The Study of Analgesic Effects of Leonurus cardiaca L. in Mice by Formalin, Tail Flick and Hot Plate Tests

Nicorandil reduces morphine withdrawal symptoms, potentiates morphine antinociception, and ameliorates liver fibrosis in rats

AIMS

Chronic liver disease (CLD) is a serious medical condition affecting patients globally and pain management poses a unique challenge. ATP-sensitive potassium channels (K_ATP) are expressed in nociceptive neurons and hepatic cells. We tested the hypothesis whether morphine and nicorandil, K_ATP channel opener, alone and in combination possess hepatoprotective, antinociceptive effect and alter morphine physical dependence.

MAIN METHODS

Intraperitoneal injection (i.p.) of carbon tetrachloride (CCl₄) induced liver fibrosis in male Wistar rats. Nicorandil (15 mg/kg/day) was administered per os for two weeks. Morphine (3.8, 5, 10 mg/kg, i.p.) was administered prior to antinociception testing in tail flick and formalin tests. Morphine physical dependence following naloxone injection, fibrotic, oxidative stress markers, and liver histopathology were assessed.

KEY FINDINGS

Morphine alone, produced insignificant changes of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), hyaluronic acid (HA), hepatic hydroxyproline (Hyp), malondialdehyde (MDA), and superoxide dismutase (SOD) levels and exerted significant antinociception in the pain models. Nicorandil alone protected against liver damage (decreased serum ALT, AST, HA, hepatic Hyp, MDA, increased SOD levels, improved fibrosis scores). Nicorandil/morphine combination produced remarkable hepatoprotection and persistent analgesia compared to morphine alone as evidenced by reduced (EC50) of morphine. Nicorandil augmented morphine analgesia and markedly decreased withdrawal signs in morphine-dependent rats.

SIGNIFICANCE

The data showed for the first time, the hepatoprotection and augmented antinociception mediated by nicorandil/morphine combination in liver fibrosis via antioxidant and antifibrotic mechanisms. Nicorandil ameliorated withdrawal signs in morphine dependence in CLD. Thus, combining nicorandil/morphine provides a novel treatment strategy to ameliorate hepatic injury, potentiate antinociception and overcome morphine-induced physical dependence in liver fibrosis.

Lamiaceae in Mexican Species, a Great but Scarcely Explored Source of Secondary Metabolites with Potential Pharmacological Effects in Pain Relief

The search for molecules that contribute to the relief of pain is a field of research in constant development. Lamiaceae is one of the most recognized families world-wide for its use in traditional medicine to treat diseases that include pain and inflammation. Mexico can be considered one of the most important centers of diversification, and due to the high endemism of this family, it is crucial for the in situ conservation of this family. Information about the most common genera and species found in this country and their uses in folk medicine are scarcely reported in the literature. After an extensive inspection in bibliographic databases, mainly Sciencedirect, Pubmed and Springer, almost 1200 articles describing aspects of Lamiaceae were found; however, 217 articles were selected because they recognize the Mexican genera and species with antinociceptive and/or anti-inflammatory potential to relieve pain, such as Salvia and Agastache. The bioactive constituents of these genera were mainly terpenes (volatile and non-volatile) and phenolic compounds such as flavonoids (glycosides and aglycone). The aim of this review is to analyze important aspects of Mexican genera of Lamiaceae, scarcely explored as a potential source of secondary metabolites responsible for the analgesic and anti-inflammatory properties of these species. In addition, we point out the possible mechanisms of action involved and the modulatory pathways investigated in different experimental models. As a result of this review, it is important to mention that scarce information has been reported regarding species of this family from Mexican genera. In fact, despite Calosphace being one of the largest subgenera of Salvia in the world, found mainly in Mexico, it has been barely investigated regarding its potential biological activities and recognized bioactive constituents. The scientific evidence regarding the different bioactive constituents found in species of Lamiaceae demonstrates that several species require further investigation in preclinical studies, and of course also in controlled clinical trials evaluating the efficacy and safety of these natural products to support their therapeutic potential in pain relief and/or inflammation, among other health conditions. Since Mexico is one of the most important centers of diversification, and due to the high endemism of species of this family, it is crucial their rescue, in situ conservation, and investigation of their health benefits.

Chemical diversity analysis and biological activities evaluation of different polyphenolic extracts of Marrubium deserti De Noé from Algeria

ETHNOPHARMACOLOGICAL RELEVANCE

Marrubium deserti De Noé (Lamiaceae) commonly known as desert horehound, is a small perennial herb distributed in arid climates. This plant has been used in Algeria for the treatment of cold, cough, fever and inflammation.

AIM OF THE STUDY

This study aimed to perform a phytochemical analysis and to evaluate the effect of diethyl ether (ExDiEth), n-butanol (ExBut) and hydroalcoholic (ExHyD) extracts of the aerial parts of M. deserti De Noé on inflammation, nociceptive response and fever in animal models.

MATERIALS AND METHODS

The total phenolic content and the different phenolic fraction (flavones-flavonols, free aglycones, anthocyanidins, C-glycosides and flavonic heterosides) were quantified in order to study the chemical diversity. The anti-inflammatory effect was evaluated using carrageenan-induced paw oedema test and the nociceptive response was determined by the chemical method using acetic acid-induced writhing response and formalin-induced paw licking tests and by the thermal method using the hot plate in mice. In addition, anti-fever was investigated using yeast-induced pyrexia in rats.

RESULTS

Quantitative analysis revealed that among all extracts, ExBut had a higher phenolic content and the aerial parts of M. deserti De Noé collected from two different sites (Biskra and Tamanresset) had a significant difference in the contents of flavonic heterosids and flavones-flavonols. PCA and CA showed a strong intra-specific variability of M. deserti De Noé individuals. Our results showed that the ExDiEth, ExBut and ExHyD treatments prevented the increase of paw oedema by 56.25%, 66.65% and 45.56% inhibition percent, respectively. Moreover, treatments with these extracts significantly (p<0.05) decreased the number of writhing and increased the reaction time to thermal stimulation as well as demonstrated reduction in paw licking time both at early and late phases. Likewise, they also showed a significant reduction of yeast-induced pyrexia till 4 h of treatment.

CONCLUSION

Results from this study show that M. deserti De Noé aerial parts exhibited anti-inflammatory, analgesic with central and peripheral actions and antipyretic activities which could be associated with the presence of some phytochemicals as flavones, flavonols, flavonic heterosids and phenolic acids.

Novel 1,3,4-Oxadiazole Derivatives of Pyrrolo[3,4-d]pyridazinone Exert Antinociceptive Activity in the Tail-Flick and Formalin Test in Rodents and Reveal Reduced Gastrotoxicity

Despite the availability of the current drug arsenal for pain management, there is still a clinical need to identify new, more effective, and safer analgesics. Based on our earlier study, newly synthesized 1,3,4-oxadiazole derivatives of pyrrolo[3,4-d]pyridazinone, especially 10b and 13b, seem to be promising as potential analgesics. The current study was designed to investigate whether novel derivatives attenuate nociceptive response in animals subjected to thermal or chemical noxious stimulus, and to compare this effect to reference drugs. The antinociceptive effect of novel compounds was studied using the tail-flick and formalin test. Pretreatment with novel compounds at all studied doses increased the latency time in the tail-flick test and decreased the licking time during the early phase of the formalin test. New derivatives given at the medium and high doses also reduced the late phase of the formalin test. The achieved results indicate that new derivatives dose-dependently attenuate nociceptive response in both models of pain and exert a lack of gastrotoxicity. Both studied compounds act more efficiently than indomethacin, but not morphine. Compound 13b at the high dose exerts the greatest antinociceptive effect. It may be due to the reduction of nociceptor sensitization via prostaglandin E₂ and myeloperoxidase levels decrease.

A mechanistic approach to HPLC analysis, antinociceptive, anti-inflammatory and postoperative analgesic activities of panch phoron in mice

Background

Panch phoron is a mixture of five spices containing an equal proportion of Foeniculum vulgare (fennel), Trigonella foenum-graecum Linn (fenugreek), Nigella sativa (black cumin), Cuminum cyminum (cumin) and Brassica nigra (black mustard). The mixture is commonly used in Bangladeshi cuisine and possesses many pharmacological effects. In this study, we evaluated the antinociceptive and anti-inflammatory activities of aqueous panch phoron extract (PPE) in vivo, its possible mechanism of action and phytochemical analysis by High-Performance Liquid Chromatography (HPLC). We also investigated the effect of PPE on postoperative pain in mice.

Methods

HPLC was carried out using LC-20A Modular HPLC system to identify the bioactive compounds present in PPE. Five groups of Swiss albino male mice (n = 6 per group) were orally treated with 10 ml/kg of distilled water or 10 mg/kg of sodium diclofenac or three doses of PPE (100 mg/kg, 300 mg/kg, 500 mg/kg). In vivo assessment was carried out by the writhing test, tail-flick test, formalin test, and carrageenan induced paw edema test. The opioid antagonist, naloxone was used in the acetic acid test to evaluate the involvement of opioid receptors. To assess the effect of PPE in postoperative pain, mice that underwent sciatic nerve surgery were measured for the paw withdrawal latency in a hot water bath.

Results

In HPLC analysis, different types of phenolic compounds and flavonoids, including catechin hydrate, para-coumaric acid, vanillic acid, and syringic acid were detected. Treatment with PPE exhibited dose-dependent antinociceptive and anti-inflammatory activities in pain models (p < 0.05). Furthermore, naloxone did not reverse the effect of PPE in the writhing test. Mice that underwent sciatic nerve surgery showed that the paw withdrawal latency increased gradually over 7 days.

Conclusions

Our results demonstrate that PPE has significant antinociceptive and anti-inflammatory activities and can provide significant postoperative analgesia.

Leonurus cardiaca L. as a Source of Bioactive Compounds: An Update of the European Medicines Agency Assessment Report (2010)

Leonurus cardiaca L. (motherwort) is a perennial herb, native to Asia and southeastern Europe, with widespread global occurrence in present days. The plant was historically used as cardiotonic and for treating gynaecological afflictions (such as amenorrhea, dysmenorrhea, menopausal anxiety, or postpartum depression). Although its use in oriental and occidental medicine is relatively well documented, the recent progress registered raises the need for an update of the Medicines Agency assessment report on Leonurus cardiaca L., herba (2010). The current study presents the progress made within the 2010-2018 timeframe regarding the potential applications and scientific evidences supporting the traditional use of motherwort, in the same time suggesting future research opportunities.

Medicinal Plants of the Family Lamiaceae in Pain Therapy: A Review

Recently, numerous side effects of synthetic drugs have lead to using medicinal plants as a reliable source of new therapy. Pain is a global public health problem with a high impact on life quality and a huge economic implication, becoming one of the most important enemies in modern medicine. The medicinal use of plants as analgesic or antinociceptive drugs in traditional therapy is estimated to be about 80% of the world population. The Lamiaceae family, one of the most important herbal families, incorporates a wide variety of plants with biological and medical applications. In this study, the analgesic activity, possible active compounds of Lamiaceae genus, and also the possible mechanism of actions of these plants are presented. The data highlighted in this review paper provide valuable scientific information for the specific implications of Lamiaceae plants in pain modulation that might be used for isolation of potentially active compounds from some of these medicinal plants in future and formulation of commercial therapeutic agents.

Analgesic properties of aqueous bark extract of Adansonia digitata in Wistar rats

The study investigated the analgesic effect of the aqueous extract of the bark of Adansonia digitata using Wistar rats. Thirty Wistar rats weighing between 150 and 170g of either sex were used for the study. Animal were picked randomly and grouped into six with each group made up of five animals (3 females and 2 males). Oral administration of 10ml/kg of normal saline were given to control group; 5mg/kg of indomethacin to reference group; and 25mg/kg, 50mg/kg, 100mg/kg or 200mg/kg of aqueous extracts of Adansonia digitata to each of the test groups respectively.Hotplate and formalin paw-licking tests were used for nociceptive assessment. Animals treated with aqueous bark extract of Adansonia digitata showed significantly (p<0.05) prolonged response time to thermal stimuli (4.42±0.11s) compared with control group (3.29±0.29s) in a dose dependent manner. Results formalin paw-licking test showed that at early phase, animals administered with aqueous bark extract of Adansonia digitata significantly (p<0.05) have reduced paw-licking time (47.88±3.48-40.80±3.85s) compared with the control group (91.51±7.32s). In the late phase, aqueous bark extract of Adansoni adigitata significantly (p<0.05) reduced the paw-licking time (43.57±2.6-25.49±3.46s) compared with the control group (66.31±5.04s). It is hereby concluded that aqueous bark extract of A. digitata possesses a strong analgesic effect.

Methanolic Extract of Clinacanthus nutans Exerts Antinociceptive Activity via the Opioid/Nitric Oxide-Mediated, but cGMP-Independent, Pathways

The objectives of the present study were to determine the mechanisms of antinociceptive effect of methanol extract of Clinacanthus nutans (Acanthaceae) leaves (MECN) using various animal nociceptive models. The antinociceptive activity of orally administered 10% DMSO, 100 mg/kg acetylsalicylic acid (ASA), 5 mg/kg morphine, or MECN (100, 250, and 500 mg/kg) was determined using the acetic acid-induced abdominal constriction (ACT), formalin-induced paw licking (FT), and hot plate tests (HPT). The role of opioid and nitric oxide/cyclic guanosine monophosphate (NO/cGMP) systems was also investigated. The results showed that MECN produced a significant (p < 0.05) antinociceptive response in all nociceptive models with the recorded ED₅₀ value of 279.3 mg/kg for the ACT, while, for the early and late phases of the FT, the value was >500 mg/kg or 227.7 mg/kg, respectively. This antinociceptive activity was fully antagonized by naloxone (a nonselective opioid antagonist) but was partially reversed by l-arginine (l-arg; a nitric oxide [NO] precursor), Nω-nitro-l-arginine methyl ester hydrochloride (l-NAME; an NO synthase inhibitor), or their combinations thereof. In contrast, 1H-[1,2,4]oxadiazole[4,3-a]quinoxalin-1-one (ODQ; a soluble guanylyl cyclase inhibitor) enhanced the extract's antinociception. UHPLC analysis revealed the presence of several flavonoid-based compounds with antinociceptive action. In conclusion, MECN exerted the peripherally and centrally mediated antinociceptive activity via the modulation of the opioid/NO-mediated, but cGMP-independent, systems.