Anti-inflammatory and anti-hypersensitive effects of the chalcone isocordoin and its semisynthetic derivatives in mice.

Isocordoin (1), a chalcone isolated from different plants, has been found to present a range of interesting biological properties. This study aimed to evaluate the anti-hypersensitive and anti-inflammatory effects of isocordoin (1) and several natural and semisynthetic derivatives (2-10). Initial evaluation of (1), dihydroisocordoin (2) and six semisynthetic derivatives (3-8) in the inhibition of abdominal writhes induced by acetic acid model showed that only isocordoin dimethylether (5) caused more than 70% of inhibition. Further evaluation of 5 for its anti-oedematogenic activity and anti-hypersensitivity effect induced by carrageenan, lipopolysaccharide (LPS), bradykinin (BK), prostaglandin E2 (PGE2), and epinephrine showed that isocordoin dimethylether (5) presented a discrete inhibition of carrageenan- and LPS-induced hypersensitivity, and of carrageenan-induced paw oedema, and that it was able to significantly reduce both the oedema and hypersensitivity induced by BK. Furthermore, when tested in the PGE2 model, 5 interfered only with the paw-oedema, without showing any effect against the paw-hypersensitivity. Evaluation of the natural isocordoin (1), together with the semisynthetic derivatives isocordoin dimethylether (5), isocordoin methylether (9), and dihydroisocordoin methylether (10) in the BK-induced oedema and hypersensitivity showed that the monoalkylated derivatives 10 and 9 had the strongest antinociceptive activity. The results of this investigation indicate that both monoalkylation of the C-4' phenolic hydroxyl group and reduction of the double bond in the α,ß-unsaturated system of the chalcone skeleton favor activity.

Topical anti-inflammatory phytomedicine based on Sphagneticola trilobata dried extracts.

CONTEXT: The aerial parts of Sphagneticola trilobata (L.) Pruski (Asteraceae) are popularly used to treat topical inflammation, but have not been fully investigated. OBJECTIVE: To identify polar compounds in S. trilobata extracts and develop a new topical phytomedicine based on the kaurenoic acid (KA) content while monitoring and demonstrating its topical anti-inflammatory activity. MATERIALS AND METHODS: Ethanol spray-dried extract of S. trilobata was analysed by LC-MS while the KA content from semisolid was analysed by LC-UV. The extent of ear edema induced by applying 20 µL of croton oil (2.5%), arachidonic acid (AA; 2 mg/ear) and decanoylphorbol-13-acetate (TPA; 2.5 mg/ear) in mice was used to evaluate the biological activity of the semisolids, which were applied 30 min before the phlogistic agents. RESULTS: Eight phenylpropanoids and four oleanane-type triterpenoid saponins were identified, majority of them reported for the first time in this species, in addition to KA. The semisolid containing 1.0% of dried extract reduced the ear edema induced by croton oil [77.2 ± 4.5%; ID50 = 0.49 (0.28-0.87%)], TPA (81.5 ± 2.4%) and AA (39.1 ± 6.9%), with decreasing effect at higher KA concentrations. This was accompanied by neutrophil migration inhibition as investigated by biochemical and histological assays. DISCUSSION AND CONCLUSION: The anti-inflammatory effects were (at least in part) due to the interference in protein kinase C (PKC) activation, AA-cascade products and neutrophil migration inhibition, demonstrating the efficacy of the folk topical usage of this plant. The results support the development of a novel topical anti-inflammatory phytomedicine properly standardized to treat inflammatory dermatological diseases.

The antihypersensitive and antiinflammatory activities of a benzofuranone derivative in different experimental models in mice: the importance of the protein kinase C pathway.

BACKGROUND: Benzofuranone (BF1) was synthesized and its effects evaluated on mechanical hypersensitivity and paw edema models induced by different agents and on neuropathic pain induced by partial ligation of the sciatic nerve. An attempt was also made to elucidate the mechanism of action. METHODS: Swiss mice were used for the tests. Hypersensitivity was induced by intraplantar injection of carrageenan, bradykinin (BK), prostaglandin E2 (PGE2), epinephrine, lipopolysaccharide, or complete Freund adjuvant or by using a neuropathic pain model (evaluated with von Frey filament 0.6 g). The antiinflammatory effects were investigated in a paw edema model induced by carrageenan, PGE2, and BK (measured with a plethysmometer). The involvement of protein kinase C (PKC) was investigated through a nociception model induced by phorbol myristate acetate. RESULTS: BF1 inhibited the hypersensitivity and paw edema induced by intraplantar injection of carrageenan, BK, and PGE2 (P < 0.001), and it was effective in reducing the hypersensitivity evoked by complete Freund adjuvant or epinephrine (P < 0.001) but not by lipopolysaccharide (P = 0.2570). BF1 inhibited the licking behavior induced by phorbol myristate acetate (P < 0.001), suggesting involvement of the PKC pathway. A reduction in hypersensitivity of mice submitted to partial ligation of the sciatic nerve (P < 0.001) was observed, with inhibition of neutrophil migration and interleukin-1ß production into the spinal cord. BF1 treatment did not interfere with locomotor activity (P = 0.0783) and thermal withdrawal threshold (P = 0.5953), which are important adverse effects of other analgesics. CONCLUSIONS: BF1 has dose-dependent antihypersensitive and antiinflammatory effects in both acute and chronic models of pain and inflammation, possibly mediated through interference with the PKC activation pathway. The easy and fast synthesis of this compound, low-cost, low-concentration-requirement, and once-daily-administration drug suggest it as a candidate for future clinical studies.

Antihyperalgesic effects of myrsinoic acid B in pain-like behavior induced by inflammatory and neuropathic pain models in mice.

BACKGROUND: Myrsinoic acid B (MAB) is a diprenylated benzoic acid widely found in the vegetal kingdom. Recent studies demonstrate that MAB has important antinociceptive effects in models of chemically or thermally induced nociception in mice. METHODS: In the present study we evaluated the effect of MAB in different models of inflammatory and neuropathic hypersensitivity in mice. RESULTS: This study demonstrates that the pretreatment with MAB, given orally (8.4 to 83.8 µmol/kg), inhibited carrageenan- and complete Freund adjuvant-induced mechanical hypersensitivity. When administered after the induction of hypersensitivity, MAB also reduced the mechanical hypersensitivity in the ipsilateral and in the contralateral hindpaws of mice injected with complete Freund adjuvant, interfering with a signaling cascade already established. MAB reversed the hypersensitivity (mechanical and thermal) of operated animals, with similar results to those observed with gabapentin. MAB activity was evident when administered either systemically (PO or IV) or intrathecally, suggesting interference in the central pathways of pain control. Furthermore, MAB seems to present an antiinflammatory effect evidenced by the interference in both the neutrophil migration and in the increase of interleukin-1ß levels after carrageenan injection. Of note, MAB treatment did not interfere with mechanical or thermal sensitivity in healthy mice, a frequent characteristic of commonly used analgesics, such as morphine or gabapentin. Side effects including interference in locomotor activity, motor performance, and body temperature in animals treated with MAB were absent. CONCLUSIONS: MAB reduced mechanical and thermal hypersensitivity in mice submitted to models of inflammatory and neuropathic pain, showing excellent potential for treating persistent pain in humans.

A new naphthoquinone isolated from the bulbs of Cipura paludosa and pharmacological activity of two main constituents.

Cipura paludosa (Iridaceae) is a plant that is distributed in the north region of Brazil. Its bulbs are used in folk medicine to treat inflammation and pain. Four naphthalene derivatives have been isolated from the bulbs of this plant. Three of them have been identified as the known naphthalene derivatives, eleutherine, iso-eleutherine, and hongkonin. The structure of the fourth and new component was determined as 11-hydroxyeleutherine by extensive NMR study. In addition, the IN VIVO effect of the two major compounds, eleutherine and iso-eleutherine, was evaluated in carrageenan-induced hypernociception and inflammation in mice. Eleutherine and iso-eleutherine (1.04-34.92 µmol/kg), dosed intraperitoneally (i.p.) or orally (p.o.), decreased the carrageenan-induced paw oedema (i.p. - inhibitions of 36 ± 7 % and 58 ± 14 %, respectively; p.o. - inhibitions of 36 ± 7 % and 58 ± 14 %, respectively). Iso-eleutherine, but not eleutherine, significantly reduced (inhibitions of 39 ± 4 %) the plasma extravasation induced by intradermal (i.d.) injection of carrageenan. Likewise, eleutherine and iso-eleutherine (1.04-34.92 µmol/kg, i.p. or p.o.) were also effective in preventing the carrageenan-induced hypernociceptive response (i.p. - inhibition of 59 ± 4 % and 63 ± 1 %, respectively; p.o. - inhibitions of 36 ± 7 % and 58 ± 14 %, respectively). It was also suggested that the anti-inflammatory and anti-hypernociceptive effects of eleutherine or iso-eleutherine partly depend on the interference with the synthesis or activity of mast cell products, kinins, cytokine, chemokines, prostanoids, or sympathetic amines. Our findings show that two major compounds of C. paludosa contain pharmacologically active constituents that possess antinociceptive and anti-inflammatory activity, justifying, at least in part, its popular therapeutic use for treating conditions associated with pain.

Aleurites moluccanus and its main active constituent, the flavonoid 2″-O-rhamnosylswertisin, in experimental model of rheumatoid arthritis.

ETHNOPHARMMACOLOGICAL RELEVANCE: Aleurites moluccana is used in folk medicine to treat pain, fever, asthma, hepatitis, gastric ulcer and inflammatory process in general, and the nut oil had been topically applied to treat arthritis and other joint pain, however the seeds are classified as toxic for oral use. AIM: Faced with the need for new alternative to treat the symptoms and modify rheumatoid arthritis (RA) the aim of this work was to evaluate the effects of A. moluccanus' leaves dried extract in rats and mice submitted to complete Freund adjuvant (CFA)-induced RA. MATERIAL AND METHODS: Wistar Rats and Swiss mice were submitted to CFA-induced RA in the right hindpaw. They received A. moluccanus extract (orally; p.o.), dexamethasone (subcutaneously), 2″-O-rhamnosylswertisin (p.o.) or vehicle (p.o.), from the 14th day after the CFA injection for up to 8 days. The mechanical hypersensitivity was evaluated using the von Frey filaments and the paw-oedema was measured using a plethysmometer. The rats' injected hindpaw was used to perform the histological analysis. RESULTS: A. moluccanus was able to significantly reduce the mechanical hypersensitivity in both ipsi- and contralateral hindpaws of mice injected with CFA, in a dose dependent manner. Furthermore, the paw-oedema was progressively reduced by A. moluccanus. Similar results were obtained for the positive-control drug dexamethasone and the isolated compound 2″-O-rhamnosylswertisin. Besides the effects mentioned above, the extract was also effective to repair the joint damage in CFA-induced RA rats, including reduction of fibrosis, cartilage degradation and bone erosion scores. CONCLUSION: These results together with the literature data reinforce the anti-hypersensitivity and anti-inflammatory activity of A. moluccanus extract. Part of the observed effects is due to the presence of the compound 2″-O-rhamnosylswertisin. The fact that the extract acted as a disease modifier point this herbal product as a promisor and safe tool to treat RA and other associated chronic diseases.

Anti-hypersensitivity effects of the phthalimide derivative N-(4methyl-phenyl)-4-methylphthalimide in different pain models in mice.

The treatment of chronic pain remains a challenge for clinicians worldwide, independent of its pathogenesis. It motivates several studies attempting to discover strategies to treat the disease. The in silico analysis using molecular docking approach demonstrated that the phthalimide N-(4methyl-phenyl)-4-methylphthalimide (MPMPH-1) presented high affinity to adenylyl-cyclase enzyme (AC). It also prominently reduced the mechanical hypersensitivity of mice challenged by Forskolin, an AC activator. This effect lasted for up to 48h after Forskolin injection, presenting activity longer than MDL-12330A (AC inhibitor). MPMPH-1 was also effective in reducing the hypersensitivity induced by IL-1ß, bradykinin, prostaglandin E2 or epinephrine, chemical mediators that have, among others, AC as pivotal protein in their signalling cascade to induce mechanical-pain behaviour. The compound presented marked inhibition in inflammatory-pain models induced by carrageenan, lipopolysaccharide or complete Freund's adjuvant, including neutrophil migration inhibition. Furthermore, it also seems to act in both peripheral and pain central-control pathways, being also effective in reducing the persistent cancer-pain behaviour induced by melanoma cells in mice. MPMPH-1 could represent a promising pharmacological tool to treat acute and chronic painful diseases, with good bioavailability, local activity, and lack of locomotor-activity interference. Further studies are necessary to determine the exact mechanism of action but it seems to involve AC enzyme as possible target.

Ipomoea pes-caprae (L.) R. Br (Convolvulaceae) relieved nociception and inflammation in mice - A topical herbal medicine against effects due to cnidarian venom-skin contact.

ETHNOPHARMACOLOGICAL RELEVANCE: Ipomoea pes-caprae is known as bayhops, beach morning glory or goat's foot, and in Brazil as salsa-de-praia. Its leaves are used in worldwide folk medicine for the relief of jellyfish-stings symptoms. The literature only reports the neutralizing effects of nonpolar plant derived over jellyfish venoms, without validating the popular use or exploring the mechanism of action. AIM OF THE STUDY: This study aimed to evaluate and validate the topical effects of a semisolid containing hydroethanolic extract obtained from the aerial parts of I. pes-caprae using different models of paw- and ear-oedema and spontaneous nociception in mice, attempting to better understand the mechanism involved in its effect. MATERIALS AND METHODS: Leaf and stem of I. pes-caprae were extracted by ethanol 50% (v/v) and the soft-extract was incorporated in Hostacerin® cream base at 0.5%, 1.0% and 2% (w/w). The anti-hypersensitivity effects were evaluated by injecting the Physalia physalis venom into the right mice's hindpaw pre-treated either with the semisolid containing the I. pes-caprae extract or with the isolated majority compound 3,5-Di-O-caffeoylquinic acid (ISA). The topical anti-inflammatory activity was investigated using both preclinical models: paw oedema induced by trypsin, bradykinin (BK), histamine and carrageenan, and ear oedema induced by capsaicin. Additionally, the model of spontaneous nociception induced by trypsin and capsaicin were used to verify the topical antinociceptive activity. RESULTS: The animals pre-treated with the semisolid containing I. pes-caprae extract or with the intraplantar injection of the major component (ISA) had the mechanical hypersensitivity induced by P. physalis venom significantly reduced. Significant inhibition was also observed in paw-oedema induced by trypsin, histamine and BK, and in a less extent in carrageenan-induced paw oedema. Similar effect was observed in mice challenged to the capsaicin-induced ear-oedema. Besides the vascular effects, the extract interfered with leukocyte migration induced by histamine injection. Finally, the semisolid presented significant inhibition in trypsin- and capsaicin-induced spontaneous nociception. CONCLUSIONS: The hydroethanolic extract of I. pes-caprae showed compliance with the topical popular use of the herbal product to relieve the symptoms evoked by the cnidarian venom-skin contact, such as neurogenic oedema and nociception. The extract components seem to interfere with the effects resulting from the TRPV1, B2R and PAR-2 activation, once it interfered with painful-behaviour and oedema induced by capsaicin, BK and trypsin, pointing the histaminergic system as the main target, once it is an important mediator in the signalling pathway of the aforementioned receptors.