite the existing reports on the correlation between TRP channels and the analgesic effects of Lig, a comprehensive understanding of their underlying mechanisms of action remains elusive. AIM OF THE STUDY: The objective of this study is to elucidate the mechanism of action of Lig on the analgesic target TRPA1 channel. METHODS: The therapeutic effect of Lig was evaluated in a rat acute soft tissue injury model. The analgesic target was identified through competitive inhibition of TRP channel agonists at the animal level, followed by Fluo-4/Ca2+ imaging on live cells overexpressing TRP proteins. The potential target was verified through in-gel imaging, colocalization using a Lig-derived molecular probe, and a drug affinity response target stability assay. The binding site of Lig was identified through protein spectrometry and further analyzed using molecular docking, site-specific mutation, and multidisciplinary approaches. RESULTS: The administration of Lig effectively ameliorated pain and attenuated oxidative stress and inflammatory responses in rats with soft tissue injuries. Moreover, the analgesic effects of Lig were specifically attributed to TRPA1. Mechanistic studies have revealed that Lig directly activates TRPA1 by interacting with the linker domain in the pre-S1 region of TRPA1. Through metabolic transformation, 6,7-epoxyligustilide (EM-Lig) forms a covalent bond with Cys703 of TRPA1 at high concentrations and prolonged exposure time. This irreversible binding prevents endogenous electrophilic products from entering the cysteine active center of ligand-binding pocket of TRPA1, thereby inhibiting Ca2+ influx through the channel opening and ultimately relieving pain. CONCLUSIONS: Lig selectively modulates the TRPA1 channel in a bimodal manner via non-electrophilic/electrophilic metabolic conversion. The epoxidized metabolic intermediate EM-Lig exerts analgesic effects by irreversibly inhibiting the activation of TRPA1 on sensory neurons. These findings not only highlight the analgesic mechanism of Lig but also offer a novel nucleophilic attack site for the development of TRPA1 antagonists in the pre-S1 region.

Chemical Investigation and Antinociceptive Activity Evaluation of Marrubium Vulgare L. Aqueous Extract.

Marrubium vulgare L. (Lamiaceae) has a long history of use in traditional herbal medicine for the treatment of respiratory tract infections, inflammatory conditions, and pain. This study aimed to investigate the chemical composition, acute toxicity, and antinociceptive effects of the aqueous extract from M. vulgare leaves (AEMV). Antioxidant activity was evaluated using DPPH and reducing power assays. The chemical composition of AEMV was determined through LC-MS/MS, and the levels of total phenolics, flavonoids, and condensed tannins were quantified. Acute oral toxicity was assessed in male Swiss mice with a single oral dose of AEMV (1, 2, 5 g/kg). The analgesic impact was examined through writhing, hot plate, and formalin tests. Our findings not only confirmed the safety of the extract in animal models but also revealed significant antioxidant activity in AEMV. High-performance liquid chromatography (HPLC) analysis identified important bioactive compounds, with marrubiin being a major component. Furthermore, AEMV demonstrated robust antinociceptive properties in all conducted tests, highlighting its potential as a valuable natural source of bioactive compounds suitable for a wide range of therapeutic applications.

Evaluation of Rhododendri Mollis Flos and its representative component as a potential analgesic.

Rhododendri Mollis Flos (R. mole Flos), the dried flowers of Rhododendron mole G. Don, have the ability to relieve pain, dispel wind and dampness, and dissolve blood stasis, but they are highly poisonous. The significance of this study is to explore the analgesic application potential of R. mole Flos and its representative component. According to the selected processing methods recorded in ancient literature, the analgesic activities of wine- and vinegar-processed R. mole Flos, as well as the raw product, were evaluated in a writhing test with acetic acid and a formalin-induced pain test. Subsequently, the HPLC-TOP-MS technique was utilized to investigate the changes in active components before and after processing once the variations in activities were confirmed. Based on the results, rhodojaponin VI (RJ-Vl) was chosen for further study. After processing, especially in vinegar, R. mole Flos did not only maintain the anti-nociception but also showed reduced toxicity, and the chemical composition corresponding to these effects also changed significantly. Further investigation of its representative components revealed that RJ-VI has considerable anti-nociceptive activity, particularly in inflammatory pain (0.3 mg/kg) and peripheral neuropathic pain (0.6 mg/kg). Its toxicity was about three times lower than that of rhodojaponin III, which is another representative component of R. mole Flos. Additionally, RJ-VI mildly inhibits several subtypes of voltage-gated sodium channels (IC50 > 200 µM) that are associated with pain or cardiotoxicity. In conclusion, the chemical substances and biological effects of R. mole Flos changed significantly before and after processing, and the representative component RJ-VI has the potential to be developed into an effective analgesic.

Phytochemical, Pharmacological, and Molecular Docking Study of Dry Extracts of Matricaria discoidea DC. with Analgesic and Soporific Activities.

Pineapple weed (Matricaria discoidea DC.) is a widespread plant in Europe and North America. In ethnomedicine, it is well-known for its anti-inflammatory and spasmolytic activities. The aim of this research was to develop novel methods of M. discoidea processing to obtain essential oil and dry extracts and to investigate their phytochemical compositions. Moreover, the molecular docking of the main substances and the in vivo studies on their soporific and analgesic activities were conducted. The essential oil and two dry extracts from M. discoidea were prepared. A total of 16 phenolic compounds (seven flavonoids, seven hydroxycinnamic acids, and two phenolic acids) in the dry extracts were identified by means of UPLC-MS/MS. In the essential oil, nine main terpenoids were identified by gas chromatography (GC). It was shown that phenolic extraction from the herb was successful when using 70% ethanol in a triple extraction method and at a ratio of 1:14-1:16. The in vivo studies with rodents demonstrated the analgesic activity of the M. discoidea extracts and improvements in the sleep of animals. The dry extracts of M. discoidea did not show any toxicity. The molecular docking analysis showed a high probability of COX-1,2 inhibition and NMDA receptor antagonism by the extracts.

Anti-inflammatory, analgesic, antitussive and antipyretic activities of polyphenol-enriched fraction from Nymphaea candida.

ETHNOPHARMACOLOGICAL RELEVANCE: "Snow-white waterlily" (Nymphaea candida) dried flower possesses various efficacy in Uighur medicine such as reducing fever and nourishing the liver, anti-inflammatory and cough relieving, moistening the throat and quenching thirst. AIM OF THE STUDY: Polyphenols are characteristic component of N. candida as well as its quality markers, and the purpose of this study was to conduct investigations into anti-inflammatory, antitussive, antipyretic, and analgesic activities of the polyphenol-enriched fraction from N. candida (NCTP) in order to validate the traditional efficacy of this plant. MATERIALS AND METHODS: The polyphenols in NCTP were analyzed by HPLC, and an acute oral toxicity study was conducted for NCTP. The anti-inflammatory activities of NCTP were evaluated using xylene induced ear edema, capillary permeability, cotton pellet granuloma, and carrageenan-induced rat paw edema, of which multiple biochemical indices were measured in carrageenan-induced rat paw edema such as prostaglandin E2 (PGE2), cyclooxygenase-2 (COX-2),5-lipoxygenase (5-LOX), interleukin-6 (IL-6), interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α), malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione (GSH) activities; the analgesic activities were investigated using acetic acid writhing, hot plate test, and formalin test; the anti-tussive and antipyretic effects were tested by ammonia induced cough in mice and yeast-induced fever respectively. RESULTS: NCTP with LD50 of 5222 mg/kg was low toxicity and safety. NCTP (200 mg/kg) could significantly reduce ear swelling and capillary permeability by 30.63% and 31.37%, respectively. NCTP revealed 15.76% inhibiting activities in cotton pellet granuloma in mice at a dosage of 200 mg/kg. Furthermore, NCTP (50, 100, and 200 mg/kg) substantially decreased carrageenin-induced paw edema in rats between 1 and 5 h, and NCTP could decrease PGE2, 5-LOX, COX-2 levels as well as IL-6, IL-1ß, TNF-α activities compared with the control group; NCTP could decrease MDA contents in carrageenin-induced rise, and increase SOD and GSH activities. Furthermore, the dose-dependent inhibition effect of NCTP on pain was revealed in the hot plate experiment. In addition to reducing the amount of writhes brought on by acetic acid, NCTP (50, 100, and 200 mg/kg) significantly inhibited pain latency against both stages of the formalin test. Moreover, NCTP (50, 100, 200 mg/kg) showed the better antitussive activities in mice in a dose-dependent manner. In the yeast-induced pyrexia test, dosages of 50, 100, and 200 mg/kg resulted in a statistically significant drop in rectal temperature. CONCLUSION: The experimental results proved the analgesic, anti-inflammatory, anti-tussive and antipyretic activities of the polyphenol-enriched fraction from N. candida, and supported the traditional use of this plant as well.

Antinociceptive Effect of Dillenia indica (Linn.) Mediated by Opioid and Cannabinoid Systems: Pharmacological and Chemical Studies.

Dillenia indica (Linn.) has been reported by several biological activities, including anti-inflammatory, antioxidant, antidiabetic, anti-hyperglycemic, antiproliferative, antimutagenic, anticholinesterase, and antimicrobial. In Brazilian traditional medicine, the fruits of D. indica have been used to treat general topical pain and inflammation, but with no scientific validation. Thus, aiming to study its chemical constitution and antinociceptive properties, the crude extract (CE) and fractions obtained from the fruits of D. indica were submitted to an in vivo pharmacological evaluation and a dereplication study by LC-MS/MS analysis, assisted by the Global Natural Product Social Molecular Networking (GNPS). The oral antinociceptive activity of the fruits of D. indica and the possible participation of the opioid and cannabinoid systems were demonstrated in the formalin-induced nociception model. The chemical dereplication study led us to identify several known chemical constituents, including flavonoids, such as caffeoylmalic acid, naringenin, quercetin, and kaempferol. According to literature data, our results are compatible with significant antinociceptive and anti-inflammatory activities. Therefore, the flavonoid constituents of the fruits of D. indica are probably responsible for its antioxidant, anti-inflammatory, and antinociceptive effects mediated by both opioid and cannabinoid systems, confirming its folk use in the treatment and relief of pain.

Discovery of highly functionalized grayanane diterpenoids from the flowers of Rhododendron molle as potent analgesics.

A systematical investigation on the chemical constituents of the flowers of Rhododendron molle (Ericaceae) led to the isolation and characterization of thirty-eight highly functionalized grayanane diterpenoids (1-38), including twelve novel analogues molleblossomins A-L (1-12). Their structures were elucidated by comprehensive methods, including 1D and 2D NMR analysis, calculated ECD, 13C NMR calculations with DP4+ probability analysis, and single crystal X-ray diffraction. Molleblossomins A (1), B (2), and E (5) are the first representatives of 2ß,3ß:9ß,10ß-diepoxygrayanane, 2,3-epoxygrayan-9(11)-ene, and 5,9-epoxygrayan-1(10),2(3)-diene diterpenoids, respectively. Molleblossomins G (7) and H (8) represent the first examples of 1,3-dioxolane-grayanane conjugates furnished with the acetaldehyde and 4-hydroxylbenzylidene acetal moieties, respectively. All grayanane diterpenoids 1-38 were screened for their analgesic activities in the acetic acid-induced writhing model, and all of them exhibited significant analgesic activities. Diterpenoids 6, 13, 14, 17, 20, and 25 showed more potent analgesic effects than morphine at a lower dose of 0.2 mg/kg, with the inhibition rates of 51.4%, 68.2%, 94.1%, 66.9%, 97.7%, and 60.0%, respectively. More importantly, even at the lowest dose of 0.04 mg/kg, rhodomollein X (14), rhodojaponin VI (20), and rhodojaponin VII (22) still significantly reduced the number of writhes in the acetic acid-induced pain model with the percentages of 61.7%, 85.8%, and 64.6%, respectively. The structure-activity relationship was summarized and might provide some hints to design novel analgesics based on the functionalized grayanane diterpenoids.

Antiedema and antinociceptive potential of the essential oil of Pectis elongata Kunt (Asteraceae) from the Brazilian Amazon.

ETHNOPHARMACOLOGICAL RELEVANCE: Pectis elongata, a herbaceous species that is known in northern Brazil as "cominho" or "limãozinho", is traditionally used in the region for the treatment of fevers, colds, hypotension, genitourinary and gastric disorders, and pain. AIM OF THE STUDY: Determine the chemical composition and acute oral toxicity and evaluate whether Pectis elongata essential oil (PeEO) has antiedema and antinociceptive activity. MATERIALS AND METHODS: The chemical composition was determined using gas chromatography coupled to mass spectrometry (GC/MS) and the degree of toxicity determined by the LD50. The antiedema and antinociceptive potential was evaluated via the λ-carrageenan-induced paw edema test and formalin test, respectively. RESULTS: Citral (geranial and neral) was characterized as a major component of the PeEO, representing 89% of the total identified compounds. According to OECD criteria (2002), the EO was considered non-toxic since it presented LD50 values over 2000 mg kg-1. Its antiedema potential was observed at doses of 200 and 400 mg kg-1 (p ≤ 0.05). At a dose of 400 mg kg-1, PeEO also showed antinociceptive potential (p ≤ 0.05), both in the neurogenic phase and in the inflammatory phase. CONCLUSIONS: PeEO, which is rich in citral, did not induce any characteristic signs of acute oral toxicity and was also efficient in reducing carrageenan-induced paw edema, in addition to presenting antinociceptive potential and acting on both central and peripheral pain. It is thus a promising candidate for the development of a new herbal medicine with anti-inflammatory and analgesic action.

Antinociceptive and anti-inflammatory potential, and chemical characterization of the dichloromethane fraction of Solanum lycocarpum (Solanaceae) ripe fruits by LC-DAD-MS.

ETHNOPHARMACOLOGICAL RELEVANCE: Solanum lycocarpum A. St. Hil. (Solanaceae) is a species from the Brazilian Cerrado, exhibiting several medicinal properties, being used by the population in the treatment of ulcers, bronchitis, asthma and hepatitis, which involve inflammatory processes. AIM OF THIS STUDY: This study aimed to chemically characterize the dichloromethane fraction (DCM), as well as verify its antinociceptive, anti-inflammatory and antioxidant potential. MATERIALS AND METHODS: The DCM fraction was obtained by partitioning the ethanol extract. The chemical constituents of the DCM fraction were characterized by LC-DAD-MS. The DPPH and FRAP assays were used to evaluate the antioxidant potential. The carrageenan-induced paw edema model was used to assess the anti-inflammatory effects, and the inflammatory infiltrate was evaluated by qualitative and quantitative histological analyses. The antinociceptive action of the DCM fraction was evaluated by acetic acid-induced abdominal writhing test, formalin-induced nociception and hot-plate test. RESULTS: Steroidal alkaloids solasonine, solasodine and solamargine, as well as the alkaloid peiminine/imperialine and caffeoylquinic acids, were annotated in DCM fraction by LC-DAD-MS. The DCM fraction showed antioxidative action in the in vitro DPPH and FRAP tests, as well as an anti-inflammatory effect for the three evaluated doses of 30, 100 and 300 mg/kg in the fourth and sixth hours after the administration of carrageenan. The histological analyses evidenced considerably reduction in leukocyte migration and the number of polymorphonuclear leukocytes. The study also demonstrated antinociceptive activity for the DCM fraction, which reduced abdominal writhing at three concentrations evaluated, as well as a decrease in paw licking in the formalin-induced nociception test both in the neurogenic phase and the inflammatory phase, with greater effectiveness compared to the anti-inflammatory indomethacin. The DCM fraction also increased the latency time of the animals in the hot plate test 60 min after treatment, although it did not seem to involve the opioidergic system. CONCLUSION: This work evidenced that the dichloromethane fraction of S. lycocarpum fruit possesses antinociceptive and anti-inflammatory potential, which supports its use in folk medicine for management inflammatory conditions.

Ionomic analysis, polyphenols characterization, analgesic, antiinflammatory and antioxidant capacities of Cistus laurifolius leaves: in vitro, in vivo, and in silico investigations.

This study aims to investigate the chemical and mineral composition, antioxidant, analgesic, and anti-inflammatory effects of the aqueous extract of Cistus laurifolius var. atlanticus Pit. (Cistaceae). Additionally, molecular docking interactions of various ligands with antioxidant protein target urate oxidase (1R4U) and anti-inflammatory protein target cyclooxygenase-2 (3LN1), revealing potential dual activities and highlighting specific residue interactions. The chemical characterization focused at first glance on the mineral composition which showed that C. laurifolius extract is a mineral-rich source of potassium (K), magnesium (Mg), manganese (Mn), sodium (Na), phosphorus (P), and zinc (Zn). We next performed, ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis, the latter showed various polyphenols in C. laurifolius extract including Gallic acid as the predominant polyphenol. Isoquercetin, Taxifolin and Astragalin were also among the major flavonoids detected. The antioxidant capacity of C. laurifolius leaves was tested using 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1- picrylhydrazyl (DPPH) and reducing power (RP) assays. In vitro analysis of the anti-inflammatory property of C. laurifolius leaves was conducted by the albumin denaturation test and the in vivo was assessed in the sequel by carrageenan-induced paw edema test. The analgesic activity was evaluated in vivo using tail flick, acetic acid-induced contortion, and plantar tests. The findings showed that the leave extract had a powerful antioxidant activity with an IC50 values of 2.92 ± 0.03 µg/mL (DPPH) and 2.59 ± 0.09 µg/mL (in RP test). The studied extract strongly abolished the induced inflammation (82%). Albumin denaturation test recorded an IC50 value of 210 µg/mL. Importantly, the oral administration of C. laurifolius extract considerably reduced the nociceptive effect of acetic acid in rats, showing a significant analgesic effect in a dose-related manner. Altogether, our results showed that C. laurifolius can be a promising source of phytochemicals for drug development potential.

Essential oil from leaves of Myrciaria floribunda (H. West ex Willd.) O. Berg has antinociceptive and anti-inflammatory potential.

Myrciaria floribunda is a plant that is distributed across different Brazilian biomes such as the Amazon, Caatinga, Cerrado, and Atlantic Forest, and it possesses antioxidant, antimicrobial, and anticancer properties. The antinociceptive and anti-inflammatory properties of the essential oil from M. floribunda leaves (MfEO) were examined in this study using mouse models. Gas chromatography-mass spectrometry was employed to describe the oil, and the results revealed that δ-cadinene, bicyclogermacrene, α-cadinol, and epi-α-muurolol predominated in the chemical profile. The oil stimulated a decrease in nociception in the chemical and thermal models used to evaluate acute antinociceptive activity. Findings from the use of pain pathway blockers to study the presumed underlying mechanism indicated opioid pathway activity. The anti-edematogenic effect, decreased cell migration, and generation of pro-inflammatory cytokines provided evidence of the anti-inflammatory potential of the essential oil from M. floribunda. According to this research, the essential oil from M. floribunda can effectively alleviate acute pain and inflammation.

Chemical composition, antinociceptive and anti-inflammatory activities of the curzerene type essential oil of Eugenia uniflora from Brazil.

ETHNOPHARMACOLOGICAL RELEVANCE: The Eugenia uniflora leaf infusion is widely used in folk medicine to treat gastroenteritis, fever, hypertension, inflammatory and diuretic diseases. AIM OF THE STUDY: This work evaluated the acute oral toxic, antinociceptive, and anti-inflammatory activities of the curzerene chemotype of Eugenia uniflora essential oil (EuEO). MATERIAL AND METHODS: EuEO was obtained by hydrodistillation and analyzed by GC and GC-MS. The antinociceptive action in mice was evaluated for the peripheral and central analgesic activity using abdominal contortion and hot plate tests (50, 100, and 200 mg/kg); xylene-induced ear swelling was carried out for the nociception test, and carrageenan-induced cell migration test. Spontaneous locomotor activity was assessed in the open field test to rule out any nonspecific sedative or muscle relaxant effects of EuEO. RESULTS: The EuEO displayed a yield of 2.6 ± 0.7%. The major compounds classes were oxygenated sesquiterpenoids (57.3 ± 0.2%), followed by sesquiterpene hydrocarbons (16.4 ± 2.6). The chemical constituents with the highest concentrations were curzerene (33.4 ± 8.5%), caryophyllene oxide (7.6 ± 2.8%), ß-elemene (6.5 ± 1.8%), and E-caryophyllene (4.1 ± 0.3%). Oral treatment with EuEO, at doses of 50, 300, and 2000 mg/kg, did not change the behavior patterns or mortality of the animals. EuEO (300 mg/kg) did not cause a reduction in the number of crossings in the open field compared to the vehicle group. The aspartate aminotransferase (AST) level was higher in EuEO-treated groups (50 and 2000 mg/kg) when compared to the control group (p < 0.05). EuEO, at doses of 50, 100, and 200 mg/kg, reduced the number of abdominal writhings by 61.66%, 38.33%, and 33.33%. EuEO did not show increased hot plate test time latency in any of the intervals analyzed. At 200 mg/kg, EuEO decreased paw licking time, with inhibition of 63.43%. In formalin-induced acute pain, EuEO decreased paw licking time at doses of 50, 100, and 200 mg/kg in the first phase, with inhibition of 30.54%, 55.02%, and 80.87%. The groups treated with EuEO at doses of 50, 100, and 200 mg/kg showed ear edema reduction of 50.26%, 55.17%, and 51.31%, respectively. Moreover, EuEO inhibited leukocyte recruitment only at a dose of 200 mg/kg. The inhibitory values of leukocyte recruitment after 4 h of carrageenan application were 4.86%, 4.93%, and 47.25% for 50, 100, and 200 mg/kg of essential oil, respectively. CONCLUSION: The EuEO, curzerene chemotype, has significant antinociceptive and anti-inflammatory activities and low acute oral toxicity. This work confirms the antinociceptive and anti-inflammatory of this species as the traditional use.

Chemical characterization, antinociceptive and anti-inflammatory effect of Lippia lacunosa, a species used by the Bandeirantes.

ETHNOPHARMACOLOGICAL RELEVANCE: Lippia lacunosa Mart. & Schauer is an endemic plant from the Serra do Espinhaço mountain range located on the Atlantic plateau, Brazil. It is known as "chá de pedestre" and "rosmaninho" in folk medicine. This species has a characteristic mango aroma and is widely used by the population for flu, colds, sinus infections, coughing, relaxing baths, and foot baths after long walks. It is often confused with and, therefore, used interchangeably with L. rotundifolia and L. pseudothea. AIM OF THE STUDY: This study aimed to increase scientific knowledge on the ethnopharmacological use of Lippia lacunosa through the evaluation of the micromolecular composition and anti-inflammatory and antinociceptive activities of the hexane and ethanolic extracts, essential oil, and fractions in mice. MATERIALS AND METHODS: The chemical profile of L. lacunosa extracts and fractions were obtained by chromatographic methods such as Ultra-Performance Liquid Chromatography (UPLC), Gas Chromatography (GC), Column Chromatography (CC), and Thin Layer Chromatography (TLC). Carrageenan-induced paw edema was used to investigate the anti-inflammatory activity in mice. Mechanical allodynia induced by carrageenan and hot plate tests were employed to evaluate the antinociceptive activity. RESULTS: The main constituents found in the essential oil were the monoterpenes myrcene (13.81%), linalool (6.84%), ipsenone (21.2%), and myrcenone (25.44%); and sesquiterpenes elemol (7.30%) and spathulenol (3.15%). The chromatograph fractionation of essential oil yielded a fraction rich in the main compounds (F33), ipsenone and mircenone. In experimental models of paw edema and mechanical allodynia induced by carrageenan (600 µg, 30 µL, i.pl.), the administration of hexane extract, essential oil (50 or 100 mg/kg, p.o.) or majority fraction (10 mg/kg, p.o.) reduced paw edema. The ethanolic extract (100 mg/kg) reduced mechanical allodynia only in the 2 nd h of evaluation. On the other hand, the hexane extract (50 or 100 mg/kg) and essential oil (100 mg/kg), as well as the majority fraction (10 mg/kg), reduced mechanical allodynia throughout the evaluation period. The hexane extract, essential oil, and majority fraction F33 also reduced the heat-induced nociceptive response. Also, majority fraction F33 did not affect the time mice spent in the rota-rod apparatus. CONCLUSIONS: The elucidation of the composition of the essential oil and the demonstration of the activity of L. lacunosa in experimental models of acute inflammation and also in models of nociceptive and inflammatory pain can help to increase knowledge on the ancient ethnopharmacological use by the Bandeirantes, aiming at the evaluation of the species as a candidate for herbal medicine or phytopharmaceutical in the treatment of patients with inflammatory and painful conditions.

Chemical characterization, anti-nociceptive and anti-inflammatory activities of Plukenetia conophora seed oil in experimental rodent models.

ETHNOPHARMACOLOGICAL RELEVANCE: The seed of the African walnut, Plukenetia conophora Mull.-Arg is well-known for its nutritional and medicinal values. The seed oil is widely used in massages to relieve pain, as nerve tonic and to enhance sexual performance. OBJECTIVE: The study aimed at investigating the chemical profile, antinociceptive and anti-inflammatory activities of P. conophora oil (PCO). METHODS: Seed oil of P. conophora was characterized using Gas-Liquid Chromatographic method (GC-MS) and oral acute toxicity evaluated at 2000 mg/kg. Antinociceptive effects were evaluated in hot plate, acetic acid and formalin-induced paw licking tests. The anti-inflammatory effects were investigated in egg albumin and carrageenan-, formalin and complete Freund adjuvant (CFA)-induced paw oedema models. The levels of pro-inflammatory cytokines in the fluid exudates were also evaluated in carrageenan air pouch model. RESULTS: PCO exhibited high content of alpha linolenic acid (ALA). No toxicity was observed at 2000 mg/kg of PCO. PCO (50-200 mg/kg) demonstrated significant anti-nociceptive activity in pain models. PCO exhibited anti-inflammatory activity against oedema formation by phlogistic agents. The increased inflammatory oedema and oxidative stress in CFA-treated rats were also attenuated by PCO. The PCO (100 and 200 mg/kg) significantly reduced the levels of TNF-α (59.3% and 85.2%) and IL-6 (27.5% and 72.5%) in carrageenan-induced air pouch model. CONCLUSION: The results of this study suggest that ALA-rich seed oil of Plukenetia conophora demonstrated anti-nociceptive and anti-inflammatory activities via inhibition of pro-inflammatory cytokines and oxidative stress, lending supportive evidences for its use in painful inflammatory conditions.

Antioxidant, anti-inflammatory and analgesic activity of Mimosa acutistipula (Mart.) Benth.

ETHNOPHARMACOLOGICAL RELEVANCE: Medicinal plants belonging to the genus Mimosa, such as Mimosa tenuiflora, M. caesalpinifolia, and M. verrucosa are known for their popular use for asthma, bronchitis and fever. Ethnopharmacological studies report that Mimosa acutistipula is used to treat alopecia and pharyngitis, conditions that can be related to oxidative stress, inflammatory processes and painful limitations. However, there is no studies on its efficacy and mechanism of action. AIM OF THE STUDY: To elucidate the antioxidant, anti-inflammatory, analgesic and antipyretic activity of M. acutistipula leaves. MATERIALS AND METHODS: Phytochemical profile of M. acutistipula extracts was evaluated by several reaction-specific methods. Secondary metabolites such as tannins, phenols and flavonoids were quantified with colorimetric assays. In vitro antioxidant potential was evaluated using DPPH and ABTS + as free radical scavenging tests, FRAP and phosphomolybdenum as oxide-reduction assays, and anti-hemolytic for lipid peroxidation evaluation. In vivo anti-inflammatory evaluation was performed by paw edema, and peritonitis induced by carrageenan. Analgesic effect and its possible mechanisms were determined by acetic acid-induced abdominal writhing and the formalin test. Antipyretic activity was evaluated by yeast-induced fever. RESULTS: Cyclohexane, chloroform, ethyl acetate and methanol extracts of leaves had presence of tannins, flavonoids, phenol, alkaloids, terpenes (except methanolic extract), and saponins (only for methanolic and chloroformic extracts). In phenols, flavonoids and tannins quantification, methanolic and ethyl acetate extract had higher amounts of this phytocompounds. Ethyl acetate extract, due to its more expressive quantity of phenols and flavonoids, was chosen for carrying out the in vivo tests. Due to the relationship between oxidative stress and inflammation, antioxidant tests were performed, showing that ethyl acetate extract had a high total antioxidant activity (70.18%), moderate activity in DPPH radical scavenging, and a moderate ABTS + radical inhibition (33.61%), and FRAP assay (112.32 µg Fe2+/g). M. acutistipula showed anti-inflammatory activity, with 54.43% of reduction in paw edema (50 mg/kg) when compared to the vehicle. In peritonitis test, a reduction in the concentration of NO could be seen, which is highly involved in the anti-inflammatory activity and is responsible for the increase in permeability. In the analgesic evaluation, most significant results in writhing test were seen at 100 mg/kg, with a 34.7% reduction of writhing. A dual mechanism of action was confirmed with the formalin test, both neurogenic and inflammatory pain were reduced, with a mechanism via opioid route. In the antipyretic test, results were significantly decreased at all concentrations tested. CONCLUSION: M. acutistipula leaves ethyl acetate extract showed expressive concentrations of phenolic compounds and antioxidant activity. It also exhibited anti-inflammatory and analgesic activity, besides its antipyretic effect. Thus, these results provide information regarding its popular use and might help future therapeutics involving this specimen.

Analgesic and anti-inflammatory potential of ethanolic extract from Serjania erecta leaves.

ETHNOPHARMACOLOGICAL RELEVANCE: The infusion of Serjania erecta Radlk (Sapindaceae) (popular name "cipó-cinco-folhas") leaves is used in popular medicine to treat back pain. The anti-inflammatory, anti-hyperalgesic and anti-nociceptive properties of the ethanolic extract from S. erecta leaves (EESE) has not been yet completely clarified. AIM OF THE STUDY: The present study investigated the anti-hyperalgesic, anti-nociceptive and anti-inflammatory properties of EESE in experimental models in mice. MATERIAL AND METHODS: EESE was fractionated by chromatographic techniques and the compound was identified by nuclear magnetic resonance (NMR), infrared (IR) spectrum, ultraviolet (UV) methods. Mice received a single dose of EESE by oral route (30, 100, and 300 mg/kg, p.o.) and were submitted to nociception induced by formalin, pleurisy induced by carrageenan and peritonitis induced by zymosan models. Mice also received EESE (30 and 100 mg/kg, p.o.) for 22 days in Complete Freund Adjuvant (CFA) model and another group received EESE for 7 days (30 and 100 mg/kg, p.o.) in pleurisy induced by Bacillus Calmette-Guerin (BCG). The cytotoxicity (MTT), phagocytic and chemotactic inhibitory activities of EESE were performed in in vitro assays. RESULTS: The fractionation of EESE led to the identification of kaempferol-3-O-α-L-rhamnopyranoside. The oral administration of all doses of EESE decreased the nociceptive response induced by formalin. EESE significantly inhibited leukocyte migration in carrageenan-induced pleurisy and zymosan peritonitis models. The daily administration of EESE during for 7 days inhibited the leukocyte migration and the mycobacteria growth of pleural material obtained from animals which received BCG. EESE significantly reduced edema, cold allodynia and mechanical hyperalgesia responses induced by CFA. EESE did not induce cytotoxicity, and also decreased the leukocyte phagocytic activity, as well as, neutrophil chemotaxis. CONCLUSIONS: EESE showed analgesic and anti-inflammatory properties in acute and persistent experimental models in mice. EESE also reduced in vitro leukocyte chemotaxis and phagocytic activity without inducing cytotoxicity. The continuous oral treatment with EESE was effective against hyperalgesia and inflammation and these results could explain the popular use of S. erecta as an analgesic natural agent.

Analgesic and anti-inflammatory activities of ethyl acetate and butanol fractions from Vitex polygama hydroalcoholic leaf extract.

This study evaluated the analgesic and anti-inflammatory activities of Vitex polygama. Ethyl acetate and butanol fractions (10-30 mg/kg), obtained from the hydroalcoholic leaf extract, showed an antinociceptive effect in the acetic acid-induced abdominal writhing test, formalin test and modified hot plate test in mice, indicating a peripheral anti-inflammatory action. Ethyl acetate and butanol fractions were effective in inhibiting nitric oxide and TNF-α production, respectively, in RAW 264.7 macrophages. Both fractions (10-30 mg/kg) showed an acute analgesic effect in mice with vincristine-induced neuropathic pain exposed to a thermal stimulus. Through ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-UV-MS/MS) it was possible to identify seven major compounds: isoorientin, orientin, vitexin, isovitexin, O-p-hydroxybenzoyl orientin, O-caffeoyl-orientin, and di-caffeoylquinic acid. Orientin and isoorientin were isolated from ethyl acetate fraction and had their identity confirmed by nuclear magnetic resonance (NMR). Glucosyl flavones appear to be the main metabolites responsible for the anti-inflammatory and analgesic activities observed for V. polygama.

Design, Synthesis and Biological Evaluation of Novel N-Alkyl-4-Methyl-2,2- Dioxo-1H-2λ6,1-Benzothiazine-3-Carboxamides as Promising Analgesics.

INTRODUCTION: An analysis of the literature on the painkillers long used in traditional medicine, which are isolated from plant materials, has shown that many of them are alkylamides of various carboxylic acids. This fact served as the basis for the study of a large group of N-alkyl-4- methyl-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxamides as potential new analgesics. The objects of the study were synthesized in the traditional way involving the initial conversion of 4-methyl- 2,2-dioxo-1H-2λ6,1- benzothiazine-3-carboxylic acid to imidazolide, in which imidazolide was used as an acylating agent. The method is simple to implement and, as a rule, gives high yields of final alkylamides. However, in reaction with sterically hindered tert-butylamine, along with the "normal" product, an unexpected formation of N-tert-butyl-4-methyl-1-(4-methyl-2,2-dioxo-1H-2λ6,1- benzothiazine-3-carbonyl)-2,2-dioxo-2λ6,1-benzothiazine-3-carboxamide was observed, which was characterized by X-ray diffraction analysis as a monosolvate with N,N-dimethylformamide. These synthetic problems can be avoided using a more powerful acylating agent, 4-methyl-2,2-dioxo-1H- 2λ6,1- benzothiazine-3-carbonyl chloride. BACKGROUND: A large group of new N-alkyl-4-methyl-2,2-dioxo-1H-2λ6,1-benzothiazine-3- carboxamides was synthesized. OBJECTIVE: On the basis of molecular docking, some derivatives of N-alkyl-4-methyl-2,2-dioxo-1H- 2λ6,1-benzothiazine-3-carboxamides have been designed. Their preliminary structure-activity relationships (SAR) have been studied. The most rational approaches to the synthesis of lead compounds have been developed. The most active compounds have shown high anti-inflammatory and analgesic activities. METHODS: The structure of all compounds prepared has been confirmed by the data of elemental analysis, 1H- and 13C NMR spectroscopy, and electrospray ionization liquid chromato-mass spectrometry. For rational drug design, optimization of further pharmacological screening and prediction of a possible mechanism of pharmacological action, molecular docking has been performed. For the determination of activity, pharmacological studies have been carried out. RESULTS: Pharmacological tests have determined that the transition from N-aryl(heteroaryl) alkylamides to "pure" N-alkylamides we carried out is accompanied by a significant reduction and even complete loss of anti-inflammatory effect with remaining analgesic activity. CONCLUSION: According to the studies, compounds from N-alkyl-4-methyl-2,2-dioxo-1H-2λ6,1- benzothiazine-3-carboxamides are potential anti-inflammatory and analgesic agents.

Anti-Inflammatory, analgesic and anti-pyretic activity of Fagonia bruguieri DC in rats.

Traditional medicine has employed the plant Fagonia bruguieri DC. to alleviate inflammation, fever and pain. The goal of this study was to test the anti-inflammatory, analgesic and antipyretic properties of the methanol extract of whole plant of Fagonia bruguieri (F. bruguieri). The writhing test and Eddy's hot plate test were used to assess the analgesic potential of F. bruguieri at three different doses. Carrageenan-induced rat paw edema was applied to investigate anti-inflammatory activity, whereas antipyretic activity was estimated in Brewer's yeast induced pyrexia model. Flavonoids, alkaloids, saponins, tannins and glycosides were found in F. bruguieri's phytochemical analysis. F. bruguieri at 750 mg/kg reduced writhing count by 62.23 percent, while F. bruguieri enhanced latency in Eddy's hot plate test. In carrageenan-induced edema, F. bruguieri at 750 mg/kg exhibited considerable anti-inflammatory effect (41.11 percent) after 2 nd, 3 rd and 4 th hours of therapy. F. bruguieri was also found to show antipyretic properties. The anti-inflammatory, analgesic and antipyretic properties of F. bruguieri were confirmed in this study, which might be attributable to the presence of several phyto-constituents.

Analgesic, Anti-inflammatory, Antipyretic, and In Silico Measurements of Sonneratia caseolaris (L.) Fruits from Sundarbans, Bangladesh.

Sonneratia caseolaris is a widely distributed mangrove plant having much therapeutic importance in traditional medicine. This plant is reported for possessing numerous compounds that are already used for many therapeutic purposes. After finding the presence of antioxidant components in the qualitative antioxidative assay, we went to conduct quantitative tests where the total contents of phenolics, flavonoids, and tannins were estimated as 122 mg GAE/gm, 613 mg QE/gm, and 30 mg GAE/gm, respectively. In DPPH free radical, H2O2, and superoxide radical scavenging assay, the SC50 values were found to be 87, 66, and 192 µg/ml, respectively. In FeCl3 reducing power assay, the RC50 of SC extract and ascorbic acid were 80 and 28 µg/ml, respectively. This extract revealed a significant peripheral analgesic effect in the acetic acid-induced writhing model in mice by reducing the writhing impulse by about 21% and 39% at 250 and 500 mg/kg doses, respectively, and a central analgesic effect in the tail immersion method by elongating the time up to about 22% and 37% at the same doses. In the anti-inflammatory test in mice, this extract reduced the paw edema size over the observed period in a dose-dependent manner. It also showed a significant reduction in the elevated rectal temperature of mice in the observing period in Brewer's yeast-induced pyrexia model. In silico analysis revealed better binding characteristics of ellagic acid and luteolin among other compounds with various receptors that might be responsible for antioxidative and anti-inflammatory properties. From our observation, we suppose that SC fruits might be a potential source of drug leads for various inflammatory disorders.