Tracheal relaxation of five medicinal plants used in Mexico for the treatment of several diseases

Agastache Species: A Comprehensive Review on Phytochemical Composition and Therapeutic Properties

The Agastache genus is part of the Lamiaceae family and is native to North America, while one species, Agastache rugosa (A. rugosa), is native to East Asia. A review on the phytochemistry and bioactivity of Agastache genus was last performed in 2014. Since then, a lot of progress has been made on the characterization of the phytochemical and pharmacological profiles of Agastache species. Thus, the purpose of this paper is to present a summary of the findings on the phytochemistry and biological effects of several Agastache species, including both extracts and essential oil characterization. We performed a comprehensive search using PubMed and Scopus databases, following PRISMA criteria regarding the study selection process. The available data is focused mainly on the description of the chemical composition and bioactivity of A. rugosa, with fewer reports referring to Agastache mexicana (A. mexicana) and Agastache foeniculum (A. foeniculum). Agastache species are characterized by the dominance of flavonoids and phenolic acids, as well as volatile compounds, particularly phenylpropanoids and monoterpenes. Moreover, a series of pharmacological effects, including antioxidant, cytotoxic, antimicrobial, anti-atherosclerotic, and cardioprotective properties, have been reported for species from the Agastache genus.

A Systematic Approach to Agastache mexicana Research: Biology, Agronomy, Phytochemistry, and Bioactivity

Mexico is the center of origin of the species popularly known as toronjil or lemon balm (Agastache mexicana Linton & Epling). Two subspecies have been identified and are commonly called purple or red (Agastache mexicana Linton & Epling subspecies. mexicana) and white (Agastache mexicana subspecies xolocotziana Bye, E.L. Linares & Ramamoorthy). Plants from these subspecies differ in the size and form of inflorescence and leaves. They also possess differences in their chemical compositions, including volatile compounds. Traditional Mexican medicine employs both subspecies. A. mexicana exhibits a broad range of pharmacological properties, such as anti-inflammatory, anxiolytic, and antioxidant. A systematic vision of these plant’s properties is discussed in this review, exposing its significant potential as a source of valuable bioactive compounds. Furthermore, this review provides an understanding of the elements that make up the species’ holistic system to benefit from lemon balm sustainably.

Airway smooth muscle relaxant activity of Cordia dodecandra A. DC. mainly by cAMP increase and calcium channel blockade

ETHNOPHARMACOLOGICAL RELEVANCE

The fight against chronic respiratory diseases needs the exploration of new active compounds with properties that contribute to diminish the symptoms or resolve the disease alongside current therapy.

MATERIALS AND METHODS

Eight extracts obtained from the bark and leaves of a Mayan medicinal plant used to treat asthma, Cordia dodecandra A. DC., were investigated for their relaxant effect on rat isolated tracheal rings pre-contracted with carbachol [1 µM]. The underlying functional mode of action of the most effective extract was assessed and the chromatographic fingerprints of more active extracts were analyzed.

RESULTS

The dichloromethane bark extract (DECd-b) was the most effective and potent (E_max= 87.57 ± 1.32 %; EC₅₀ = 392.7 ± 5.18 µg/mL). DECd-b relaxant effect was maximized in presence of isoproterenol (β-adrenergic agonist, [10 µM]) and theophylline (phosphodiesterase unspecific inhibitor, [10 µM]). DECd-b also showed efficient relaxation of KCl [80 mM]-induced contraction and inhibition of CaCl₂-induced contraction. Pre-incubation with propranolol (non-selective β-adrenergic antagonist, [10 µM]), SQ22536 (adenylyl cyclase inhibitor; [100 µM]), ODQ (guanylyl cyclase inhibitor; [10 µM]), l-NAME (nitric oxide synthase inhibitor; [10 µM]), indomethacin (a cyclooxygenase unspecific inhibitor; [10 µM]), glibenclamide (ATP-sensitive potassium channel blocker; [10 µM]) and 2-aminopyridine (voltage-gated potassium channel blocker [100 µM]) did not modify the DECd-b relaxant-effect curve. The chromatographic analysis of DECd-b suggests the cordiaquinones presence with double conjugated bounds such as menaquinone.

CONCLUSIONS

Results suggest that DECd-b induces relaxation mainly by cAMP increase and Ca²⁺ channel blockade. The chromatographic profiles and UV spectrum of DECd-b and HECd-l suggest the presence of molecules with structure of meroterpenoid naphthoquinones. This work report scientific evidence of C. dodecandra medicinal specie, which contributes to the pharmacological and phytochemical background of C. dodecandra providing an added value to the traditional use of this specie.

Flavonoids, Sterols and Lignans from Cochlospermum vitifolium and Their Relationship with Its Liver Activity

The sterols β-sitostenone (1), stigmast-4,6,8(14),22-tetraen-3-one (2), β-sitosterol (3) and stigmasterol (4), the aromatic derivatives antiarol (5) and gentisic acid (6), the phenylpropanes coniferyl alcohol (7), epoxyconiferyl alcohol (8) and ferulic acid (9), the apocarotenoid vomifoliol (10), the flavonoids naringenin (11), 7,4′-dimethoxytaxifolin (7,4′-dimethoxydihydroquercetin, 12), aromadendrin (13), kaempferol (14), taxifolin (dihydroquercetin, 15), prunin (naringenin-7-O-β-d-glucoside, 16), populnin (kaempferol-7-O-β-d-glucoside, 17) and senecin (aromadendrin-7-O-β-d-glucoside, 18) and the lignans kobusin (19) and pinoresinol (20), were isolated from the dried bark of Cochlospermum vitifolium Spreng (Cochlospermaceae), a Mexican medicinal plant used to treat jaundice, liver ailments and hepatitis C. Fourteen of these compounds were isolated for the first time from this plant and from the Cochlospermum genus. Compounds 3–4, 6–7, 9–11, 13–17 and 20 have previously exhibited diverse beneficial liver activities. The presence of these compounds in C. vitifolium correlates with the use of this Mexican medicinal plant.

Mechanism of action of relaxant effect of Agastache mexicana ssp.mexicana essential oil in guinea-pig trachea smooth muscle

CONTEXT

Agastache mexicana ssp. mexicana (Kunth) Lint & Epling (Lamiaceae), popularly known as 'toronjil morado', is used in Mexican traditional medicine for the treatment of several diseases such as hypertension, anxiety and respiratory disorders.

OBJECTIVE

This study investigates the relaxant action mechanism of A. mexicana ssp. mexicana essential oil (AMEO) in guinea-pig isolated trachea model.

MATERIALS AND METHOD

AMEO was analyzed by GC/MS. The relaxant effect of AMEO (5-50 μg/mL) was tested in guinea-pig trachea pre-contracted with carbachol (3 × 10 ^- 6 M) or histamine (3 × 10 ^- 5 M) in the presence or absence of glibenclamide (10 ^- 5 M), propranolol (3 × 10 ^- 6 M) or 2',5'-dideoxyadenosine (10 ^- 5 M). The antagonist effect of AMEO (10-300 μg/mL) against contractions elicited by carbachol (10 ^- 15-10 ^- 3 M), histamine (10 ^- 15-10 ^- 3 M) or calcium (10-300 μg/mL) was evaluated.

RESULTS

Essential oil composition was estragole, d-limonene and linalyl anthranilate. AMEO relaxed the carbachol (EC₅₀=18.25 ± 1.03 μg/mL) and histamine (EC₅₀=13.3 ± 1.02 μg/mL)-induced contractions. The relaxant effect of AMEO was not modified by the presence of propranolol, glibenclamide or 2',5'-dideoxyadenosine, suggesting that effect of AMEO is not related to β₂-adrenergic receptors, ATP-sensitive potassium channels or adenylate cyclase activation. AMEO was more potent to antagonize histamine (pA₂' = -1.507 ± 0.122) than carbachol (pA₂' = -2.180 ± 0.357). Also, AMEO antagonized the calcium chloride-induced contractions.

CONCLUSION

The results suggest that relaxant effect of AMEO might be due to blockade of calcium influx in guinea-pig trachea smooth muscle. It is possible that estragole and d-limonene could contribute majority in the relaxant effect of AMEO.

Spasmogenic and spasmolytic activities of Agastache mexicana ssp. mexicana and A. mexicana ssp. xolocotziana methanolic extracts on the guinea pig ileum

ETHNOPHARMACOLOGICAL RELEVANCE

Agastache mexicana has been used in traditional medicine for relief of abdominal pain and treatment of other diseases. Two subspecies have been identified: A. mexicana ssp. mexicana (AMM) and A. mexicana ssp. xolocotziana (AMX) and both are used traditionally without distinction or in combination.

AIM OF THE STUDY

To determine the effect of methanol extracts of A. mexicana ssp. mexicana and A. mexicana ssp. xolocotziana on gut motility and their possible mechanism of action.

MATERIALS AND METHODS

The effect of AMM and AMX methanol extracts were tested on the spontaneous activity in the isolated guinea pig ileum and on tissues pre-contracted with KCl, electrical field stimulation (EFS) or ACh. In addition, the possible mechanism of action of each subspecies on gut motility was analyzed in the presence of hexametonium, indomethacin, L-NAME, verapamil, atropine or pyrylamine. A comparative chromatographic profile of these extracts was also done to indicate the most abundant flavonoids presents in methanol extracts of both subspecies.

RESULTS

AMM, but not AMX, induced a contractile effect in the guinea pig ileum. This spasmogenic effect was partially inhibited by atropine, antagonist of muscarinic receptors; and pyrilamine, antagonist of H₁ receptors. In contrast, AMX, but not AMM, diminished the contractions induced by KCl, EFS or ACh. The spasmolytic activity of AMX was partially inhibited by hexamethonium, ganglionic blocker; and indomethacin, inhibitor of the synthesis of prostaglandins; but not by L-NAME, inhibitor of nitric oxide synthase. In addition, AMX diminished the maximal contraction induced by CaCl₂ in a calcium-free medium. Chromatographic analyses of these methanol extracts showed the presence of acacetin and tilanin in both.

CONCLUSIONS

These results suggest that in folk medicine only AMX should be used as spasmolytic, and not in combination with AMM as traditionally occurs, due to the spasmogenic effects of the latter. In addition, activation of nicotinic receptors, prostaglandins and calcium channels, but not nitric oxide mechanisms, could be responsible for the spasmolytic activity of AMX. On the other hand, release of ACh and histamine could be involved in the spasmogenic effect induced by AMM. Acacetin and tilanin are present in methanol extracts of both subspecies and both flavonoids were more abundant in AMX than AMM. Our findings contribute to the validation of the traditional use of Agastache mexicana in relieving gastrointestinal disorders, but indicate that the subspecie that should be used for this effect is A. mexicana ssp. xolocotziana.

Gnaphaliin A and gnaphaliin B synergize the relaxant effect of salbutamol but not of ipratropium in guinea pig trachea

OBJECTIVE

This work was aimed to investigate the pharmacodynamic interactions between gnaphaliins A and B with ipratropium bromide (IBR) and salbutamol (SAL) using the guinea pig trachea model through application of the combination index (CI)-isobologram equation.

METHODS

The guinea pig trachea rings in isolated chamber with Krebs-Henseleit solution (37°C) were contracted with carbachol (3 μm), and then, concentration-relaxant effect curves were constructed for individual drugs and in combination at fixed constant ratios (1 : 1, 3 : 1 and 1 : 3). Median effect and combination index (CI)-isobologram equations were used for determining interactions.

KEY FINDINGS

Gnaphaliin A and gnaphaliin B showed clear synergistic interaction with salbutamol, reducing the dose of salbutamol more than sevenfolds to produce the same relaxant effect. However, the combination of either flavonoids with ipratropium bromide showed no interaction.

CONCLUSIONS

Applying the combination index-isobologram method, we determined that gnaphaliin A and gnaphaliin B have synergistic effect with salbutamol due probably to their inhibitory effect on phosphodiesterases to maintain high levels of cAMP in the tracheal smooth muscle. However, these compounds did not show any effect with ipratropium.

A Study of Agastachis Herba on Ovalbumin-induced Asthma in the Mouse

Agastachis Herba is one of the well-known medicinal herbs in Korean traditional medicine. This study was taken up to examine the beneficial effects of Agastachis Herba on a mice model of asthma. BALB/c mice were sensitized and challenged with ovalbumin to produce a murine model of asthma. Methanol extracts of Agastachis Herba were orally administered to the ovalbumin-induced asthmatic mice. The effects of methanol extract of Agastachis Herba on airway hyper responsiveness, immune cell distributions in bronchoalveolar lavage fluid, ovalbumin-specific immunoglobulin E in serum, and histopathological changes were evaluated. Mice treated with the methanol extract of Agastachis Herba showed reduction of airway hyper responsiveness as well as inhibited immune cell infiltration in bronchoalveolar region. Also ovalbumin-specific immunoglobulin E levels in bronchoalveolar lavage fluid significantly decreased in extract treated mice. Histopathological findings showed significant beneficial changes in inflammatory cell infiltration.