Research Paper Free radical scavenging activity of Pfaffia glomerata (Spreng.) Pederson (Amaranthaceae) J. F. de Souza Daniel1, K. Z. Alves2, D. da Silva Jacques2, P. V. da Silva e Souza2, M. G. de Carvalho1, R. B. Freire2, D. T. Ferreira3, M. F. I. Freire4 ABSTRACT Objective: To evaluate the free radical scavenging and cytotoxic activities of the butanolic 1Laboratório de Produtos Naturais (BuOH) extract, methanolic (MeOH) extract and 20-hydroxyecdysone extracted from – LPM, Departamento de Química, the roots of Pfaffia glomerata. Universidade Federal Rural do Rio Materials and methods: Pfaffia glomerata roots were collected, powdered and extracted de Janeiro, Seropédica, Rio de with methanol by maceration at room temperature. The extract was concentrated under 2 Janeiro, Brazil; Laboratório de vacuum, yielding a residue, followed by a butanol extraction. The 20-hydroxyecdysone Toxicologia Ambiental (EC) was obtained by chromatographic separation of the BuOH fraction. An amount of (Imunotoxicologia) – LATAI, Departamento de Biologia Animal, 10 mg of each dry extract and EC was dissolved in 0.1% dimethyl sulphoxide–phosphate- Universidade Federal Rural do Rio buffered-saline solution (DMSO–PBS) and screened for their capabilities on scavenging de Janeiro, Seropédica, RJ, Brazil; thiobarbiturate reactive substances (TBARS). The antioxidant activity of each extract was 3Laboratório de Pesquisas em determined in vitro by measuring malonyldialdehyde (MDA) and 4-hydroxynonenal (4- Moléculas Bioativas – LPMBA, HNE) in erythrocyte ghosts treated with ferric-ascorbate. The investigation has also Departamento de Química, included the cytotoxicity measurement by Trypan blue exclusion test and tetrazolium Universidade Estadual de Londrina, reduction assay in mice peritoneal macrophages. 4 Londrina-PR, Brazil; Laboratório Results: The free radical scavenging activity of EC was higher than that present in the de Fitossanidade – LAF, Instituto de BuOH fraction. The MeOH extract showed a remarkable pro-oxidant activity. The EC- Pesquisas Jardim Botânico do Rio de Janeiro, Rio de Janeiro, RJ, free radical reaction–inhibition was almost twice of that of the control α-Tocopherol Brazil (αT). The Trypan blue exclusion assay confirmed toxicity of the MeOH extract, whose lethality surpassed 80% of the treated macrophages after 1 h of 0.01 mg exposure per Received: 24.7.2004 106 cells. Revised: 30.10.2004 Conclusions: The present study shows the antioxidant effect of the Brazilian Ginseng. Accepted: 3.11.2004 The scavenging effect was evidenced for EC as well the BuOH fraction. The MeOH extract showed cytotoxicity on mice peritoneal macrophages. Such toxicity is probably Correspondence to: due to ginsenosides present in this latter fraction and warrants further toxicological R.B. Freire evaluation of the Brazilian Ginseng roots. E-mail: [email protected] KEY WORDS: Antioxidant, bio-protective; Brazilian Ginseng; cytotoxicity; free radical scavenger. [5],[6] Introduction inflammatory diseases. Being one of the most popular herbs in Brazil, many users claim that there is no cytotoxicity Like other medicinal plants, there are difficulties in the attributed to P. glomerata, which might have an antioxidant botanical identification of the genus Pfaffia, in which the property.[7] Its medicinal activity is attributed to the glomeric popularly known Ginseng is included. Pfaffia glomerata acid, a triterpenoid, and pfameric acid, a nortriterpenoid (Brazilian Ginseng) is currently commercialized as Pfaffia together with ecdysterone, rubrosterone, oleanolic acid and paniculata (unpublished data). Oral administration of powdered beta-glucopyranosyl oleanolate that were isolated from the roots of P. paniculata inhibits the growth of allogenic cancer roots of P. glomerata.[8] Nevertheless, there exists a controversy cells in mice.[1],[2] Pfaffia glomerata roots are used as a tonic that members of this genus might cause oxidative stress and aphrodisiac[3] as well as in the treatment of diabetes[4] and because of their chemical properties or due to their 174 Indian J Pharmacol | June 2005 | Vol 37 | Issue 3 | 174-178 Antioxidant activity of the Brazilian Ginseng metabolites.[3],[9],[10] This concern is related to some of its con- Figure 1. Structural formula of 20-hydroxyecdysone stituents, which, if present in the crude extracts, may have a potential toxicity.[3],[9] Although extracts from the roots of P. OH OH glomerata seem to have a central nervous system depressant activity,[11] a protective effect against induced neurotoxicity has been related to some of its constituents.[12] The aqueous extract protects the gastric mucosa and inhibits gastric acid secretion OH in rats.[13] However, the presence of certain plant constituents may be responsible for the diverse array of cellular insults[10],[14] HO that could produce effects ranging from altered physiology to cell death.[3],[9],[10] The occurrence of these substances might OH reinforce the contraindication of the Brazilian Ginseng for those HO suffering from allergy, depression, drug addiction, hormonal H imbalance, pregnancy, or cardiovascular diseases.[3],[9],[10],[15]– O [17],[19] In the present study, we examined the free radical scavenging properties and the antioxidant activity of 20- 60 min before the compound exposure.[7],[8],[20],[22] Samples were hydroxy-ecdysterone (Fig. 1) as well as of the methanolic incubated and compared with a distilled water control in order (MeOH) and butanolic (BuOH) extracts from the roots of P. to calculate the percentage of inhibition of malonyldialdehyde glomerata. The cellular viability of normal mice macrophages (MDA)[20],[21] and MDA plus 4-HNE.[20] Appropriate vehicle control exposed to constituents of the plant was also evaluated. constituted of 1% dimethyl sulphoxide subsequently diluted 1:10 (v/v) with PBS. α-Tocopherol (αT) 2000 IU was used as a Materials and methods positive control. Plant Malonyldialdehyde (MDA) determination Pfaffia glomerata roots were collected in January 2000 in In the MDA assay, 0.65 ml of 10.3 mM N-methyl-2-phenyl- Icaraíma/Paraná State, Brazil, and identified by a botanist (W. indole in acetonitrile was added to 0.2 ml of the previously M. Kranz, personal communication). A voucher specimen (No. stimulated systems (1.6 mg/ml erythrocytes ghosts, 2 mM 18695) was deposited at the Herbarium of the Universidade deoxyribose, 100 mM FeCl3, 100 mM ascorbate, 20 mM Estadual de Londrina (FUEL), Brazil. KH2PO4–KOH buffer, pH 7.4) either in the presence or in the Preparation of extract absence of 0.5 ml extracts and (or) αT. After vortexing for 3– Powdered roots (500 g) were extracted with methanol by 4 s and adding 0.15 ml of HCl 37%, samples were mixed well, maceration at room temperature. The solvent was removed closed with a tight stopper, and incubated at 45 °C for 60 min. by distillation under vacuum to yield a 55 g solid residue The samples were then allowed to cool on ice, centrifuged, (MeOH extract). The crude residue was dissolved in MeOH/ and the absorbance measured spectrophotometrically at H2O (9:1) and extracted five times using 200 ml n-butanol. 586 nm. The n-butanol was removed and concentrated to dryness giving Malonyldialdehyde plus 4-Hydroxynonenal (MDA + 4-HNE) rise to a solid residue (BuOH fraction). The BuOH fraction (3 g) determination was eluted with H2O, MeOH and ethyl-acetate (AcOEt) in an The MDA + 4-HNE were determined spectrophoto- Amberlite XAD-2 resin generating 12 fractions. Fractions 5 metrically at 586 nm and expressed as micromolar using a and 6 were eluted with methanol in a Sephadex LH-20 calorimetric assay for lipid peroxidation.[20] Briefly, 0.65 ml of chromatography column. It gave 50 mg of purified 20- 10.3 mM N-methyl-2-phenyl-indole in acetonitrile was added hydroxyecdysone (EC). The collected fractions were evaporated to 1 ml of previously incubated solutions containing 0.2 ml to dryness and analyzed by silica gel TLC and visualized by UV of erythrocytes ghosts, 5 mM FeSO4, 500 mM ascorbate, (254 and 366 nm) and iodine vapor. 2 mM octanoic acid in 0.1 M Tris–HCl, pH 7.4 and 0.5 ml of Screening each sample, as described before. After vortexing for 3–4 s In this assay, a malondialdehyde (MDA) or a 4- 0.15 ml of 15.4 M methanesulfonic acid was added and the hydroxynonenal (4-HNE) 10 mM standard was used to samples were mixed well and incubated at 44 °C for 40 min. construct standard curves (from 2 to 20 nmol/ml) against The samples were then allowed to cool on ice, centrifuged, which unknown samples were plotted.[19]–[22] The TBARS was and the absorbance measured spectrophotometrically at expressed in terms of MDA or 4-HNE concentrations in nmol/ 586 nm. ml. All the samples were run in duplicate. The lipid peroxidation Erythrocyte ghosts (EG) was carried out in erythrocyte ghosts by the action of a ferric- Albino mice red blood cells (AMRBC) pellet was washed ascorbate induction. The TBARS were detected by the for leukocyte separation using 20 ml of TRIS buffer, pH 7.4 thiobarbituric acid method.[21] The fractions and extracts, used (6.05 g Tris, 6.42 g NaCl, 420 ml 0.1 M HCl, 580 ml de-ion- as dry material, were solubilized in 1 ml 10% dimethyl ized water) and centrifuged at 1600 g for 10 min.[9],[10] The sulphoxide (w/v) and subsequently diluted to 1:10 (v/v) with superior phase was discarded and the procedure was repeated phosphate buffered saline (0.1 M PBS, pH 7.2). The screening twice. An equal volume of TRIS buffer was added to final pellet was carried out by oxidizing a sample material at 37°C for and incubated for a minimum of 4 h at 4°C. Lysis of different intervals (30, 60, 90, 120 and 180 min) and erythrocytes was performed on ice with precooled conditions. measuring the MDA and the 4-HNE content 3 min after and A 15 ml resealing solution (301 mg MgSO4, 372 mg KCl in Indian J Pharmacol | June 2005 | Vol 37 | Issue 3 | 174-178 175 de Souza Daniel JF, et al.