Gastroprotective effect of the alkaloid boldine: Involvement of non-protein sulfhydryl groups, prostanoids and reduction on oxidative stress

Boldine: a narrative review of the bioactive compound with versatile biological and pharmacological potential

OBJECTIVE

Boldine is a plant-derived bioactive compound that has a beneficial impact on human health. Boldine is an aporphine alkaloid mainly obtained from the leaves and bark of the Chilean Boldo tree (Peumus boldus, Family: Monimiaceae). There are plenty of preclinical evidence supports that boldine exerts its beneficial effects against various diseases. Lumiskin™, a patented and marketed formulation by Revitol Skincare for skin brightening, contains Dicetyl boldine, a boldine derivative.

CONTENT

All the available information on the Chilean boldo tree (P. boldus Molina) species was actualized by systematically searching the scientific databases (PubMed, SciFinder, Web of Science, Google Scholar, Scopus and others) and scientific literature. This article covers the recent advances in pharmacokinetic, toxicological, pharmacological/biological activities, and molecular mechanisms of the bioactive compound to understand health benefits of boldine better.

SUMMARY

Boldine exerts antioxidant, hepatoprotective, anti-atherosclerotic, anti-diabetic, analgesic, antipyretic, anti-inflammatory, anti-epileptic, neuroprotective, nephroprotective, anti-arthritis, anticancer and nootropic effects. Moreover, boldine exhibits its various pharmacological activities by altering antioxidant parameters (MDA, superoxide dismutase, glutathione), peroxynitrite, inflammatory markers apoptotic index, caspase-3, acetyl-cholinesterase, myeloperoxidase, TNF-α (Tumor necrosis factor-α), iNOS, Bcl-2-associated X protein (BAX), ACE-1(Angiotensin-converting enzyme-1), dopamine D2 receptors and nicotinic acetylcholine receptor. Boldine has the potential to modulate a variety of biological networks.

OUTLOOK

Due to its versatile pharmacological effects reported in various experimental animals as well as in randomized clinical trials for the treatment of facial melasma and for treatment of urinary stone lithotripsy in children as a complementary phytotherapy; in the future, this compound might be developed as a novel drug for a different indication.

Diuretic, Natriuretic, And Ca2+-Sparing Effect Of The Alkaloid Boldine In Rats

BACKGROUND

Previous studies indicate the renal vasodilating effects of boldine, an alkaloid found in Peumus boldus. However, its potential to induce diuresis still needs to be studied.

METHODS

Wistar rats were used and the urine volume was noted for 8 h and further studied.

RESULTS

The acute treatment at 0.1 and 0.3 mg/kg of boldine showed a diuretic, natriuretic, and Ca2+-sparing effect in rats without changing the urinary elimination of K+and Cl-. When boldine was given in combination with hydrochlorothiazide, there was an increase in urinary volume compared to the vehicle group. However, this was not different from the treatments in its isolated form. Urine Ca2+values ​​remained low but were not enhanced by this association. The excretion of Na+and Cl- was significantly increased compared to the group that received only vehicle or boldine. On the other hand, although the association of amiloride plus boldine did not result in a diuretic effect, the increase in Na+and the reduction in K+excretion were significantly potentiated. Furthermore, in the presence of the non-selective muscarinic receptor antagonist atropine, boldine showed reduced capacity to increase urinary volume, maintaining the natriuretic and Ca2+-sparing effect, besides a very evident K+-sparing action. Similar results were obtained in the presence of the non-selective cyclooxygenase inhibitor indomethacin. Furthermore, boldine showed an ex vivo antiurolithiasis activity, reducing calcium oxalate's precipitation and crystallization.

CONCLUSIONS

This study reveals the diuretic, natriuretic, Ca2+-sparing, and antiurolithiatic effects of boldine, an action possibly related to muscarinic receptor activation and prostanoid generation.

Coconut oil based self-nano emulsifying delivery systems mitigate ulcerogenic NSAIDs side effect and enhance drug dissolution: Formula optimization, in-vitro, and in-vivo assessments

Gastric ulcer is a common gastrointestinal ailment that affects many people worldwide. NSAIDs induced ulcers are the second most common etiology of gastric ulcers. Coconut oil has well-known potential anti-ulcerogenic characteristics. This work aimed to develop and optimize diclofenac potassium (a highly used model drug of NSAIDs) as self-nanoemulsifying delivery system containing coconut oil (DFP-COSNEDS) to overcome its ulcerogenic effect. A mixture design was applied for formula optimization and investigation of the effect of different formulation factors on the droplet size (DS) and polydispersity index (PDI) of the prepared DFP-COSNEDS. The optimized formulae showed good self-emulsification characters and better drug dissolution compared with the drug suspension. The ulcer protection was assessed in-vivo using 7 groups of adult male Wistar rats. Oxidative stress parameters (MDA, GSH, and SOD), inflammatory mediators (PGE-2, TNF-α, and IL-6) and peroxisome proliferator-activated receptor-γ (PPAR-γ) gene expression were measured. The results revealed that pure coconut oil and DFP-COSNEDS containing 25 % of coconut oil showed close figures to normal group and better values than famotidine (FAM) group. In conclusion, coconut oil showed high potential for gastric-protection activity against DFP induced ulcer. DFP-COSNEDS offers dual benefits of improving DFP dissolution and alleviating its ulcerogenic effect.

Biotransformation of Modified Benzylisoquinoline Alkaloids: Boldine and Berberine and In Silico Molecular Docking Studies of Metabolites on Telomerase and Human Protein Tyrosine Phosphatase 1B

Natural nitrogen heterocycles biotransformation has been extensively used to prepare synthetic drugs and explore the fate of therapeutic agents inside the body. Herein, the ability of filamentous fungi to biotransform boldine and berberine was investigated. Docking simulation studies of boldine, berberine and their metabolites on the target enzymes: telomerase (TERT) and human protein tyrosine phosphatase 1B (PTP-1B) were also performed to investigate the anticancer and antidiabetic potentials of compounds in silico. The biotransformation of boldine and berberine with Cunninghamella elegans NRRL 2310, Rhodotorula rubra NRRL y1592, Penicillium chrysogeneum ATCC 10002, Cunninghamella blackesleeana MR198 and Cunninghamella blackesleeana NRRL 1369 via demethylation, N- oxidation, glucosidation, oxidation and hydroxylation reactions produced seven metabolites, namely: 1,10-didesmethyl-boldine (1), laurolitsine (2), 1,10-didesmethyl-norboldine (3), boldine-9-O-β-D-glucoside (4), tridesmethyl berberine (5), demethylene berberine (6), and lambertine (7). Primarily, the structures of the metabolites were established by one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) analyses and mass spectrometry. In silico molecular docking simulation of the metabolites of boldine and berberine to the proteins TERT and PTP-1B, respectively, revealed good binding MolDock scores comparable to boldine and berberine and favorable interactions with the catalytic sites of the proteins. In conclusion, this study presented promising biologically prepared nitrogen scaffolds (isoquinolines) of boldine and berberine.

Treatment of Gastrointestinal Disorders-Plants and Potential Mechanisms of Action of Their Constituents

The worldwide prevalence of gastrointestinal diseases is about 40%, with standard pharmacotherapy being long-lasting and economically challenging. Of the dozens of diseases listed by the Rome IV Foundation criteria, for five of them (heartburn, dyspepsia, nausea and vomiting disorder, constipation, and diarrhoea), treatment with herbals is an official alternative, legislatively supported by the European Medicines Agency (EMA). However, for most plants, the Directive does not require a description of the mechanisms of action, which should be related to the therapeutic effect of the European plant in question. This review article, therefore, summarizes the basic pharmacological knowledge of synthetic drugs used in selected functional gastrointestinal disorders (FGIDs) and correlates them with the constituents of medicinal plants. Therefore, the information presented here is intended as a starting point to support the claim that both empirical folk medicine and current and decades-old treatments with official herbal remedies have a rational basis in modern pharmacology.

Boldine, an Alkaloid from Peumus boldus Molina, Induces Endothelium-Dependent Vasodilation in the Perfused Rat Kidney: Involvement of Nitric Oxide and Small-Conductance Ca2+-Activated K+ Channel

Boldine, 2,9-dihydroxy-1,10-dimethoxyaporphine, is the main alkaloid found in the leaves and bark of Peumus boldus Molina. In recent years, boldine has demonstrated several pharmacological properties that benefit endothelial function, blood pressure control, and reduce damage in kidney diseases. However, the renal vasodilator effects and mechanisms remain unknown. Herein, perfused rat kidneys were used to study the ability of boldine to induce vasodilation of renal arteries. For that, left kidney preparations with and without functional endothelium were contracted with phenylephrine and received 10–300 nmol boldine injections. The preparations were then perfused for 15 min with phenylephrine plus L-NAME, indomethacin, KCl, tetraethylammonium, glibenclamide, apamin, charybdotoxin, or iberiotoxin. In 30, 100, and 300 nmol doses, boldine induced a dose-and endothelium-dependent relaxing effect on the renal vascular bed. No vasodilator effects were observed in preparations lacking functional endothelium. While the inhibition of the cyclooxygenase enzyme through the addition of indomethacin did not cause any change in the vasodilating action of boldine, the nonselective nitric oxide synthase inhibitor L-NAME fully precluded the vasodilatory action of boldine at all doses tested. The perfusion with KCl or tetraethylammonium (nonselective K⁺ channels blocker) also abolished the vasodilatory effect of boldine, indicating the participation of K⁺ channels in the renal action of boldine. The perfusion with glibenclamide (selective ATP-sensitive K⁺ channels blocker), iberiotoxin (selective high-conductance Ca²⁺-activated K⁺ channel blocker), and charybdotoxin (selective high- and intermediate-conductance Ca²⁺-activated K⁺ channel blocker) did not modify the vasodilatory action of boldine. On the other hand, the perfusion with apamin (selective small-conductance Ca²⁺-activated K⁺ channel blocker) completely prevented the vasodilatory action of boldine at all doses tested. Together, the present study showed the renal vasodilatory properties of boldine, an effect dependent on the generation of nitric oxide and the opening of a small-conductance Ca²⁺-activated K⁺ channel.

Natural Aporphine Alkaloids with Potential to Impact Metabolic Syndrome

The incidence and prevalence of metabolic syndrome has steadily increased worldwide. As a major risk factor for various diseases, metabolic syndrome has come into focus in recent years. Some natural aporphine alkaloids are very promising agents in the prevention and treatment of metabolic syndrome and its components because of their wide variety of biological activities. These natural aporphine alkaloids have protective effects on the different risk factors characterizing metabolic syndrome. In this review, we highlight the activities of bioactive aporphine alkaloids: thaliporphine, boldine, nuciferine, pronuciferine, roemerine, dicentrine, magnoflorine, anonaine, apomorphine, glaucine, predicentrine, isolaureline, xylopine, methylbulbocapnine, and crebanine. We particularly focused on their impact on metabolic syndrome and its components, including insulin resistance and type 2 diabetes mellitus, endothelial dysfunction, hypertension and cardiovascular disease, hyperlipidemia and obesity, non-alcoholic fatty liver disease, hyperuricemia and kidney damage, erectile dysfunction, central nervous system-related disorder, and intestinal microbiota dysbiosis. We also discussed the potential mechanisms of actions by aporphine alkaloids in metabolic syndrome.

Ethnopharmacology, Phytochemistry and Biological Activities of Native Chilean Plants

The native flora of Chile has unique characteristics due to the geographical situation of the country, with the vast desert in the North, Patagonia in the South, the Andean Mountains on the east and the Pacific Ocean on the west. This exclusivity is reflected in high concentrations of phytochemicals in the fruits and leaves of its native plants. Some examples are Aristotelia chilensis (Molina), Stuntz (maqui), Berberis microphylla G. Forst. (calafate), Peumus boldus Molina (boldo), Ribes magellanicum Poir. (Magellan currant), Ugni molinae Turcz. (murtilla), Rubus geoides Sm. (miñe miñe), Drimys winteri J.R.Forst. & G.Forst. (canelo), Luma apiculata (DC.) Burret (arrayán) distributed throughout the entire Chilean territory. Some of these Chilean plants have been used for centuries in the country's traditional medicine. The most recent studies of phytochemical characterization of parts of Chilean plants show a wide spectrum of antioxidant compounds, phenolic components, terpenoids and alkaloids, which have shown biological activity in both in vitro and in vivo studies. This manuscript covers the entire Chilean territory characterizing the phytochemical profile and reporting some of its biological properties, focusing mainly on antioxidant, anti-inflammatory, antimicrobial, chemopreventive and cytotoxic activity, and potential against diabetes, metabolic syndrome and gastrointestinal disorders.