Bacopa monnieri and its constituents is hypotensive in anaesthetized rats and vasodilator in various artery types

Modulatory potential of Bacopa monnieri against aflatoxin B1 induced biochemical, molecular and histological alterations in rats

Oxidative injury is concerned with the pathogenesis of several liver injuries, including those from acute liver failure to cirrhosis. This study was designed to explore the antioxidant activity of Bacopa monnieri (BM) on Aflatoxin B1 (AFB1) induced oxidative damage in Wistar albino rats. Aflatoxin B1 treatment (200 μg/kg/day, p.o.) for 28 days induced oxidative injury by a significant alteration in serum liver function test marker enzymes (AST, ALT, ALP, LDH, albumin and bilirubin), inflammatory cytokines (IL-6, IL-10 and TNF-α), thiobarbituric acid reactive substances (TBARS) along with reduction of antioxidant enzymes (GSH, SOD, CAT), GSH cycle enzymes and drug-metabolizing enzymes (AH and AND). Treatment of rats with B. monnieri (20, 30 and 40 mg/kg for 5 days, p.o.) after 28 days of AFB1 intoxication significantly restored these parameters near control in a dose-dependent way. Histopathological examination disclosed extensive hepatic injuries, characterized by cellular necrosis, infiltration, congestion and sinusoidal dilatation in the AFB1-treated group. Treatment with B. monnieri significantly reduced these toxic effects resulting from AFB1. B. monnieriper se group (40 mg/kg) did not show any significant change and proved safe. The cytotoxic activity of B. monnieri was also evaluated on HepG2 cells and showed a good percentage of cytotoxic activity. This finding suggests that B. monnieri protects the liver against oxidative damage caused by AFB1, which aids in the evaluation of the traditional usage of this medicinal plant.

Cardioprotective and hypotensive mechanistic insights of hydroethanolic extract of Cucumis melo L. kernels in isoprenaline-induced cardiotoxicity based on metabolomics and in silico electrophysiological models

Background: Cardiovascular diseases (CVD) continue to threaten health worldwide, and account for a significant portion of deaths and illnesses. In both developing and industrialized nations, they challenge their health systems. There are several traditional uses of Cucurbitaceae seeds in Pakistan, India, Iran, and China, including treating cardiovascular, neurological, and urogenital diseases. Methods: In the present work, integrated techniques of metabolomics profiling and computational cardiomyocyte stimulation were used to investigate possible mechanisms of C. melo in isoprenaline (ISO)-induced myocardial infarction. In vitro, vasoconstrictions, paired atria, and in vivo invasive blood pressure measurement models were performed to explore the mechanism of action of C. melo hydroethanolic seed extract (Cm-EtOH). Results: Results showed that Cm-EtOH demonstrates NO-based endothelium-derived relaxing factor (EDRF) vasorelaxant response, negative chronotropic and inotropic response in the atrium, and hypotensive effects in normotensive rats. Results also revealed that Cm-EtOH decreases cardiomyocyte hypertrophy and reverts the altered gene expressions, biochemical, and metabolites in ISO-induced myocardial infarction (MI) rats. The extract additionally reversed ISO-induced MI-induced oxidative stress, energy consumption, and amino acid metabolism. Moreover, C. melo seeds increased EDRF function, energy production, and antioxidant capacity to treat myocardial and vascular disorders. In computational cardiomyocyte simulation, gallic acid reduced action potential duration, upstroke velocity (dV/dtmax), and effective refractory period. Conclusion: This study highlights the therapeutic potential of C. melo seeds to treat cardiovascular diseases and provides mechanistic insight into its antihypertensive and cardioprotective activities.

Fumaria indica (Hausskn.) Pugsley Hydromethanolic Extract: Bioactive Compounds Identification, Hypotensive Mechanism, and Cardioprotective Potential Exploration

Fumaria indica (Hausskn.) Pugsley (FIP), a member of the Papaveraceae family, has a documented history of use in traditional medicine to treat cardiovascular ailments, particularly hypertension, and has shown substantial therapeutic efficacy among native cultures worldwide. However, the identification of bioactive compounds and the mechanism of hypotensive effect with the cardioprotective potential investigations are yet to be determined. The study aimed to identify bioactive compounds, explore the hypotensive mechanism and cardioprotective potential, and assess the safety of Fumaria indica (Hausskn.) Pugsley hydromethanolic extract (Fip.Cr). LC ESI-MS/MS analysis was performed to identify the bioactive compounds. In vitro experiments were conducted on isolated rat aorta and atria, and an in vivo invasive BP measurement model was used. Acute and subacute toxicities were assessed for 14 and 28 days, respectively. Isoproterenol (ISO) was used to develop the rats' myocardial infarction damage model. The mRNA levels of NLRP3 inflammasome and the abundance level of Firmicutes and Lactobacillus were measured by qRT-PCR. The hypotensive effect of FIP bioactive compounds was also investigated using in silico methods. Fip. Cr LC ESI-MS/MS analysis discovered 33 bioactive compounds, including alkaloids and flavonoids. In isolated rat aorta, Fip.Cr reversed contractions induced by K+ (80 mM), demonstrating a calcium entry-blocking function, and had a vasorelaxant impact on phenylephrine (PE) (1 μM)-induced contractions unaffected by L-NAME, ruling out endothelial NO participation. Fip.Cr caused negative chronotropic and inotropic effects in isolated rat atria unaffected by atropine pretreatment, eliminating cardiac muscarinic receptor involvement. Safety evaluation showed no major adverse effects. In vivo, invasive BP measurement demonstrated a hypotensive effect comparable to verapamil. Fip.Cr protected the rats from ISO-induced MI interventions significantly in biometrical and cardiac serum biochemical indicators and histological examinations by reducing inflammation via inhibiting NLRP3 inflammasome and elevating Firmicutes and Lactobacillus levels. The network pharmacology study revealed that the FIP hypotensive mechanism might involve MMP9, JAK2, HMOX1, NOS2, NOS3, TEK, SERPINE1, CCL2, and VEGFA. The molecular docking study revealed that FIP bioactive compounds docked better with CAC1C_ HUMAN than verapamil. These findings demonstrated that Fip.Cr's hypotensive mechanism may include calcium channel blocker activity. Fip.Cr ameliorated ISO-induced myocardial infarction in rats by attenuating inflammation, which might be via inhibiting NLRP3 inflammasome and may prove beneficial for treating MI.

Phenyl glycosides from Bacopa monnieri with their antioxidant and anti-inflammatory activities

Bacopa monnieri (L.) Wettst (Plantaginaceae), is traditionally used in many countries as neural tonic and memory enhancer, or to relieve acute pain and inflammation. This study described the isolation and identification of one new, bacomoside D3 (1), and seven known phenyl glycosides (2 - 8). The structures of isolates were established by analysis of their spectroscopic data or hydrolysis followed by HPLC analysis together with a comparison to those reported in the literature. These compounds were evaluated for antioxidant and anti-inflammatory activities. Among them, compounds 4 and 5 exhibited strong DPPH radical scavenging activity with IC50 values of 9.77 ± 0.08 and 3.50 ± 0.04 µM, respectively. Compounds 2 and 5 significantly inhibited TNF-α production in LPS-stimulated RAW264.7 cells with IC50 values of 40.60 ± 3.05 and 38.19 ± 1.75 µM, respectively. Furthermore, the active compounds could be efficient inhibitors of oxidants by interfering with the DPPH activity in silico study.

Combinatory Approaches Targeting Cognitive Impairments and Memory Enhancement: A Review

The objective of this paper is to look at how natural medicines can improve cognition and memory when used with sildenafil, a popular erectile dysfunction medicine that also has nootropic properties. Newer treatment strategies to treat the early stages of these diseases need to be developed. Multiple factors lead to complex pathophysiological conditions, which are responsible for various long-term complications. In this review, a combination of treatments targeting these pathologies is discussed. These combinations may help manage early and later phases of cognitive impairments. The purpose of this article is to discuss a link between these pathologies and a combinational approach with the objective of considering newer therapeutic strategies in the treatment of cognitive impairments. The natural drugs and their ingredients play a major role in the management of disease progression. Additionally, their combination with sildenafil allows for more efficacy and better response. Studies showing the effectiveness of natural drugs and sildenafil are mentioned, and how these combinations could be beneficial for the treatment of cognitive impairments and amnesia are summarised. Furthermore, preclinical and clinical trials are required to explore the medicinal potential of these drug combinations.

Ayurvedic Herbal Therapies: A Review of Treatment and Management of Dementia

Dementia has been characterized by atypical neurological syndromes and several cognitive deficits, such as extended memory loss, strange behavior, unusual thinking, impaired judgment, impotence, and difficulty with daily living activities. Dementia is not a disease, but it is caused by several neurodegenerative diseases, such as Alzheimer's, Parkinson's, and Lewy's bodies. Several drugs and remedies are indicated for alleviating unusual cognitive decline, but no effective pharmacological treatment regimens are available without side effects. Herbal drugs or traditional medicines like Ayurveda have been known for facilitating and corroborating the balance between mind, brain, body, and environment. Ayurvedic therapy comprises 600 herbal formulas, 250 single plant remedies, and natural and holistic health-giving treatments that relieve dementia in patients and increase vitality. Ayurvedic Rasayana herbs [rejuvenating elements] strengthen the brain cells, enhance memory, and decrease stress. The current medicine scenario in the treatment of dementia has prompted the shift in exploring the efficacy of ayurvedic medicine, its safety, and its efficiency. This review presents the literature on several herbal treatments for improving dementia symptomatology and patients' quality of life.

Metabolomics based mechanistic insights to vasorelaxant and cardioprotective effect of ethanolic extract of Citrullus lanatus (Thunb.) Matsum. & Nakai. seeds in isoproterenol induced myocardial infraction

BACKGROUND

Cardiovascular diseases (CVDs) are a significant cause of morbidity and death in the current world, posing a challenge to both developing and industrialized nation's health systems. Citrullus lanatus (Thunb.) Matsum. & Nakai. seeds have long been utilized to supplement and enhance health and treat cardiovascular illnesses. However, its treatments for CVDs are still unknown. More research is required to fully comprehend the impact of C. lanatus seeds on vasorelaxation and myocardial infractions.

PURPOSE

Therefore, an integrated metabolomics profiling technique was used to investigate possible pathways of C. lanatus in isoproterenol (ISO)-induced myocardial infarction (MI). Isoproterenol causes long-term cardiac hypertrophy by causing cardiomyocyte compensatory loss, eventually leading to heart failure.

METHODS

In vitro models of vasoconstriction, atrium, and in vivo models of invasive blood pressure measurement and isoproterenol (ISO) induced cardiac hypertrophy in rats were used to understand underlying mechanistic by LC-MS/MS based dynamic metabolomics analysis of the serum and heart samples to be investigated the effect of ethanolic extract of C. lanatus (Cl.EtOH).

RESULTS

Cl.EtOH exhibited vasorelaxant, negative chronotropic, and inotropic effects in in-vitro models whereas, a potent hypotensive effect was observed in normotensive rats. The Cl.EtOH protected the animals from ISO-induced myocardial infarction (MI) with therapeutic interventions in left ventricular thickness, cardiomyocyte hypertrophy, mRNA gene expression, biochemical assays, and metabolomic profiling of serum and heart tissues.

CONCLUSIONS

For the first time, our study confirmed that C. lanatus seeds (Cl.EtOH) possess significant antihypertensive and prevent ISO-induced myocardial infarction. These findings comprehensively demonstrated mechanistic insights of Cl.EtOH in vasorelaxation and myocardial infarction. The current study provides evidence for further mechanistic studies and the development of C. lanatus seeds as a potential therapeutic intervention for patients with cardiovascular disorders.

Metabolomics analysis delineates the therapeutic effects of hydroethanolic extract of Cucumis sativus L. seeds on hypertension and isoproterenol-induced myocardial infarction

Cucumis sativus L., widely cultivated as an edible vegetable. Its seeds are well reputed for cardiovascular preventive properties. However, the mechanisms underlying for cardiovascular protection of C. sativus are still unidentified. Therefore, this study utilized a metabolomics approach to investigate putative mechanisms of C. sativus seeds in myocardial infarction (MI) and in vitro models of vasoconstriction, atrium, and invasive blood pressure measurement. Results showed that Cu.EtOH extract showed a vasorelaxant response with potent hypotensive effect in normotensive rats and L-NAME induced hypertension. Cu.EtOH caused a negative inotropic and positive chronotropic effect on the atrium. Cu.EtOH protected the animals from ISO-induced myocardial infarction (MI) interventions in left ventricular thickness, cardiomyocyte hypertrophy, mRNA gene expression, and biochemical assays. The metabolomics data suggested that Cu.EtOH mainly affected amino acid metabolism, BCAA degradation, ketone bodies degradation, and oxidative stress. Our study showed that Cu.EtOH suppressed inflammation with a strong anti-myocardial infarction impact. Additionally, our findings indicated Cu.EtOH reverted the amino acid metabolism, BCAA, and ketone bodies degradation. The findings show the antihypertensive mechanism of Cu.EtOH may include the modulation of endothelium-derived relaxing factor (EDRF) produced from nitric oxide (NO) and is connected with vascular endothelial function. C. sativus seeds, in particular, played a pivotal role in the treatment of myocardial and vascular disorders by enhancing the EDRF mechanism, energy generation, and antioxidant capacity. In summary, our findings showed the mechanistic insights on the therapeutic potential of C. sativus seeds for cardiovascular disorders.

Effect of Ayurveda intervention in the integrated management of essential hypertension- a retrospective observational study

BACKGROUND

A study titled 'Integration of AYUSH (Ayurveda) with National Programme for Prevention and Control of Cancer, Diabetes, Cardiovascular Diseases and Stroke (NPCDCS)' implemented in India in three districts of three states, namely Bhilwara (Rajasthan), Gaya (Bihar), and Surendranagar (Gujarat) since 2015 for the management of various non-communicable diseases (NCDs) through integrated approach.

OBJECTIVE(S)

To evaluate the effect of Ayurveda medication, lifestyle modification, and Yoga in integration with standard care for the management of essential hypertension.

MATERIAL AND METHODS

A retrospective analysis of the demographic and clinical records available from NPCDCS-AYUSH Integration Project was done. The data of participants with Essential Hypertension (EHTN), aged between 30 and 60 years, who had completed six months integrated management as per the treatment protocol of the NPCDCS-AYUSH Integration project between July 2018 and March 2019 were taken and distributed in two groups based on their intervention. Those advised for lifestyle modification and Yoga in addition to standard care with any of the five medicines/combinations i.e. Amlodipine or Atenolol or Amlodipine + Atenolol or Losartan or Telmisartan were assigned Group I and those who were given Ayurveda medication, lifestyle modification and Yoga in addition to standard care were assigned to Group II. The change in blood pressure was analysed and dose reduction/discontinuation of conventional medications was also observed.

RESULTS

Data of 1938 participants who had completed treatment under the NPCDCS program was analysed. At the 6th month, systolic and diastolic blood pressure was significantly reduced (P < 0.01) in all categories of Group I and Group II from baseline. Further, the dose of conventional medicine was reduced in 33.1% of participants of Group I and in 30.4% participants of Group II when compared to 0 day while conventional medicines were discontinued in 15.1% of Group I and 36.7% of Group II participants.

CONCLUSION

Ayurveda medication along with lifestyle management and Yoga effectively controls systolic and diastolic blood pressure and further helps in reducing/discontinuation of dose of conventional medicines in EHTN participants.

Characterization of Metabolites in Plasma, Urine and Feces of Healthy Participants after Taking Brahmi Essence for Twelve Weeks Using LC-ESI-QTOF-MS Metabolomic Approach

Brahmi essence, developed from Bacopa monnieri (L.) Wettst. standardized extract and mulberry juice, was proven to improve the memory speed of healthy participants aged 55–80 years old, following a 12-week dietary program. However, the metabolites have not yet been reported. Our objective was to characterize the altered metabolites in the plasma, urine, and feces of healthy volunteers after consumption of Brahmi essence for 12 weeks, using the LC-MS metabolomics approach. The altered metabolites were selected from OPLS-DA S-plots; 15 metabolites in the plasma, 7 in the urine, and 17 in the feces samples were tentatively identified by comparison with an online database and literature. The metabolites in the plasma samples were in the classes of amino acids, acylcarnitine, and phospholipids. Benzeneactamide-4-O-sulphate and 3-hydroxyhippuric acid were found in urine samples. The metabolites in the class of amino acids, together with jujubogenin and pseudojujubogenin, were identified in the fecal samples. The aminoacyl-tRNA, aromatic amino acids, and branched-chain amino acid biosynthetic pathways were mainly related to the identified metabolites in all three samples. It could be implied that those metabolites and their pathways might be linked with the effect of Brahmi essence on memory speed.

Bioactive Compounds and Traditional Herbal Medicine: Promising Approaches for the Treatment of Dementia

Dementia is a term that encompasses a group of clinical symptoms affecting memory, thinking and social abilities, characterized by progressive impairment of memory performance and cognitive functions. There are several factors involved in the pathogenesis and progression of dementia, such as old age, brain ischemia, toxin exposure, and oxidative stress. There are extensive similarities between dementia and Alzheimer's disease (AD) either in clinical manifestations or experimental animal models. AD is the most dominant form of dementia, characterized by the accumulation of beta-amyloid protein and cholinergic neurotransmission deficits in the brain. Currently available medications for the treatment of dementia, such as choline esterase inhibitors, N-methyl-D-aspartate (NMDA) antagonists (memantine), have short-term efficacy and only relieve symptoms rather than targeting the main underlying pathogenesis. Several animal studies and clinical trials are being conducted to provide a rational approach to these medicinal plants in the prevention or treatment of memory deficits. This review highlights the potential effects of medicinal plants and their derived lead molecules, and explains the related mechanisms and effects reviewed from published literature as major thrust aspects and hopeful strategies in the prevention or treatment of dementia.

Secondary Metabolites of Plants as Modulators of Endothelium Functions

According to the World Health Organization, cardiovascular diseases are the main cause of death worldwide. They may be caused by various factors or combinations of factors. Frequently, endothelial dysfunction is involved in either development of the disorder or results from it. On the other hand, the endothelium may be disordered for other reasons, e.g., due to infection, such as COVID-19. The understanding of the role and significance of the endothelium in the body has changed significantly over time—from a simple physical barrier to a complex system encompassing local and systemic regulation of numerous processes in the body. Endothelium disorders may arise from impairment of one or more signaling pathways affecting dilator or constrictor activity, including nitric oxide–cyclic guanosine monophosphate activation, prostacyclin–cyclic adenosine monophosphate activation, phosphodiesterase inhibition, and potassium channel activation or intracellular calcium level inhibition. In this review, plants are summarized as sources of biologically active substances affecting the endothelium. This paper compares individual substances and mechanisms that are known to affect the endothelium, and which subsequently may cause the development of cardiovascular disorders.

New Nutraceutical Combination Reduces Blood Pressure and Improves Exercise Capacity in Hypertensive Patients Via a Nitric Oxide-Dependent Mechanism

Background

High blood pressure (BP) has long been recognized as a major health threat and, particularly, a major risk factor for stroke, cardiovascular disease, and end‐organ damage. However, the identification of a novel, alternative, integrative approach for the control of BP and cardiovascular protection is still needed.

Methods and Results

Sixty‐nine uncontrolled hypertension patients, aged 40 to 68 years, on antihypertensive medication were enrolled in 2 double‐blind studies. Forty‐five were randomized to placebo or a new nutraceutical combination named AkP05, and BP, endothelial function, and circulating nitric oxide were assessed before and at the end of 4 weeks of treatment. Twenty‐four patients were randomized to diuretic or AkP05 for 4 weeks and underwent a cardiopulmonary exercise test to evaluate the effects of AkP05 on functional capacity of the cardiovascular, pulmonary, and muscular systems. Vascular and molecular studies were undertaken on mice to characterize the action of the single compounds contained in the AkP05 nutraceutical combination. AkP05 supplementation reduced BP, improved endothelial function, and increased nitric oxide release; cardiopulmonary exercise test revealed that AkP05 increased maximum O₂ uptake, stress tolerance, and maximal power output. In mice, AkP05 reduced BP and improved endothelial function, evoking increased nitric oxide release through the PKCα/Akt/endothelial nitric oxide synthase pathway and reducing reactive oxygen species production via NADPH‐oxidase inhibition. These effects were mediated by synergism of the single compounds of AkP05.

Conclusions

This is the first study reporting positive effects of a nutraceutical combination on the vasculature and exercise tolerance in treated hypertensive patients. Our findings suggest that AkP05 may be used as an adjunct for the improvement of cardiovascular protection and to better control BP in uncontrolled hypertension.

Bacopa Monnieri Protects the Directly Affected Organ as Well as Distant Organs Against I/R Injury by Modulating Anti-Inflammatory and Anti-Nitrosative Pathways in A Rat Model for Infra-Renal Aortic Occlusion

OBJECTIVE

To investigate the protective effect and underlying mechanisms of B. monnieri, a medicinal plant, on kidney and skeletal muscle injury induced by infra-renal abdominal aorta clamping for 2-hours (ischemia) and following removal of the clamp (reperfusion, 2-hours).

METHODS

Rats were divided into four groups (n = 6): (I) animals given only saline (sham-control); (II) animals given B. monnieri extract for 10-days (300 mg/kg/day) (Bacopa-treated sham); (III) animals subjected to ischemia/reperfusion (I/R); (IV) animals given B. monnieri extract and then subjected to I/R. Kidneys and lower extremity muscles were examined for GPx, CAT, iNOS, 3-NT, IL-1β and TNF-α. Apoptosis and injury were evaluated by TUNEL and H&E staining, respectively.

RESULTS

I/R resulted in TUNEL positive cells, periarterial edema and glomerular capillary dilatation, decreased GPx activity, unchanged CAT, iNOS, 3-NT, IL-1β and TNF-α in kidney. B. monnieri minimized renal remote reperfusion injury, and Group IV showed a lower degree of renal histopathology score when compared to the others. B. monnieri mitigated muscle I/R injury, decreased muscle hypertrophy, myofibril abnormalities and apoptosis. Muscle 3-NT and cytokine levels were increased by I/R, and B. monnieri inhibited iNOS and 3-NT both in sham-control and I/R groups. Muscle GPx unaffected by I/R or B. monnieri, but CAT was inhibited only in B. monnieri-treated I/R group. Muscle iNOS, 3-NT, IL-1β, TNF-α levels and CAT activity of B. monnieri-treated I/R rats were lower than those in sham-control or Bacopa-treated sham.

CONCLUSIONS

B. monnieri can protect the directly affected organ as well as distant organs against I/R injury by modulating anti-inflammatory and anti-nitrosative pathways.

Insights Into the Molecular Aspects of Neuroprotective Bacoside A and Bacopaside I

Bacopa monnieri, commonly known as Brahmi, has been extensively used as a neuromedicine for various disorders such as anxiety, depression and memory loss. Chemical characterization studies revealed the major active constituents of the herb as the triterpenoid saponins, bacosides. Bacoside A, the vital neuroprotective constituent, is composed of four constituents viz., bacoside A3, bacopaside II, jujubogenin isomer of bacopasaponin C (bacopaside X) and bacopasaponin C. B. monnieri extracts as well as bacosides successfully establish a healthy antioxidant environment in various tissues especially in the liver and brain. Free radical scavenging, suppression of lipid peroxidation and activation of antioxidant enzymes by bacosides help to attain a physiological state of minimized oxidative stress. The molecular basis of neuroprotective activity of bacosides is attributed to the regulation of mRNA translation and surface expression of neuroreceptors such as AMPAR, NMDAR and GABAR in the various parts of the brain. Bioavailability as well as binding of neuroprotective agents (such as bacosides) to these receptors is controlled by the Blood Brain Barrier (BBB). However, nano conversion of these drug candidates easily resolves the BBB restriction and carries a promising role in future therapies. This review summarizes the neuroprotective functions of B. monnieri extracts as well as its active compounds (bacoside A, bacopaside I) and the molecular mechanisms responsible for these pharmacological activities.

Hetero-Tricyclic Lead Scaffold as Novel PDE5A Inhibitor for Antihypertensive Activity: In Silico Docking Studies

Objective:

To screen the phytochemicals for phosphodiesterase 5A (PDE5A) inhibitory potential and identify lead scaffolds of antihypertensive phytochemicals using in silico docking studies.

Methods:

In this perspective, reported 269 antihypertensive phytochemicals were selected. Sildenafil, a PDE5A inhibitor was used as the standard. In silico docking study was carried out to screen and identify the inhibiting potential of the selected phytochemicals against PDE5A enzyme using vLife MDS 4.4 software.

Results:

Based on docking score, π-stacking, H-bond and ionic interactions, 237 out of 269 molecules were selected which have shown one or more interactions. Protein residue Gln817A was involved in H-boding whereas Val782A, Phe820A and Leu804A were involved in π-stacking interaction with ligand. The selected 237 phytochemicals were structurally diverse, therefore 82 out of 237 molecules with one or more tricycles were filtered out for further analysis. Amongst tricyclic molecules, 14 molecules containing nitrogen heteroatom were selected for lead scaffold identification which finally resulted in three different basic chemical backbones like pyridoindole, tetrahydro-pyridonaphthyridine and dihydro-pyridoquinazoline as lead scaffolds.

Conclusion:

In silico docking studies revealed that nitrogen-containing tetrahydro-pyridonaphthyridine and dihydro-pyridoquinazoline tricyclic lead scaffolds have emerged as novel PDE5A inhibitors for antihypertensive activity. The identified lead scaffolds may provide antihypertensive lead molecules after its optimization.

Vasodilatory Effects and Mechanisms of Action of Bacopa monnieri Active Compounds on Rat Mesenteric Arteries

B. monnieri extract (BME) is an abundant source of bioactive compounds, including saponins and flavonoids known to produce vasodilation. However, it is unclear which components are the more effective vasodilators. The aim of this research was to investigate the vasorelaxant effects and mechanisms of action of saponins and flavonoids on rat isolated mesenteric arteries using the organ bath technique. The vasorelaxant mechanisms, including endothelial nitric oxide synthase (eNOS) pathway and calcium flux were examined. Saponins (bacoside A and bacopaside I), and flavonoids (luteolin and apigenin) at 0.1-100 µM caused vasorelaxation in a concentration-dependent manner. Luteolin and apigenin produced vasorelaxation in endothelial intact vessels with more efficacy (Emax 99.4 ± 0.7 and 95.3 ± 2.6%) and potency (EC50 4.35 ± 1.31 and 8.93 ± 3.33 µM) than bacoside A and bacopaside I (Emax 83.6 ± 2.9 and 79.9 ± 8.2%; EC50 10.8 ± 5.9 and 14.6 ± 5.4 µM). Pretreatment of endothelial intact rings, with L-NAME (100 µM); an eNOS inhibitor, or removal of the endothelium reduced the relaxant effects of all compounds. In K+-depolarised vessels suspended in Ca2+-free solution, these active compounds inhibited CaCl2-induced contraction in endothelial denuded arterial rings. Moreover, the active compounds attenuated transient contractions induced by 10 µM phenylephrine in Ca2+-free medium containing EGTA (1 mM). Thus, relaxant effects occurred in both endothelial intact and denuded vessels which signify actions through both endothelium and vascular smooth muscle cells. In conclusion, the flavonoids have about twice the potency of saponins as vasodilators. However, in the BME, there is ~20 × the amount of vaso-reactive saponins and thus are more effective.

Neuropharmacological and cognitive effects of Bacopa monnieri (L.) Wettst - A review on its mechanistic aspects

Bacopa monnieri (L.) - (BM) is a perennial, creeping herb which is widely used in traditional ayurvedic medicine as a neural tonic to improve intelligence and memory. Research into the biological effects of this plant has burgeoned in recent years, promising its neuroprotective and memory boosting ability among others. In this context, an extensive literature survey allows an insight into the participation of numerous signaling pathways and oxidative mechanism involved in the mitigation of oxidative stress, along with other indirect mechanisms modulated by bioactive molecules of BM to improve the cognitive action by their synergistic potential and cellular multiplicity mechanism. This multi-faceted review describes the novel mechanisms that underlie the unfounded but long flaunted promises of BM and thereby direct a way to harness this acquired knowledge to develop innovative approaches to manipulate its intracellular pathways.

Celosia argentea L. (Amaranthaceae) a vasodilator species from the Brazilian Cerrado - An ethnopharmacological report

ETHNOPHARMACOLOGICAL RELEVANCE

Celosia argentea L. (Amaranthaceae), popularly known as "crista de galo", is used in folk medicine due to its diuretic and hypotensive effects. However, there are no reports in the literature regarding its pharmacological effects on the cardiovascular system as well as no data proving the safety of this species.

AIM

To perform a detailed ethnopharmacological investigation of the ethanol soluble fraction from C. argentea (ESCA) using male and female Wistar rats.

MATERIAL AND METHODS

Firstly, a morpho-anatomical characterization was performed to determine the quality control parameters for the identification of the species under investigation. Then, the ethanol extract was obtained and chemically characterized by LC-DAD-MS. Furthermore, an oral acute toxicity study was performed in female Wistar rats. Finally, the possible diuretic and hypotensive effects of three different doses of ESCA (30, 100 and 300 mg/kg) were evaluated in male Wistar rats. Besides, the vasodilatory response of ESCA in mesenteric vascular beds (MVBs) and its involvement with nitric oxide/cGMP and prostaglandin/cAMP pathways as well as potassium channels were evaluated.

RESULTS

The main secondary metabolites present in ESCA were phenolic compounds, megastigmanes and triterpenoid saponins. ESCA caused no toxic effects in female rats nor increased urinary excretion in male rats after acute administration. However, ESCA significantly increased the renal elimination of potassium and chloride, especially at the end of 24 h after administration. Intermediary dose (100 mg/kg) of ESCA was able to promote significant acute hypotension and bradycardia. Moreover, its cardiovascular effects appear to be involved with the voltage-dependent K⁺ channels activation in MVBs.

CONCLUSION

This study has brought new scientific evidence of preclinical efficacy of C. argentea as a hypotensive agent in normotensive rats. Apparently, these effects are involved with the activation of the voltage-sensitive K⁺ channels contributing to the reduction of peripheral vascular resistance and cardiac output.

Extract of Aquilaria crassna leaves and mangiferin are vasodilators while showing no cytotoxicity

The leaves of Aquilaria spp. promote “physiological balance”, and are “cardiotonic and provide blood nourishment”. In Asia, these leaves are increasingly consumed as tea and claimed to provide benefits to cardiovascular function, albeit without any scientific proof. Therefore, this study sought to evaluate the action of Aquilaria crassna leaf aqueous extract (AE) on vascular function and vascular smooth muscle cytotoxicity. AE and a main constituent, mangiferin were investigated for their vasorelaxation of rat mesenteric arteries and aortae in vitro. Acute cytotoxicity of AE (0.1–1000 μg/ml) and mangiferin (0.1–100 μM) on rat enzymatically isolated vascular smooth muscle cells was assayed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide. AE dilated rat mesenteric arteries (EC₅₀∼107 μg/ml, E_max∼95%) more than aorta (EC₅₀∼265 μg/ml, E_max∼76%, p < 0.05).

AE-induced vasodilation in mesenteric artery was reduced by endothelial removal (EC₅₀∼202 μg/ml, p < 0.05), incubation with endothelial nitric oxide synthase (eNOS) (100 μM, L-NAME) (EC₅₀∼309 μg/ml, p < 0.05), and partly reduced by L-type Ca²⁺ channel blockade at higher concentrations. Likewise, mangiferin (1–100 μM) dilated the mesenteric artery more potently than the aorta. However, its maximum relaxation was less than with AE (41% in the mesenteric artery and <10% in the aorta). Isolated vascular smooth muscle cells incubated in AE or mangiferin for 1 h showed no cytotoxicity. Thus, AE is a vasorelaxant while being free of acute cytotoxicity towards vascular smooth muscle, thus potentially ameliorating human vascular dysfunction.

Structural characteristics, bioavailability and cardioprotective potential of saponins

Cardiovascular diseases are the leading cause of death, accounting about 31% deaths globally in 2012. The major risk factors causing cardiovascular diseases are coronary atherosclerosis, hyperlipidemia, myocardial infarction, and stroke. The dominating cause of cardiovascular diseases is accredited to our modern lifestyle and diet. Medicinal plants have been used for the prevention and treatment of cardiovascular diseases from centuries. The in built chirality and chemical space of natural products have been playing an important role in providing leads and templates for pharmacophore synthesis. This review highlights one of the important naturally occurring class saponins and their role in cardioprotection along with structural characteristics and pharmacological effects such as antioxidant, Ca²⁺ ion regulation, antiapoptotic, antiatherosclerosis, antihyperlipidemic, hypocholesterolemic, angiogenic, vasodilatory, and hypotensive. The characteristic cholesterol lowering, hemolytic, and anticoagulant properties of the saponins prompted us to select as one of the natural products class for cardioprotection. This review covers the most updated information on saponins related to their cardioprotective effects, mechanism of action, bioavailability, and structure activity relationship.

A bacosides containing Bacopa monnieri extract alleviates allodynia and hyperalgesia in the chronic constriction injury model of neuropathic pain in rats

BACKGROUND

The current therapy of neuropathic pain is inadequate and is limited by the extent of pain relief and the occurrence of dose dependant side effects. Insufficient control of pain with conventional medications prompts the use of complementary and alternative medicine therapies by patients with neuropathic pain. This study therefore investigated a standardized methanolic extract of Bacopa monnieri, a widely reputed nootropic plant, for prospective antinociceptive effect in the chronic constriction injury (CCI) model of neuropathic pain.

METHODS

Placement of four loose ligatures around the sciatic nerve produced partial denervation of the hindpaw in rats. Bacopa monnieri (40 and 80 mg/kg, p.o) and the positive control, gabapentin (75 mg/kg, i.p), were administered daily after CCI or sham surgery and the behavioral paradigms of static- and dynamic-allodynia (paw withdrawal threshold to von Frey filament stimulation [PWT] and paw withdrawal latency to light-brushing [PWL]), cold-allodynia (paw withdrawal duration [PWD] to acetone), heat- (PWL to heat-stimulus) and punctate-hyperalgesia (PWD to pin-prick) were assessed on days 3, 7, 14 and 21.

RESULTS

CCI consistently generated static- (days 3-21), dynamic- (days 14-21) and cold-allodynia (days 3-21) plus heat- and mechano-hyperalgesia (days 3-21). The tested doses of Bacopa monnieri significantly attenuated the CCI-induced allodynia and hyperalgesia, exemplified by increased PWT (days 7-21), PWL to light brushing (days 14-21) and heat (days 7-21) as well as decreased PWD to pin prick and cold stimuli (days 3-21). The extract also counterbalanced the CCI-induced aberrations in the nociceptive behaviors by increasing the pain threshold to that of pre-surgery baseline. Gabapentin also afforded analogous beneficial behavioral profile but of higher magnitude.

CONCLUSIONS

Our findings suggest that Bacopa monnieri can be used as adjuvant therapy for neuropathic pain conditions afflicted with allodynia and hyperalgesia.

Neurocognitive Effect of Nootropic Drug Brahmi (Bacopa monnieri) in Alzheimer's Disease

Alzheimer's disease (AD) is a progressive neurodegenerative disease of the elderly. The rapid increase in its incidence has necessitated development of newer drugs. Ayurvedic herbal medications are increasingly researched due to their biosafety profile and usefulness in cognitive impairment. In this article, we critically reviewed one such Medhya Rasayana (nootropic drug) Brahmi-derived from extract of Bacopa monnieri (EBm). Studies have shown that EBm promotes free radical scavenger mechanisms and protects cells in prefrontal cortex, hippocampus, and striatum against cytotoxicity and DNA damage implicated in AD. It also reduces lipoxygenase activity reducing lipid peroxidation, increases glutathione peroxidase and chelates iron. Administration of EBm was seen to protect the cholinergic neurons and reduce anticholinesterase activity comparable to donepezil, rivastigmine, and galantamine. It also reduces hippocampal β-amyloid deposition and stress-induced hippocampal damage. The neuroprotective effect of EBm is also due to nitric oxide-mediated cerebral vasodilation. EBm improved the total memory score and maximum improvement was seen in logical memory and paired associate learning in humans and reversed phenytoin-induced memory impairment in experimental model. EBm has not shown any serious clinical, neurological, hematological complications, or vital organs damage in experimental studies. Rats showed marked reduction in fertility; however, libido was unaffected. There is no experimental evidence of genotoxicity or teratogenesis by use of EBm. Mild nausea and gastrointestinal upset are seen in humans. Brahmi promises to be a novel agent in AD; however, further human trials are recommended to verify the efficacy and rule out any side effects as evidenced by the experimental models.

A Pharmacological Examination of the Cardiovascular Effects of Malayan Krait (Bungarus candidus) Venoms

Cardiovascular effects (e.g., tachycardia, hypo- and/or hypertension) are often clinical outcomes of snake envenoming. Malayan krait (Bungarus candidus) envenoming has been reported to cause cardiovascular effects that may be related to abnormalities in parasympathetic activity. However, the exact mechanism for this effect has yet to be determined. In the present study, we investigated the in vivo and in vitro cardiovascular effects of B. candidus venoms from Southern (BC-S) and Northeastern (BC-NE) Thailand. SDS-PAGE analysis of venoms showed some differences in the protein profile of the venoms. B. candidus venoms (50 µg/kg-100 µg/kg, i.v.) caused dose-dependent hypotension in anaesthetised rats. The highest dose caused sudden hypotension (phase I) followed by a return of mean arterial pressure to baseline levels and a decrease in heart rate with transient hypertension (phase II) prior to a small decrease in blood pressure (phase III). Prior administration of monovalent antivenom significantly attenuated the hypotension induced by venoms (100 µg/kg, i.v.). The sudden hypotensive effect of BC-NE venom was abolished by prior administration of hexamethonium (10 mg/kg, i.v.) or atropine (5 mg/kg, i.v.). BC-S and BC-NE venoms (0.1 µg/kg-100 µg/ml) induced concentration-dependent relaxation (EC₅₀ = 8 ± 1 and 13 ± 3 µg/mL, respectively) in endothelium-intact aorta. The concentration-response curves were markedly shifted to the right by pre-incubation with L-NAME (0.2 mM), or removal of the endothelium, suggesting that endothelium-derived nitric oxide (NO) is likely to be responsible for venom-induced aortic relaxation. Our data indicate that the cardiovascular effects caused by B. candidus venoms may be due to a combination of vascular mediators (i.e., NO) and autonomic adaptation via nicotinic and muscarinic acetylcholine receptors.

Bacopa monnieri extract increases rat coronary flow and protects against myocardial ischemia/reperfusion injury

Background

This study explored Bacopa monnieri, a medicinal Ayurvedic herb, as a cardioprotectant against ischemia/reperfusion injury using cardiac function and coronary flow as end-points.

Methods

In normal isolated rat hearts, coronary flow, left ventricular developed pressure, heart rate, and functional recovery were measured using the Langendorff preparation. Hearts were perfused with either (i) Krebs-Henseleit (normal) solution, (control), or with 30, 100 μg/ml B. monnieri ethanolic extract (30 min), or (ii) with normal solution or extract for 10 min preceding no-perfusion ischemia (30 min) followed by reperfusion (30 min) with normal solution. Infarct volumes were measured by triphenyltetrazolium staining. L-type Ca²⁺-currents (I_{Ca, L}) were measured by whole-cell patching in HL-1 cells, a mouse atrial cardiomyocyte cell line. Cytotoxicity of B. monnieri was assessed in rat isolated ventricular myocytes by trypan blue exclusion.

Results

In normally perfused hearts, B. monnieri increased coronary flow by 63 ± 13% (30 μg/ml) and 216 ± 21% (100 μg/ml), compared to control (5 ± 3%) (n = 8–10, p < 0.001). B. monnieri treatment preceding ischemia/reperfusion improved left ventricular developed pressure by 84 ± 10% (30 μg/ml), 82 ± 10% (100 μg/ml) and 52 ± 6% (control) compared to pre- ischemia/reperfusion. Similarly, functional recovery showed a sustained increase. Moreover, B. monnieri (100 μg/ml) reduced the percentage of infarct size from 51 ± 2% (control) to 25 ± 2% (n = 6-8, p < 0.0001). B. monnieri (100 μg/ml) reduced I_{Ca, L} by 63 ± 4% in HL-1 cells. Ventricular myocyte survival decreased at higher concentrations (50–1000 μg/ml) B. monnieri.

Conclusions

B. monnieri improves myocardial function following ischemia/reperfusion injury through recovery of coronary blood flow, contractile force and decrease in infarct size. Thus this may lead to a novel cardioprotectant strategy.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-017-1637-z) contains supplementary material, which is available to authorized users.

Acute and chronic toxicities of Bacopa monnieri extract in Sprague-Dawley rats

BACKGROUND

Bacopa monnieri is a medicinal plant which has long been used in Ayurvedic medicines to augment brain function and to improve memory. The purpose of our study was to identify and evaluate possible toxic effects of B. monnieri extract in rats by assessing hematological, biochemical, and histopathological parameters.

METHODS

Acute oral toxicity of Bacopa monnieri extract was studied in female rats by giving a single orally administered dose at a level of 5,000 mg/kg. The rats were monitored for toxic signs for 14 days. In the chronic toxicity test, groups of both female and male rats were given daily oral doses of B. monnieri extract at dose levels of either 30, 60, 300 or 1,500 mg/kg for 270 days. The behavior and health of the animals was then monitored. At the end of the observation period, the body and organ weights of the rats in each group were measured. Blood was collected and necropsy was performed to evaluate their hematology, blood clinical chemistry, and microanatomy.

RESULTS

The acute toxicity test found no significant differences between the experimental and the control group rats. In the chronic toxicity test, animal behavior and health of the experimental groups were normal, just as in the control rats. All values of other parameters assessed remained within the normal range.

CONCLUSION

A single oral administration of B. monnieri extract at the dose of 5,000 mg/kg did not cause any serious undesirable effects. B. monnieri extract at doses of 30, 60, 300 and 1,500 mg/kg given for 270 days did not produce any toxicity in rats.

LC-ESI-QTOF-MS based screening and identification of isomeric jujubogenin and pseudojujubogenin aglycones in Bacopa monnieri extract

Bacopa monnieri (L.) Wettst. (Scrophulariaceae) is an Ayurvedic medicinal plant used as a memory enhancer. Its major chemical constituents are Bacopa saponins consisting of jujubogenin and pseudojujubogenin glycosides. These two aglycones are isomers different at the positions of prenyl substitution i.e., at C-23 for jujubogenin and at C-22 for pseudojujubogenin. In this study, we demonstrate the rapid and comprehensive characterization of saponin glycosides in B. monnieri using liquid chromatography with electrospray ionization quadrupole time-of-flight mass spectrometer (LC-ESI-QTOF-MS). This shows that ESI-QTOF-MS in positive-ion mode, jujubogenin and pseudojujubogenin glycosides could be discriminated by the peak abundance ratio of m/z 455 [Aglycone+H-H2O](+) to m/z of 473 [Aglycone+H](+). Furthermore, the sequence of sugar moieties can be observed. In a similar manner, the isomeric saponins; deoxyjujubogenin and deoxypseudojujubogenin glycosides can be distinguished using the m/z 437[Aglycone+H-H2O](+) and m/z 455[Aglycone+H](+) peak ratio. Use of the negative-ion mode with MS/MS fragmentation can provide information about the type of sugar linked to the aglycone i.e., at m/z 633 (aglycone+glucose) or at m/z 603 (aglycone+arabinose). With our method, 62 chemical constituents in B. monnieri including saponin glycosides, flavonoids, and alkaloids were identified. This is the first systematic study in structural characterization on isomeric saponins and other metabolites in B. monnieri using ESI-QTOF-MS.

Overview of Antagonists Used for Determining the Mechanisms of Action Employed by Potential Vasodilators with Their Suggested Signaling Pathways

This paper is a review on the types of antagonists and the signaling mechanism pathways that have been used to determine the mechanisms of action employed for vasodilation by test compounds. Thus, we exhaustively reviewed and analyzed reports related to this topic published in PubMed between the years of 2010 till 2015. The aim of this paperis to suggest the most appropriate type of antagonists that correspond to receptors that would be involved during the mechanistic studies, as well as the latest signaling pathways trends that are being studied in order to determine the route(s) that atest compound employs for inducing vasodilation. The methods to perform the mechanism studies were included. Fundamentally, the affinity, specificity and selectivity of the antagonists to their receptors or enzymes were clearly elaborated as well as the solubility and reversibility. All the signaling pathways on the mechanisms of action involved in the vascular tone regulation have been well described in previous review articles. However, the most appropriate antagonists that should be utilized have never been suggested and elaborated before, hence the reason for this review.

Anti-Hypertensive Herbs and Their Mechanisms of Action: Part II

Traditional medicine has a history extending back to thousands of years, and during the intervening time, man has identified the healing properties of a very broad range of plants. Globally, the use of herbal therapies to treat and manage cardiovascular disease (CVD) is on the rise. This is the second part of our comprehensive review where we discuss the mechanisms of plants and herbs used for the treatment and management of high blood pressure. Similar to the first part, PubMed and ScienceDirect databases were utilized, and the following keywords and phrases were used as inclusion criteria: hypertension, high blood pressure, herbal medicine, complementary and alternative medicine, endothelial cells, nitric oxide (NO), vascular smooth muscle cell (VSMC) proliferation, hydrogen sulfide, nuclear factor kappa-B (NF-κB), oxidative stress, and epigenetics/epigenomics. Each of the aforementioned keywords was co-joined with plant or herb in question, and where possible with its constituent molecule(s). This part deals in particular with plants that are used, albeit less frequently, for the treatment and management of hypertension. We then discuss the interplay between herbs/prescription drugs and herbs/epigenetics in the context of this disease. The review then concludes with a recommendation for more rigorous, well-developed clinical trials to concretely determine the beneficial impact of herbs and plants on hypertension and a disease-free living.

Beneficial effects of Bacopa monnieri extract on opioid induced toxicity

The present study examined the hepatotoxicity and nephrotoxicity of morphine and illicit street heroin and their amelioration by a standardized methanolic extract of Bacopa monnieri (L.) (mBME) in rats. Morphine or street heroin was administered at a dose of 20 mg/kg for 14 and 21 days. mBME (40 mg/kg) or ascorbic acid (50 mg/kg) was administered two hours before morphine or street heroin. High performance liquid chromatography (HPLC) was used for the standardization of bacoside-A major components in mBME. The antioxidant potential of mBME was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay. Administration of morphine and street heroin resulted in marked elevation of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and creatinine. Histopathological changes induced by morphine and street heroin after 14 days were of reversible nature while treatment for 21 days was associated with irreversible changes. Pretreatment with mBME or ascorbic acid restored the elevation of serum ALT, AST and creatinine and protected liver and kidneys from the toxicological influence of morphine and street heroin. HPLC analysis showed that mBME contained bacoside-A major components i.e. bacoside-A₃ (37.5 μg/mg), bacopaside-II (4.62 μg/mg) and bacopasaponin-C (1.91 μg/mg). The EC₅₀ for the DPPH free radical scavenging assay revealed that mBME possessed strong antioxidant potential. These results concluded that as compared to morphine, street heroin was associated with severe biochemical and histopathological changes in the liver and kidneys. Bacopa monnieri having strong antioxidant potential may provide a beneficial herbal remedy for the efficient management of opioid related hepatotoxicity and nephrotoxicity.

Autonomic Nervous System Mediates the Hypotensive Effects of Aqueous and Residual Methanolic Extracts of Syzygium polyanthum (Wight) Walp. var. polyanthum Leaves in Anaesthetized Rats

Syzygium polyanthum (Wight) Walp. var. polyanthum leaves are consumed as a traditional Malay treatment of hypertension. This study investigates hypotensive potential of aqueous (AESP) and residual methanolic (met-AESP) extracts of S. polyanthum leaves and possible involvement of autonomic receptors. AESP and met-AESP (20 to 100 mg/kg) were intravenously administered into anaesthetized Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rats. Blood pressure and heart were monitored for 20 min. AESP and met-AESP induced significant dose-dependent hypotension, but only 100 mg/kg AESP caused mild bradycardia (n = 5). AESP-induced hypotension was more potent than that of met-AESP in WKY. AESP has a faster onset time than that of met-AESP in both WKY and SHR. However, met-AESP-induced hypotension was more sustained than that of AESP in SHR. Blockages of autonomic ganglion and α-adrenergic receptors using hexamethonium and phentolamine (n = 5 for each group) partially attenuated AESP-induced hypotension, suggesting involvement of α-adrenergic receptors. Blockages of autonomic ganglion, β-adrenergic, cholinergic receptors, and nitric oxide production using hexamethonium, propranolol, atropine, and N-ω-nitro-l arginine methyl ester (L-NAME) (n = 5 for each group) partially attenuated met-AESP-induced hypotension, suggesting involvement of β-adrenergic and cholinergic receptors via nitric oxide production.

Neuropharmacological review of the nootropic herb Bacopa monnieri

This review synthesizes behavioral research with neuromolecular mechanisms putatively involved with the low-toxicity cognitive enhancing action of Bacopa monnieri (BM), a medicinal Ayurvedic herb. BM is traditionally used for various ailments, but is best known as a neural tonic and memory enhancer. Numerous animal and in vitro studies have been conducted, with many evidencing potential medicinal properties. Several randomized, double-blind, placebo-controlled trials have substantiated BM's nootropic utility in humans. There is also evidence for potential attenuation of dementia, Parkinson's disease, and epilepsy. Current evidence suggests BM acts via the following mechanisms-anti-oxidant neuroprotection (via redox and enzyme induction), acetylcholinesterase inhibition and/or choline acetyltransferase activation, β-amyloid reduction, increased cerebral blood flow, and neurotransmitter modulation (acetylcholine [ACh], 5-hydroxytryptamine [5-HT], dopamine [DA]). BM appears to exhibit low toxicity in model organisms and humans; however, long-term studies of toxicity in humans have yet to be conducted. This review will integrate molecular neuroscience with behavioral research.

Bacopa monnieri increases cerebral blood flow in rat independent of blood pressure

Bacopa monnieri (L.) Wettst. (Brahmi in India and Thailand) is an ayurvedic dementia treatment, but its effect on cerebral blood flow (CBF) is still unknown. We sought to test its chronic and acute effects on CBF compared with Ginkgo biloba and donepezil. CBF was measured by laser Doppler from rat cerebral cortex after 8 weeks of daily oral dosing of these drugs. Systolic blood pressure was also measured using the tail cuff method or via arterial cannulation. In rats treated with B. monnieri (40 mg/kg), CBF was 25% increased [2927 ± 123 perfusion units, (PU)] compared with shams (2337 ± 217 PU, p < 0.05, nine rats). G. biloba (60 mg/kg) also increased CBF (by 29% to 3019 ± 208 PU, p < 0.05, nine rats). No clear effect was obtained with donepezil (1 mg/kg). Chronic administration of the preparations had no effect on blood pressure. In contrast, intravenous acute infusion of these herbals (20-60 mg/kg) had marked dose-dependent hypotensive actions (diastolic ~31 mmHg lower with 40 mg/kg of either extract), which correspondingly reduced CBF by ~15%. Likewise, CBF fell slightly with acute intravenous sodium nitroprusside and rose with noradrenaline. Donepezil (1 mg/kg) was slightly hypotensive without affecting CBF. Increased CBF with B. monnieri may account for its reported procognitive effect, and its further exploration as an alternative nootropic drug is worthwhile.