Hypericum perforatum quercetin from

Fig. 2.49. Profile of Hypericum perforatum extract with the H LC-MS attributions of the components detected. 1 = chlorogenic acid isomer 2 = 3-0- -coumaroylquinic acid 3 = chlorogenic acid 4 = rutin 5 = hyperoside 6 = isoquercitrin 7 = 3,3, , , 7-pentahydroxyflavanone 7-0-rhamnopyranoside 8 = quercitrin 9 = quercetin 10 = 13,118 tapigenin 11 = pSeudohypericin 12 = hypericin 13 = hyperforin analogue 14 = hyperform dialogue 15 = hyperforin 16 = adhyperforin. Reprinted with permission from M. Brolis eta. [ ].

Flavonoids in the diet have been widely promoted as important antioxidant contributors. Their neuroprotective properties, because of this effect, have been demonstrated by several workers. However, they have also been demonstrated to have MAOI activity and this has been proposed as part of the explanation of the use of the common herb, St Johns Wort, Hypericum perforatum L., as an antidepressant. This dual role has now been proposed for a variety of flavonoids, such as kaempferol (22) from the leaves of Ginkgo biloba L., a widely used herbal product which has been suggested as a preventative agent against neurodegeneration. Quercetin (23), similarly, has also shown to inhibit MAO-B " and reverse the effects of induced catalepsy, which mimics the bradykinesia associated with PD. Tangeretin (24) also inhibits MAO-B and crosses the blood brain barrier in a rat model. 

Rutin extraction from buckwheat was optimally performed using between 50% and 60% ethanol with a 3-hr maceration (Kreft et al., 1999). Repeating the extraction two times was sufficient to extract most of the rutin. Lie et al. (2000) demonstrated the optimization of influencing factors such as extraction temperatures, extraction times, and solvent concentrations in a conventional extraction of dry powdered material of Hypericum perforatum. Applied extraction conditions caused variations to favor different components in the mixture. Higher extraction efficiency was achieved with moderately polar solvents to extract flavonoids such as rutin, isoquercitrin, and quercetin. The optimum extraction conditions for dry Hypericum perforatum leaf powder were determined as 44% to 69% ethanol in acetone with a 5.3- to 5.9-hr maceration at 55°C. 

Silva, B. Oliveira, P. J. Dias, A. Malva, J. O., Quercetin, kaempferol and biapigenin from Hypericum perforatum are neuroprotective against excitotoxic insults, Neurotox. Res., 2008, 13, 265-279. 

Figure 8 Thin-layer chromatography of Hypericum perforatum. The chromatograms show no important differences between the herbai drug and the extract except the red spots in front. Both spots are the resuit of chiorophyll, which is eliminated by the extraction procedure. Red spots Hypericin and pseudohypericin yeiiow and orange spots fiavonoids (glycosides R, 0.5 agly-cones R, 0.8) blue spot ubiquitous plant acids. Reference traces on the left Hypericin chlorogenic acid and quercetin. (Reproduced with permission from Beat Meier, Zeller AG, Herbal Remedies, Romanshorn, Switzerland.)...

Liu et al. [391] extracted nine major active components from Hypericum perforatum (rutin, hyperoside, isoquercitrin, quercetin, quercitrin, psuedohypericin. 

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