Anti-stress activity

Rapin JR, Lamproglou I, Drieu K, DeFeudis FV. (1994). Demonstration of the "anti-stress" activity of an extract of Ginkgo biloba (EGb 761) using a discrimination learning task. Gen Pharmacol. 25(5) 1009-16. 

Mutant mice lackingNPY showincreased anxiety-relatedbehavior (Palmiter et al. 1998) a full description of the behavioral phenotype of NPY receptor-null mutant mice is not available yet. However, data from Y2 receptor-null mutants support an anti-stress activity of NPY (Tschenett et al. 2003). In addition to the anxiolytic and anti-stress effects of NPY, a relationship to alcohol intake has been described. Voluntary ethanol consumption is increased in NPY and Yi receptor-null mutant mice, whereas either NPY overexpression or potentiation of NPY signaling through blockade of Y2 receptors suppresses rodent alcohol intake (Thiel et al. 1998,2002 Thorsell et al. 2002). Thus, in addition to anxiety and depression, alcohol dependency may be a promising clinical field for newly developed NPY receptor hgands. 

On the other hand, Fowler ef al. recently measured MAO-A and MAO-B activities in the human brain using positron emission tomography and ["CJdorgyline and ["C]L-deprenyl-D2, and showed that administration of EGb (120 mg/day, for 1 month) to 10 subjects had no influence on brain MAO-A and MAO-B [166]. Moreover, for the same dosages at which EGb (25, 50, and 100 mg/kg, p.o., for 5 days) exerted antistress properties, EGb did not exhibit any activity indicative of MAO inhibition in mice [167]. Therefore, there is uncertainty about whether MAO inhibition is the mechanism responsible for the anti-stress activity of EGb. This will be the subject of further study. 

In addition to its antileprosy effect, deoxyfructoserotonin shows a considerable anti-stress activity, especially on ulcer formation by restraint (25). 

Bishayee, A., et al "Mechanism of anti-stress activity of Mikania cordata root extract in albino mice," International Journal of Pharmacognosy, 1995, Vol. 33, no. 3 pp 215-221. 

Withania somnifera Dunal is called Indian ginseng because of its powerful anti-stress activities [32]. Apart from immunomodulatory effects, it also has a central nervous depressant action mediated via the y-aminobutyric acid (GABA) receptors [33, 34]. 

Ginsenosides markedly prolong the time of survival in normobaric hypoxia stress mice, and regenerate locomotory activity in mice. They possess anti-stress activities and show effects on neurotransmitters. The observed anti-heat stress effects of ginsenosides may be mediated by brain monoamines and the hypothalamus (HPA) system. Ginsenosides selectively modulate the circadian variations of brain 5-hydroxytryptamine (5-HT), 5-hydroxy-indole-3-acetic acid (5-HIAA), nor-epinedrine (NE) and dopamine (DA) levels, but as a function of the time of the light-dark cycle [79, 80]. 

Anti-stress activity in relation to plants is well manifested for both strains (Table 15.2). In the presence of metal ions, higher roots of the... 

The most potent activities (gastric antisecretory activity in the pylorus-ligated rat or anti-ulcer activity on stress-induced gastric lesion in rat) have been observed with compounds (30), (31) [106], (32) [107], (33) and (34) [108], which were shown neither to be histamine H2 receptor inhibitors nor to act as anticholinergic agents. Thus, the activity of compound (32), for example, has been reported to be superior to that of cimetidine [107],... 

In this connexion we will stress again that, although there is often a correspondence between toxic action of organo-phosphorus insecticides and anti-cholinesterase activity (p. 67), the relationship is not always simple. Thus parathion (p. 178), not itself an esterase inhibitor, is converted in vivo into an enzyme inhibitor.1 On the other hand, Aldridge2 has shown that the inhibitor paroxan can be hydrolysed enzymically to produce non-inhibitory substances. 

An inhibitory effect of 8-OH-DPAT on forskolin-stimulated adenylyl cyclase activity is observed in hippocampal membranes of the guinea pig and rat, and has been used as an index of the functional activities of 5-HTIA receptors [178]. Cold stress induces a reduction of the inhibitory effect of 8-OH-DPAT in the hippocampus isolated from 18-month-old rats, although it has no influence on either the affinity or number of [3H]8-OH-DPAT binding sites. The administration of EGb (50 mg/kg p.o. for 14 days) prevents the cold stress-induced reduction in the inhibitory effect of 8-OH-DPAT on forskolin-stimulated adenylyl cyclase activity in old rats. These results indicate that EGb prevents the stress-induced desensitization of hippocampal 5-HTu receptors thus, its effects might explain anti-stress and antidepressant properties of EGb [177]. 

Vaccinium myrtillus, commonly known as bilberry fruit, originates mainly from northern and central Europe (Bisset, 1994). This well known plant is rich in flavonoids, the polyphenolic compounds that promote anti-oxidant activity (Bisset, 1994). A study conducted on the antioxidative potential of V. myrtillus showed potent protective action on LDL particles during in vitro copper-mediated oxidation. The study concluded that this extract may be more potent than either ascorbic acid or butylated hydroxy-toluene in the protection of LDL particles from oxidative stress (Mitcheva, 1993 Bisset, 1994). 

Anti-inflammatory activity of Bik is highly correlated to glomerulonephritis [4,95,96]. Bik provides protection to renal cells from ischemia/reperfusion injury by reducing immune-mediated apoptotic signals that typically lead to cell death [4, 30, 81]. Bik also has a protective affect on proximal tubule epithelial cells under stress [97]. Bik levels increase with a-1-microglobulin during renal tubule damage [4]. 

Several other activities are reported for Astragalus spp. the cycloartane saponins from A. sieversienus show an hypocholesterolemic action [219], while astramembrannin I, 87, and astrasieversianin I, 92 produce antileukocytopenic and anti-stress effects in mice [319]. Aqueous extract of A. membranaceus root causes significant stimulation of melanocyte proliferation using the sulphorhodamine B (SRB) test. This result supports the use of these extracts in traditional treatments of vitiligo [191]. 

---