Extract of Chenopodium album lowers blood pressure in rats through endothelium-dependent and -independent vasorelaxation.

OBJECTIVES: To investigate the antihypertensive effect of crude extract of Chenopodium album (Ca.Cr), based on its medicinal use in hypertension. METHODS: Ca.Cr and its fractions were tested in-vivo in normotensive anesthetized rats for blood pressure-lowering effect. In-vitro experiments were performed on isolated rat aortae to explore the vascular mechanism(s). RESULTS: In normotensive anesthetized rats, Ca.Cr produced a dose-dependent (1-300mg/kg) fall (30%mmHg) in mean arterial pressure (MAP). Among the fractions, nHexane was the most potent (46% fall). In rat aortic rings precontracted with phenylephrine (PE), Ca.Cr and its fractions (except Ca.Aq) produced endothelium-dependent vasorelaxation, which was partially reversed with endothelium removal and by pretreating intact aortic rings with L-NAME (10µM) and atropine (1µM). This relaxation to Ca.Cr and fractions (nHexane, ethylacetate and chloroform) was also eliminated with indomethacin pretreatment, however, it unmasked a vasoconstriction effect with Ca.Cr only. Surprisingly, the aqueous fraction produced a calcium sensitive strong vasoconstriction instead of vasorelaxation. The crude extract and its fractions (except Ca.Aq) also antagonized vasoconstriction induced with high K+ (80mM), suggesting calcium antagonistic effect. The aqueous fraction produced mild vasorelaxation against high K+. This effect was further confirmed when pretreatment of the aortic rings with different concentrations of crude extract and fractions suppressed CaCl2 concentration response curves, similar to verapamil. In acute toxicity test, Ca.Cr extract was found safe up to 5g/kg body weight in mice. CONCLUSION: These findings suggest that crude extract and fractions of C. album produced vasorelaxant effect through muscarinic receptors linked-NO pathway, prostaglandin (endothelium-dependent) and calcium antagonism (endothelium-independent), which explains the blood pressure lowering effect of C. album in rats.

Antioxidant Flavonoid Diosmetin Is Cardioprotective in a Rat Model of Myocardial Infarction Induced by Beta 1-Adrenergic Receptors Activation.

Myocardial infarction (MI) is a common and life-threatening manifestation of ischemic heart diseases (IHD). The most important risk factor for MI is hypertension. Natural products from medicinal plants have gained considerable attention globally due to their preventive and therapeutic effects. Flavonoids have been found to be efficacious in ischemic heart diseases (IHD) by alleviating oxidative stress and beta-1 adrenergic activation, but the mechanistic link is not clear. We hypothesized that antioxidant flavonoid diosmetin is cardioprotective in a rat model of MI induced by beta 1-adrenergic receptor activation. To test this hypothesis, we evaluated the cardioprotective potential of diosmetin on isoproterenol-induced MI in rats by performing lead II electrocardiography (ECG), cardiac biomarkers including troponin I (cTnI) and creatinine phosphokinase (CPK), CK-myocardial band, (CK-MB), lactate dehydrogenase (LDH), alanine aminotransferase (ALT), and aspartate aminotranferase (AST) by using biolyzer 100, as well as histopathological analysis. We found that diosmetin (1 and 3 mg/kg) attenuated isoproterenol-induced elevation in the T-wave and deep Q-wave on the ECG, as well as heart-to-body weight ratio and infarction size. In addition, pretreatment with diosmetin attenuated the isoproterenol-induced increase in serum troponin I. These results demonstrate that flavonoid diosmetin may provide therapeutic benefit in myocardial infarction.

Vasorelaxant and Antihypertensive Effects of Bergenin on Isolated Rat Aorta and High Salt-Induced Hypertensive Rats.

Bergenin is a phenolic glycoside that has been reported to be present in some medicinal plants which are traditionally used for their antihypertensive actions. So, bergenin was investigated for antihypertensive and vasorelaxant experiments in a rat model. Bergenin produced a significant fall in the mean arterial pressure (MAP) of rats. To explore the involvement of NO and muscarinic receptors, rats were pretreated with L-NAME and atropine in-vivo. The L-NAME did not change significantly the effect of bergenin on MAP excluding the involvement of NO. Unlike the L-NAME, atropine pretreatment reduced the effect of bergenin on MAP, indicating the role of muscarinic receptors. In in-vitro study, the bergenin produced endothelium-dependent (at lower concentrations) and independent (at higher concentrations) vasorelaxation, which was attenuated significantly in the presence of atropine and indomethacin but not with L-NAME. While a partial response was observed against K+-induced contractions. This was further confirmed when bergenin partly shifted the CaCl2-CRCs toward right. Bergenin also suppressed the PE peak formation, indicating the antagonist effect against the release of Ca2+. Moreover, the bergenin-induced vasorelaxant response was not markedly attenuated with TEA, while significantly ablated with 4-AP and BaCl2. In conclusion, the antihypertensive effects of bergenin are due to Ca2+ channel blockade, K+ channels activation, and muscarinic receptor-linked vasodilation.

LC-MS/MS-Based Metabolomic Profiling of Constituents from Glochidion velutinum and Its Activity against Cancer Cell Lines.

This study aimed to establish the phytochemical profile of Glochidion velutinum and its cytotoxic activity against prostate cancer (PC-3) and breast cancer (MCF-7) cell lines. The phytochemical composition of G. velutinum leaf extract and its fractions was established with the help of total phenolic and flavonoid contents and LC-MS/MS-based metabolomics analysis. The crude methanolic extract and its fractions were studied for pharmacological activity against PC-3 and MCF-7 cell lines using the MTT assay. The total phenolic content of the crude extract and its fractions ranged from 44 to 859 µg GAE/mg of sample whereas total flavonoid contents ranged from 20 to 315 µg QE/mg of sample. A total of forty-eight compounds were tentatively dereplicated in the extract and its fractions. These phytochemicals included benzoic acid derivatives, flavans, flavones, O-methylated flavonoids, flavonoid O- and C-glycosides, pyranocoumarins, hydrolysable tannins, carbohydrate conjugates, fatty acids, coumarin glycosides, monoterpenoids, diterpenoids, and terpene glycosides. The crude extract (IC50 = 89 µg/mL), the chloroform fraction (IC50 = 27 µg/mL), and the water fraction (IC50 = 36 µg/mL) were found to be active against the PC-3 cell line. However, the crude extract (IC50 = 431 µg/mL), the chloroform fraction (IC50 = 222 µg/mL), and the ethyl acetate fraction (IC50 = 226 µg/mL) have shown prominent activity against breast cancer cells. Moreover, G. velutinum extract and its fractions presented negligible toxicity to normal macrophages at the maximum tested dose (600 µg/mL). Among the compounds identified through LC-MS/MS-based metabolomics analysis, epigallocatechin gallate, ellagic acid, isovitexin, and rutin were reported to have anticancer activity against both prostate and breast cancer cell lines and might be responsible for the cytotoxic activities of G. velutinum extract and its bioactive fractions.

Antihypertensive Activity in High Salt-Induced Hypertensive Rats and LC-MS/MS-Based Phytochemical Profiling of Melia azedarach L. (Meliaceae) Leaves.

Melia azedarach L. leaves have been traditionally used but not scientifically evaluated for antihypertensive activity. The focus of the present work was to carry out the detailed phytochemical profiling and antihypertensive potential of methanolic extract and subsequent fractions of this plant. The tandem mass spectrometry-based phytochemical profiling of M. azedarach extract (Ma.Cr) and fractions was determined in negative ionization mode while molecular networking was executed using the Global Natural Product Social (GNPS) molecular networking platform. This study resulted in the identification of 29 compounds including flavonoid O-glycosides, simple flavonoids, triterpenoidal saponins, and cardenolides as the major constituents. Ma.Cr at the concentration of 300 mg/kg resulted in a fall in blood pressure (BP), i.e., 81.44 ± 2.1 mmHg in high salt-induced hypertensive rats in vivo, in comparison to normotensive group, i.e., 65.36 ± 1.8 mmHg at the same dose. A decrease in blood pressure was observed in anaesthetized normotensive and hypertensive rats treated with extract and various fractions of M. azedarach. A reasonable activity was observed for all fractions except the aqueous fraction. The highest efficacy was shown by the ethyl acetate fraction, i.e., 77.06 ± 3.77 mmHg in normotensive and 88.96 ± 1.3 mmHg in hypertensive anaesthetized rats. Ma.Cr and fractions showed comparatively better efficacy towards hypertensive rats as compared to rats with normal blood pressure. Blood pressure-lowering effects did not change upon prior incubation with atropine. In vitro testing of Ma.Cr and polarity-based fractions resulted in L-NAME sensitive, endothelium-dependent vasodilator effects on aortic tissues. Pretreatment of aorta preparations with Ma.Cr and its fractions also blocked K+-induced precontractions indicating Ca2+ channel blocking activity comparable to verapamil. The extract and polarity-based fractions did not reveal a vasoconstrictor response in spontaneously beating isolated rat aorta. Ma.Cr and fractions when used in atrial preparations resulted in negative inotropic and chronotropic effects. These effects in atrial preparations did not change in the presence of atropine. These effects of extract and fractions explained the antihypertensive potential of M. azedarach and thus provided a scientific basis for its ethnopharmacological use in the treatment of hypertension. Among the constituents observed, flavonoids and flavonoid O-glycosides were previously reported for antihypertensive potential.

Investigation into the Antihypertensive Effects of Diosmetin and Its Underlying Vascular Mechanisms Using Rat Model.

OBJECTIVE: Diosmetin is a flavonoid that is found in many important medicinal plants that have antihypertensive therapeutic potential. Diosmetin has been shown to have antiplatelet, anti-inflammatory and antioxidant properties, which suggests that it could be a potential candidate for use in antihypertensive therapy. METHODS: In vivo and in vitro methods were used for our investigation into the antihypertensive effects of diosmetin. RESULTS: Diosmetin significantly decreased the mean arterial pressure (MAP). The effects of diosmetin on the MAP and heart rate were more pronounced in hypertensive rats. To explore the involvement of the muscarinic receptors-linked NO pathway, Nω-nitro-L-arginine methyl ester (L-NAME) and atropine were pre-administered in vivo. The pretreatment with L-NAME did not significantly change the effects of diosmetin on the MAP by excluding the involvement of NO. Unlike L-NAME, the atropine pretreatment reduced the effects of diosmetin on the MAP, which demonstrated the role of the muscarinic receptors. In the in vitro study, diosmetin at lower concentrations produced endothelium-dependent and -independent (at higher concentrations) vasorelaxation, which was attenuated significantly by the presence of atropine and indomethacin but not L-NAME. Diosmetin was also tested for high K+-induced contractions. Diosmetin induced significant relaxation (similar to verapamil), which indicated its Ca2+ antagonistic effects. This was further confirmed by diosmetin shifting the CaCl2 CRCs toward the right due to its suppression of the maximum response. Diosmetin also suppressed phenylephrine peak formation, which indicated its antagonist effects on the release of Ca2+. Moreover, BaCl2 significantly inhibited the effects of diosmetin, followed by 4-AP and TEA, which suggested that the K+ channels had a role as well. CONCLUSIONS: The obtained data showed the Ca2+ channel antagonism, potassium channel activation and antimuscarinic receptor-linked vasodilatory effects of diosmetin, which demonstrated its antihypertensive potential.

Tandem high resolution mass spectrometry based phytochemical composition of Sauromatum guttatum tubers and its enzyme inhibitory potential with molecular docking.

Sauromatum guttatum has been traditionally used in the treatment of snakebite and tumors in India, Pakistan, and China. However, it lacks detailed phytochemical composition like other members of the family Araceae. Therefore, the aim of the present study was to investigate the phytochemical composition of crude methanolic extract and subsequent fractions from S. guttatum tubers and to determine their enzyme inhibitory potentials. The phytochemical profile was studied through tandem high-resolution mass-based phytochemical analysis and Global Natural Product Social (GNPS) molecular networking. Similarly, crude extract and fractions were also investigated for enzyme inhibitory activity against urease and α-glucosidase. Twenty-six compounds were dereplicated belonging to flavone C-glycosides, flavone O-glycosides, phenolic acids, phenolic acid glycosides, and iridoid glycosides. The n-butanol fraction was particularly found rich in flavone di-C-glycosides including schaftoside, isoschaftoside, neoschaftoside, and vicenin-2. The n-butanol fraction exhibited the highest in vitro inhibition against urease and α-glucosidase with IC50 values of 113.7 µg/mL and 155.3 µg/mL, respectively. The results of enzyme inhibition potential were also supported by in silico molecular docking studies against the above-mentioned enzymes. This is the first report on the detailed phytochemical profile of S. guttatum tubers, and these results will contribute to the chemosystematic knowledge of the Araceae family. The results of this study also suggest that S. guttatum may find possible applications in the treatment of gastrointestinal disorders and diabetes.

Insight into the cardiovascular mechanisms of blood pressure lowering effect of gitogenin: a steroidal saponin.

Background/objectives: Steroidal saponins are widely distributed in medicinal plants with potential applications in cardiovascular disorders. Gitogenin, a saponin, has not been explored as antihypertensive; this investigation was aimed to explore its blood pressure lowering potential and underlying mechanisms.Methodology: The effect of gitogenin was evaluated on blood pressure in vivo, using normotensive rat model and the underlying cardiovascular mechanism(s) in vitro, in isolated rat aorta and in atria preparations using PowerLab data acquisition system (ADInstrument, Australia).Results: Intravenous injection of gitogenin decreased mean arterial pressure (MAP) in anesthetized rats. Atropine (1 mg/kg) and L-NAME (100 mg/kg) pretreatment significantly (*p < .05) attenuated effect on MAP to gitogenin. In isolated intact aortic rings, gitogenin induced endothelium-dependent vasodilatation (maximum 65%), which was ablated (maximum 22%) with L-NAME (100 mg/kg) and atropine (1 µM) pretreatment or endothelium removal. Gitogenin was found more potent against angiotensin II precontractions without effect on high K+ and low K+ precontractions. In isolated rat right atria, gitogenin suppressed rate and force of contractions. Atropine (1 µM) pretreatment partially inhibited effect of gitogenin on force and eliminated its effect on rate. Combined atropine (10 µM) and atenolol (0.5 µM) pretreatment was without effect on force of contractions but eliminated effect of gitogenin on rate with 25% increase.Conclusion: These findings indicate that antihypertensive effect of gitogenin is the outcome of vascular and cardiac effects; agonistic effect on vascular M3 and cardiac M2 receptors; and being more selective for M2. Increase in the rate of atrial contraction might be of clinical importance.

Assessing the ethnobotanical potential of Carissa opaca berries by merging outcomes from metabolomics profiling, enzyme assays, and in silico docking studies.

The phytochemical profile of Carissa opaca fruit extract and fractions was established through dereplication strategies employing LC-MS/MS and global natural product social molecular networking (GNPS). Crude extract and fractions were evaluated for their potential to inhibit α-glucosidase and urease in vitro. Flavonoid-O-glycosides, flavonoid-C-glycosides, flavonoids, proanthocyanidin B2, phenolics, and triterpenoids were annotated as the major classes of secondary metabolites present in the extract and fractions. α-Glucosidase inhibition was associated with n-butanol and ethyl acetate fractions comparable to acarbose (IC50 = 120.43 µg/mL) with IC50 values of 123.67 and 131.72 µg/mL, respectively. The ethyl acetate fraction showed good urease inhibition comparable with thiourea (IC50 = 103.71 µg/mL) with an IC50 value of 109.14 µg/mL. Molecular docking studies of compounds observed in the crude extract and bioactive fractions had significant binding scores, which supported results for enzyme inhibition in vitro. This study provided a detailed phytochemical profile of C. opaca fruit and its enzyme inhibition potential.

Antihypertensive Activity of Sauromatum guttatum Mediated by Vasorelaxation and Myocardial Depressant Effects. / O Efeito Anti-Hipertensivo de Sauromatum Guttatum Mediado por Efeitos Vasorrelaxante e Depressivos Miocárdicos.

BACKGROUND: Sauromatum guttatum (S. guttatum) is used in the treatment of blood disorders and reportedly has a spasmolytic activity through Ca2+ channel inhibition. OBJECTIVES: The aim of this study was to investigate the antihypertensive potential of S. guttatum in high salt-induced hypertensive Sprague-Dawley (SD) rat model (HSHRs). METHODS: SD rats were divided into normotensive, hypertensive, S. guttatum and verapamil treated groups. S. guttatum crude extract (Sg.Cr) (100, 150 and 300 mg/kg/day) and verapamil (5, 10 and 15 mg/kg/day) were administered orally along with NaCl. Aortic rings and right atrial strips from normotensive rats were used to investigate the underlying mechanisms. The level of statistical significance was set at 5%. RESULTS: Mean arterial pressure decreased in the Sg.Cr and verapamil-treated hypertensive groups in a dose-dependent manner (p < 0.001). In the vascular reactivity study, acetylcholine induced relaxations with an EC50 value of 0.6 µg/mL (0.3-1.0) in Sg.Cr-treated hypertensive rats (300 mg/kg), suggesting endothelial preservation. In isolated normotensive rat aorta, Sg.Cr-treated rats showed vasorelaxation with an EC50 value of 0.15 mg/mL (0.10-0.20), ablated by endothelial denudation or pretreatment with L-NAME and atropine. Sg.Cr treatment caused relaxation against high K+-induced contractions, like verapamil. Sg.Cr showed negative inotropic (82%) and chronotropic effects (56%) in isolated rat atrial preparations reduced with atropine. The phytochemical investigation indicated presence of alkaloids, flavonoids and tannins. CONCLUSION: S. guttatum has a vasodilatory effect through endothelial function preservation, muscarinic receptor-mediated NO release and Ca2+ movement inhibition, while atrial myocardial depressant effect can be linked to the muscarinic receptor. These findings provide pharmacological base for using S. guttatum extract as an antihypertensive medication.

FUNDAMENTO: A Sauromatum guttatum (S. guttatum) é utilizado no tratamento de doenças do sangue e supostamente tem atividade espasmolítica através da inibição dos canais de Ca2+. OBJETIVOS: O objetivo deste estudo foi investigar o potencial anti-hipertensivo de S. guttatum em modelo de rato Sprague-Dawley (SD) com hipertensão induzida por dieta com alto teor de sal (HIDATS). MÉTODOS: Ratos SD foram divididos em normotensos, hipertensos e grupos tratados com verapamil e S. guttatum. Extrato bruto de S. guttatum (Sg.B) (100, 150 e 300 mg/kg/dia) e verapamil (5, 10 e 15 mg/kg/dia) foram administrados por via oral junto com NaCl. Anéis aórticos e faixas do átrio direito de ratos normotensos foram utilizados para investigar os mecanismos subjacentes. O nível de significância estatística adotado foi de 5%. RESULTADOS: A pressão arterial média diminuiu nos grupos hipertensos tratados com Sg.B e verapamil de forma dose-dependente (p <0,001). No estudo de reatividade vascular, a acetilcolina induziu relaxamentos com valor CE50 de 0,6 µg/mL (0,3­1,0) em ratos hipertensos tratados com Sg.B (300 mg/kg), sugerindo preservação endotelial. Em aorta isolada de rato normotenso, o Sg.B exibiu vasorrelaxamento com valor de CE50 de 0,15 mg/mL (0,10-0,20), após ablação por desnudamento endotelial ou pré-tratamento com L-NAME e atropina. O tratamento com Sg.B causou relaxamento contra contrações induzidas por K+ alto, como o verapamil. O Sg.B mostrou efeitos inotrópicos (82%) e cronotrópicos (56%) negativos em preparações isoladas atriais de ratos reduzidas com atropina. A avaliação fitoquímica indicou a presença de alcaloides, flavonoides e taninos. CONCLUSÃO: O S. guttatum possui efeito vasodilatador através da preservação da função endotelial, liberação de NO mediada pelo receptor muscarínico e inibição do movimento de Ca2+, enquanto o efeito depressor do miocárdio atrial pode estar ligado ao receptor muscarínico. Esses achados fornecem a base farmacológica para o uso do extrato de S. guttatum como um medicamento anti-hipertensivo.

Butyrlycholine esterase inhibitory activity and effects of extracts (fruit, bark and leaf) from Zanthoxylum armatum DC in gut, airways and vascular smooth muscles.

BACKGROUND: Fruit, bark and leaves of Zanthoxylum armatum DC are popular remedies for gastrointestinal, cardiovascular and respiratory disorders in the subcontinent traditional practices. The aim of the study was to individually probe the profile of methanol extracts from three different parts of Zanthoxylum armatum. METHODS: The ex-vivo muscle relaxant effects of extracts were assessed in the isolated intestine, trachea and thoracic aortic rings and were compared with the positive controls and CRC were constructed. The anti-diarrheal effect of extracts was evaluated in mice by inducing diarrhea with castor oil. The extracts were also studied for acute toxicity and butyrylcholine esterase inhibition. RESULTS: The extracts from fruit, bark and leaves of Z. armatum showed inhibitory effect against the butyrylcholine esterase enzyme with percent inhibition of 50.75 ± 1.23, 82.57 ± 1.33, and 37.52 ± 1.11respectively, compared to standard serine (IC50: 0.04 ± 0.001 µmol/L). The fruit and bark extracts provided 75, and 52% diarrheal protection, compared to verapamil (96%). In isolated rabbit jejunum strips, increasing addition of the extracts inhibited the spontaneous and high K+ precontractions with EC50 values of 0.71 and 3 mg/mL for fruit, EC50 values of 0.61 and 0.5 mg/mL for bark, EC50 0.81 and 3.1 mg/mL for leaves, like verapamil. The extracts induced a concentration-dependent relaxation of the carbachol (1 µM) and high K+ (80 mM) precontractions with EC50 values of 2.4 and 0.9 mg/mL for fruit, EC50 values of 1.2 and 3 for leaves. The bark extract was equipotent against both contractions with EC50 3.1 and 0.7 mg/mL, respectively. In the aortic rings, the fruit extract completely relaxed the phenylephrine (1 µM)-induced contractions with (EC50 value = 0.8 mg/ml) and a partial inhibition of high K+ induced contractions. The leaves extract completely relaxed the aortic contractions with (EC50 values = 1.0 and 8.5 mg/ml). The extracts caused no acute toxicity up to 3 g/kg dose. CONCLUSIONS: The experiments revealed that the extracts of aerial parts of Z. armatum have antidiarrheal properties in vivo and showed spasmolytic effect in intestinal and tracheal preparations with possible mechanism involving the blockage of Ca++ channels. These experiments provide enough justification for use of this plant in ethnomedicine in diarrhea, gut and bronchial spasms.

Curative effects of Distemonanthus benthamianus Baillon. Trunk-bark extracts on enteropathogenic Escherichia coli 31-induced diarrhea in rats.

Background Distemonanthus benthamianus is used in the Western part of Cameroon to treat diarrheal episodes and infections. This study assessed its trunk-bark extracts activity against enteropathogenic Escherichia coli 31 (EPEC 31)-induced diarrhea in rats. Methods Aqueous and methanolic extracts were analyzed through high-performance liquid chromatography (HPLC). In vitro minimum inhibitory and bactericidal concentrations (MICs/MBCs) were evaluated on Enterococcus faecalis (ATCC 10,541), E. coli (ATCC 6539), Klebsiella pneumoniae (ATCC 13,883), Salmonella typhi (ATCC 6539) strains and on Proteus mirabilis, Pseudomonas aeruginosa (PA 01) and Shigella flexneri isolates using the microdilution method. Diarrhea was induced by inoculating rats with EPEC 31 (1.5 × 108 CFU/mL; p.o). Serum transaminases level assay and enzyme-linked immunosorbent assay (ELISA) for cytokines determination were performed. Hematoxylin-eosin (H-E) staining was used for intestinal tissue analysis. Results HPLC fingerprints of extracts showed presence of gallic acid and other unidentified compounds. The lowest MIC of 256 µg/mL was obtained with methanolic extract. At 100 mg/kg, both extracts significantly (p<0.001) inhibited diarrhea, with the methanolic extract being the most active. In addition, the methanolic extract significantly (p<0.001) increased the relative mass of the liver compared to negative control (Tween-DMSO 8%). The aqueous extract (100 mg/kg) significantly (p<0.01) increased alanine aminotransferase (ALT) serum concentration; while the methanolic extract (100 mg/kg) exhibited similar effect over aspartate aminotransferase (AST). At 50 and 100 mg/kg, the methanolic extract significantly (p<0.05 and p<0.01) decreased the Interleukin-1ß (IL-1ß) serum level, compared to negative control (Tween-DMSO 8%). Serum level of tumor necrosis factor alpha (TNF-α) significantly (p<0.001) decreased with 100 mg/kg of aqueous extract and all doses of methanolic extract. Inhibition of inflammatory cells tissue infiltration and epithelial regeneration was highly noticed in the ileum and colon of extracts-treated rats than in ciprofloxacin-treated animals. Conclusion These findings suggest that D. benthamianus trunk-bark extracts displayed therapeutic effects against infectious diarrhea in rats.

Total phenolic and flavonoid contents and antihypertensive effect of the crude extract and fractions of Calamintha vulgaris.

BACKGROUND: Calamintha vulgaris L., has been used medicinally in the management hypertension. PURPOSE: To investigate the antihypertensive mechanisms of extract of C. vulgaris L., in Sprague-Dawley (SD) rat. STUDY DESIGN: Total phenol and total flavonoid contents were determined in the crude extract through HPLC. In vivo and in vitro pharmacological approaches were utilized to test the crude extract and fractions of C. vulgaris in Sprague-Dawley (SD) rats. The effect on mean arterial pressure (MAP) was compared in normotensive and high salt-induced hypertensive rats. METHODS: Crude extract and nHexane, chloroform, ethylacetate and aqueous fractions of C. vulgaris were tested. In vitro experiments were carried out in isolated rat and rabbit aortae, to probe vascular mechanism(s). Extract was also evaluated for acute toxicity study in mice. RESULTS: Crude extract and fractions of C. vulgaris induced a fall in MAP in normotensive and high salt-induced hypertensive rats at different doses. The effect was more significant in the hypertensive rats (Max. fall, 38.67 ± 2.17 vs 44.16 ± 4.67 mmHg). Among the fractions, chloroform was more effective (Max. fall, 53.20 ±â€¯1.23 mmHg) and aqueous the least (Max. fall, 38.66 ±â€¯1.12 mmHg). Normotensive rats pretreated with atropine (2 mg/kg) or L-NAME (100 µg/kg) ablated fall in MAP to the extract and fractions. In isolated rat aorta, extract induced endothelium-dependent vasodilatory effect, which was ablated with atropine (1 µM), L-NAME (10 µM), atropine + L-NAME, TEA (10 µM) pretreatment and denudation of aorta. Indomethacin (10 µM) pretreatment ablated vasodilatation at lower concentrations and unmasked a vasoconstrictor effect, followed by relaxation at higher concentrations. Extract and fractions inhibited high K+-precontractions and rightward shifted Ca+2 concentration response curves, similar to verapamil. Total phenolic and flavonoid contents were found 39.41 ± 0.18 (mg of GAE/g) and 12.03 ±â€¯0.23 (mg of QUE/g), respectively. HPLC analysis showed the presence of quercetin and rutin CONCLUSION: Results obtained indicate that the antihypertensive effect of C. vulgaris is the outcome of vasodilation, which is mediated through combination of muscarinic receptor-linked NO, activation of TEA-sensitive K+ channels, prostacyclin and Ca+2 antagonism.

Antihypertensive effect of the methanolic extract from Eruca sativa Mill., (Brassicaceae) in rats: Muscarinic receptor-linked vasorelaxant and cardiotonic effects.

ETHNOPHARMACOLOGICAL RELEVANCE: Eruca sativa Mill., (Brassicaceae) is a popular remedy for the treatment of hypertension in Pakistan. However, direct effect of the extract and its fractions on blood pressure and vascular tone are unknown. AIM OF THE STUDY: This investigation was aimed to explore the pharmacological base for the traditional use of E. sativa in hypertension. MATERIALS AND METHODS: In-vivo blood pressure study was carried out using normotensive and high salt-induced hypertensive rats under anaesthesia. The cardiovascular mechanisms were explored using rat aorta and atria in-vitro. Preliminary phytochemical analysis, spectrophotometric detection of total phenols, flavonoids and HPLC analysis of crude extract were performed using quercetin and erucin as marker compounds. RESULTS: Intravenous injection of crude extract induced a fall in mean arterial pressure (MAP) in both normotensive (max fall: 41.79 ±â€¯1.55% mmHg) and hypertensive (max fall: 58.25 ±â€¯0.91% mmHg) rats. Atropine (1 mg/kg) pretreatment attenuated this effect significantly (p < 0.001), suggesting the involvement of muscarinic receptor in its antihypertensive effect. Fractions also induced atropine-sensitive antihypertensive effect. Similarly, oral administration of crude and aqueous extracts resulted a fall in MAP in the hypertensive rats. In isolated rat aortic rings from normotensive rats, crude extract and fractions induced an endothelium-dependent relaxation. This relaxation was partially inhibited with L-NAME and atropine pretreatment and with denudation of aortic rings, indicating involvement of muscarinic receptor-linked nitric oxide (NO). In aorta from the hypertensive rats, crude extract and fractions induced endothelium-independent relaxation. This relaxation was not affected by pretreatment with L-NAME or atropine. Crude extract and fractions also suppressed phenylephrine contractions in Ca+2 free/EGTA medium. In isolated rat atrial preparations, crude extract and fractions induced negative inotropic and chronotropic effects with a positive inotropic effect by the n-hexane fraction, which were not affected with atropine pretreatment. Phytochemical screening and spectrophotometric analysis indicated the presence of phenols and flavonoids, whereas HPLC analysis of crude extract revealed the presence of quercetin (flavonoid) and erucin (isothiocyanate). CONCLUSION: The results suggest that E. sativa is an antihypertensive remedy which is mainly due to its vasodilatory and partly cardiac effects. Muscarinic receptors-linked NO release and dual inhibitory effect on Ca+2 influx and release underlie the vasodilation. This finding provides pharmacological base to the traditional use of E. sativa in hypertension. The presence of quercetin and erucin further support this finding.

Inhibitory Effects of Glycyrrhiza glabra and Its Major Constituent Glycyrrhizin on Inflammation-Associated Corneal Neovascularization.

Glycyrrhiza glabra L. (Leguminosae) is widely used in folk medicines. Glycyrrhizin, an active compound of G. glabra, possesses anti-inflammatory activity. This study investigates the G. glabra methanol extract and glycyrrhizin for the treatment of corneal neovascularization (CNV). G. glabra was extracted in 70% aqueous methanol. Phytochemical tests, thin layer chromatography (TLC), and high performance liquid chromatography (HPLC) were used for the analysis of chemical composition. The topical solution of G. glabra methanol extract (2% w/v) and glycyrrhizin (1% w/v) was prepared in normal saline. After corneal burn (1 N NaOH), animals were left untreated for a week so that neovascularization appears in all groups. Treatments started on day 7 and continued for next 21 consecutive days. The animals were treated with 3 drops of various topical solutions thrice a day. Digital photograph analysis and histological studies were used for the evaluation of CNV. Phytochemical analysis of the G. glabra methanol extract showed the presence of saponins, phenols, carbohydrates, flavonoids, and proteins. TLC and HPLC confirmed the presence of glycyrrhizin. Photograph analysis of the extract and glycyrrhizin treated group showed a considerable decrease in CNV. Histological study of G. glabra and glycyrrhizin treated groups showed no blood vessels with properly arranged collagen fibers. This study showed that G. glabra and glycyrrhizin can be used for the treatment of CNV. Bioassay guided isolation can lead to preparation of ophthalmic solutions for the treatment of CNV.

Vascular mechanisms underlying the hypotensive effect of Rumex acetosa.

CONTEXT: Rumex acetosa L. (Polygonaceae) is well known in traditional medicine for its therapeutic efficacy as an antihypertensive. OBJECTIVE: The study investigates antihypertensive potential of crude methanol extract (Ra.Cr) and fractions of Rumex acetosa in normotensive and hypertensive rat models and probes the underlying vascular mechanisms. MATERIALS AND METHODS: Ra.Cr and its fractions were tested in vivo on normotensive and hypertensive Sprague-Dawley rats under anaesthesia for blood pressure lowering effect. In vitro experiments on rat and Oryctolagus cuniculus rabbit aortae were employed to probe the underlying vasorelaxant mechanism. RESULTS: In normotensive rats under anaesthesia, Ra.Cr caused fall in MAP (40 mmHg) at 50 mg/kg with % fall of 27.88 ± 4.55. Among the fractions tested, aqueous fraction was more potent at the dose of 50 mg/kg with % fall of 45.63 ± 2.84. In hypertensive rats under similar conditions, extract and fractions showed antihypertensive effect at same doses while aqueous fraction being more potent, exhibited 68.53 ± 4.45% fall in MAP (70 mmHg). In isolated rat aortic rings precontracted with phenylephrine (PE), Ra.Cr and fractions induced endothelium-dependent vasorelaxation, which was partially blocked in presence of l-NAME, indomethacin and atropine. In isolated rabbit aortic rings pre-contracted with PE and K+-(80 mM), Ra.Cr induced vasorelaxation and shifted Ca2+ concentration-response curves to the right and suppressed PE peak formation, similar to verapamil, in Ca2+-free medium. DISCUSSION AND CONCLUSIONS: The data indicate that l-NAME and atropine-sensitive endothelial-derived NO and COX enzyme inhibitors and Ca2+ entry blocking-mediated vasodilator effect of the extract explain its antihypertensive potential.

Airways and vascular smooth muscles relaxant activities of Gaultheria trichophylla.

The aim of this experimental work was to explore the potential pharmacological activities of Gaultheria trichophylla Royle in hyperactive respiratory and vascular conditions. Gaultheria trichophylla was extracted with solvents, phytochemical detection tests were performed, and rabbit trachea and aorta strips were used to evaluate its effects on airways and vascular smooth muscles. Qualitative phytochemical tests showed the presence of flavonoids, alkaloids, anthraquinones, saponins, terpenoids, and condensed tannins. The methanol extract caused inhibition (EC50 values of 3.12 mg/mL) of carbachol (1 µM) and partial relaxation of K+(80 mM) caused contractions in tracheal strips. The chloroform extract was comparatively more potent against carbachol than K+ induced contraction with EC50 values of 0.64 and 2.26 mg/mL, respectively. However, the n-hexane extract showed more potency against K+ than cabachol induced contractions, as in case with verapamil, with EC50 values of 0.61 and 6.58 mg/mL, respectively. In isolated prepared trachea, the extracts displaced the carbachol concentration response curves and maximum response was suppressed. In rabbit aorta preparations, methanol and n-hexane extracts partially relaxed phenylephrine (1 µM) and K+ induced vasoconstrictions. However, the chloroform extract inhibited phenylephrine induced contractions and exhibited a vasoconstrictor effect at lower concentrations and a relaxant effect at higher concentrations against K+ precontractions. The data indicates that, in addition to others, the extracts of G .trichophylla possess verapamil like Ca++ channel blocking components which explain the possible role of this plant in respiratory and vascular conditions.

Mechanisms underlying the antihypertensive properties of Urtica dioica.

BACKGROUND: Urtica dioica has traditionally been used in the management of cardiovascular disorders especially hypertension. The aim of this study was to explore pharmacological base of its use in hypertension. METHODS: Crude methanolic extract of U. dioica (Ud.Cr) and its fractions (Ud.EtAc, Ud.nHex, Ud.Chl and Ud.Aq) were tested in vivo on normotensive and hypertensive rats under anesthesia for blood pressure lowering effect. In-vitro experiments on rat and rabbit aortae were employed to probe the vasorelaxation mechanism(s). The responses were measured using pressure and force transducers connected to PowerLab Data Acquisition System. RESULTS: Ud.Cr and fractions were found more effective antihypertensive in hypertensive rats than normotensive with remarkable potency exhibited by the ethyl acetate fraction. The effect was same in the presence of atropine. In isolated rat aortic rings, Ud.Cr and all its fractions exhibited L-NAME sensitive endothelium-dependent vasodilator effect and also inhibit K(+) (80 mM)-induced pre-contractions. In isolated rabbit thoracic aortic rings Ud.Cr and its fractions induced relaxation with more potency against K(+) (80 mM) than phenylephrine (1 µM) like verapamil, showing Ud.EtAc fraction the most potent one. Pre-incubation of aortic rings with Ud.Cr and its fractions exhibited Ca(2+) channel blocking activity comparable with verapamil by shifting Ca(2+) concentration response curves to the right. Ud.Cr and its fractions also ablated the intracellular Ca(2+) release by suppressing PE peak formation in Ca(2+) free medium. When tested on basal tension, the crude extract and all fractions were devoid of any vasoconstrictor effect. CONCLUSIONS: These data indicate that crude methanolic extract and its fractions possess antihypertensive effect. Identification of NO-mediated vasorelaxation and calcium channel blocking effects explain the antihypertensive potential of U. dioica and provide a potential pharmacological base to its medicinal use in the management of hypertension.

Intestinal and vascular smooth muscle relaxant effect of Viscum album explains its medicinal use in hyperactive gut disorders and hypertension.

BACKGROUND: Viscum album has shown inhibitory effect on different smooth muscles but underlying mechanisms in gut and vascular smooth muscles are not well defined. Additionally, the plant has also importance in managing hyperactive gut and cardiovascular disorders. The current study was aimed to probe a pharmacological base of the smooth muscle relaxant effect of V. album in gut and vascular preparations. METHODS: V. album crude extract (Va. Cr) and its ethyl acetate fraction (Va. EtAc) were studied using in vitro techniques. The antispasmodic activity was performed using isolated rabbit jejunum while the vasorelaxant effects were studied in rabbit aortic rings. RESULTS: Va. Cr and Va. EtAc inhibited spontaneous and high K(+)-induced contractions with EC50 values of 0.31 mg/mL (0.15-0.57) and 0.62 mg/mL (0.3-0.95), respectively. This advocates an antispasmodic effect probably operated through calcium channels blockade (CBB). The proposed mechanism was confirmed by a pretreatment of the tissue with Va. Cr (0.01-0.3 mg/mL), which shifted the Ca(++) concentration-response curves (CRCs) rightward, similar to verapamil. Moreover, Va. Cr showed a partial relaxation against high K(+) and PE (1 µM) induced contractions in isolated rabbit aorta rings. Va. EtAc caused complete relaxation of high K(+) precontraction and partially relaxed PE (1 µM) induced contractions, suggesting inhibitory effect on Ca(++) entry, in addition to other possible mechanisms. CRCs were shifted to the right correspondingly to verapamil when the aortic rings were pretreated with Va. Cr and Va. EtAc. CONCLUSIONS: These data indicated that Va. Cr possesses smooth muscle relaxant effect mediated through voltage-dependent Ca(++) channel blockade (CCB), which explains its spasmolytic and vasorelaxant activity. The CCB activity is concentrated more in Va. EtAc. This study provides an evidence for the medicinal importance of V. album in gut spasm and possibly hypertension.

Gut modulatory and butyrylcholinesterase inhibitory activities of Gaultheria trichophylla.

CONTEXT: Gaultheria trichophylla Royle (Ericaceae) and related species have been used in the traditional system of medicine for the treatment of diarrhoea, pain and inflammation. OBJECTIVE: The present investigation explores G. trichophylla for its potential activity in hyperactive gut disorders. MATERIALS AND METHODS: Antidiarrheal activity was evaluated on castor oil induced diarrhoea in mice with reference to standard drug verapamil. Gut modulatory activity was performed on isolated jejunum tissue preparations on spontaneous and high potassium induced contractions. Butyrylcholinesterase (BChE) inhibitory activity was performed with an in vitro study. Extract was tested for toxicity in mice. RESULTS: In the in vivo studies, the methanol extract of G. trichophylla and verapamil significantly (p < 0.05, 0.01, 0.001) inhibited the frequency of defecation as well as wetting of faeces when compared with the negative control. The methanol (Gt. MeOH) extract of G. trichophylla caused a dose-dependent inhibitory effect on spontaneous contractions in isolated rabbit jejunum preparations and exhibited a partial inhibitory effect against high K+ (80 mM) induced precontractions. Gt. MeOH shifted the Ca2+ concentration-response curves (CRCs) to the right, suggesting calcium channel blocking like constituents. In an in vitro assay Gt. MeOH inhibited BChE enzyme with an IC50 values of 35.52 ± 1.17 µg/mL. The extract showed no toxicity in mice at the dose of 3 g/kg. DISCUSSION AND CONCLUSION: This study provides evidence that G. trichophylla possesses combinations of inhibitory and stimulatory effects mediated through possible cholinergic and less potent calcium blocking constituents, respectively. The latter may be responsible for the antidiarrheal effect.