A major reason for the ginseng is blocking ACTH effects (i.e. high ACTH triggers cortisol release from the adrenals):
Neurosci Lett. 2003 May 29;343(1):62-6. Links
Effects of ginseng saponin administered intraperitoneally on the hypothalamo-pituitary-adrenal axis in mice.
Kim DH, Moon YS, Jung JS, Min SK, Son BK, Suh HW, Song DK.
Department of Psychiatry, College of Medicine, Institute of Natural Medicine, Hallym University, Chunchon, Kangwon-Do, 200-702, South Korea.
Intraperitoneal injection of ginseng total saponin (GTS; 5 and 20 mg/kg) raised plasma corticosterone levels in mice. However, interestingly, pretreatment of animals with the same doses of GTS (5 and 20 mg/kg) significantly attenuated the immobilization stress-induced increase in plasma corticosterone levels. Of the ginsenosides Rb(1), Rb(2), Rc, Rd, Re, Rf, Rg(1), 20(S)-Rg(3), and 20(R)-Rg(3) injected intraperitoneally at doses of 0.1-2 mg/kg, Rc (2 mg/kg) significantly inhibited the immobilization stress-induced increase in plasma corticosterone levels. GTS and Rc administered intraperitoneally did not affect the immobilization stress-induced elevation of plasma adrenocorticotropic hormone (ACTH) level. Pretreatment with GTS and Rc significantly attenuated the increase in plasma corticosterone levels induced by intraperitoneal injection of ACTH (30 microg/kg). These results suggest that GTS and Rc inhibit the immobilization stress-induced increase in plasma corticosterone levels by blocking ACTH action in the adrenal gland. Ginseng may be proposed to be useful for treatment of stress related disorders.
In other words, it seems to "compete" with ACTH, therefore blocking its effects.
This study also found a cortisol lowering effect in another high cortisol condition in humans - depression:
Int J Gynaecol Obstet. 1999 Dec;67(3):169-74. Related Articles, Links
Effect of Korean red ginseng on psychological functions in patients with
severe climacteric syndromes.
Tode T, Kikuchi Y, Hirata J, Kita T, Nakata H, Nagata I.
Department of Obstetrics and Gynecology, National Defense Medical College,
Tokorozawa, Saitama, Japan. qw104765@...
OBJECTIVE: To evaluate the degree of psychological dysfunction and levels of
stress hormones in postmenopausal women with climacteric syndromes and effect
of Korean red ginseng (RG) on them. METHODS: ACTH, cortisol and DHEA-S in
peripheral blood from 12 postmenopausal women with climacteric syndromes or 8
postmenopausal women without any climacteric syndrome were measured before and
days after treatment with daily oral administration of 6 g RG. Blood samples
were collected in the early morning on the bed-rest. In postmenopausal women
with climacteric syndromes such as fatigue, insomnia and depression,
psychological tests using the Cornell Medical Index (CMI) and the State-Trait
Inventory (STAI) were performed before and 30 days after treatment with RG.
RESULTS: CMI score as well as anxiety (A)-state in STAI score in postmenopausal
women with climacteric syndromes was significantly higher than that without
climacteric syndrome, while DHEA-S levels in postmenopausal women with
syndromes were about a half of those without climacteric syndrome.
Consequently, cortisol/DHEA-S (C/D) ratio was significantly higher in
women with climacteric syndromes than in those without climacteric syndrome.
postmenopausal women with climacteric syndromes were treated with daily oral
administration of 6 g RG for 30 days, CMI and STAI A-state scores decreased
within normal range. Although the decreased DHEA-S levels were not restored to
the levels in postmenopausal women without climacteric syndrome, the C/D ratio
decreased significantly after treatment with RG. CONCLUSIONS: Improvement of
CMI and STAI scores in postmenopausal women suffering climacteric syndromes,
particularly fatigue, insomnia and depression, by RG seemed to be brought about
in part by effects of RG on stress-related hormones as shown by a decrease in
Eleanor M. Kellon, V.M.D.
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