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Revista Brasileira de Farmacognosia

Print version ISSN 0102-695X

Rev. bras. farmacogn. vol.20 no.1 Curitiba Jan./Mar. 2010

http://dx.doi.org/10.1590/S0102-695X2010000100022 

ARTIGO

 

Free radical scavenging and anti-edematogenic activities of Paullinia elegans Cambess., Sapindaceae, leaves extracts

 

Atividades sequestradora de radicais livres e anti-edematogênica de extratos das folhas de Paullinia elegans Cambess., Sapindaceae

 

 

Rodrigo N. GuimarãesI; Maria Conceição T. TruittiII; Ciomar A. Bersani-AmadoII; Anelise S. N. FormagioI; Flávia P. CardosoI; Willian F. da CostaI; Maria Conceição de SouzaIII; Maria Helena Sarragiotto*,I

IDepartamento de Química, Universidade Estadual de Maringá, 87020-900 Maringá-PR, Brazil
IIDepartamento de Farmácia e Farmacologia, Universidade Estadual de Maringá, 87020-900 Maringá-PR, Brazil
IIIDepartamento de Biologia, Universidade Estadual de Maringá, 87020-900 Maringá-PR, Brazil

 

 


ABSTRACT

Ethanol extract of the leaves of Paullinia elegans Cambess., Sapindaceae, and its hexane, chloroform, ethyl acetate, and hydroethanol fractions were evaluated for their antiedematogenic and free radical scavenging activities. The ethanol extract and the hexane fraction produced statistically significant inhibition (74.4 and 76.0%, respectively) of the ear edema induced by croton oil in mice, observed at doses of 5 mg/ear. The ethyl acetate and hydroethanol fractions showed significant radical scavenging effect in the DPPH assay, with IC50 of 36.7 and 30.1 µg/mL, respectively. Fractionation of the extracts through chromatographic methods afforded epifriedelanol, oleanolic acid 3-O-acetyl, a mixture of stigmasterol 3-β-O-glucopyranoside and sitosterol 3-β-O-glucopyranoside, kaempferol 3,7-O-α-dirhamnopyranoside, kaempeferol-3-O-α-rhamnopyranoside and 2-O-methyl-chiro-inositol. The compounds were identified on the basis of their NMR spectral data and comparison with those of literature.

Keywords: Paullinia elegans, anti-edematogenic activity, free radical scavenging activity, chemical constituents.


RESUMO

O extrato etanólico das folhas de Paullinia elegans Cambess., Sapindaceae, e as frações n-hexano, clorofórmio, acetato de etila e hidroetanólica, obtidas de seu fracionamento, foram avaliadas quanto às suas atividades anti-edematogênica e sequestradora de radicais livres. O extrato etanólico e a fração hexano produziram inibição significativa (74,4 e 76,0%, respectivamente) do edema da orelha induzido pelo óleo de cróton em ratos, em doses de 5 mg/orelha. As frações acetato de etila e hidroetanólica mostraram atividade sequestradora de radicais livres no ensaio de DPPH, com IC50 de 36,7 e de 30,1 µg/mL, respectivamente. O fracionamento dos extratos pelo uso de métodos cromatográficos resultou no isolamento do epifriedelanol, ácido 3-O-acetil oleanólico, mistura do stigmasterol 3-β-O-glucopiranosídeo e sitosterol 3-β-O-glucopiranosídeo, canferol, canferol 3,7-O-α-diramnopiranosídeo, canferol 3-O-α-ramnopiranosídeo e 2-O-metil-chiro-inositol. Os compostos foram identificados com base na comparação de seus dados espectroscópicos de RMN com os da literatura.

Unitermos: Paullinia elegans, atividade anti-edematogênica, atividade sequestradora de radical livre, constituintes químicos.


 

 

INTRODUCTION

Paullinia elegans Cambess., Sapindaceae, is found to occur in Brazil, Uruguay, Argentine and Paraguay. In Brazil, this species is known as ''cipó-timbó''. Chemical studies of the seeds of Paullinia elegans describe the isolation of cis-13-eicosenoic acid, cis-11-octadecenoic acid and 2,4-dihydroxy-3-methylenebutyronitrile (Spitzer, 1995, 1996). Species of the genus are known to contain fatty acids (Spitzer, 1996), and purin alkaloids (Weckerle et al., 2003) as major constituents.

Our preliminary studies on the pharmacological properties of P. elegans showed that the ethanol extract of the leaves presented significant inhibition (79.6±0.85%, at 10 µg/mL) of the growth of Trypanosoma cruzi epimastigotes (Truiti et al., 2005), and reduction of the volume of pleural inflammatory exudates in carrageenan induced pleurisy model in mouse, at doses of 500 mg.kg-1 (Truiti et al., 2006).

In the present study we report the results of the free radical scavenging and anti-edematogenic activities evaluation of the ethanol extract and its fractions from Paullinia elegans leaves. The chemical composition of the fractions was investigated through chromatographic methods and the isolated compounds were characterized by NMR spectral data and comparison with those reported in literature.

 

MATERIAL AND METHODS

General experimental procedures

NMR spectra were recorded on a Varian Mercury Plus BB spectrometer operating at 300 MHz for 1H and 75.5 for 13C, using CDCl3, D2O or CD3OD as solvents and TMS as internal standard. Columns chromatographies were performed using Sephadex LH-20 or silica gel 60 Merck (70-230 mesh ASTM). TLC was performed on precoated silica gel 60G or 60GF254 Merck.

Plant material

Paullinia elegans Cambess., Sapindaceae, leaves were collected in March 2000 in Porto Rico, Paraná, Brazil. The plant was identified by Dr. Maria Conceição de Souza and a voucher specimen (HNUP 463) has been deposited at the Herbarium of the Biology Department, State University of Maringá, Paraná, Brazil.

Animals

Male Swiss mice, weighing between 25 and 35 g were used in the experiments. The animals were kept in boxes for 72 h at room temperature, on a 12 h day-night cycle, with food and water ad libitum. The experimental protocols were approved by the Committee for Ethics and Animal Experimentation of the State University of Maringá.

Extract preparation and fractionation

Air-dried leaves of P. elegans (395 g) were exhaustively extracted by maceration with 95% ethanol at room temperature. Evaporation of the solvent afforded the ethanol extract (35 g). Part of this extract (12.6 g) was dissolved in EtOH-H2O 1:1 and partitioned with n-hexane, chloroform and ethyl acetate. The solvent was evaporated to give the hexane (1.8 g), chloroform (2.8 g), ethyl acetate (3.0 g) and hydromethanol (5.0 g) fractions.

Isolation of the constituents

The n-hexane fraction (1.58 g) was purified on chromatographic column of silica gel, eluting with a mixture of n-hexane:ethyl acetate in increasing polarity, to afford epifriedelanol (13.5 mg) and 3-O-acetyl oleanolic acid (99.0 mg). The chloroform fraction (1.8 g) was submitted to a chromatographic column on silica gel, eluting with a mixture of n-hexane, ethyl acetate and methanol in increasing polarity, to give a mixture of stigmasterol 3-O-β-glucopyranoside and sitosterol 3-O-β-glucopyranoside (154 mg). Purification of the ethyl acetate fraction (700 mg) on a silica gel chromatographic column, eluting with a mixture of chloroform and ethanol in increasing polarity, afforded kaempferol (31.2 mg), kaempferol 3,7-O-α-dirhamnopyranoside (22.4 mg) and kaempeferol-3-O-α-rhamnopyranoside (10.5 mg). The hydroethanol fraction (504 mg) was purified on Sephadex LH-20 to give the same compounds isolated from ethyl acetate fractions together with 2-O-methyl-chiro-inositol (60 mg).The isolated compounds were identified by comparison of their NMR data with those reported in the literature (Agrawal, 1989; Mahato & Kundu, 1994; Kundu et al., 2000; Abraham et al., 2005).

Anti-inflammatory assay

Edema was induced in mice by applying 20 µL of croton oil solution (10 µg/µL) dissolved in 7:3 acetone/ water, to the inner surface of both ears, according to Van Arman (1974). A solution (20 µL) of the extract and fractions (0.25 mg/µL), or of indomethacin (0.05 mg/µL) was applied to the inner surface of the left ear. The same volume of the solvent of each solution was applied to the right ear as a control. After 6 h, the animals were killed and the ears sectioned in discs of 6.0 mm of diameter each. The discs were weighed in an analytical balance for the determination of the edema inhibition percentage.

DPPH free radical scavenging assay

Free radical scavenging activities of the ethanol extract and of the n-hexane, ethyl acetate, and hydroethanol fractions were determined using 1,1-diphenyl-1-picrylhydrazyl free radical (DPPH) method. Various concentrations of the samples were added to 3 mL of daily-prepared methanol DPPH solution (0.1 mM). The mixture was shaken and left to stand at room temperature in the dark. After 30 min, absorbance was measured at 517 nm against a blank containing all reagents except the test samples. BHT was used as the positive control. Assays were carried out in triplicate.

Statistical analysis

The results for anti-edematogenic activity are presented as mean±standard error of the mean (SEM). The data were submitted to analysis of variance (ANOVA), followed by Tukey's test. p<0.05 was considered as the significance level.

 

RESULTS AND DISCUSSION

Application of croton oil to the left ear of the mice induced a very evident inflammatory response by hour 6. The weight of the ear doubled was compared to the right ear (basal, with no croton oil applied). The effects of the ethanol extract and its fractions on croton oil-induced rat ear edema are shown in Table 1 and Figure 1. The topic application of ethanol extract and hexane fraction produced a significant anti-inflammatory effect (p<0.001) compared to the control groups. The hexane fraction showed a percentage of 76% of inflammation inhibition, which was comparable to that of indomethacin (83% of inhibition). Esters of fatty acids, epifriedelanol and 3-O-acetyl oleanolic acid were isolated from the hexane fraction. The results indicate that the anti-inflammatory activity of the plant can be attributed to these compounds.

 

 

The data for free radical scavenging assay are reported in Table 2. The IC50(Table 2) correspond to the concentrations for 50% of inhibition of DPPH and were calculated from the graph of I% (inhibition percentage) versus extract concentration in µg/mL. The percentage of inhibition of DPPH (I%) was calculated using the equation: I%: (Ablank -Asample/Ablank) x 100, where Ablank is the absorbance of the blank solution and Asample is the absorbance of the ethanolic extract or fractions test samples.

 

 

The ethyl acetate and hydroethanol fractions exhibited the highest free radical scavenging activity with IC50of 36.7 and 30.1 µg/mL, respectively. The flavonoids kaempferol and its glycoside derivatives, kaempferol 3,7-O-α-dirhamnopyranoside and kaempeferol-3-O-α-rhamnopyranoside were identified as the main components of these fractions. The hydroethanol fraction afforded also the sugar 2-O-methyl-chiro-inositol. The antioxidant effects observed for ethyl acetate and hydroethanol fractions are probably due the presence of kaempferol, since the DPPH free radical activity of this flavonoid has been reported in the literature (Seyoum et al., 2006).

 

ACKNOWLEDGEMENTS

We are grateful to CAPES and CNPq for fellowships (A.S.N.F., F.P.C.) and to Fundação Araucária (Paraná State, Brazil) for financial support.

 

REFERENCES

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Truiti MCT, Ferreira ICP, Zamuner MLM, Nakamura CV, Sarragiotto MH, Souza MC 2005. Antiprotozoal and molluscicidal activities of five Brazilian plants. Braz J Med Biol Res 38: 1873-1878.         [ Links ]

Van Arman GC 1974. Anti-inflammatory drugs. Clin Pharmacol Ther 16: 900-904.         [ Links ]

Weckerle CS, Stutz MA, Baumann TW 2003. Purine alkaloids in Paullinia. Phytochemistry 64: 735-742.         [ Links ]

 

 

Received 21 August 2008; Accepted 26 November 2008

 

 

* E-mail: mhsarragiotto@uem.br, Tel. +55 44 3261 3657.

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