Eleuthero: benefits, dosage, contraindications

Adaptogenic

Siberian ginseng appears to modify the levels of various neurotransmitters and hormones involved in the stress response, primarily at the level of the HPA axis (hypothalamic-pituitary-adrenal axis). Various mechanisms have been proposed, including inhibition of catechol-O-methyltransferase, which inactivates catecholamines. As a result, catecholamine levels are not depleted, and the release of new catecholamines by nerve synapses decreases. Theoretically, this effect reduces the risk of exhaustion of the body's adaptive responses to stress. Additionally, eleutherosides have been shown to improve carbohydrate metabolism and energy supply and to increase the synthesis of proteins and nucleic acids, although the direct molecular targets responsible for this adaptive response remain unknown. It has also been reported in vitro that eleutherosides bind to receptor sites for progestogens, estrogens, mineralocorticoids, and glucocorticoids and can therefore theoretically exert many important pharmacological actions during the body's stress response. Thus, the overall action of the herb has been described as "adaptogenic". Although the mechanism of action responsible is still not clear, several theories have been proposed to explain the effect of Siberian ginseng on allostatic systems. Indeed, research has shown that Siberian ginseng can act in different ways, depending on the stage of the stress response, to support the 'stress system'. Research suggests that there is a stress threshold below which the herb increases the stress response and above which it decreases the stress response.

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Neurological

Eleutherococcus protects neurons and inhibits apoptosis of brain cells. In animal research, an aqueous extract of Eleutherococcus inhibited inflammation and microglial activation in cerebral ischemia. In cultured rat cortical neurons, Eleutherococcus extracts were shown to have protective effects on neurite regeneration and synapse reconstruction in cultured rat cortical neurons damaged by beta-amyloid. This effect would be due, at least in part, to eleutheroside B. In mice, eleutheroside E prevented the behavioral disturbances induced by sleep deprivation, notably reductions in latency to enter a dark chamber and in locomotion, as well as the increase in monoamines (serotonin and dopamine) in the hippocampus, which suggests that this component of Eleutherococcus could be valuable for stress associated with chronic insomnia.

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Cardiovascular

Eleutherococcus, when administered orally to rats (at a dose of 1 ml/kg for 8 days), showed protective effects on the heart. These benefits, which include protection against cardiac rhythm disturbances (antiarrhythmic effects), appear to be due to an increase in the levels of the body's natural opioid peptides. In laboratory studies, Eleutherococcus also exhibits a vasorelaxant effect. This effect could be caused by several mechanisms, such as increased production of nitric oxide (a gas that relaxes blood vessels), activation of muscarinic receptors (receptors involved in controlling the nervous system), or by influencing certain channels in cells that regulate the passage of potassium ions. In a study conducted on cultured neonatal rat cardiac cells, a specific component of Eleutherococcus, acanthopanax senticoside B (which is part of the plant's saponins), protected these cells against damage caused by oxidative stress. It did so by reducing lipid peroxidation (a type of cellular damage) and by increasing the activity of the body's antioxidant defense mechanisms.

Hypoglycemic

Eleutherococcus (Siberian ginseng) has hypoglycemic properties observed in laboratory (in vitro) and animal (in vivo) studies. - It reduces glucose absorption by inhibiting an enzyme called alpha-glucosidase, thereby limiting the amount of glucose that enters the bloodstream. - Eleutherosides, components of Eleutherococcus, particularly eleutherosides E and B, allow glucose to enter cells without relying on insulin, the hormone normally required for this process. - Eleutherococcus can counteract obstacles to glucose transfer caused by certain proteins (β-lipoproteins) in cell membranes. - Syringin, a constituent, improves glucose utilization and may lower blood glucose levels. This may be due to increased release of acetylcholine, which stimulates insulin release, or by promoting beta-endorphin secretion, resulting in reduced blood glucose.

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Immunomodulator

Eleutherococcus extract has demonstrated immunomodulatory effects, including increased cellular and humoral activity, activation and proliferation of immunocompetent cells, and stimulation and inhibition of cytokine synthesis, in human, animal, and in vitro research. According to a review, immunomodulatory polysaccharides or saponins isolated from Eleutherococcus stimulated macrophages, promoted antibody formation, activated complement, and increased T lymphocyte proliferation. In rabbits, Eleutherococcus extract produced a sustained immunostimulant effect and increased phagocytic activity. In vitro, syringin, a constituent of Eleutherococcus root, stimulated phagocytosis by rat blood macrophages (immune system cells that help fight infections). Also, Eleutherococcus reduced the occurrence of allergic reactions. Histamine release from rat peritoneal mast cells, as well as secretion of tumor necrosis factor (TNF)-alpha and interleukin (IL)-6, were also inhibited. Similar results were observed in other animal studies, suggesting an anti-allergic effect of Eleutherococcus.

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Antiviral

In vitro, a liquid extract of Eleutherococcus inhibited productive replication of RNA viruses, human rhinovirus, respiratory syncytial virus, and influenza A virus. However, it does not appear to affect DNA viruses such as adenovirus or herpes simplex virus type 1.

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Anticancer

In animal studies, Eleutherococcus or its components have shown antitumor effects. The cytotoxic and antiproliferative effects of Eleutherococcus have been demonstrated in various in vitro studies. Eleutherococcus extract has shown antineoplastic activity against leukemia, hepatoma, and prostate cancer cells.