iridoids and Pain

Pain and inflammation are the major symptoms of almost every human disease. Herbal preparations from Morinda lucida are used to treat pain and inflammation in traditional medicine. However, the analgesic and anti-inflammatory activities of some of the plant's chemical constituents are not known.. The aim of this study is to evaluate the analgesic and anti-inflammatory activities and possible mechanisms of these activities of iridoids from Morinda lucida.. The compounds were isolated using column chromatography and characterized by NMR spectroscopy and LC-MS. Anti-inflammatory activity was evaluated using carrageenan-induced paw edema. Whereas, the analgesic activity was assessed in the hot plate and acetic acid-induced writhing assays. Mechanistic studies were conducted using pharmacological blockers, determination of antioxidant enzymes, lipid peroxidation, and docking studies.. The iridoid, ML2-2 exhibited inverse dose-dependent anti-inflammatory activity (42.62% maximum at 2 mg/kg p. o). ML2-3 produced dose-dependent anti-inflammatory activity (64.52% maximum at 10 mg/kg p. o.). Anti-inflammatory activity of diclofenac sodium was 58.60% at 10 mg/kg p. o. Furthermore, ML2-2 and ML2-3 produced analgesic activity (P < 0.01) of 44.44 ± 5.84 and 54.18 ± 19.01%. at 10 mg/kg p. o. respectively in the hot plate assay and 64.88 and 67.44% in the writhing assay. ML2-2 significantly elevated catalase activity. However, ML2-3 elevated SOD and catalase activity significantly. In the docking studies, both iridoids formed stable crystal complexes with delta and kappa opioid receptors, and the COX-2 enzyme with very low free binding energies (ΔG) from -11.2 to -14.0 kcal/mol. However, they did not bind with the mu opioid receptor. The lower bound RMSD of most of the poses were found to be ≤ 2. Several amino acids were involved in the interactions through various inter molecular forces.. These results indicate that ML2-2 and ML2-3 possessed very significant analgesic and anti-inflammatory activities via acting as both delta and kappa opioid receptor agonist, elevation of anti-oxidant activity and inhibition of COX-2.

Topics: Analgesics; Anti-Inflammatory Agents; Antioxidants; Carrageenan; Catalase; Cyclooxygenase 2; Edema; Humans; Inflammation; Iridoids; Morinda; Pain; Plant Extracts; Receptors, Opioid, delta; Rubiaceae; Superoxide Dismutase

Patrinia scabra Bunge is a well-known herbal medicine for its favorable treatment on inflammatory diseases owing to its effective ingredients, in which iridoid glycoside plays an extremely significant role. This article aimed to improve the content of total iridoid glycosides in crude extract through a series optimization of extraction procedure. Moreover, considering that both pain and inflammation are two correlated responses triggered in response to injury, irritants or pathogen, the article investigated the anti-inflammatory and analgesic activities of P. scabra to screen out the active fraction.. P. scabra was extracted by ultrasonic-microwave synergistic extraction (UMSE) to obtain total iridoid glycosides (PSI), during which a series of conditions were investigated based on single-factor experiments. The extraction process was further optimized by a reliable statistical method of response surface methodology (RSM). The elution fractions of P. scabra extract were prepared by macroporous resin column chromatography. Through the various animal experiment including acetic acid-induced writhing test, formalin induced licking and flinching, carrageenan-induced mice paw oedema test and xylene-induced ear edema in mice, the active fractions with favorable analgesic and anti-inflammatory effect were reasonably screen out.. The content of PSI could reach up to 81.42 ± 0.31 mg/g under the optimum conditions as follows: ethanol concentration of 52%, material-to-liquid ratio of 1:18 g/mL, microwave power at 610 W and extraction time of 45 min. After gradient elution by the macroporous resin, the content of PSI increased significantly. Compared with other concentrations of elution liquid, the content of PSI in 30 and 50% ethanol eluate was increased to reach 497.65 and 506.90 mg/g, respectively. Owing to the pharmacology experiment, it was reasonably revealed that 30 and 50% ethanol elution fractions of P. scabra could relieve pain centrally and peripherally, exhibiting good analgesic and anti-inflammatory activities.. Patrinia scabra possessed rich iridoids and exhibited significant analgesic and anti-inflammatory activities.

Topics: Analgesics; Animals; Anti-Inflammatory Agents; Inflammation; Iridoid Glycosides; Iridoids; Mice; Microwaves; Pain; Patrinia; Phytotherapy; Plants, Medicinal; Ultrasonics

The present study was undertaken to evaluate the in vivo analgesic activities of the extracts prepared from the aerial parts and roots of Scrophularia kotscyhana and to isolate the bioactive metabolites from the most active extract. Analgesic activities of all extracts and subextracts at the doses of 5, 10 and 30 mg/kg (i.p.) were examined using hot plate test in mice. Among the tested extracts, MeOH extract prepared from the aerial parts and the n-butanol subextract prepared thereof displayed the best analgesic activity at all doses. Phytochemical studies on n-butanol subextract led to the isolation of two new iridoid glycosides as an inseparable mixture, 8-O-acetyl-4'-O-(E)-(p-coumaroyl)-harpagide (1) and 8-O-acetyl-4'-O-(Z)-(p-coumaroyl)-harpagide (2) along with five known secondary metabolites, β-sitosterol 3-O-β-glucopyranoside (3), apigenin 7-O-β-glucopyranoside (4), apigenin 7-O-rutinoside (5), luteolin 7-O-β-glucopyranoside (6) and luteolin 7-O-rutinoside (7). The iridoid mixture (1 and 2), 3 and 4 elicited significant inhibition of pain at 5 mg/kg dose.

Topics: Analgesics; Animals; Apigenin; Chemical Fractionation; Glucosides; Glycosides; Iridoid Glycosides; Iridoids; Luteolin; Mice; Pain; Plant Components, Aerial; Plant Extracts; Pyrans; Scrophularia; Sitosterols

Lamiophlomis rotata (Benth.) Kudo is a perennial herb (Labiatae) used as the Tibetan traditional medicine with the effects of alleviating pain, detumescence, hemostasis, promoting blood circulation to remove blood stasis and reinforcing marrow. In this study, we investigated the antinociceptive and anti-inflammatory activities of iridoid glycosides extract of L. rotata (IGLR) in mice. Our results showed that the iridoid glycosides extract could decrease acetic-acid-induced writhings times and formalin-induced lickings times, inhibit carrageenan-induced hind paw edema and xylene-induced ear swelling, and suppress peritoneal capillary permeability and leukocyte infiltration also induced by acetic acid in mice. All of these results suggested that the iridoid glycosides extract possesses the significant antinociceptive and anti-inflammatory activities.

Topics: Acetic Acid; Analgesics; Animals; Anti-Inflammatory Agents; Behavior, Animal; Capillary Permeability; Ear Diseases; Edema; Formaldehyde; Glycosides; Iridoids; Lamiaceae; Mice; Mice, Inbred BALB C; Neutrophil Infiltration; Pain; Peritoneal Cavity; Phytotherapy; Plant Components, Aerial; Plant Extracts; Xylenes

Many traditional Indian medicinal plants which contain large quantity of a secoiridoid, swertiamarin are being used to relieve pain. Iridoids present in a wide variety of medicinal plants possess a large number of medicinal properties. In the present study in vivo antinociceptive activity of swertiamarin isolated from E. axillare was carried out using three different methods in mice. In the hot plate method, a significant increase in the latency period was observed for the treatment with swertiamarin at 100 and 200 mg/kg bw after 30 and 45 min. The percent protection observed after 45 min was 109.42, 147.42 and 157.14, respectively, for the standard paracetamol and swertiamarin at 100 and 200 mg/kg bw treatments. A significant increase in the tail withdrawal reflex was observed for the swertiamarin treatment at both the doses with percent protections of 150 and 200, respectively. In both these methods, swertiamarin produced potent activity than that of standard paracetamol. In the acetic acid induced writhing, swertiamarin at 100 and 200 mg/kg bw reduced the number of writhes significantly. Dose dependent results were observed in all the three methods and among the two doses, swertiamarin at 200 mg/kg bw showed potent activity. These results prove that swertiamarin possess both peripheral and central antinociceptive activity.

Topics: Acetaminophen; Acetic Acid; Analgesics; Analgesics, Non-Narcotic; Animals; Gentianaceae; Glucosides; Iridoid Glucosides; Iridoids; Male; Mice; Pain; Phytotherapy; Plant Extracts; Pyrones; Rats; Rats, Wistar; Tail

Gentiopicroside is one of the secoiridoid compound isolated from Gentiana lutea. It exhibits analgesic activities in the mice. The anterior cingulate cortex (ACC) is a forebrain structure known for its roles in pain transmission and modulation. Painful stimuli potentiate the prefrontal synaptic transmission and induce glutamate NMDA NR2B receptor expression in the ACC. But little is known about Gentiopicroside on the persistent inflammatory pain and chronic pain-induced synaptic transmission changes in the ACC. The present study was undertaken to investigate its analgesic activities and central synaptic modulation to the peripheral painful inflammation. Gentiopicroside produced significant analgesic effects against persistent inflammatory pain stimuli in mice. Systemic administration of Gentiopicroside significantly reversed NR2B over-expression during the chronic phases of persistent inflammation caused by hind-paw administration of complete Freunds adjuvant (CFA) in mice. Whole-cell patch clamp recordings revealed that Gentiopicroside significantly reduced NR2B receptors mediated postsynaptic currents in the ACC. Our findings provide strong evidence that analgesic effects of Gentiopicroside involve down-regulation of NR2B receptors in the ACC to persistent inflammatory pain.

Topics: Analgesics, Non-Narcotic; Animals; Blotting, Western; Chronic Disease; Cyclic AMP; Down-Regulation; Excitatory Postsynaptic Potentials; Freund's Adjuvant; Glucosides; Glutamic Acid; Inflammation; Iridoid Glucosides; Iridoids; Mice; Mice, Inbred C57BL; Pain; Pain Measurement; Patch-Clamp Techniques; Receptors, GABA-A; Receptors, N-Methyl-D-Aspartate; Synaptic Transmission

We examined the effects of the aqueous fraction (AF) on nociception models mice induced by the chemical and the thermal stimuli so as to elucidate the analgesic activity and provide scientific basis for the clinical use of Paederia scandens.. The AF of MeOH extract from P. scandens was evaluated on anti-nociceptive activity in mice using chemical and thermal models of nociception.. Given orally, the aqueous fraction at doses of 200, 400 and 800 mg/kg produced significant inhibitions on chemical nociception induced by intraperitoneal acetic acid and subplantar formalin injections and on thermal nociception in the tail-flick test and in the hot plate test. More significant inhibition of nociception was observed at dose of 800 mg/kg of this fraction. In the pentobarbital sodium -induced sleeping time test and the open-field test, the aqueous fraction neither significantly enhanced the pentobarbital sodium -induced sleeping time nor impaired the motor performance, indicating that the observed anti-nociception was unlikely due to sedation or motor abnormality.. These results suggested that the aqueous fraction produced anti-nociception possibly related to the iridoid glycosides and polysaccharides in this fraction.

Topics: Analgesics; Animals; Dose-Response Relationship, Drug; Glycosides; Iridoids; Mice; Mice, Inbred ICR; Pain; Pain Measurement; Plant Extracts; Polysaccharides; Rubiaceae

Infusions of Verbascumlasianthum flowers have been used for hemorrhoids in Turkish folk medicine. In order to evaluate the scientific basis for this practice, in vivo anti-inflammatory and antinociceptive activities of Verbascum lasianthum Boiss. ex Bentham flowers were investigated. A methanolic extract of the flowers was shown to possess significant inhibitory activity in the carrageenan-induced hind paw edema model and in p-benzoquinone-induced writhings in mice. Through bioassay-guided fractionation and isolation procedures eight compounds, 6-O-(4'''-O-trans-p-coumaroyl)-alpha-L-rhamnopyranosylaucubin (1), 6-O-(4'''-O-trans-p-methoxycinnamoyl)-alpha-L-rhamnopyranosylaucubin (2), sinuatol (3), aucubin (4), geniposidic acid (5), catalpol (6), ajugol (7) and ilwensisaponin A (8) were isolated and their structures were elucidated by spectral techniques. An iridoid glucoside, aucubin (4) and a triterpenoid saponin, ilwensisaponin A (8) were found to possess significant antinociceptive and anti-inflammatory activities, per os without inducing any apparent acute toxicity or gastric damage. Results of the present study support the continued and expanded utilization of plants employed in Turkish folk medicine.

Topics: Analgesics; Animals; Anti-Inflammatory Agents; Biological Assay; Edema; Flowers; Hemorrhoids; Iridoids; Male; Medicine, Traditional; Mice; Pain; Pain Measurement; Phytotherapy; Plant Extracts; Plants, Medicinal; Spectrum Analysis; Turkey; Verbascum