Antioxidant Activity of Two Phloroglucinol Derivatives from Dryopteris crassirhizoma

Abstract

The MeOH extracts from approximately 200 Korean plants were investigated in an ongoing search for natural products with potent antioxidant activity. Among them, the MeOH extract of the rhizome of Dryopteris crassirhizoma NAKAI (Aspidiaceae) had a significant antioxidant effect on the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity. D. crassirhizoma is a pteridophyte and its rhizome is a well known Chinese crude drug, which has been used clinically in Korea, Japan, and China as a vermicide. 1) In addition, phloroglucinol derivatives (albaspidin, aspidin, flavaspidic acids, and dryocrassin) and kaempferol acetyl rhamnosides (crassirhizomosides A-C and sutchuenoside A) have been isolated from this plant source previously. 2,3) The phloroglucinol derivatives possessed antibacterial, 4) antitumor promoting, 5) nitric oxide inhibitory, 6) and anti-reverse transcriptase activities. 7) More recently, we reported the antibacterial activity of the phloroglucinol derivatives from this plant. 8) However, the antioxidant activity of the phloroglucinol derivatives isolated from D. crassirhizoma has not been reported. The aim of this study was to evaluate the antioxidant activity of the compounds isolated from D. crassirhizoma. MATERIALS AND METHODSPlant Rhizome of Dryopteris crassirhizoma was collected in Mt. Sulak, Korea in July 2002 and identified by Prof. Ki-Hwan Bae, College of Pharmacy, Chungnam National University, Korea. A voucher specimen (CNU 1011) was deposited in the herbarium of the College of Pharmacy, Chungnam National University, Korea.Isolation of Flavaspidic Acids PB (1) and AB (2) The dried rhizome (1 kg) of D. crassirhizoma was extracted with MeOH (3 l, 48 hϫ2) at room temperature and the MeOH solution was then concentrated to dryness in vacuo to afford a dark brown syrupy residue (150 g). The MeOH extract was suspended in H 2 O (1 l) and then shaken with EtOAc (1 lϫ2). The EtOAc-soluble fraction (80 g) was subjected to column chromatography on silica gel and eluted with hexane (10% acetone) and increasing amount of acetone to 80% acetone. Eight fractions (each 1 l) were collected. These fractions were tested in DPPH radical scavenging assay in vitro as a model for antioxidant activity. The fractions 5 and 6 showed antioxidant activity. A combined fraction of fractions 5 and 6 (8 g) was subjected to column chromatography on Sephadex LH-20 using MeOH to afford two compounds: flavaspidic acid PB (1, 300 mg), and flavaspidic acid AB (2, 150 mg).Flavaspidic Acid PB (1 DPPH Radical Scavenging Activity DPPH radical scavenging activity was measured according to the procedure described by Takao et al. 9) Ten microliters of each sample, dissolved in DMSO, was prepared in a 96 well plate and then 190 ml of 200 mM ethanolic DPPH solution was added. The mixture was incubated at room temperature for 30 min and the absorbance of the reaction mixture was measured at 517 nm. DPPH radical scavenging activity (%) is expressed as follows:DPPH radical scavenging activity (%)ϭ(A control ϪA sample )/A control ϫ...

Croton cajucara BENTH. Leaf Extract Scavenges the Stable Free Radical DPPH and Protects Against Oxidative Stress Induced by Paraquat

“…In the last few years some medicinal plants containing flavonoids have been reported to possess strong antioxidant properties. [12][13][14][15] Phytochemical analysis on leaf extracts from Croton cajucara has revealed the presence of different flavonoids such as 3,7,4Ј-tri-O-methylkaempferol and 3,7-di-O-methylkaempferol. 8) Hence, in the present study leaves were screened for in vivo and in vitro antioxidant properties using standard procedures.…”

“…Given the implication of ROS in the pathogenesis of a wide variety of clinical disorders and the strong antioxidant properties recently reported for different medicinal plants, [12][13][14][15] the aim of this work was to verify a possible antioxidant activity of the leaf extracts of Croton cajucara using both in vitro (capacity to scavenge the stable free radical 2,2-diphenyl-1-picrylhydrazyl, DPPH) and in vivo (percentage survival of Saccharomyces cerevisiae cells and oxidative stress in rats treated with paraquat) approaches.…”

“…9,10) Their antiradical property is directed towards highly reactive oxygen species (ROS) implicated in the initiation of lipid peroxidation; moreover, flavonoids are soluble chain-breaking inhibitors of the peroxidation process, scavenging intermediate peroxyl and alkoxyl radicals and chelating metal ions which are of major importance for the initiation of radical reactions. 11) Given the implication of ROS in the pathogenesis of a wide variety of clinical disorders and the strong antioxidant properties recently reported for different medicinal plants, [12][13][14][15] the aim of this work was to verify a possible antioxidant activity of the leaf extracts of Croton cajucara using both in vitro (capacity to scavenge the stable free radical 2,2-diphenyl-1-picrylhydrazyl, DPPH) and in vivo (percentage survival of Saccharomyces cerevisiae cells and oxidative stress in rats treated with paraquat) approaches.…”

A review of the use of pteridophytes for treating human ailments

“…The free radical scavenging bioactive principles viz. flavan-4-ol glycosides, abacopterins, huperzine A, isoquercetin, di-E-caffeoyl-meso-tartaric acid, flavaspidic acid PB, flavaspidic acid AB, flavan-3-ol, kaempferol, A-type proanthocyanidins, and afzelechin, have been derived from a few ferns including Abacopteris penangiana, Huperzia selago, Equisetum arvense, and Dryopteris crassirhizoma (Lee et al, 2003;Staerk et al, 2004;Mimica et al, 2008). Fig.…”

“…A. evecta and Selaginella tamariscina have been shown to have significant antidiabetic activity (Miao et al, 1996;Nguyen, 2005). According to Singh (1999) and Lee et al (2003), Asplenium polyodon, Asplenium nidus, A. capillusveneris, Ophioglossum gramineum, and H. arifolia have anti-cancer, antidiabetic, and antiviral activity. Chloroform extracts of Actiniopteris radiata (Linn.)…”