Fitoquimica

J. of Supercritical Fluids 30 (2004) 51–61

Extraction of indole alkaloids from Tabernaemontana catharinensis using supercritical CO2 +ethanol: an evaluation of the process variables and the raw material origin
Camila G. Pereira a , Márcia O.M. Marques b , Ala´de S. Barreto d , ı d , Eloise C. Fernandes c , M. Angela A. Meireles a,∗ Antonio C. Siani
LASEFI–DEA/FEA–UNICAMP (State University ofCampinas), Cx. P. 6121, 13083-970 Campinas, São Paulo, Brazil b LPN–Laboratório de Produtos Naturais, IAC, Cx.P. 28, 13001-970 Campinas, São Paulo, Brazil c Centro de Genética, Biologia Molecular e Fitoqu´mica, IAC, Cx. P. 28, 13001-970 Campinas, São Paulo, Brazil ı LQPN, Instituto de Tecnologia em Fármacos, FIOCRUZ, R. Sizenando Nabuco, 100, 21041-250 Rio de Janeiro – RJ, Brazil Received 10September 2002; received in revised form 31 March 2003; accepted 22 May 2003
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d

Abstract Indole alkaloids from Tabernaemontana catharinensis, collected from different places, were extracted using a mixture of supercritical CO2 plus ethanol. The effects of the process variables: temperature, pressure, solvent flow rate, and percentage of cosolvent on the total yield, chemical composition of theextract, and extraction kinetics were determined. The extracts were solvent-partitioned and their composition analyzed by TLC, GC-MS and 1 H and 13 C NMR. Voacangine and coronaridine were identified as the major compounds in the extracts; the individual alkaloids were quantified by GC-FID using external standard. At 250 bar and 45 ◦ C the largest yield (1.29%) and the faster extraction rate wereobtained; increasing the percentage of cosolvent improved the extraction rate as well as the yield. Employing an intermittent process consisting in six pressurization–depressurization steps appreciably reduced the total extraction time. © 2003 Elsevier B.V. All rights reserved.
Keywords: Supercritical extraction; SFE; Cosolvent; Indole alkaloids; Tabernaemontana catharinensis; Leishmaniasis

1.Introduction The use of supercritical fluid has been considered a good option for extraction and/or fractionation of natural products, particularly for food and pharmaceutical ingredients. The easy removal of solvent from the final
∗ Corresponding author. Tel.: +55-19-3788-4033; fax: +55-19-3788-4027. E-mail address: meireles@fea.unicamp.br (M.A.A. Meireles).

extract, the high selectivity and theuse of moderate process temperatures are the most significant advantages of supercritical fluid extraction (SFE). The use of supercritical CO2 to extract alkaloids such as caffeine from coffee beans and tea has generated many patents [1]; nonetheless, the extraction of several other classes of alkaloids is still an open field [2]. Tabernaemontana catharinensis A. DC. (syn. Peschiera catharinensis A.DC. Miers) is a 5–6 m height arboreal species belonging to the Apocynaceae

0896-8446/$ – see front matter © 2003 Elsevier B.V. All rights reserved. doi:10.1016/S0896-8446(03)00112-8

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C.G. Pereira et al. / J. of Supercritical Fluids 30 (2004) 51–61

Fig. 1. Chemical structure of the major indole alkaloids of T. catharinensis [5].

family that is rich in indole alkaloids. It ispopularly known as ‘jasmim’ (jasmine), ‘leiteira de dois irmãos’ (milkweed), and ‘casca de cobra’ (snake skin) and it occurs in Argentine, Uruguay, Paraguay and Southern Brazil. In folk medicine, it is used as an antidote for snakebites, to relieve toothache, and as a vermifuge to eliminate warts [3]. The crude extracts from its seeds and leaves showed in vivo antineoplasic activity and the aqueous oralcoholic leaf extracts produced significant dose-related anti-inflammatory and analgesic effects in rats [4]. Several indole alkaloids have been isolated from T. catharinensis including the leishmanicidal coronaridine and voacangine (Fig. 1) [5,6]. Leishmaniasis is an endemic infectious disease considered a worldwide public health problem. It refers to the syndrome caused by the protozoan...