Magnolia: benefits, dosage, contraindications

Anxiolytic

The bark of Magnolia officinalis has been used in traditional Chinese medicine to treat various mental disorders, including anxiety. Researchers have focused their efforts on demonstrating the antidepressant, anxiolytic, and sedative effects of decoctions containing Magnolia. The GABA system plays a crucial role in our brain by regulating our response to stress and anxiety. Honokiol and dihydrohonokiol, two natural compounds from Magnolia, exert anxiolytic effects in animals by interacting with gamma-aminobutyric acid A (GABA-A) receptors and muscarinic receptors. One study also explored the effects of dihydrohonokiol-B, a cousin of honokiol, which, when combined with anxiolytic drugs like diazepam, shows increased efficacy. This synergy suggests that Magnolia could potentially enhance the effects of conventional anxiety treatments. Magnolia extracts have also shown an affinity for adenosine A(1) receptors, a type of receptor in the brain that plays a role in the regulation of sleep and anxiety, which is consistent with traditional anxiolytic activities.

Usages associés

Antibacterial

Honokiol and magnolol have a marked antimicrobial effect against: - Actinobacillus actinomycetemcomitans, a rod belonging to the human oral flora involved in periodontal diseases. - Porphyromonas gingivalis, a bacterial species present in the oral cavity, responsible for gingivitis and that may promote Alzheimer's disease by releasing toxic proteins. - Prevotella intermedia, a pathogenic bacterium involved in periodontal infections, including gingivitis and periodontitis. - Micrococcus luteus, a bacterium found in soil, dust, water and air; it is part of the natural skin flora and can also colonize the mouth and mucous membranes, notably the oropharynx and the human upper respiratory tract. They were NOT active against Shigella flexneii, Staphylococcus epidermidis, Enterobacter aerogenes, Proteus vulgaris, Escherichia coli and Pseudomonas aeruginosa. A bark extract and magnolol inhibited the growth of Helicobacter pylori, the bacterium responsible for gastric ulcer, in an in vitro study.

Usages associés

Neurological

Research suggests that magnolol and honokiol may play a key role in improving cholinergic function, essential for memory and learning. They promote the increase in acetylcholine, a vital neurotransmitter, particularly in the hippocampus, the region of the brain associated with the formation of memories. This action could be beneficial in the context of Alzheimer's disease, where neuronal communication is often impaired. In addition to increasing acetylcholine, these components also nourish neurons (neurotrophic effect), promoting healthy neuronal function. Their antioxidant effect reduces reactive oxygen species and further strengthens their neuroprotective properties. Research has shown that Magnolia may also help reduce levels of beta-amyloid peptide, a component associated with the progression of Alzheimer's disease, and protect against the cell death it induces.

Usages associés

Antiallergic

The magnolia contains a compound called magnone. This compound is particularly interesting for allergic symptoms such as nasal congestion and rhinitis. Its action is based on its ability to counter the activity of platelet-activating factor, a key element in the body's allergic and inflammatory reactions. Regarding asthma treatment, magnolia appears promising by intervening in cortisol metabolism. It inhibits the enzyme responsible for converting cortisol into cortisone, which increases the availability of corticosterone, a glucocorticoid similar to cortisol and useful in asthma management. The compounds magnolol and honokiol, also present in magnolia, offer a dual action: they relax the airways by acting as calcium antagonists and reduce type IV allergic reactions mediated by T lymphocytes. In addition, magnolia alkaloids act against acetylcholine-induced contractions, thus providing an additional pathway by which magnolia may help in the treatment of asthma.

Usages associés

Anticancer

Laboratory studies show that magnolol, a compound from magnolia, may have beneficial effects against leukemia. This action is due to its ability to intervene in various cellular signaling pathways, which are crucial in the development and progression of cancer. Magnolol and honokiol act by regulating the expression of certain genes and by promoting apoptosis, the programmed process of cell death. This mechanism is particularly important because it allows cancer cells to be eliminated in a controlled manner. Furthermore, obovotol, as well as certain alkaloids present in magnolia, also contribute to these anticancer effects. These substances could enhance magnolia's antitumor activity by targeting different stages and mechanisms involved in the growth and survival of cancer cells.

Anti-inflammatory

The lignans of magnolia, particularly magnolol and honokiol, play a key role in modulating inflammatory responses. They are able to downregulate the activation of nuclear factor kappa B (NF-κB), a central element in the control of gene transcription for inflammatory responses. By blocking NF-κB activation, magnolol and honokiol help reduce the expression of genes involved in pro-inflammatory processes. In addition, these lignans interfere with the formation of eicosanoids, important signaling molecules in inflammatory and immune processes. They inhibit the production of prostaglandin E2 and thromboxane B2, two notable eicosanoids. This is likely due to the inhibitory effect of magnolol and honokiol on key enzymes such as phospholipase A2 and cyclooxygenase, which are involved in eicosanoid synthesis.

Usages associés

Digestive effect

Magnolia is an antispasmodic that works by relaxing the smooth muscles of the digestive tract. Magnolol and honokiol are both noncompetitive muscarinic antagonists and inhibit contractions induced by acetylcholine, serotonin, or calcium-dependent contractions induced by acetylcholine. Furthermore, magnolia extracts have anti-gastric-ulcer activity. Indeed, intragastric administration of an aqueous and methanolic magnolia extract (400 mg/kg) reduced gastric juice secretion and increased the pH of gastric secretions in mice pretreated with indomethacin.

Antioxidant

When absorbed by the body, honokiol exhibits significant antioxidant properties, particularly effective against hydroxyl radicals. These radicals are reactive oxygen species known for their potential to cause cellular damage. Honokiol's antioxidant effectiveness is attributed to the presence of allyl groups in its chemical structure. These allyl groups enable more effective interactions with free radicals, neutralizing their harmful activity. By comparison, honokiol shows greater antioxidant capacity than magnolol, another compound from magnolia. This difference is mainly explained by higher activity of the allylic groups in honokiol, which strengthen its ability to neutralize free radicals.

Antidepressant

In animals, a mixture of honokiol and magnolol with ginger rhizome produces a synergistic antidepressant effect by regulating serotonergic functions and gastrointestinal system functions. Indeed, the mixture of honokiol and magnolol increased serotonin levels in various regions of the brain, and the ginger rhizome reduced cholecystokinin levels in the gastric mucosa and serum gastrin in rats.

Usages associés

Cardiovascular

Magnolia's positive effects on atherosclerosis are attributed to the antioxidant activities of magnolol and honokiol. Laboratory research suggests that honokiol reduces the expression of inducible nitric oxide synthase, the generation of reactive oxygen species, intracellular calcium accumulation, and mitigates the effects of low-density oxidized lipoprotein. Magnolol also interferes with the generation of reactive oxygen species.