Medicinal Plants in the Treatment of Hypertension: A Review

Plant-Derived Coumarins: A Narrative Review of Their Structural and Biomedical Diversity

Plant-derived coumarin (PDC) is a naturally occurring heterocyclic backbone that belongs to the benzopyrone family. PDC and its based products are characterized by low toxicity and high distribution in a variety of herbal treatments that have numerous therapeutic potentials. These include anticoagulants, antibacterials, anti-inflammatory agents, anticancer agents, antioxidants, and others. So, it may be appropriate to investigate the qualities and potential bioactivities of PDCs. This article provides an overview of the biomedical potentials, availability, and clinical use possibilities of PDCs, with a focus on their important modes of action, using information on various pharmacological qualities discovered. The data used in this study came from published research between 2015 and 2023. We reviewed a selection of databases, including PubMed, Scopus, Web of Science, and Google Scholar, during that period. In conclusion, because of their abundance in medicinal plants, the clinical biochemistry attributes of PDCs are currently of interest. In a variety of medical specialties, PDCs serve a useful role as therapeutic agents.

Safety classification of herbal medicine use among hypertensive patients: a systematic review and meta-analysis

Background

The use of herbal medicines (HMs) for the treatment of hypertension (HTN) is increasing globally, but research on the potential adverse effects and safety of HMs in HTN patients is limited. Therefore, this systematic review and meta-analysis aim to determine the global prevalence of HM usage among HTN patients and assess the safety of identified herbs based on current scientific evidence.

Methods

The PubMed/MEDLINE, EMBASE (Ovid), and Cumulated Index to Nursing and Allied Health Literature (CINAHL) databases were searched for cross-sectional studies on the use of HM among HTN patients. Our review includes studies published in English up to the year 2023. After extracting and appraising the data from the studies, a meta-analysis was conducted using the Stata version 16.0 to estimate the pooled prevalence of HM use in patients with HTN (PROSPERO: CRD42023405537). The safety classification of the identified HM was done based on the existing scientific literature.

Results

This study analyzed 37 cross-sectional studies from 21 countries and found that 37.8% of HTN patients used HM to manage their health. The prevalence of HM use varied significantly based on publication year and geographical region. Among the 71 identified herbs, Allium sativum L., Hibiscus sabdariffa L., and Olea europaea L. were the most commonly used. However, four herbs were identified as contraindicated, 50 herbs required caution, and only 11 herbs were considered safe for use.

Conclusion

The study highlights the potential risks of toxicities and adverse effects associated with HM use in the treatment of HTN. Ensuring patient safety involves using safe HMs in appropriate doses and avoiding contraindicated HMs. Future research should focus on identifying commonly used herbs, especially in resource-limited countries with poor HTN management, and additional clinical research is required to assess the toxicity and safety of commonly used HMs.

Anti-obesity Properties of Phytochemicals: Highlighting their Molecular Mechanisms against Obesity

Obesity is a complex, chronic and inflammatory disease that affects more than one-third of the world's population, leading to a higher incidence of diabetes, dyslipidemia, metabolic syndrome, cardiovascular diseases, and some types of cancer. Several phytochemicals are used as flavoring and aromatic compounds, also exerting many benefits for public health. This study aims to summarize and scrutinize the beneficial effects of the most important phytochemicals against obesity. Systematic research of the current international literature was carried out in the most accurate scientific databases, e.g., Pubmed, Scopus, Web of Science and Google Scholar, using a set of critical and representative keywords, such as phytochemicals, obesity, metabolism, metabolic syndrome, etc. Several studies unraveled the potential positive effects of phytochemicals such as berberine, carvacrol, curcumin, quercetin, resveratrol, thymol, etc., against obesity and metabolic disorders. Mechanisms of action include inhibition of adipocyte differentiation, browning of the white adipose tissue, inhibition of enzymes such as lipase and amylase, suppression of inflammation, improvement of the gut microbiota, and downregulation of obesity-inducing genes. In conclusion, multiple bioactive compounds-phytochemicals exert many beneficial effects against obesity. Future molecular and clinical studies must be performed to unravel the multiple molecular mechanisms and anti-obesity activities of these naturally occurring bioactive compounds.

Cucumber (Cucumis sativus L.) Fruit and Combination with Losartan Attenuate the Elevation of Blood Pressure in Hypertensive Rats Induced by Angiotensin II

Objectives

Cucumis sativus L. (C. sativus) is vegetable commonly used for managing blood pressure and often consumed in combination with standard antihypertensive therapy, despite lack of scientific evidence supporting their use. Combination of herbs and standard medication could have positive or negative effects. Therefore, this study aimed to evaluate the antihypertensive activity of C. sativus and the combined effect with losartan in the hypertensive rat model induced by angiotensin II. Angiotensin II is a component of the renin-angiotensin-aldosterone system that, upon binding to its receptor, constricts blood vessels leading to elevation of blood pressure.

Methods

In an antihypertensive study, rats received C. sativus orally at doses of 9, 18, 27, and 36 mg/kg (full dose); while in a combination study, animals received losartan 2.25 mg/kg combined by either with C. sativus 9 or 18 mg/kg. The standards group received losartan 2.25 mg/kg or 4.5 mg/kg (full dose).

Results

Blood pressure was measured using the tail-cuff method. C. sativus significantly attenuated angiotensin II-induced hypertension as observed in groups receiving C. sativus at 9, 18, 27, and 36 mg/kg at 30 minutes after induction showed the average change (Δ) of systolic blood pressure (SBP) and diastolic blood pressure (DBP) with respect to time zero were 28.8/18.3, 24.8/15.8, 22.8/15.5, and 11.5/9.0 mmHg, respectively. Whereas the average change (Δ) of SBP and DBP in the rats receiving the combination of half doses of C. sativus and losartan were 8.8/9.0 mmHg, respectively. These diminished effects were better than a full dose of C. sativus and comparable with a full dose of losartan (6.5/7.8 mmHg).

Conclusion

The present findings indicate that C. sativus dose-dependently blocks blood pressure elevation induced by angiotensin II. The combination of half dose of C. sativus and losartan has an additive effect in lowering blood pressure.

Green synthesis-assisted copper nanoparticles using Aegle marmelos leaves extract: physical, optical, and antimicrobial properties

In the present report, Aegle marmelos leaf powder was used to synthesize copper nanoparticles (CuNPs) using a simple and cost-effective method. A. marmelos leaves have various medicinal uses including for the treatment of diarrhoea, constipation, diabetes, cholera, skin diseases, earache, blood purification, heart problems, and so on. The plant biomolecules induce the reduction of Cu2+ ions to CuNPs and also act as a capping and stabilizing agent. The formation of CuNPs was confirmed using photoluminescence (PL) excitation and emission spectra on a Shimadzu RF-5301 PC spectrofluorophotometer and the absorbance spectra of a UV-visible spectrophotometer at different stages during the synthesis process. In addition, other properties of synthesized CuNPs were also investigated using X-ray diffraction, Fourier transform infrared spectroscopy, and transmission electron microscopy techniques. The average size of the synthesized CuNPs was in the range 20-40 nm. Furthermore, the synthesized NPs were also considered for an antimicrobial study against Gram-positive Staphylococcus aureus and Proteus, and Gram-negative Escherichia coli and Salmonella spp. using the agar well diffusion method. The zone of inhibition against the Gram-positive bacteria was greater than the zone of inhibition against the Gram-negative bacteria. These investigation results suggest that synthesized NPs are promising nanomaterials for use as antimicrobial agents.

Vasorelaxant Mechanism of Herbal Extracts from Mentha suaveolens, Conyza canadensis, Teucrium polium and Salvia verbenaca in the Aorta of Wistar Rats

Mentha suaveolens (MS), Conyza canadensis (CC), Teucrium polium (TP) and Salvia verbenaca (SV) are used in Morocco to treat hypertension. Our aim was to characterize the composition and vasoreactivity of extracts of MS, CC, TP and SV. The chemical compositions of aqueous extracts of MS, SV and TP, and of a hydromethanolic extract of CC, were identified by HPLC-DAD. The vasoreactive effect was tested in rings of the thoracic aorta of female Wistar rats (8-14 weeks-old) pre-contracted with 10 µM noradrenaline, in the absence or presence of L-NAME 100 µM, indomethacin 10 µM or atropine 6 µM, to inhibit nitric oxide synthase, cyclooxygenase or muscarinic receptors, respectively. L-NAME and atropine decreased the vasorelaxant effect caused by low concentrations of MS. Atropine and indomethacin decreased the vasorelaxant effect of low concentrations of SV. High concentrations of MS or SV and the effect of SV and TP were not altered by any antagonist. The activation of muscarinic receptors and NO or the cyclooxygenase pathway underlie the vasorelaxant effect of MS and SV, respectively. Neither of those mechanisms underlines the vasorelaxant effect of CC and TP. These vasorelaxant effect might support the use of herbal teas from these plants as anti-hypertensives in folk medicine.