Phenolic compounds from leaves ofHamamelis virginiana

Abstract

The North-American bush Hamamelis virghliana L. (Hamamelidaceae) is successfully cultivated in the moist subtropical Adzhariya region of Georgia. The leaves and preparations of this plant are included in pharmacopeia of many countries and are widely used as a vascular circulation regulator, anti-inflammatory, antihemorrhagic, astringent, and cosmetic componentAccording to the literature, the leaves and bark ofH. virginiana contain tanning agents such as the gallic glycoside hamamelitannin, free gallic acid, flavonoids, and bitter principles [1, 4].The leaves of//. virginiana ~own in Georgia are rich in phenolic compounds, the total content of which reaches 14%, The phenolic compounds are isolated from aqueous alcohol extracts of the air-dried leaves (45 and 70% ethanol) with subsequent extraction by ethylacetate. The combined compounds are separated into the pure components by adsorption and partition chromatography on silica-gel, polyamide, and Sephadex (LH-20) columns using various solvent systems. The following flavonols, phenolcarboxylic acids, hydrolyzed tannides, anthocyanidines, and catechins were isolated: kaempferol (3,5,7,4'pentahydroxyflavone), mp 278-281~ ~a~ (EtOH) 368. 268 nm; quercetin (3,5,7,3',4'-pentahydroxyflavone), mp 311-314~ ~-,~ax (EtOH). 370. 255 rim: trifolin (kaempferol-3-O-13-D-galactoside), mp 192-194'~C, )'m~,x (EtOH), 354, 267 nm [5]; kaempferol-3-O-~-D-glucuronide, mp 175-178~C. Z,,a,,.~ (EtOH), 350, 266 nm [6, 71; hyperin (quercetin-3-O-~-D-galactoside), mp 235-239~ ~,,~L, (EtOH), 360, 262 nm [8]; quercituron or mikwelianin (quercetin-3-O-13-D-glucuronide), mp 189-190~ ~'~,ax (EtOH) 357. 257 nm [7]; caffeic, chlorogenic, and gallic acids, mp 192-194, 202-204. and 250-25 I'~C, respectively [8, 9]: hamamelitanin (2',5-digalloyihamamelose), mp 137-144~ [10]; cyanidine and delfinidine, ~'m,,~ 535,546 nm, respectively (in CH3OH-HCI) [9, 111; (+)-catechin, mp 175-176~C. ~'m,,x (EtOH), 280 nm [9]. The flavonoid galactosides and glucuronides are isolated tor the first time from H. rirginiana.

AVALIAÇÃO DA ATIVIDADE ANTIULCEROGÊNICA DE Hamamelis virginiana L. E Sambucus australis Cham. & Schltdl.

“…As células hepáticas convertem o etanol em um composto de maior toxicidade, o etanaldeído, que reduz os níveis de glutationa no fígado, ocasionando peroxidação lipídica e desencadeando a produção de radicais livres (Raphael & Kuttan, 2003), tornando-se importante a presença de compostos antioxidantes, como taninos e flavonóides, nas drogas vegetais. Vennat et al, (1992); Masaki et al, (1994); Haslam (1996); Sagareishvili et al, (1999); Silva et al, (2000); Choi et al, (2002); Tourino et al, (2008); relataram a existência de compostos responsáveis por essa atividade em H. virginiana. Já foi também demonstrado que os taninos estão associados com atividade antiulcerogênica em outras plantas (Esaki et al, 1985) e que auxiliam na cicatrização, devido à sua capacidade de complexação com proteínas, formando uma película sobre a região danificada (Lopes et al, 2005).…”

“…A fração de polifenol nas folhas é representada por uma mistura de galotaninos e proantocinidinas (Erdelmeier, 1996). Isolaram-se também, nas folhas, canferol, quercetina 3-O--D-glucoronideo, cianidina, catequina, entre outros polifenóis (Sagareishvili et al, 1999).…”

A review of phytotherapy of Acne vulgaris

“…Hydroxycinnamic acids and flavonoids (e. g. myricetin, leucodelphinidin, quercetin, kaempferol, and gallic acid) are found mainly in the leaves of Hamamelis virginiana. Phenolic compounds from leaves of Hamamelis virginiana were studied by Sagareishvili et al (1999), where kaempferol, quercetin, trifolin, kaempferol 3-O-β-D-glucuronide, quercetin 3-O-β-D-glucuronide were isolated.…”