Urter til hjernen – engelsk artikel



Botanical Brain Boosters

Michael Thomsen, N.D., M.H.There is little doubt that the active constituents found in some herbal medicines can have a profound effect on brain function. A variety of plants and/or their isolated constituents contain potentially mind-altering, sedative, and/or analgesic effects. Although many of these “brain boosting” phytomedicines have a long historical use in shamanistic and ritual practices, modern pharmacological researchers have long neglected to examine their potential benefits for memory and learning. However, as allopathic healthcare’s understanding of botanical medicines evolves, the modern world is beginning to better understand the profound effects such treatments can safely have on concentration, learning, and memory.


Plants for Thoughts Following is information on how some herbals can improve the health of the mind.


Bacopa (Bacopa monniera): The main active constituents of this phytomedicine are dammarane-type tetracyclic triterpenoid saponins. Specifically, the scientific literature often refers to two fractions of saponins called bacoside A and bacoside B. Early experimental studies indicate that bacopa may accelerate gamma-amino butyric acid (GABA) synthesis from glutamate and inhibit GABA metabolism.1 Studies have also shown that it can improve reaction time as well as learning and retention of new material and memory in rats.2However, while further experiments confirm that bacopa can improve the maze-learning ability of rats3, a later study reports no evidence of central nervous system- (CNS) stimulating or -sedating effects.4 Thissuggests that the action of the botanical’s bacosides are nootropic focusing on improving concentration, learning and memory. Clinical studies show that bacopa can improve mental performance and memory in patients suffering from anxiety, and a recent study suggests that it may have the greatest beneficial effect on short-term memory.5 Bacopa is safe for children, and studies indicate that it may be useful for treating attention deficit disorder (ADD) in youngsters. It also is used in Ayurvedic medicine to enhance memory and as a mild sedative as well as treat epilepsy and insomnia. However, it is important to note that both this herb and gotu kola (Centella asiatica) are known as Brahmi in Sanskrit. The recommended dosage of bacopa is 3 g to 6g daily of the dry herb, or 6 mL to 12 mL of a liquid extract daily.


Common periwinkle (Vinca minor): This botantical’s leaves have been used for centuries in Europe to treat headaches, poor memory and vertigo. Common periwinkle’s active constituents are its indole alkaloids, which include vincamine and pervincamine. Vincamine can improve the whole cerebral vascular system (CVS) by increasing both cerebral oxygen and glycose uptake as well as normalising cerebral microcirculation. This plant constituent also can reduce blood viscosity and dilate blood vessels. Common periwinkle can treat poor memory, speech disorders, vertigo, and headaches caused by cerebral sclerosis, cerebral blood flow problems, and metabolism disorders. It is widely used to treat older people with memory deterioration and concentration problems as well as emotional disorders such as depression, lack of interest, aggression, and apathy. The recommended dosage of common periwinkle is 3g to 6g daily of the dry herb, or 6 mL to 12 mL of a liquid extract daily. This phytomedicine has very few noted side effects, even after long-term use in extensive trials. It can be safely administered orally, and it is very well tolerated. However, this phytomedicine is contraindicated in pregnancy.


Ginkgo biloba (Ginkgo biloba): In order to be truly effective, this plant needs to be formulated as a standardized extract that contains 24% flavonoid glycosides, such as ginkgoflavone glycosides, and 6% terpenoids, such as ginkgolides and bilobalide. Several studies have shown that gingko biloba extracts standardized in this way can offer a variety of beneficial effects in the treatment of senile dementia, including Alzheimer’s disease.6 Ginkgo biloba possesses an antioxidant action that possibly can prevent damage to neurons and other cells. The herb also may provide health benefits to healthy individuals. For example, one study reports that a single high dose of the botanical taken one hour before an exam improved the subjects’ short-term memories.7 Taking this study into account, it seems plausible that normal doses of ginkgo biloba given over a longer period would produce stronger memory benefits. Additionally, other studies have shown that this phytomedicine may enhance long-term memory, abstract reasoning and other cognitive functions.8 The recommended dosage of ginkgo biloba is 6 g to 12 g daily of the dry herb, and 120 mg to 240 mg of a standardized extract.


Peony (Paeonia lactiflora):
This plant reportedly has cognitive-enhancing properties that are linked to paeoniflorin, one of its active constituents. Researchers in the Oriental medicines department at the Toyama Medical and Pharmaceutical University in Japan claim that a specific Dang qui Four combination[[[em dash]]]a type of Traditional Chinese Medicine (TCM) formula containing paeoniflorin as well as the ligusticum (Ligusticum wali) constituent tetramethylpyrazine (TMP) can improve spatial working memory in rats.9 Japanese researchers also report that daily administration of paeoniflorin isolated from peony can significantly attenuate learning impairment in aged rats. Their data indicates that this constituent of peony may have therapeutic potential in the treatment of senile dementia and age-induced cognitive dysfunction.10 The recommended dosage of peony is 2 g to 6 g of the dry herb daily, or 4 mL to 12 mL of a liquid extract daily.


Panax ginseng (Panax ginseng):
This well-known herb needs little introduction. There are some studies that claim that when rats were given standardized panax ginseng before they ran through a maze, the botanical improved the animals’ learning, memory and endurance.11 Some studies also report that panax ginseng can significantly decreases reaction times in humans between the ages of 40 years and 60 years.12 However, there are many misconceptions about the use of panax ginseng. One fallacy is that it is not suitable for women, when it actually can be a wonderful whole-body tonic, or adaptogen, for both sexes. In addition, it can be a particularly useful medicinal for menopausal women in the treatment of fatigue, stress, and hot flashes. Another misconception about panax ginseng is that most people find it to be too stimulating. While it can be overly stimulating for some people, the majority find that it can provide a new level of well-being. The recommended dosage of panax ginseng is 0.5 g to 3.0 g daily of the dried main or lateral roots of the herb, depending on the quality of the root and the application. It is important to note that preparations from the phytomedicine’s root hairs are therapeutically inferior and should be avoided. A ratio of Rg1to Rb1ginsenosides greater than 0.5 is now accepted as a marker of ginseng quality. Although panax ginseng generally is safe, it is contraindicated in certain situations including in cases of acute infections accompanied by signs of heat and inflammation, acute asthma, hypertension (HTN), and excessive menorrhagia. Also, concurrent use of this phytomedicine with stimulants such as caffeine and amphetamines should be avoided as it is a potent stimulant. Additionally, it should not be used with monoamine oxidase (MAO) inhibitors and warfarin, although its interactions with these drugs are unclear.


Schisandra (Schisandra chinensis):
This herb is a wonderful adaptogen and mental tonic. Its active constituents, schizandrins and gomisins/dibenzocyclooctane lignans, can have a general stimulant effect on the central nervous system (CNS). Schisandra reportedly has been shown to improve learning and reduce depression in mice.13 Also, Japanese researchers at the University of Tokyo’s department of chemical pharmacology report that they conducted a study in which a formulation containing schisandra and panax ginseng apparently beneficially affected memory registration and consolidation in memory-impaired mice through direct action on the learning and memory process.14 The recommended dosage of schisandra is 2 g to 6 g of the dry herb daily, or 4 mL to 12 mL of a liquid extract daily.


Siberian Ginseng (Eleutherococcus senticosus):
Like panax ginseng, this plant is a member of the ivy family. However, it is only distantly related to panax ginseng. Siberian ginseng’s active constituents are the glycosides known as eleutherosides. Several different eleutherosides have been isolated. . .some of which are not unique while others are quite rare, such as eleutheroside E. It is believed that eleutherococcus E is the major contributor to the adaptogenic action of Siberian ginseng, although triterpenoids as well as glycans named eleutherans A to F have also been isolated in the herb. Clinical studies have shown that Siberian ginseng can increase stamina and endurance in healthy subjects exposed to adverse conditions. It has also been shown that it can improve concentration and learning.15 The recommended dosage of Siberian ginseng is 1 g to 4 g daily of the dry herb, or 2 mL to 8 mL of a liquid extract daily.  


Michael Thomsen, N.D., M.H., is a consultant in the herbal medicine industry and has cowritten a variety of books. Selected References 1 Dey PK, Datta C. Indian Journal of Experimental Biology 4: 216-219, 1966. 2 Singh HK, Dhawan BN. Journal of Ethnopharmacology 5: 205-214, 1982. 3 Dey CD, Bose S, Mitra S. Indian Journal of Physiology and Allied Sciences 30 (3): 88-97, 1976. 4 Singh HK, Rastogi RP, Srimal RC, et al. Phytotherapy Research 2 (2): 70-75, 1988. 5 Singh HK, Dhwan BN. Indian Journal of Pharmacology 29 (5): S359-S365, 1997. 6 Kanowski S, Herrmann WM, Stephan K, et al. Pharmacopsychiatry 29 (2): 47-56, 1996. 7 Warburton DM. Br J Clin Pharmacol 36 (2): 137, 1993. 8 Subhan Z, Hindmarch I. Int J Clin Pharmacol Res 4 (2): 89-93, 1986. 9 Stough C, Bonyhai A. Proceedings of the 3rd Pan Pacific Brain Topography Conference 21.1.98, no 31. 10 Wantabe H. Candidates for cognitive enhancer extracted from medicinal plants; paeoniflorin and tetramethylpyrazine. Behav Brain Res 83 (1-2): 135-141, 1997. 11 Nitta H, Matsumoto K, Shimizu M, et al. Biol Pharm Bull 18 (10): 1439-1442, 1995. 12 Ying Y, Zhang JT, Shi CZ, et al. Yao Hsueh Pao 29 (4): 241-245, 1994. 13 Chang HM, But PP. Pharmacology and Applications of Chinese Materia Medica: Volume 1. Singapore, China, World Scientific, 1987. 14 Hancke JL, et al. Planta Medica 52: 542, 1986. 15 Farnsworth NR, et al. Economic and Medicinal Plant Research: Volume 1, 1985.


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