HPLC-DAD analysis, antinociceptive and anti-inflammatory properties of the ethanolic extract of Hyptis umbrosa in mice

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.

Subtribe Hyptidinae (Lamiaceae): A promising source of bioactive metabolites

ETHNOPHARMACOLOGICAL RELEVANCE

The subtribe Hyptidinae contains approximately 400 accepted species distributed in 19 genera (Hyptis, Eriope, Condea, Cantinoa, Mesosphaerum, Cyanocephalus, Hypenia, Hyptidendron, Oocephalus, Medusantha, Gymneia, Marsypianthes, Leptohyptis, Martianthus, Asterohyptis, Eplingiella, Physominthe, Eriopidion and Rhaphiodon). This is the Lamiaceae clade with the largest number of species in Brazil and high rates of endemism. Some species have been used in different parts of the world mainly as insecticides/pest repellents, wound healing and pain-relief agents, as well as for the treatment of respiratory and gastrointestinal disorders.

AIM OF THE REVIEW

This review aims to discuss the current status concerning the taxonomy, ethnobotanical uses, phytochemistry and biological properties of species which compose the subtribe Hyptidinae.

MATERIALS AND METHODS

The available information was collected from scientific databases (ScienceDirect, Pubmed, Web of Science, Scopus, Google Scholar, ChemSpider, SciFinder ACS Publications, Wiley Online Library), as well as other literature sources (e.g. books, theses).

RESULTS

The phytochemical investigations of plants of this subtribe have led to the identification of almost 300 chemical constituents of different classes such as diterpenes, triterpenes, lignans, α-pyrones, flavonoids, phenolic acids and monoterpenes and sesquiterpenes, as components of essential oils. Extracts, essential oils and isolated compounds showed a series of biological activities such as insecticide/repellent, antimicrobial and antinociceptive, justifying some of the popular uses of the plants. In addition, a very relevant fact is that several species produce podophyllotoxin and related lignans.

CONCLUSION

Several species of Hyptidinae are used in folk medicine for treating many diseases but only a small fraction of the species has been explored and most of the traditional uses have not been validated by current investigations. In addition, the species of the subtribe appear to be very promising as alternative sources of podophyllotoxin-like lignans which are the lead compounds for the semi-synthesis of teniposide and etoposide, important antineoplastic agents. Thus, there is a wide-open door for future studies, both to support the popular uses of the plants and to find new biologically active compounds in this large number of species not yet explored.

Toxicological and Pharmacological Activities of Leptohyptis macrostachys (Benth.) Harley and J.F.B.Pastore (Lamiaceae) on Intestinal Smooth Muscle

Leptohyptis macrostachys, previously known as Hyptis macrostachys Benth., is used in folk medicine to relieve the symptoms of asthma, cough, and bronchitis. Recently, we showed that the ethanol extract obtained from Leptohyptis macrostachys has selective spasmolytic activity on guinea pig ileum. Therefore, the aim of this study was to characterize the spasmolytic mechanism of this extract, investigated whether it presents toxicological and antidiarrheal activities. Therefore, the crude ethanolic extract of Leptohyptis macrostachys was analyzed by high-performance liquid chromatographic-diode array detection (HPLC-DAD). The spasmolytic effect was evaluated on guinea pig ileum, toxicological activity using rats and antidiarrheal activity using male and female mice. In HPLC-DAD analysis, Rosmarinic acid (5.44%) was the most abundant phenolic compound, being considered as a chemical marker. The spasmolytic potency of the extract on histamine-induced contraction was reduced in the presence of 1 mM TEA+, a selective big-conductance K+ channels blocker (BKCa). The extract produces a dose-dependent antidiarrheal activity, inhibiting equipotently defecation frequency and liquid stool formation. In addition, the extract has inhibited in a dose-dependent manner both castor oil-induced intestinal transit and intestinal fluid content. Thus, the spasmolytic activity of the extract involves positive modulation of BKCa and its antidiarrheal activity is related to inhibition of intestinal motility and secretion.

Antinociceptive activity of petroleum ether fraction obtained from methanolic extract of Clinacanthus nutans leaves involves the activation of opioid receptors and NO-mediated/cGMP-independent pathway

BACKGROUND

Methanol extract (MECN) of Clinacanthus nutans Lindau leaves (family Acanthaceae) demonstrated peripherally and centrally mediated antinociceptive activity via the modulation of opioid/NO-mediated, but cGMP-independent pathway. In the present study, MECN was sequentially partitioned to obtain petroleum ether extract of C. nutans (PECN), which was subjected to antinociceptive study with aims of establishing its antinociceptive potential and determining the role of opioid receptors and L-arginine/nitric oxide/cyclic-guanosine monophosphate (L-arg/NO/cGMP) pathway in the observed antinociceptive activity.

METHODS

The antinociceptive potential of orally administered PECN (100, 250, 500 mg/kg) was studied using the abdominal constriction-, hot plate- and formalin-induced paw licking-test in mice (n = 6). The effect of PECN on locomotor activity was also evaluated using the rota rod assay. The role of opioid receptors was determined by pre-challenging 500 mg/kg PECN (p.o.) with antagonist of opioid receptor subtypes, namely β-funaltrexamine (β-FNA; 10 mg/kg; a μ-opioid antagonist), naltrindole (NALT; 1 mg/kg; a δ-opioid antagonist) or nor-binaltorphimine (nor-BNI; 1 mg/kg; a κ-opioid antagonist) followed by subjection to the abdominal constriction test. In addition, the role of L-arg/NO/cGMP pathway was determined by prechallenging 500 mg/kg PECN (p.o.) with L-arg (20 mg/kg; a NO precursor), 1H-[1, 2, 4] oxadiazolo [4,3-a]quinoxalin-1-one (ODQ; 2 mg/kg; a specific soluble guanylyl cyclase inhibitor), or the combinations thereof (L-arg + ODQ) for 5 mins before subjection to the abdominal constriction test. PECN was also subjected to phytoconstituents analyses.

RESULTS

PECN significantly (p < 0.05) inhibited nociceptive effect in all models in a dose-dependent manner. The highest dose of PECN (500 mg/kg) also did not significantly (p > 0.05) affect the locomotor activity of treated mice. The antinociceptive activity of PECN was significantly (p < 0.05) inhibited by all antagonists of μ-, δ-, and κ-opioid receptors. In addition, the antinociceptive activity of PECN was significantly (p < 0.05) reversed by L-arg, but insignificantly (p > 0.05) affected by ODQ. HPLC analysis revealed the presence of at least cinnamic acid in PECN.

CONCLUSION

PECN exerted antinocicpetive activity at peripheral and central levels possibly via the activation of non-selective opioid receptors and modulation of the NO-mediated/cGMP-independent pathway partly via the synergistic action of phenolic compounds.

The Hypnotic, Anxiolytic, and Antinociceptive Profile of a Novel µ-Opioid Agonist

5'-4-Alkyl/aryl-1H-1,2,3-triazole derivatives PILAB 1-12 were synthesized and a pharmacological screening of these derivatives was performed to identify a possible effect on the Central Nervous System (CNS) and to explore the associated mechanisms of action. The mice received a peritoneal injection (100 µmol/kg) of each of the 12 PILAB derivatives 10 min prior to the injection of pentobarbital and the mean hypnosis times were recorded. The mean hypnosis time increased for the mice treated with PILAB 8, which was prevented when mice were administered CTOP, a µ-opioid antagonist. Locomotor and motor activities were not affected by PILAB 8. The anxiolytic effect of PILAB 8 was evaluated next in an elevated-plus maze apparatus. PILAB 8 and midazolam increased a percentage of entries and spent time in the open arms of the apparatus compared with the control group. Conversely, a decrease in the percentages of entries and time spent in the closed arms were observed. Pretreatment with naloxone, a non-specific opioid antagonist, prior to administration of PILAB 8 exhibited a reverted anxiolytic effect. PILAB 8 exhibited antinociceptive activity in the hot plate test, and reduced reactivity to formalin in the neurogenic and the inflammatory phases. These data suggest that PILAB 8 can activate µ-opioid receptors to provoke antinociceptive and anti-inflammatory effects in mice.