Bradycardic and Antiarrhythmic Effects of the D-Limonene in Rats

Endothelial-dependent relaxation of α-pinene and two metabolites, myrtenol and verbenol, in isolated murine blood vessels

Epidemiological evidence shows that residential proximity to greenspaces is associated with lower risk of all-cause and cardiovascular mortality; however, the mechanism(s) underlying this link remains unclear. Plants emit biogenic volatile organic compounds such as α-pinene that could elicit beneficial cardiovascular effects. To explore the role of α-pinene more directly, we studied the metabolism and the vascular effects of α-pinene. We found that exposure of mice to α-pinene (1 ppm, 6 h) generated two phase I oxidation metabolites, cis- and trans-verbenol [(1R,2R,5R)-verbenol and (1 R,2S,5R)-verbenol)] and myrtenol [(1S,5R)-(+)-myrtenol] that were identified in urine by GC-MS. Precontracted naïve murine male and female aorta and superior mesenteric artery (SMA) were relaxed robustly (60% tension reduction) by increasing concentrations of α-pinene, myrtenol, and verbenol to 0.3 mM, whereas 1 mM α-pinene was vasotoxic. The SMA was six times more sensitive than the aorta to α-pinene. Both myrtenol and verbenol were equally potent and efficacious as parent α-pinene in male and female SMA. The sensitive portion of the α-pinene-, myrtenol-, and verbenol-induced relaxations in male SMA was mediated by 1) endothelium, 2) eNOS-derived NO, and 3) guanylyl cyclase (GC) activity. Moreover, α-pinene activated the transient receptor potential ankyrin-1 (TRPA1) channel whereas the metabolites did not. Endothelial-derived NO regulates blood flow, blood pressure, and thrombosis, and it is plausible that inhaled (and ingested) α-pinene (or its metabolites) augments NO release to mediate the cardiovascular benefits of exposure to greenness.NEW & NOTEWORTHY A common plant-derived biogenic volatile organic compound, α-pinene, and two of its metabolites, myrtenol and verbenol, stimulate vasorelaxation in murine superior mesenteric artery. Both α-pinene- and its metabolites induce vasorelaxation by activation of the endothelium, nitric oxide, and guanylyl cyclase. α-Pinene also activates the transient receptor potential ankyrin-1. Positive associations between greenness exposure and human cardiovascular health may be a result of the vascular action of α-pinene and its metabolites, a novel consideration.

The Effect of Ginger Supplementation on the Improvement of Dyspeptic Symptoms in Patients With Functional Dyspepsia

Background Functional dyspepsia (FD) is a common gastrointestinal disorder with a higher occurrence in the Western world. Conventional medications are not effective for FD with patients turning to alternative herbal medicines such as ginger. This study aimed to evaluate the effect of ginger supplementation on the improvement of FD symptoms. Methodology A before-and-after clinical study was conducted at the University of Debrecen, Internal Medicine outpatient department over a period of four weeks. Two Swanson ginger supplements each at a dose of 540 mg/day before lunch and dinner were given to 51 FD patients. Wilcoxon signed-rank test was used to estimate the differences in FD symptoms after ginger supplementation and at the baseline. The p-value was determined to test the association between variables, with p-values <0.05 considered the cutoff for statistically significant association. Results In this study, after four weeks of ginger supplementation, we observed a significant change in most dyspepsia symptoms as follows: postprandial fullness (p = 0.033, 95% CI = 0.01-0.26), early satiety (p = 0.001, 95% CI = 0.10-0.37), epigastric pain (p = 0.000, 95% CI = 0.16-0.42), epigastric burning (p = 0.003, 95% CI = 0.10-0.45), and heartburn (p = 0.209, 95% CI = -0.04-0.20). Conclusions Based on our findings ginger can be considered as a promising alternative supplementary medicine for FD.

In Silico Prediction of Selected Bioactive Compounds Present in Alpinia elegans (C.Presl) K.Schum Seed Oil as Potential Drug Candidates Against Human Cancer Cell Lines

OBJECTIVE

Alpinia elegans (Zingiberaceae) is a Philippine endemic plant reported to have various folkloric uses. The seed oil of A. elegans has been shown to contain a majority of the following bioactive compounds: D-limonene, α-pinene, and caryophyllene oxide. The study sought to determine if the bioactive compounds found in A. elegans seed oil would be a good natural, inexpensive, and less-detrimental alternative for cancer treatment.

METHODS

The study utilized in silico (Way2Drug predictive services, SwissADME, AutoDock 4) experiment to examine the aforementioned compounds as viable therapeutic candidates against human cancer cell lines.

RESULT

Results determined that the compounds D-limonene, α-pinene, and caryophyllene oxide were most potent against thyroid gland carcinoma (8505C) cells, brain glaucoma (Hs 683) cells, and promyeloblast leukemia (HL-60) cells, respectively. Additionally, D-limonene was the only compound to show arrhythmia as an adverse effect. Predictions showed that the compounds could inhibit cellular growth factors and serine/threonine-protein kinase activity. The compounds generated a bioavailability score of 0.55 and exhibited blood-brain barrier (BBB) penetration. D-limonene, α-pinene, and caryophyllene oxide had binding energy of -4.59, -5.43, and -6.92, respectively.

CONCLUSION

The binding energy indicated that the ligands could securely dock to the receptors, thus suggesting that interaction between the ligands and receptors was stable. Results have shown that the compounds are promising candidates against human cancer cell lines by inhibiting cell proliferation and inducing apoptosis.

Mentha: Nutritional and Health Attributes to Treat Various Ailments Including Cardiovascular Diseases

A poor diet, resulting in malnutrition, is a critical challenge that leads to a variety of metabolic disorders, including obesity, diabetes, and cardiovascular diseases. Mentha species are famous as therapeutic herbs and have long served as herbal medicine. Recently, the demand for its products, such as herbal drugs, medicines, and natural herbal formulations, has increased significantly. However, the available literature lacks a thorough overview of Mentha phytochemicals' effects for reducing malnutritional risks against cardiovascular diseases. In this context, we aimed to review the recent advances of Mentha phytochemicals and future challenges for reducing malnutritional risks in cardiovascular patients. Current studies indicated that Mentha species phytochemicals possess unique antimicrobial, antidiabetic, cytotoxic, and antioxidant potential, which can be used as herbal medicine directly or indirectly (such as food ingredients) and are effective in controlling and curing cardiovascular diseases. The presence of aromatic and flavor compounds of Mentha species greatly enhance the nutritional values of the food. Further interdisciplinary investigations are pivotal to explore main volatile compounds, synergistic actions of phytochemicals, organoleptic effects, and stability of Mentha sp. phytochemicals.

(-)-Carvone Modulates Intracellular Calcium Signaling with Antiarrhythmic Action in Rat Hearts

Fundamento:

A (-)-carvona é um monoterpeno encontrado em óleos essenciais com atividade antioxidante e anti-inflamátoria.

Objetivos:

O objetivo deste estudo foi analisar a propriedade antiarrítmica da (-)-carvona no coração de rato e seus efeitos sobre a sinalização de Ca⁺² intracelular.

Métodos:

Os efeitos da (-)-carvona foram avaliados sobre a contratilidade atrial (0,01 – 4 mM) e ventricular (0,5 mM), e no eletrocardiograma (0,5mM). A fração de encurtamento, a corrente de cálcio do tipo L (I_Ca,L) e a sinalização de Ca⁺² foram medidas no cardiomiócito isolado (0,5 mM). O efeito antiarrítmico foi avaliado no modelo de arritmia induzida por sobrecarga de cálcio (0,5 mM) (n = 5). Um p < 0,05 foi adotado como nível de significância estatística.

Resultados:

No átrio, a (-)-carvona causou inotropismo negativo de maneira concentração-dependente (EC₅₀ 0,44 ± 0,11 mM) e diminuiu o inotropismo positivo induzido pelo CaCl₂ (0,1 – 8,0 mM) e BAY K8644 (5 - 500 nM), um agonista de canal de cálcio do tipo L. Em coração isolado, a (-)-carvona (0,5mM) reduziu a contratilidade ventricular em 73% e a frequência cardíaca (em 46%), aumentou o Pri (30,7%, tempo desde o início da onda P até a onda R) e o QTc (9,2%, uma medida de despolarização e repolarização dos ventrículos), sem mudar a duração do complexo QRS. A (-)-carvona diminuiu a fração de encurtamento (61%), a (I_Ca,L) (79%) e o transiente intracelular de Ca⁺² (38%). Além disso, a (-)-carvona apresentou ação antiarrítmica, identificada pela redução do escore de arritmia (85%) e ocorrência de fibrilação ventricular.

Conclusão:

A (-)-carvona reduz a entrada de Ca⁺² através de canais de Ca⁺² do tipo L e, assim, diminui a contratilidade cardíaca e o Ca⁺² intracelular e apresenta promissora atividade antiarrítmica no coração de ratos.

Monoterpenes and their derivatives as agents for cardiovascular disease management: A systematic review and meta-analysis

BACKGROUND

Monoterpenes are one of the most studied plant's secondary metabolites, they are found abundantly in essential oils of aromatic plants. They also have a great range of pharmacological properties, such as antihypertensive, bradycardic, antiarrhythmic and hypotensive. In the face of the burden caused by cardiovascular disease (CVDs) worldwide, studies using monoterpenes to assess their cardiovascular effects have increased over the years.

PURPOSE

This systematic review aimed to summarize the use of monoterpenes in animal models of any CVDs.

METHODS

PubMed, SCOPUS, LILACS and Web of Science databases were used to search for articles that used monoterpenes, in any type of administration, to treat or prevent CVDs in animal models. The PRISMA guidelines were followed. Two independent researchers extracted main characteristics of studies, methods and outcomes. Data obtained were analyzed qualitatively and quantitatively.

RESULTS

At the ending of the search process, 33 articles were selected for the systematic review. Of these, 17 articles were included in the meta-analysis. A total of 16 different monoterpenes were found for the treatment of hypertension, myocardial infarction, pulmonary hypertension, cardiac hypertrophy and arrhythmia. The main actions include hypotension, bradycardia, vasodilatation, antiarrhythmic, and antioxidant and antiapoptotic properties. From our data, it can be suggested that monoterpenes may be a significant source for new drug development. However, there is still a need to apply these knowledge into clinical research and a long path to pursue before putting them in the market.

CONCLUSION

The variability of cardiovascular effects demonstrated by the monoterpenes highlighted them as a promising candidates for treatment or prevention of CVDs. Nevertheless, studies that investigate their biological sites of action needs to be further encouraged.

Can limonene be a possible candidate for evaluation as an agent or adjuvant against infection, immunity, and inflammation in COVID-19?

Coronavirus disease (COVID-19) caused by novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an ongoing pandemic and presents a public health emergency. It has affected millions of people and continues to affect more, despite the tremendous social preventive measures. The therapeutic strategy relies on suppressing infectivity and inflammation, along with immune modulation. The identification of candidate drugs effective for COVID-19 is crucial, thus many natural products including phytochemicals are also being proposed for repurposing and evaluated for their potential in COVID-19. Among numerous phytochemicals, limonene (LMN), a dietary terpene of natural origin has been recently showed to target viral proteins in the in-silico studies. LMN is one of the main compounds identified in many citrus plants, available and accessible in diets and well-studied for its therapeutic benefits. Due to dietary nature, relative safety and efficacy along with favorable physicochemical properties, LMN has been suggested to be a fascinating candidate for further investigation in COVID-19. LMN showed to modulate numerous signaling pathways and inhibits inflammatory mediators, including cytokines, chemokines, adhesion molecules, prostanoids, and eicosanoids. We hypothesized that given the pathogenesis of COVID-19 involving infection, inflammation, and immunity, LMN may have potential to limit the severity and progression of the disease owing to its immunomodulatory, anti-inflammatory, and antiviral properties. The present article discusses the possibilities of LMN in SARS-CoV-2 infections based on its immunomodulatory, anti-inflammatory, and antiviral properties. Though, the suggestion on the possible use of LMN in COVID-19 remains inconclusive until the in-silico effects confirmed in the experimental studies and further proof of the concept studies. The candidature of LMN in COVID-19 treatment somewhat appear speculative but cannot be overlooked provided favorable physiochemical and druggable properties. The safety and efficacy of LMN are necessary to be established in preclinical and clinical studies before making suggestions for use in humans.

Terpenoids as Potential Geroprotectors

Terpenes and terpenoids are the largest groups of plant secondary metabolites. However, unlike polyphenols, they are rarely associated with geroprotective properties. Here we evaluated the conformity of the biological effects of terpenoids with the criteria of geroprotectors, including primary criteria (lifespan-extending effects in model organisms, improvement of aging biomarkers, low toxicity, minimal adverse effects, improvement of the quality of life) and secondary criteria (evolutionarily conserved mechanisms of action, reproducibility of the effects on different models, prevention of age-associated diseases, increasing of stress-resistance). The number of substances that demonstrate the greatest compliance with both primary and secondary criteria of geroprotectors were found among different classes of terpenoids. Thus, terpenoids are an underestimated source of potential geroprotectors that can effectively influence the mechanisms of aging and age-related diseases.