Boldo (Peumus boldus Mol.) – Importance and Health Benefits

Peumus boldus Mol., more commonly known as Boldo, is a Chilean tree that has been used for thousands of years for its medicinal benefits. It’s an effective antioxidant that can be used to prevent diseases caused by free radical damage.

Peumus boldus, the only species in the genus Peumus, is commonly known as boldo (from the Mapudungun name foḻo). This tree of the family Monimiaceae is natively endemic to the central region of Chile, occurring from 33° to 40° southern latitude.

Boldo has also been introduced to Europe and North Africa, though it is not often seen outside botanical gardens.

Together with litre, quillay, peumo, bollén and other indigenous plants, it is a characteristic component of the sclerophyllous forest endemic to central Chile.

Its leaves, which have a strong, woody and slightly bitter flavor and camphor-like aroma, are used for culinary purposes, primarily in Latin America.

The leaves are used in a similar manner to bay leaves and also used as an herbal tea, primarily in Chile, Bolivia, Argentina, Paraguay, Peru, Uruguay, Brazil and bordering countries in South America.

Boldo is in the family Monimiaceae, which is closely related to the family Lauraceae (which includes many other plants used for their aromatic leaves, such as cinnamon, cassia, bay leaf, and camphor laurel).

Recently, Boldo is also known to relieve gastrointestinal issues, bladder infections, gallstones and liver disease. It also works as a diuretic, increasing urine flow and promoting detoxification.

Boldo is also recognized as a herbal remedy in a number of pharmacopoeias, mainly for the treatment of liver ailments.

Boldine in particular, being the major and most characteristic alkaloidal constituent of this plant species, now emerges as its most interesting active principle from the pharmacological viewpoint.

The recent demonstration that boldine is an effective antioxidant in both biological and non-biological systems has opened up the perspective of a broad range of uses in medicine and industry.

Given the toxicological data on this alkaloid, its antioxidative properties situate it as a potentially useful substance in many disease states featuring free-radical related oxidative injury.

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Uses of Boldo

In Brazil, Argentina, Chile, Uruguay, and Paraguay, boldo is mixed with yerba mate or other teas to moderate its flavor. Some families keep a boldo plant at home for this purpose, although boldo teabags are readily available in nearly all supermarkets.

Boldo and plants with similar properties are widely used as mild folk medicine in various South American countries in both urban and rural areas, even among people who do not usually drink herbal teas other than mate beverage.

Boldo is officially listed as phytotherapic plant as cholagogue and choleretic, for treatment of mild dyspepsia in Brazilian pharmacopoeia.

Boldo leaves have slightly bitter soft flavor and a bit coniferous rough taste when brewed in tea. They are used as a culinary herb to spike many savory dishes with fish, mushrooms, vegetables and as a component in sauces.

In some local South American kitchens boldo leaves are also popular to wrap frying fish and meat. Boldo fruits, when dried, are used to make spicy condiments.

This review attempts to cover and discuss the studies conducted over the last four decades on the chemical and pharmacological properties of boldo and its main constituent which will not take us to:

Boldine and its antioxidant or health-promoting properties

The increasing recognition of the participation of free radical-mediated oxidative events in the initiation and/or progression of cardiovascular, tumoural, inflammatory and neurodegenerative disorders, has given rise to the search for new antioxidant molecules.

An important source of such molecules has been plants for which there is an ethno-cultural base for health promotion. An important example of this is boldo (Peumus boldus Mol.), a chilean tree whose leaves have been traditionally employed in folk medicine and is now widely recognized as a herbal remedy by a number of pharmacopoeias.

Boldo leaves are rich in several aporphine-like alkaloids, of which boldine is the most abundant one.

Research conducted during the early 1990s led to the discovery that boldine is one of the most potent natural antioxidants. Prompted by the latter, a large and increasing number of studies emerged, which have focused on characterizing some of the pharmacological properties that may arise from the free radical-scavenging properties of boldine.

The present review attempts to exhaustively cover and discuss such studies, placing particular attention on research conducted during the last decade. Mechanistic aspects and structure-activity data are discussed.

The review encompasses pharmacological actions, which arise from its antioxidant properties (e.g., cyto-protective, anti-tumour promoting, anti-inflammatory, anti-diabetic and anti-atherogenic actions), as well as those that do not seem to be associated with such activity (e.g., vasorelaxing, anti-trypanocidal, immuno- and neuro-modulator, cholagogic and/or choleretic actions).

Based on the pharmacological and toxicological data now available, further research needs and recommendations are suggested to define the actual potential of boldine for its use in humans.

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Health Benefits of Boldo (Peumus boldus Mol.)

According to a recent detailed research, below are the amazing health benefits of Boldo (Peumus boldus Mol.):

Mechanism of Action

Pharmacology:

Constituents: Boldine is a major active alkaloidal constituent of boldo. In addition to boldine, boldo contains ascaridole, benzaldehyde, boldin, boldoglucin, bornyl-acetate, 1,8-cineol, coclaurine, coumarin, cuminaldehyde, 2-decanone, 6(a)-7 dehydroboldine, diethylphthalate, eugenol, farnesol, fenchone, gamma terpinene, 2-heptaone, isoboldine, kaempferols, laurolitsine, laurotetainine, norboldine, norisocorydine, pachycarpine, P-cymene, P-cymol, pro-nuciferine, 2-octanone, reticuline, rhamnosides, sabinene, sinoacutine, terpinoline, thymol, trans verbenol, 2-tridecanone, and 2-undecanone.

Antioxidant effects: Preliminary assays showed free-radical scavenging activity in hot water extracts of boldo leaves. Assay-guided isolation led to the active compounds. Catechin proved to be the main free-radical scavenger of the extracts. Lipid peroxidation in erythrocytes was inhibited by boldo extracts. The relative concentration of alkaloids and phenolics in boldo leaves and their activity suggest that the free-radical scavenging effect is mainly due to catechin and flavonoids and that the antioxidant effect is mainly related with the catechin content. The high catechin content of boldo leaves and its bioactivity suggest that quality control of boldo folium has to combine the analysis of catechin as well as their characteristic aporphine alkaloids.

The influence of Peumus boldus on the labeling of red blood cells and plasma proteins with 99mTc was studied. Aliquots of plasma and blood cells were isolated from the mixture and treated with trichloroacetic acid (TCA). Boldo increased technetium-99m uptake by red blood cells by 90% at all concentrations, an effect that persisted in the presence of increased concentrations of stannous chloride. The authors note that these results indicate that the antioxidant action of boldo protects the stannous ion, contributing to increased reduction of the pertechnetate ion and increasing the percentage of radioactivity bound to the red blood cell in vitro.

Boldine reduced the lethal effect induced by stannous chloride on the survival of Escherichia coli in vitro.⁹ Stannous chloride strongly inactivated E. coli cells, but the toxic effect was eradicated by boldine. Boldine also prevented the modification of the supercoiled form of E. coli deoxynucleic acid plasmid caused by stannous chloride. The authors suggest that boldine may protect the stannous chloride ion from oxidation, thus avoiding the generation of reactive oxygen species.

Boldine dose-dependently inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced down-regulation of gap junctional intercellular communication in rat liver epithelial cells in vitro, and totally inhibited the TPA-induced accumulation of intracellular antioxidants. Boldine dose-dependently reversed the TPA-induced inhibition of gap junctional intercellular communication (GJIC), with nearly complete reinstatement of cellular communication at 50µM concentration of boldine. Co-incubation of boldine with TPA also caused a dose-dependent decrease in the accumulation of oxidants in the cell (p<0.001). The authors report that antioxidants, like boldine, may exercise antitumor effects through the destruction of free radicals generated in the tumor-promotion process.

Boldine, in low micromolar concentrations, was able to prevent brain homogenate autooxidation, the 2,2′-azobis(2-amidinopropane)(AAP)-induced lipid peroxidation of red cell plasma membranes, and the AAP-induced inactivation of lysozyme. These results are indicative of a high reactivity of boldine towards free radicals. The authors suggest that boldine’s antioxidant activity in vitro appears lower than synthetic antioxidants such as propyl gallate but, because of its low toxicity, may be a useful therapeutic agent.

Boldine decomposed superoxide anions, hydrogen peroxides and hydroxyl radicals in a dose-dependent manner.¹ The alkaloid significantly attenuated the production of superoxide anions, hydrogen peroxide, and nitric oxide caused by liver mitochondria. The results indicate that boldine may exert an inhibitory effect on streptozotocin (STZ)-induced oxidative tissue damage and may alter antioxidant enzyme activity by the decomposition of reactive oxygen species and inhibition of nitric oxide production and by the reduction of the peroxidation-induced product formation.

Peumus boldus showed high Trolox-Equivalent Antioxidant Capacity (TEAC) and HCIO-quenching activities.

Antiplatelet effects: Boldine inhibited aggregation of rabbit platelets and inhibited the release of ATP-induced by arachidonic acid and collagen in rabbit platelets.

Chemoprotective effects: In vitro modulations of drug-metabolizing enzymes in mouse hepatoma Hepa-1 cell line and mouse hepatic microsomes were investigated. Boldine manifested inhibition activity on hepatic microsomal cytochrome P4501A-dependent 7-ethoxyresorufin O-deethylase and cytochrome P4503A-dependent testosterone 6 beta-hydroxylase activities and stimulated glutathione S-transferase activity in Hepa-1 cells. The authors concluded boldine may decrease the metabolic activation of other xenobiotics including chemical mutagens.

Gastrointestinal effects: Gotteland et al. conducted a study to assess the effects of a dry boldo extract on orocecal transit time in normal humans. Twelve volunteers received 2.5g of a dry boldo extract or a placebo (glucose) during two successive periods of four days. On the fourth day, 20g of lactulose were administered and breath hydrogen was collected every 15 minutes. Orocecal transit time was defined as the time in which breath hydrogen increased by 20ppm over the fasting level. Orocecal transit time was larger after dry boldo extract administration, compared to placebo (112.5 ± 15.4 and 87 ± 11.8 minutes respectively, p<0.05). It was concluded that dry boldo extract prolongs oro cecal transit time and gives a possible explanation for its medicinal use.

Hepatoprotective effects: Boldine acted as a hydroxide scavenger, inhibited NADPH- and NADH-dependent production of thiobarbituric acid reactive substances (TBARS), inhibited ferrous-catalyzed non-enzymatic lipid peroxidation, and inhibited lipid peroxidation initiated by t-butylhydroperoxide and carbon tetrachloride. Boldine protected microsomes against oxidation of NADPH-cytochrome P450 reductase, cytochrome P450, and glucose-6-phosphatase.

Boldine produced nearly complete inhibition of NADPH- and NADH-dependent peroxidation, and protected against the loss of cytochrome P450 2E1 produced by incubation of microsomes with NADPH plus ferric-adenosine triphosphate.

Myogenic effects: Boldine was reported to act as a specific calcium entry blocker and did not interfere with contractile machinery in rat uteri in vitro.

Vasodilatory effects: Boldine was found to be an alpha 1-adrenoceptor blocking agent in guinea-pig aorta as revealed by its competitive antagonism of noradrenaline-induced vasoconstriction with comparable efficacy to prazosin.

Pharmacodynamics/Kinetics:

In an animal study, boldine inhibited the acetylcholine-induced contraction of denervated diaphragm dose-dependently with an IC₅₀ value of 13.5µM.⁷ At 50µM, boldine specifically inhibited the amplitude of the miniature end plate potential. In addition, boldine was similar to d-tubocurarine in its action to reverse the neuromuscular blocking action of alpha-bungarotoxin.

The results showed that the neuromuscular blockade by boldine on isolated mouse phrenic-nerve diaphragm might be due to its direct interaction with the postsynaptic nicotinic acetylcholine receptor.

Boldine at higher concentrations of 300µM can induce muscle contraction through two phases, which were caused by the influx of extracellular Ca2+ and induction of Ca2+ release from the internal Ca2+ storage site, the sarcoplasmic reticulum, respectively.

When tested with isolated sarcoplasmic reticulum membrane vesicles, boldine dose-dependently induced Ca2+ release from actively loaded sarcoplasmic reticulum vesicles isolated from skeletal muscle of rabbit or rat which was inhibited by ruthenium red, suggesting that the release was through the Ca2+ release channel, also known as the ryanodine receptor.

Boldine also dose-dependently increased apparent [3H]-ryanodine binding with the EC₅₀ value of 50µM. The authors concluded that boldine could sensitize the ryanodine receptor and induce Ca2+ release from the internal Ca2+ storage site of skeletal muscle.

In Summary

Boldo is a tree that grows in the Andes mountains in South America. Interestingly, fossilized boldo leaves dating from over thirteen thousand years ago have been found in Chile. These fossils have imprints of human teeth, suggesting that boldo has a long history of dietary or medicinal use.

Boldo is used for mild gastrointestinal (GI) spasms, gallstones, achy joints (rheumatism), bladder infections, liver disease, and gonorrhea. It is also to increase urine flow to rid the body of excess fluids, reduce anxiety, increase bile flow, and kill bacteria.

How does it work?

Boldo contains chemicals that might increase urine output, fight bacterial growth in the urine, and stimulate the stomach.

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