Hypericum perforatum flavonoids from

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. 

Butterweck V, Jurgenliemk G, Nahrstedt A, Winterhoff H. Flavonoids from Hypericum perforatum show antidepressant activity in the forced swimming test. Planta Med 2000 66 3-6. 

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. 

Phytochemistry The total flavonoids isolated from this species are nearly identical to those of Hypericum perforatum. Xanthones, vitamin C, carotene, anthocyanins, essential oil, sugars, mucilage, resins, organic acids, and saponins and others have also been isolated from the plant (Plant Resources of the USSR 1986 Matsuhisa et al. 2002 Tanaka et al. 2004). 

BaUck Ml, Cox PA (1996) Plants, people, and culture the science of ethnobotany. W.H. Freeman/Sdentific American Library, New York Bandyukova VA, Khalmatov KhKh, ADmov Khl (1969) Flavonoids of Centaurea depressa. Chem Nat Compd 5(4) 274-275 Banthorpe DV, White JJ (1995) Novel anthraquinones from undifferentiated cell cultures of Galium verum. Phytochemistry 38(1) 107-111 Barakat HH, Hussein SAM, Marzouk MS, Merfort I, Linscheid M, Nawwar MAM (1997) PolyphenoUc metaboUtes of Epilobium hirsutum. Phytochemistry 46(5) 935-941 Barnes J, Anderson LA, PhiUipson DJ (2001) St John s wort Hypericum perforatum L.) a review of its chemistry, pharmacology and cUnical properties. J Pharm Pharmacol 53(5) 583-600... 

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