Kratom (Mitragyna speciosa): User demographics, use patterns, and implications for the opioid epidemic.

BACKGROUND: Kratom, a Southeast Asian plant with opioid-receptor mediated effects, has emerged as a potential substance of abuse, with limited data on its use and effects. This study characterized kratom user demographics, use patterns, and perceived drug effects. METHODS: A cross-sectional, anonymous online survey was conducted between January and December 2017. RESULTS: 2,798 kratom users - mean age 40 (SD = 12); predominantly White (90 %), female (61 %), and located in the US (97 %) - completed the survey. Kratom was primarily taken orally in doses of 1-3 g (49 %), with daily use (59 %) being most common. Kratom was used for pain (91 %), anxiety (67 %), and depression (65 %), with high ratings of effectiveness. 1,144 (41 %) used kratom to stop or reduce prescription or illicit opioid use, citing decreased opioid withdrawal and craving related to kratom use, with 411 reporting >1-year continuous abstinence from opioids attributed to kratom use. Roughly one-third of respondents reported adverse effects of kratom, largely rated as mild in severity and lasting ≤24 h. Seventeen participants (0.6 %) sought treatment for adverse effects. Fifty-six individuals (2 %) met DSM-5 criteria for a past-year moderate or severe kratom-related substance use disorder (SUD). When asked how troubled they felt regarding their kratom use, the mean (SD) rating was 3.2 (9.8) on a scale from 0 to 100. CONCLUSION: Kratom is used among White, middle-aged Americans for symptoms of pain, anxiety, depression, and opioid withdrawal. Although regular use was typical, kratom-related SUD and serious adverse effects were uncommon. Additional research on kratom epidemiology and pharmacology is imperative in light of the present opioid epidemic.

Blockade of T-type calcium channels by 6-prenylnaringenin, a hop component, alleviates neuropathic and visceral pain in mice.

Since Cav3.2 T-type Ca2+ channels (T-channels) expressed in the primary afferents and CNS contribute to intractable pain, we explored T-channel-blocking components in distinct herbal extracts using a whole-cell patch-clamp technique in HEK293 cells stably expressing Cav3.2 or Cav3.1, and purified and identified sophoraflavanone G (SG) as an active compound from SOPHORAE RADIX (SR). Interestingly, hop-derived SG analogues, (2S)-6-prenylnaringenin (6-PNG) and (2S)-8-PNG, but not naringenin, also blocked T-channels; IC50 (µM) of SG, (2S)-6-PNG and (2S)-8-PNG was 0.68-0.75 for Cav3.2 and 0.99-1.41 for Cav3.1. (2S)-6-PNG and (2S)-8-PNG, but not SG, exhibited reversible inhibition. The racemic (2R/S)-6-PNG as well as (2S)-6-PNG potently blocked Cav3.2, but exhibited minor effect on high-voltage-activated Ca2+ channels and voltage-gated Na+ channels in differentiated NG108-15 cells. In mice, the mechanical allodynia following intraplantar (i.pl.) administration of an H2S donor was abolished by oral or i.p. SR extract and by i.pl. SG, (2S)-6-PNG or (2S)-8-PNG, but not naringenin. Intraperitoneal (2R/S)-6-PNG strongly suppressed visceral pain and spinal ERK phosphorylation following intracolonic administration of an H2S donor in mice. (2R/S)-6-PNG, administered i.pl. or i.p., suppressed the neuropathic allodynia induced by partial sciatic nerve ligation or oxaliplatin, an anti-cancer agent, in mice. (2R/S)-6-PNG had little or no effect on open-field behavior, motor performance or cardiovascular function in mice, and on the contractility of isolated rat aorta. (2R/S)-6-PNG, but not SG, was detectable in the brain after their i.p. administration in mice. Our data suggest that 6-PNG, a hop component, blocks T-channels, and alleviates neuropathic and visceral pain with little side effects.

Potential Uses of Isolated Toxin Peptides in Neuropathic Pain Relief: A Literature Review.

Neuropathic pain is a subset of chronic pain that is caused by neurons that are damaged or firing aberrantly in the peripheral or central nervous systems. The treatment guidelines for neuropathic pain include antidepressants, calcium channel α2 delta ligands, topical therapy, and opioids as a second-line option. Pharmacotherapy has not been effective in the treatment of neuropathic pain except in the treatment of trigeminal neuralgia with carbamazepine. The inability to properly treat neuropathic pain causes frustration in both the patients and their treating physicians. Venoms, which are classically believed to be causes of pain and death, have peptide components that have been implicated in pain relief. Although some venoms are efficacious and have shown benefits in patients, their side-effect profile precludes their more widespread use. This review identifies and explores the use of venoms in neuropathic pain relief. This treatment can open doors to potential therapeutic targets. We believe that further research into the mechanisms of action of these receptors as well as their functions in nature will provide alternative therapies as well as a window into how they affect neuropathic pain.

Analgesic activity of Gleditsia triacanthos methanolic fruit extract and its saponin-containing fraction.

CONTEXT: Gleditsia triacanthos L. (Leguminosae) pods are used in folk medicine for pain relief as anodyne and narcotic. OBJECTIVE: The objective of this study is to evaluate analgesic activity of Gleditsia triacanthos methanolic fruit extract (MEGT) and its saponin-containing fraction (SFGT). MATERIALS AND METHODS: Peripheral analgesic activity was assessed using the acetic acid-induced writhing model in mice at doses of 140, 280, and 560 mg/kg and formalin test in rats at 100, 200, and 400 mg/kg doses. Central analgesic activity was evaluated using the hotplate method in rats (100, 200, and 400 mg/kg). RESULTS: In the writhing test, six mice groups treated with MEGT and SFGT found ED50 values 268.2 and 161.2 mg/kg, respectively, displayed a significant decrease in writhing count compared with the group treated with standard drug indomethacin (14 mg/kg). SFGT (280 and 560 mg/kg) showed 64.94 and 70.78% protection, respectively, which are more than double % protection caused by indomethacin (31.82%). In the formalin test, MEGT and SFGT (ED50 values 287.6 and 283.4 mg/kg for phase I as well as 295.1 and 290.4 mg/kg for phase II, respectively) at 400 mg/kg showed significant % inhibition in both phase I (18.86 and 52.57%) and phase II (39.36 and 44.29%) with reference to 10 mg/kg indomethacin (56.0 and 32.29%). MEGT and SFGT caused significant delay in responses in hotplate model (ED50 values 155.4 and 200.6 mg/kg, respectively) compared with that of 10 mg/kg indomethacin at 30, 60, and 120 min. DISCUSSION AND CONCLUSION: Central and peripheral analgesic activities induced by Gleditsia triacanthos fruits might account for its uses in folk medicine.

Effect of ethanolic extracts of Justicia neesii Ramam. against experimental models of pain and pyrexia.

OBJECTIVE: The main objective of this study is to evaluate the analgesic and anti-pyretic activities of ethanolic extracts of Justicia neesii Ramam. by different experimental models. MATERIALS AND METHODS: The analgesic activity of plant extract was evaluated against thermal and chemical stimulus induced by Eddy's hot plate and acetic acid respectively in mice. Brewer's yeast induced pyrexia was used to evaluate the antipyretic activity in rats and TAB vaccine induced pyrexia was used to evaluate the antipyretic activity in rabbits. RESULTS: In the hot plate model 400 mg/kg p.o. dose of J. neesii has shown its maximal effect at 3 h. The results are significant (P < 0.05) and comparable to the values of standard drug pentazocine (30 mg/kg i.p.). In acetic acid induced writhing model 400 mg/kg p.o. of plant extracts have shown highly significant activity (P < 0.001) and better than standard drug indomethacin (10 mg/kg p.o.). The 400 mg/kg p.o. dose of plant extract has given significant results against both yeast induced pyrexia and TAB vaccine induced pyrexia (P< 0.01 and 0.05 respectively). These values are comparable to that of paracetamol 100 mg/kg p.o. standard dose. CONCLUSION: This study shows that the ethanol extract of J. neesii has significant analgesic and antipyretic activity.

[Mechanism of catalytic ozonation for the degradation of paracetamol by activated carbon].

The degradation of paracetamol (APAP) in aqueous solution was studied with ozonation integrated with activated carbon (AC). The synergistic effect of ozonation/AC process was explored by comparing the degradation efficiency of APAP in three processes (ozonation alone, activated carbon alone and ozonation integrated with activated carbon). The operational parameters that affected the reaction rate were carefully optimized. Based on the intermediates detected, the possible pathway for catalytic degradation was discussed and the reaction mechanism was also investigated. The results showed that the TOC removal reached 55.11% at 60 min in the AC/O3 system, and was significantly better than the sum of ozonation alone (20.22%) and activated carbon alone (27.39%), showing the great synergistic effect. And the BOD5/COD ratio increased from 0.086 (before reaction) to 0.543 (after reaction), indicating that the biodegradability was also greatly improved. The effects of the initial concentration of APAP, pH value, ozone dosage and AC dosage on the variation of reaction rate were carefully discussed. The catalytic reaction mechanism was different at different pH values: the organic pollutions were removed by adsorption and direct ozone oxidation at acidic pH, and mainly by catalytic ozonation at alkaline pH.

Anti-inflammatory and analgesic effects of egg yolk: a comparison between organic and machine made.

OBJECTIVES: Yolk composition may be influenced by the bird's dietary intake. Quality of egg yolk from different sources is also varied. Especially egg yolk from organic sources, those prepared by the hen and duck were naturally fed. Traditional medicine users in north of Iran believe the oil extracted by direct heat from egg yolk has analgesic activity. In this work anti-inflammatory and antinociceptive activities of organic and machine made hen yolk and duck yolk were evaluated. MATERIALS AND METHODS: Three various sources of egg yolk (organic hens, duck and machine made) were chosen. Each yolk was extracted by two methods, solvent extraction (hexane) and direct heating. In order to investigate the analgesic and anti-inflammatory activity, carageenan, hot plate and writhing tests were carried out. RESULTS: The organic hen and duck oil extracted by direct heat method showed the highest activity compared to other types. Organic sources may contain some special components which are not existed in machine made eggs. Oil samples obtained by direct heat from three different kinds of egg yolk showed significant anti-inflammatory activity at 100-300 mg/kg compared to controls (p < 0.001). All samples indicated analgesic properties at all doses in writhing test. The highest activity was seen at 300 mg/kg of organic hen egg yolk oil prepared by heat (HO) and hexane extract of duck egg yolk (ED) which was similar to 5 mg/kg morphine (p > 0.001). In hot plate test all of the oil samples did not show significant difference with controls. Hexane extract of organic egg yolk (EO) (300 mg/kg) and ED (200 and 300 mg/kg) showed significant analgesic activity in hot plate test. CONCLUSIONS: This study confirms anti-inflammatory and analgesic scheme of yolk. We can also claim environmental and dietary condition is very important in yolk contents. In order to improve life quality of human beings and better efficiency for egg yolk components we suggest considering the way of feeding for poultry. We can propose organic yolk oil prepared by direct heat as an alternative remedy for inflammatory joint conditions.  

The medical plant butterbur (Petasites): analytical and physiological (re)view.

Butterbur (Petasites) is an ancient plant which has been used for medical and edible purposes with its spasmolytic agents. However, toxic alkaloid content of the plant limits its direct usage. The paper covers the pyrrolizidine alkaloids (PAs) and butterbur themes in detail in order to display the outline of alkaloid-free plant extract production for medical and edible purposes. The toxic PAs and medicinal constituents of the plant are described with emphasis on analytics, physiological effects and published patent data on alkaloid free extract production. The analytics is based on several commonly used analytical methods including liquid chromatography-mass spectrometry, gas chromatography-mass spectrometry and enzyme linked immunoassay analysis of PAs and N-oxides based on published literature data of butterbur. The analyses of major medicinal constituents of butterbur are given and the physiological effects of these compounds have been discussed to attract attention to the importance of alkaloid-free extract production. The concentration distributions of the medicinal constituents and toxic PAs in different parts of the plant and the outcomes of the published patent data provide comprehensive information for proper plant raw-material selection and production of alkaloid-free butterbur extracts. The review is intended to guide researchers interested in medical plant extracts by providing comprehensive data on the medical plant butterbur and its chemical constituents.

Liquid-phase microextraction in a microfluidic-chip--high enrichment and sample clean-up from small sample volumes based on three-phase extraction.

In this work, a microfluidic-chip based system for liquid-phase microextraction (LPME-chip) was developed. Sample solutions were pumped into the LPME-chip with a micro-syringe pump at a flow rate of 3-4 µL min(-1). Inside the LPME chip, the sample was in direct contact with a supported liquid membrane (SLM) composed of 0.2 µL dodecyl acetate immobilized in the pores of a flat membrane of polypropylene (25 µm thickness). On the other side of the SLM, the acceptor phase was present. The acceptor phase was either pumped at 1 µL min(-1) during extraction or kept stagnant (stop-flow). Amitriptyline, methadone, haloperidol, loperamide, and pethidine were selected as model analytes, and they were extracted from alkaline sample solution, through the SLM, and into 10 mM HCl or 100mM HCOOH functioning as acceptor phase. Subsequently, the acceptor phase was either analyzed off-line by capillary electrophoresis for exact quantification, or on-line by UV detection or electrospray ionization mass spectrometry for time profiling of concentrations. The LPME-chip was found to be highly effective, and extraction efficiencies were in the range of 52-91%. When the flow of acceptor phase was turned off during extraction (stop-flow), analyte enrichment increased linearly with the extraction time. After 10 min as an example, amitriptyline was enriched by a factor of 42 from only 30 µL sample solution, and after 120 min amitriptyline was enriched by a factor of 500 from 320 µL sample solution. This suggested that the LPME-chip has great potentials for very efficient analyte enrichments from limited sample volumes in the future.

Oxidative removal of acetaminophen using zero valent aluminum-acid system: efficacy, influencing factors, and reaction mechanism.

Commercial available zero valent aluminum under air-equilibrated acidic conditions (ZVA1/H+/air system) demonstrated an excellent capacity to remove aqueous organic compounds. Acetaminophen (ACTM), the active ingredient of the over-the-counter drug Tylenol, is widely present in the aquatic environment and therefore the treatment of ACTM-contaminated water calls for further research. Herein we investigated the oxidative removal of ACTM by ZVA1/H+/air system and the reaction mechanism. In acidic solutions (pH < 3.5), ZVA1 displayed an excellent capacity to remove ACTM. More than 99% of ACTM was eliminated within 16 hr in pH 1.5 reaction solutions initially containing 2.0 g/L aluminum and 2.0 mg/L ACTM at 25 +/- 1 degree C. Higher temperature and lower pH facilitated ACTM removal. The addition of different iron species Fe0, Fe2+ and Fe3+ into ZVA1/H+/air system dramatically accelerated the reaction likely due to the enhancing transformation of H2O2 to HO. via Fenton's reaction. Furthermore, the primary intermediate hydroquinone and the anions formate, acetate and nitrate, were identified and a possible reaction scheme was proposed. This work suggested that ZVA1/H+/air system may be potentially employed to treat ACTM-contaminated water.

Phytochemical analysis and antinociceptive properties of the seeds of Garcinia achachairu.

In a search for new and effective analgesic substances from the Brazilian biodiversity, the present study evaluates the chemical composition and antinociceptive potential of the methanol extract and a pure compound obtained from the seeds of Garcinia achachairu Rusby (Clusiaceae). The methanolic seed extract was directly subjected to purification by column chromatography and the purification was monitored by thin-layer chromatography. The main isolated compound was identified as Guttiferone A by comparison of conventional spectroscopic data (IR, NMR-(1)H and (13)C) to the literature data which was isolated for the first time from this plant. When evaluated in the acetic acid-induced nociception model in mice, the methanolic seed extract had an ID(50) (Inhibitory dose) of 13.1 (11.23-14.91) mg/kg and a maximal inhibition of 72 ± 4%. In the same model, Guttiferone A had an ID(50) of 4.54 (3.29-6.24) mg/kg and a maximal inhibition of 73 ± 5%. The methanolic seed extract and Guttiferone A were also active in pain models induced by formalin, capsaicin, glutamate and carrageenan. These data suggest that the antinociceptive effect of Guttiferone A partly depends on its interference with the synthesis or activity of the cytokine TNF-α, the keratinocyte-derived chemokine KC, and/or PGE(2). These data support, at least in part, the use of G. achachairu in folk medicine and suggest that this plant is an important source of compounds with a suitable profile for development as new and effective medicinal agents to treat pain processes.

Anti-nociceptive effects of Carpolobia lutea G. Don (Polygalaceae) leaf fractions in animal models.

Leaves from Carpolobia lutea (Polygalaceae) were screened to establish the antiulcer ethnomedicinal claim and to quantitatively isolate, elucidate the active compounds by semi-preparative HPLC. The anti-nociceptive effects of Carpolobia lutea (CL) G. Don (Polygalaceae) organic leaf extracts were tested in experimental models in mice. The anti-nociceptive mechanism was determined using tail-flick test, acetic acid-induced abdominal constrictions, formalin-induced hind paw licking and the hot plate test. The fractions (ethanol, ethyl acetate, chloroform, n-hexane) and crude ethyl acetate extract of CL (770 mg/kg, i.p.) produced significant inhibitions of both phases of the formalin-induced pain in mice, a reduction in acetic acid-induced writhing as well as and an elevation of the pain threshold in the hot plate test in mice. The inhibitions were greater to those produced by indomethacin (5 mg/kg, i.p.). Ethyl acetate fraction revealed cinnamic and coumaric acids derivatives, which are described for the first time in literature. These cinnamalglucosides polyphenols characterised from CL may in part account for the pharmacological activities. These findings confirm its ethnomedical use in anti-inflammatory pain and in pains from gastric ulcer-associated symptoms.

New phosphorus-containing spherical carbon adsorbents as promising materials in drug adsorption and release.

A simple method of preparation of new high surface area spherical carbon adsorbents is presented. The phosphoric acid activation upon hydrothermally formed spherules was employed to produce carbons having controlled high specific surface area (over 2100m(2)/g), large volumes of pores (1.2cm(3)/g), and high acidity. Prepared from sucrose materials show high adsorption capacities (i.e. 220mg/g(C)) toward paracetamol. It is proved that for these materials the contents of surface phosphorus are responsible for the reversibility of drug adsorption/release process.

Anti-inflammatory, analgesic and antipyretic activities of Linum usitatissimum L. (flaxseed/linseed) fixed oil.

The fixed oil of L. usitatissimum (flaxseed/linseed) inhibited PGE2-, leukotriene-, histamine- and bradykinin-induced inflammation. The oil also inhibited arachidonic acid-induced inflammation, suggesting its capacity to inhibit both cyclooxygenase and lipoxygenase pathways of arachidonate metabolism. In tail immersion model, the oil raised the pain threshold to a lesser extent than morphine but showed excellent peripherally acting, analgesic activity comparable to aspirin, against acetic acid-induced writhing in mouse. In typhoid paratyphoid A/B vaccine-induced pyrexia, the oil showed antipyretic activity comparable to aspirin. The oil contains 57.38% alpha-linolenic acid. Dual inhibition of arachidonic acid metabolism, antihistaminic and antibradykinin activities of the oil could account for the biological activity and the active principle could be alpha-linolenic acid an omega-3 (18:3, n-3) fatty acid.

Automatic twin vessel recrystallizer. Effective purification of acetaminophen by successive automatic recrystallization and absolute determination of purity by DSC.

I describe an interchangeable twin vessel (J, N) automatic glass recrystallizer that eliminates the time-consuming recovery and recycling of crystals for repeated recrystallization. The sample goes in the dissolution vessel J containing a magnetic stir-bar K; J is clamped to the upper joint H of recrystallizer body D. Empty crystallization vessel N is clamped to the lower joint M. Pure solvent is delivered to the dissolution vessel and the crystallization vessel via the head of the condenser A. Crystallization vessel is heated (P). The dissolution reservoir is stirred and heated by the solvent vapor (F). Continuous outflow of filtrate E out of J keeps N at a stable boiling temperature. This results in efficient dissolution, evaporation and separation of pure crystals Q. Pure solvent in the dissolution reservoir is recovered by suction. Empty dissolution and crystallization vessels are detached. Stirrer magnet is transferred to the crystallization vessel and the role of the vessels are then reversed. Evacuating mother liquor out of the upper twin vessel, the apparatus unit is ready for the next automatic recrystallization by refilling twin vessels with pure solvent. We show successive automatic recrystallization of acetaminophen from diethyl ether obtaining acetaminophen of higher melting temperatures than USP and JP reference standards by 8× automatic recrystallization, 96% yield at each stage. Also, I demonstrate a novel approach to the determination of absolute purity by combining the successive automatic recrystallization with differential scanning calorimetry (DSC) measurement requiring no reference standards. This involves the measurement of the criterial melting temperature T(0) corresponding to the 100% pure material and quantitative ΔT in DSC based on the van't Hoff law of melting point depression. The purity of six commercial acetaminophen samples and reference standards and an eight times recrystallized product evaluated were 98.8 mol%, 97.9 mol%, 99.1 mol%, 98.3 mol%, 98.4 mol%, 98.5 mol% and 99.3 mol% respectively.

Ginger (Zingiber officinale Roscoe) elicits antinociceptive properties and potentiates morphine-induced analgesia in the rat radiant heat tail-flick test.

Ginger (Zingiber officinale Roscoe), a well-known spice plant, has been used traditionally in the treatment of a wide variety of ailments. It has been shown that ginger is a calcium channel blocker; however, its influence on morphine analgesic effects has not been elucidated. We examined the effect of ginger root extract on nociceptive threshold and morphine-induced analgesia in male Wistar rats. To determine the effect of ginger on morphine analgesia, ginger extract (200, 400, and 600 mg/kg i.p.) was injected before a subeffective dose of morphine (2.5 mg/kg i.p.). The radiant heat tail-flick test was used to assess the nociceptive threshold before and at different times after drug administration. Our results showed that ginger extract elicited a significant antinociceptive effect. In addition, in groups that received both morphine and ginger, the observed analgesia was higher than that in groups treated with either morphine or ginger extract alone. Thus, the data indicate that ginger extract has a beneficial influence on morphine analgesia and can be an efficacious adjunct for pain management.

Anti-inflammatory, antinociceptive and antipyretic properties of the aqueous extract of Clematis brachiata leaf in male rats.

Clematis brachiata Thunb. (Ranunculaceae) is used as a folk remedy for the treatment of pain, fever and inflammatory ailments. Aqueous extract of Clematis brachiata leaf was screened for its phytochemical constituents. The anti-inflammatory investigations were carried out using carrageenan and histamine-induced edema models; acetic acid writhing, formalin-induced pain and tail immersion models were used to evaluate antinociceptive activity while a Brewer's yeast-induced hyperthermia model was employed for the antipyretic experiment. Phytochemical screening of the extract revealed the presence of tannins, saponins, flavonoids and cardiac glycosides. The extract at 100, 200 and 400 mg/kg body weight significantly (P<0.05) reduced the edema paw volumes induced by carrageenan and histamine with the 400 mg/kg body weight extract being the most potent. On the antinociceptive front, while the extract reduced the writhing caused by acetic acid and the number of licks induced by formalin in a dose dependent manner, the increase in the reaction time by the extract in the tail immersion model was not dose-dependent. Again, there was significant (P<0.05) lowering of the Brewer's yeast-provoked elevated body temperature. The results suggest that the aqueous extract of Clematis brachiata leaves can be employed in the management of inflammation, pain and fever. These activities may be due in part to the flavonoid content of the extract.

Analgesic activity of Heliopsis longipes and its effect on the nervous system.

Heliopsis longipes S.F. Blake (Asteraceae: Heliantheae) (chilcuague) is used in Mexican traditional medicine against parasites and to alleviate tooth and muscle pains. Its biocide effect has already been experimentally demonstrated; however, its analgesic action and its action on the nervous system (NS) have not been investigated yet. The objectives of this study were to evaluate the analgesic action of affinin and the H. longipes root ethanol extract, as well as their effects on the NS using an animal model. The ethanol extract was obtained by maceration, and affinin was purified from it through chromatographic techniques. Chemical and thermal analgesia were used to assess their analgesic proprieties. Irwin's test was used to evaluate their stimulating or depressing effects. The ethanol extract and affinin displayed analgesic action similar to ketorolac and stimulating effect comparable to caffeine on the nervous system of adult mice.

Antipyretic, analgesic, anti-inflammatory and antioxidant activities of two major chromenes from Melicope lunu-ankenda.

AIM OF THE STUDY: Melicope lunu-ankenda (Gaertn.) T.G. Hartley is used in Indian traditional medicine for fever, improving complexion and as a tonic. Previous studies have isolated fungicidal, antifeedant, anti-inflammatory and immunomodulatory compounds from Melicope lunu-ankenda. This study is aimed at the isolation and biological activity screening of potential molecules from the volatile oils and extracts of Melicope lunu-ankenda in the light of traditional applications. MATERIALS AND METHODS: Volatile oil of Melicope lunu-ankenda leaves was isolated by hydrodistillation, characterized by GC-FID, GC-MS, LRI determination, Co-GC and database searches. Major chromene-type compounds in Melicope lunu-ankenda leaf oil, evodione and leptonol, were isolated by preparative TLC and characterized by UV-Vis, IR, 1H-, 13C-, 13C-DEPT NMR and EIMS. They were also isolated from the petroleum ether and acetone extracts of the leaves of Melicope lunu-ankenda by column chromatography in petroleum ether-ethyl acetate. Their contents in leaf oil, leaf and inflorescence extracts were estimated by HPTLC. Antipyretic (Baker's yeast-induced fever test), analgesic (acetic acid-induced writhing, tail immersion assays), anti-inflammatory (carrageenan-induced paw edema) and in vitro antioxidant (DPPH radical, superoxide radical scavenging) activities of evodione and leptonol were tested. RESULTS AND CONCLUSIONS: Gas chromatographic analyses found 50.7% monoterpene hydrocarbons, 0.4% oxygenated monoterpenes, 3.2% sesquiterpene hydrocarbons, 0.7% oxygenated sesquiterpenes and 43.7% chromene-type compounds in Melicope lunu-ankenda leaf oil, with evodione (20.2%) and leptonol (22.5%) as its two major constituents. HPTLC estimations in the petroleum ether, acetone extracts (leaf, inflorescence) and leaf oil found evodione 1.0% (dr. wt., leaf), 1.1% (inflorescence), 0.04% (fr. wt. leaves, leaf oil), and leptonol 0.3% (leaf), 0.3% (inflorescence) and 0.04% (leaf oil). Leptonol (200 mg/kg) showed good antipyretic activity. DPPH radical scavenging assay found moderate activity for leptonol (68.7%, 500 microM), whereas evodione showed near-zero activity. A very similar trend was found in superoxide radical scavenging activity of leptonol (64.5%) and evodione (10.3%), both at 100 microg/ml. Evodione and leptonol showed moderate analgesic activities in acetic acid-induced writhing and tail immersion assays. Moderate anti-inflammatory activity was found for both evodione (59.4%) and leptonol (49.0%) at 100 mg/kg. ETHNOPHARMACOLOGICAL RELEVANCE: Biological activities of evodione and leptonol isolated from Melicope lunu-ankenda justify its traditional uses as a remedy for fever, inflammation and as a tonic.

Analgesic (omega)-conotoxins CVIE and CVIF selectively and voltage-dependently block recombinant and native N-type calcium channels.

Neuronal (N)-type Ca(2+) channel-selective omega-conotoxins have emerged as potential new drugs for the treatment of chronic pain. In this study, two new omega-conotoxins, CVIE and CVIF, were discovered from a Conus catus cDNA library. Both conopeptides potently displaced (125)I-GVIA binding to rat brain membranes. In Xenopus laevis oocytes, CVIE and CVIF potently and selectively inhibited depolarization-activated Ba(2+) currents through recombinant N-type (alpha1(B-b)/alpha(2)delta1/beta(3)) Ca(2+) channels. Recovery from block increased with membrane hyperpolarization, indicating that CVIE and CVIF have a higher affinity for channels in the inactivated state. The link between inactivation and the reversibility of omega-conotoxin action was investigated by creating molecular diversity in beta subunits: N-type channels with beta(2a) subunits almost completely recovered from CVIE or CVIF block, whereas those with beta(3) subunits exhibited weak recovery, suggesting that reversibility of the omega-conotoxin block may depend on the type of beta-subunit isoform. In rat dorsal root ganglion sensory neurons, neither peptide had an effect on low-voltage-activated T-type channels but potently and selectively inhibited high voltage-activated N-type Ca(2+) channels in a voltage-dependent manner. In rat spinal cord slices, both peptides reversibly inhibited excitatory monosynaptic transmission between primary afferents and dorsal horn superficial lamina neurons. Homology models of CVIE and CVIF suggest that omega-conotoxin/voltage-gated Ca(2+) channel interaction is dominated by ionic/electrostatic interactions. In the rat partial sciatic nerve ligation model of neuropathic pain, CVIE and CVIF (1 nM) significantly reduced allodynic behavior. These N-type Ca(2+) channel-selective omega-conotoxins are therefore useful as neurophysiological tools and as potential therapeutic agents to inhibit nociceptive pain pathways.