Antinociceptive properties of extracts and two flavonoids isolated from leaves ofDanae racemosa

Antinociceptive compounds and LC-DAD-ESIMSn profile from Dictyoloma vandellianum leaves

Limonoids, quinolone alkaloids and chromones have been reported as constituents of Dictyoloma vandellianum Adr. Juss. (Rutaceae). Although those compounds are known for their biological activities, only the anti-inflammatory activity of chromones isolated from the underground parts has been evaluated. There are no studies of the pharmacological properties of the aerial parts of D. vandellianum. The present study was carried out to determine the phytochemical profile and antinociceptive activity of the methanol extract, fractions and isolated compounds of leaves of D. vandellianum. The phytochemical profile was performed by HLPC-DAD-ESIMSⁿ and pure substances obtained were characterized by MS and NMR spectroscopy. The antinociceptive activity was assessed using the formalin assay in mice, and the motor function in the rotarod test. ME and all the fractions obtained from ME produced antinociceptive effects. Among them, the ethyl ether fraction was the most active. Data from HPLC-DAD-ESIMSⁿ showed that the ethyl ether fraction presented 42 compounds. The major compounds isolated from this fraction—gallic acid, methyl gallate and 1,2,6-tri-O-galloyl-β-d-glucopyranose–were tested and produced antinociceptive effects. Gallic acid, methyl gallate and 1,2,6-tri-O-galloyl-β-d-glucopyranose at antinociceptive doses did not affect the motor performance in mice in the rotarod test. This work is the first report of the occurrence of gallotanins in D. vandellianum. In addition, the pharmacological study showed that D. vandellianum leaves present antinociceptive activity, probably induced by gallic acid, methyl gallate and 1,2,6-tri-O-galloyl-β-d-glucopyranose.

Anti-ulcer and anti-Helicobacter pylori potentials of the ethyl acetate fraction of Physalis alkekengi L. var. franchetii (Solanaceae) in rodent

ETHNOPHARMACOLOGICAL RELEVANCE

Physalis alkekengi L. var. franchetii (Solanaceae) has been widely used in Chinese folk medicine due to its wide distribution throughout the country, for the treatment of a wide range of diseases including heat and cold, sore throat, fever, fungal infection, inflammation, toothache, rheumatism, burn, analgesic, ulcer and urinary diseases. However, the effect of P. alkekengi var. franchetii on ulcer and Helicobacter pylori infection has not been reported to date.

AIM OF THE STUDY

This study was designed to investigate the anti-inflammatory, anti-ulcer, anti-Helicobacter pylori and analgesic properties of ethyl acetate fraction of the crude aqueous methanolic extract from the aerial parts of the plant P. alkekengi L. var. franchetii in rodents.

MATERIALS AND METHODS

Acute toxicity of the crude extract of P. alkekengi L. var. franchetii (PAF) was evaluated in rats. The petroleum ether fraction (PEF), butanol fraction (BF), ethyl acetate fraction (EAF) and aqueous fraction (AF) of crude aqueous methanolic extract from PAF were screened for anti-inflammatory and anti-ulcer potential at doses of 100, 250 and 500mg/kg (p.o.), using carrageenin-induced hind paw edema and ethanol-induced gastric lesions test in rats. In vitro anti-Helicobacter pylori activity of EAF was assayed subsequently. In addition, three doses of EAF were evaluated for analgesic activity using hot plate and writhing tests, respectively. Finally, we performed a phytochemical analysis of EAF.

RESULTS

Four fractions of crude extract from PAF significantly reduced the paw volume in carrageenin-induced hind paw edema model at different doses (100, 250 and 500mg/kg, p.o.). The fraction EAF at a dose of 500mg/kg exhibited the highest (75.92%) (0.150 ± 0.045***, ***p < 0.001) anti-inflammatory potential, which is similar to indomethacin (***P < 0.001)（0.120 ± 0.014***, 80.74% inhibition of inflammation） at 5mg/kg. Pretreatment with EAF (500mg/kg, p.o.) significantly reduced the intensity of gastric mucosal damage and showed higher gastroprotective activity (90.6%) when compared to the standard drug famotidine (84.6%). In addition, EAF fraction also showed a moderate (P < 0.05) anti-Helicobacter pylori activity with a minimal inhibition concentration (MIC) of 500μg/ml. Furthermore, pain sensation was effectively inhibited at 500mg/kg, p.o. of EAF as manifested by an increase (p < 0.001) of latency time in hot plate from 30 to 90min and a decrease (p < 0.001) in count of writhing induced by acetic acid. By HPLC, we determined some steroid, terpenoid and flavonoids (four compounds): kaempferol, quercetin, Blumenol A and physalindicanols A, which were isolated from the ethyl acetate fraction and identified using ¹H NMR and ¹³C NMR spectra analysis.

CONCLUSION

This study demonstrated the anti-inflammatory, anti-ulcer, anti-Helicobacter pylori and analgesic properties of EAF of the crude extract from PAF thus justifying its traditional usage.

Natural Flavonoids as Promising Analgesic Candidates: A Systematic Review

Due to the chemical structural diversity and various analgesic mechanisms, an increasing number of studies indicated that some flavonoids from medicinal plants could be promising candidates for new natural analgesic drugs, which attract high interests of advanced users and academic researchers. The aim of this systematic review is to report flavonoids and its derivatives as new analgesic candidates based on the pharmacological evidences. Sixty-four papers were found concerning the potential analgesic activity of 46 flavonoids. In this case, the evidence for analgesic activity of flavonoids and total flavonoids was investigated. Meanwhile, the corresponding analgesic mechanism of flavonoids was discussed by generalizing and analyzing the current publications. Based on this review, the conclusion can be drawn that some flavonoids are promising candidates for painful conditions and deserve particular attention in further research and development.

Pharmacological activity of Costus spicatus in experimental Bothrops atrox envenomation

CONTEXT

Medicinal plants encompass a rich source of active compounds that can neutralize snake venoms or toxins. Costus spicatus (Jacq.) Sw. (Costaceae) is used by the Amazonian population to treat inflammation, pain and other pathological manifestations.

OBJECTIVE

To evaluate the influence of C. spicatus aqueous extract on edema, peritonitis, nociception, coagulation, haemorrhage and indirect haemolytic activity induced by Bothrops atrox venom (BAV).

MATERIALS AND METHODS

Dried and pulverized leaves were extracted with distilled water. Envenoming was induced by administration of B. atrox snake venom in Swiss Webster mice. The experimental groups consisted of BAV (at the minimum dose to induce measurable biological responses) and C. spicatus extract (CSE, 1.25, 2.5, 5.0, 7.5 and 10 mg/kg/25 μl phosphate-buffered saline) administered individually and in combination (BAVCSE). PBS was used as a control. In vitro assays were also conducted in order to evaluate phospholipase A2 coagulant activities (indirect haemolytic method).

RESULTS

CSE significantly reduced the venom-induced edema and nociception at all concentrations tested and inhibited migration of inflammatory cells at the three least concentrations (5.0, 7.5 and 10 mg/kg/25 μl PBS). CSE was not effective in inhibiting coagulant, haemorrhagic and indirect haemolytic activities of the venom.

DISCUSSION AND CONCLUSION

The data suggest that CSE could exhibit a central mechanism for pain inhibition, and may also inhibit prostaglandin synthesis. These findings corroborate the traditional administration of C. spicatus decoction to treat inflammatory disorders, including those caused by B. atrox envenomation.

Antinociceptive activity of Tibouchina pereirae, an endemic plant from the Brazilian semiarid region

The anti-nociceptive activity of an extract of Tibouchina pereirae Aubl (AETP) was investigated using two models of chemically induced pain, viz. the acetic acid-induced writhing and the formalin test, respectively, with dipyrone and indomethacin as reference drugs, respectively. In the acetic acid-induced writhing test, AETP application (100 mg/kg) caused a significant reduction of writhing produced by acetic acid. In the formalin test, AETP reduced the formalin effects significantly only in the late phase. These findings thus indicate the involvement of AETP only in peripheral antinociceptive mechanisms. In addition, AETP exhibited good antioxidant activity (EC50 approx. 15 μg/mL) in the DPPH free radical scavenging assay.

Two new triterpenoid estersaponins and biological activities of Pittosporum tobira 'Variegata' (Thunb.) W. T. Aiton leaves

Two new triterpenoid estersaponins (1, 2) were isolated from the leaves of Pittosporum tobira 'Variegata' (Thunb.) W. T. Aiton, along with one known saponin (3) and one known flavonoid glycoside (4). Their structures were established by different spectroscopic methods including 1D and 2D NMR, UV, as well as ESI-MS analysis. The investigated 80% aqueous methanol extract showed significant dose dependent inhibition of acetic acid induced abdominal writhing in mice. The n-butanol fraction exerted moderate antimicrobial activity against Staphylococcus aureus and Escherichia coli. In addition, it showed in vitro antioxidant activity with IC50 value (7.3 μg/ml) lower than that of the positive control ascorbic acid (11.2 μg/ml), using DPPH free radical scavenging activity method. Evaluation of its in vitro cytotoxicity showed strong activity against breast carcinoma (MCF-7), hepatocellular carcinoma (HepG2), and colon carcinoma (HCT) cell lines.

Antinociceptive effects of hydroalcoholic extract from Euterpe oleracea Mart. (Açaí) in a rodent model of acute and neuropathic pain

Background

Plants rich in flavonoids, such as açaí (Euterpe oleraceae Mart.), can induce antinociception in experimental animals. Here, we tested an extract obtained from the stones of açaí fruits (açaí stone extract, ASE), a native plant from the Amazon region of Brazil, in models of acute/inflammatory and chronic pain.

Methods

Antinociceptive effects of ASE were evaluated in the hot plate, formalin, acetic acid writhing, carrageenan, and neuropathic pain models, as well as in thermal hyperalgesia and mechanical allodynia models induced by spinal nerve ligation. Antinociceptive activities were modulated by the administration of cholinergic, adrenergic, opioid, and L-arginine-NO antagonists.

Results

Oral administration of ASE (30, 100, or 300 mg.kg⁻¹) dose-dependently reduced nociceptive responses to acute/inflammatory pain in mice, including thermal hyperalgesia, acetic acid-induced writhing, and carrageenan-induced thermal hyperalgesia. Moreover, ASE reduced the neurogenic and inflammatory phases after intraplantar injection of formalin in mice. The antinociceptive effect of ASE (100 mg · kg⁻¹) in a hot plate protocol, was inhibited by pre-treatment with naloxone (1 mg · kg⁻¹), atropine (2 mg · kg⁻¹), yohimbine (5 mg · kg⁻¹), or L-NAME (30 mg · kg⁻¹). Furthermore, ASE prevented chronic pain in a rat spinal nerve ligation model, including thermal hyperalgesia and mechanical allodynia.

Conclusion

ASE showed significant antinociceptive effect via a multifactorial mechanism of action, indicating that the extract may be useful in the development of new analgesic drugs.

Kaempferol, a potential cytostatic and cure for inflammatory disorders

Kaempferol (3,5,7-trihydroxy-2-(4-hydroxyphenyl)-4H-1-benzopyran-4-one) is a flavonoid found in many edible plants (e.g., tea, broccoli, cabbage, kale, beans, endive, leek, tomato, strawberries, and grapes) and in plants or botanical products commonly used in traditional medicine (e.g., Ginkgo biloba, Tilia spp, Equisetum spp, Moringa oleifera, Sophora japonica and propolis). Its anti-oxidant/anti-inflammatory effects have been demonstrated in various disease models, including those for encephalomyelitis, diabetes, asthma, and carcinogenesis. Moreover, kaempferol act as a scavenger of free radicals and superoxide radicals as well as preserve the activity of various anti-oxidant enzymes such as catalase, glutathione peroxidase, and glutathione-S-transferase. The anticancer effect of this flavonoid is mediated through different modes of action, including anti-proliferation, apoptosis induction, cell-cycle arrest, generation of reactive oxygen species (ROS), and anti-metastasis/anti-angiogenesis activities. In addition, kaempferol was found to exhibit its anticancer activity through the modulation of multiple molecular targets including p53 and STAT3, through the activation of caspases, and through the generation of ROS. The anti-tumor effects of kaempferol have also been investigated in tumor-bearing mice. The combination of kaempferol and conventional chemotherapeutic drugs produces a greater therapeutic effect than the latter, as well as reduces the toxicity of the latter. In this review, we summarize the anti-oxidant/anti-inflammatory and anticancer effects of kaempferol with a focus on its molecular targets and the possible use of this flavonoid for the treatment of inflammatory diseases and cancer.

Evaluation of antinociceptive effect of Aegiceras corniculatum stems extracts and its possible mechanism of action in rodents

ETHNOPHARMACOLOGICAL RELEVANCE

Aegiceras corniculatum (Linn.) Blanco is used in various traditional medicinal system(s) for the treatment of rheumatism, painful arthritis and inflammation. Therefore, the pharmacological studies of its antinociceptive effect was undertaken to validate its traditional use.

MATERIALS AND METHODS

n-Hexane, ethyl acetate and methanol extract(s) derived from Aegiceras corniculatum (stems) were studied using various nociceptive model(s) induced chemically or thermally in mice including acetic acid-induced writhing, formalin-induced paw licking and hot plate test.

RESULTS

In acetic acid-induced writhing test, plant extracts dose dependently decreased the writhing numbers. The methanolic extract (1-10mg/kg, i.p. in mice) of the plant was more potent than acetaminophen and acetyl salicylic acid, with an IC(50) of 4.2 ± 0.99 mg/kg. Moreover, the time of nociceptive behaviors induced by intraplantar formalin injection was also suppressed during 1st and 2nd phases in the presence of ethyl acetate extract whereas, n-hexane and methanolic extracts inhibited the paw licking in mice during the 1st (IC(50) 12 ± 0.76 mg/kg) and 2nd phases (IC(50) 3.8 ± 0.55 mg/kg). Naloxone, β-funaltrexamine, and naltrindole antagonized the n-hexane extract-induced antinociception in the first phase of formalin test indicating its non-selective analgesic response via opioid receptor(s). However, ethyl acetate extract was devoid of any opioid action. Additionally, these extracts significantly inhibited the pain stimulation in hot plate test. Withdrawal syndrome of morphine dependence was also diminished in the presence of plant extracts via potentiation of GABAergic system.

CONCLUSION

These results suggested that Aegiceras corniculatum extract(s) possesses analgesic properties and acts on the central nervous system, thereby suppressing the inflammatory pain justifying its folklore use.

Antinociceptive and anti-inflammatory effects of Costus spicatus in experimental animals

CONTEXT

Costus spicatus Swartz (Costaceae), commonly called "cana-do-brejo'" in Brazil's northeast, is a medicinal plant found in wet coastal forests. In folk medicine an infusion of the aerial parts is taken to treat inflammation and pain.

OBJECTIVE

The methanol extract obtained from the leaves of Costus spicatus (MECs) was evaluated for antinociceptive and anti-inflammatory activities.

METHODS

Analgesic and anti-inflammatory activities were studied by measuring nociception through acetic acid, formalin, and hot-plate tests, while inflammation was induced by carrageenan. All experiments were conducted with experimental animals.

RESULTS AND DISCUSSION

Following oral administration, MECs (100, 200, and 400 mg/kg) significantly reduced the number of writhes (52.8, 43.1, and 55.3%, respectively) in the writhing test and the number of paw licks during phase 1 (61.9, 54.1, and 92.1%) and phase 2 (62.5, 82.9, and 98.1%, all doses) during the formalin test when compared to the control group animals. The reaction time during the hot-plate test was increased significantly and was dose-dependent, whereas pretreatment with naloxone rigorously reduced the analgesic potential of MECs, which suggested participation of the opioid system in the modulation of pain induced by MECs. Such results were unlikely to be provoked by motor abnormality, as MECs-treated mice did not exhibit any performance alteration during the Rota-rod test. The administration of 200 and 400 mg/ kg (i.p.) of MECs exhibited an anti-inflammatory effect during the carrageenan test, which was based on interference with inflammatory mediator synthesis.

CONCLUSION

We conclude that MECs has antinociceptive and anti-inflammatory activities in rodents.

Dark chocolate receptors: epicatechin-induced cardiac protection is dependent on delta-opioid receptor stimulation

Epicatechin, a flavonoid, is a well-known antioxidant linked to a variety of protective effects in both humans and animals. In particular, its role in protection against cardiovascular disease has been demonstrated by epidemiologic studies. Low-dose epicatechin, which does not have significant antioxidant activity, is also protective; however, the mechanism by which low-dose epicatechin induces this effect is unknown. Our laboratory tested the hypothesis that low-dose epicatechin mediates cardiac protection via opioid receptor activation. C57BL/6 mice were randomly assigned to 1 of 10 groups: control, epicatechin, naloxone (nonselective opioid receptor antagonist), epicatechin + naloxone, naltrindole (δ-specific opioid receptor antagonist), epicatechin + naltrindole, norbinaltorphimine (nor-BNI, κ-specific opioid receptor antagonist), epicatechin + nor-BNI, 5-hydroxydecanoic acid [5-HD, ATP-sensitive potassium channel antagonist], and epicatechin + 5-HD. Epicatechin (1 mg/kg) or other inhibitors (5 mg/kg) were administered by oral gavage or intraperitoneal injection, respectively, daily for 10 days. Mice were subjected to 30 min coronary artery occlusion followed by 2 h of reperfusion, and infarct size was determined via planimetry. Whole heart homogenates were assayed for downstream opioid receptor signaling targets. Infarct size was significantly reduced in epicatechin- and epicatechin + nor-BNI-treated mice compared with control mice. This protection was blocked by naloxone, naltrindole, and 5-HD. Epicatechin and epicatechin + nor-BNI increased the phosphorylation of Src, Akt, and IκBα, while simultaneously decreasing the expression of c-Jun NH(2)-terminal kinase and caspase-activated DNase. All signaling effects are consistent with opioid receptor stimulation and subsequent cardiac protection. Naloxone, naltrindole, and 5-HD attenuated these effects. In conclusion, epicatechin acts via opioid receptors and more specifically through the δ-opioid receptor to produce cardiac protection from ischemia-reperfusion injury.

Effects of hawthorn seed and pulp extracts on the central nervous system

CONTEXT

Investigating potential central nervous system (CNS) activities of Crataegus monogyna Jacq. (Rosaceae), hawthorn, fruit extracts.

OBJECTIVE

Evaluating CNS effects and analgesic activities of hawthorn fruit extracts based on the traditional uses of the plant for neurosedative and pain killer actions.

MATERIALS AND METHODS

Effects of hawthorn pulp (HPE) and seed extracts (HSE) at the dose range of 1-1000 mg/kg were examined on anxiety level, spontaneous locomotor activity, motor coordination, and nociceptive perception of mice. Morphine was used as a reference drug.

RESULTS

HPE (100-1000 mg/kg) and HSE (10-1000 mg/kg) significantly decreased not only the exploratory behaviors in hole-board experiments, but also the spontaneous locomotor activities in activity cage tests. The same doses of extracts were found to be ineffective in Rota-Rod tests of mice. In tail-clip, hot-plate, and acetic acid-induced writhing tests, quite potent and dose-dependent analgesic activities were seen at 100-1000 mg/kg doses of HPE and 10-1000 mg/kg doses of HSE. Analgesic effects observed in all analgesia tests were antagonized by naloxone.

DISCUSSION

Significant and dose-dependent decreases in spontaneous locomotor activities and exploratory behaviors of animals suggested CNS depressant activities of both extracts. Complete naloxone antagonism in all applied analgesia tests indicated opioid-related analgesic activities of both extracts.

CONCLUSION

These findings seem to support the traditional use of this plant to treat stress, nervousness, sleep disorders, and pain control.

Pinostrobin from Cajanus cajan (L.) Millsp. inhibits sodium channel-activated depolarization of mouse brain synaptoneurosomes

This investigation focuses on the in vitro neuroactive properties of pinostrobin, a substituted flavanone from Cajanus cajan (L.) Millsp. of the Fabaceae family. We demonstrate that pinostrobin inhibits voltage-gated sodium channels of mammalian brain (IC(50)=23 µM) based on the ability of this substance to suppress the depolarizing effects of the sodium channel-selective activator veratridine in a synaptoneurosomal preparation from mouse brain. The resting membrane potential of synaptoneurosomes was unaffected by pinostrobin. The pharmacological profile of pinostrobin resembles that of depressant drugs that block sodium channels.

An anti-ulcerogenic flavonol diglucoside from Equisetum palustre L

ETHNOPHARMACOLOGICAL RELEVANCE

The aerial parts of Eqiusetum palustre L. is used to treat peptic ulcer in Karaman, Turkey.

AIM OF THE STUDY

The present study was undertaken to evaluate the in vivo gastroprotective potential and structure elucidation of the active constituent(s) through bioassay-guided fractionation procedures by using ethanol (EtOH)-induced ulcerogenesis model in rats.

MATERIAL AND METHODS

The 80% ethanol extract of the aerial parts was subjected to subsequent separation procedures such as solvent-solvent partition and column chromatography through bioassay-guided fractionation techniques to isolate the active anti-ulcer component(s) by using the EtOH-induced ulcer model in rats. The ulcer index was used to evaluate and to calculate the gastroprotection percentage.

RESULTS

The subextracts, n-butanol and remaining H2O, of Equisetum palustre showed potent in vivo gastroprotective activity. Bioassay-guided fractionation has revealed that a flavonol diglucoside, was isolated as an active constituent from the n-BuOH subextract of Equisetum palustre. Structure elucidation by standard spectroscopic techniques (1H NMR, 13C NMR and DEPT, etc.) revealed that this compound as kaempferol-3-O-1''-beta-d-glucopyranosyl-3-O-1'''-beta-D-glucopyranoside, which provided remarkable protection at 250 and 500 mg/kg doses (69.5 and 98.5% ulcer inhibition, respectively) against ethanol-induced gastric lesions.

CONCLUSION

Experimental data confirmed the ethnobotanical usage of Equisetum palustre, with scientific evidence, in Turkey. Additionally, kaempferol-3-O-1''-beta-D-glucopyranosyl-3-O-1'''-beta-D-glucopyranoside, a known compound, was defined as an anti-ulcerogenic compound in the present work for the first time.

Therapeutic Potential of Kalanchoe Species: Flavonoids and other Secondary Metabolites

The Kalanchoe genus (syn. Bryophyllum), family Crassulaceae, comprises 125 species, most of them native to Madagascar. The great importance of several of these species for the traditional medicine in several regions of the World, esspecially India, Africa, China and Brazil, stimulated research programs into these plants from both a pharmacological and chemical point of view. The present review focuses on the main results obtained during the last decade on the secondary metabolites isolated from these species – endowed or not with a specific biological profile – with emphasis on flavonoids. The distribution of these molecules in the genus will be summarized and special attention will be given to K. brasiliensis and K. pinnata, two species well-known for healing inflammatory and infectious processes. Ornamental Kalanchoe species are also discussed as a potential source of bioactive compounds. This review covers the period 1970–2008.

Endogenous opiates and behavior: 2007

This paper is the thirtieth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2007 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses.