Anti-leishmanial activity of alkaloidal extract from Aspidosperma ramiflorum

Abstract

Infections due to protozoa of the genusLeishmaniasis is a tropical disease caused by protozoa of the Leishmania genus. These protozoa cause a disease with different clinical forms, among them cutaneous, hyperergic, mucocutaneous, and anergic diffuse leishmaniasis (Leon et al. 1990a). The disease is endemic in some geographical areas of Brazil, where it constitutes a serious health problem (Lonardoni et al. 1999, Leon et al. 2002.The drugs of choice for the treatment of leishmaniasis are the pentavalent antimonials (Sb V ), but they present renal and cardiac toxicity. A second choice for the treatment of the disease is a diamidine (pentamidine isethionate), which also has serious side effects (Korolkovas & Burckhalter 1988). However already in some trials alternative pharmaceutical formulations have been used to reduce the toxicity of these drugs (Frezard et al. 2000) The lack of an effective anti-leishmanial drug led a renewed interest in the study of traditional remedies as sources for the development of new chemotherapeutic compounds with better activity and less toxicity. Several plants have been used for the treatment of parasitic diseases (Araujo et al. 1998). In order to find new drugs against leishmaniasis, we have studied alkaloidal extracts of Brazilian plants (Oliveira et al. 2002) as "guatambu", is a tree which grows from to 12-30 m in height and is native to the forests in Southeastern Brazil (Lorenzi 1992). Some alkaloids have been previously isolated from the stem bark (Reis et al. 1996), and the alkaloid extract of the bark showed antimicrobial activity against Gram positive and negative bacteria (Oliveira 1999). The aim of the present study is to investigate the anti-leishmanial activity of alkaloidal extracts from the stem bark of A. ramiflorum against L. (V.) braziliensis and L. (L.) amazonensis. MATERIALS AND METHODSPlant materials -A. ramiflorum Muell. Arg. was collected in the Horto Florestal de Maringá, July 2000, in Maringá, state of Paraná, Brazil. The plant was collected and identified by Prof. Dr Ismar Sebastião Moscheta and an exsiccatum deposited and authenticated at the Herbarium of the State University of Maringá, Maringá, Brazil.Extraction of plant materials -Air-dried stem bark (1 kg) was extracted with 70% ethanol at room temperature. After removal of the ethanol, the crude extract was added to a 10% acetic acid solution (v/v) and kept at 5 o overnight. After filtration, the aqueous phase was first extracted with chloroform (acid extract), then the pH raised to 10 and the resulting solution re-extracted with chloroform (basic extract). The two chloroform extracts were concentrated under reduced pressure, and then lyophilised yielding the acid (7.7 g) and basic fractions (11.6 g), which were both analyzed by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). The main bulk of the alkaloids was in the basic fraction which was called the alkaloidal extract and which was used for the assays.

Indole Alkaloids from Aspidosperma rigidum and A. schultesii and their Antiparasitic Effects

“…Three alkaloids (fendlerine, aspidoalbine, and aspidolimidine), isolated from the stem bark of A. megalocarpon, exhibited strong antimalarial activity in vitro (Mitaine et al, 1998), and several Aspidosperma alkaloids were modest antiplasmodial agents (MitaineOffer et al, 2002). Previous studies showed that an alkaloid extract of A. ramifl orum was effective against Leishmania amazonensis (Ferreira et al, 2004). Ramifl orines A and B purifi ed from A. ramifl orum showed signifi cant activity against L. amazonensis with potency values similar to those of compound 2 [LD 50 values of (16.3  1.6) μg/ ml and (4.9  0.9) μg/ml, respectively] (Tanaka et al, 2007).…”

Use of Associated Chromatographic Techniques in Bio-Monitored Isolation of Bioactive Monoterpenoid Indole Alkaloids from Aspidosperma ramiflorum

“…After that, Oliveira 1999 isolated beyond these compounds the 16-(E)-isositrikine (5), all them from stem barks (Figure 1). The basic crude extract from stem barks of A. ramiflorum showed a good antileishmanial activity (Ferreira et al, 2004), which we attributed to the presence of indole alkaloids, and soon after, we described the fractionation, purification and isolation of alkaloids responsible www.intechopen.com for the activity against Leishmania (L.) amazonensis (Tanaka et al, 2007). Our results revealed that dimeric corynanthe alkaloids Ramiflorines A (1) and B (2) were responsible for the activity against promastigote forms of L. amazonensis with significant activity (LD 50 values of 16.3 ± 1.6 µg/ml and 4.9 ± 0.9 µg/ml, respectively).…”

“…The analytical TLC contributes greatly to a preliminary characterization of the alkaloidal extract and fractions obtained from A. ramiflorum. Although the substances present in various parts of this species, ramiflorine A (1), ramiflorine B (2), 10-metoxy-geissoschizol (3), β-yohimbine (4), ()-16-(E)-Isositsirikine (5), they are already known and described (Marques, 1998;Marques et al, 1996;Oliveira, 1999;Ferreira et al, 2004), TLC plates at R f values of substances determined and revealed by UV light and specific reagents such as p-anisaldehyde and Dragendorff allow a prior identification of substances quickly and conclusively. Under UV light, substances with chromophore, i.e.…”

“…Although there are many techniques developed for the isolation of natural products, PTLC is pretty used, being considered a relatively simple and inexpensive technique for separation and purification of small quantities of substances intended for chemical and physical-chemical studies. Although the migration time and the removal of the bands of substances are not easy and efficient, the LABIPROS team isolated by means of PTLC, stem barks and leaves of A. ramiflorum the same substances already isolated by other teams using different techniques (Marques et al, 1996;Ferreira et al, 2004). Figure 5 shows a preparative board applied, eluted and reveled in UV light 254 nm, one of alkaloidal fractions obtained from acid-base extraction of A. ramiflorum, composed of three main substances, of class MIA.…”

Cytotoxicity, genotoxicity and mechanism of action (via gene expression analysis) of the indole alkaloid aspidospermine (antiparasitic) extracted from Aspidosperma polyneuron in HepG2 cells

“…Low toxicity and absence of contraindications of infusions of Aspidosperma shells have contributed to their increasing use (Weniger et al 2001;Ferreira et al 2004). Several examples of its medicinal effects can be distinguished: A. ramiflorum is used in the treatment of leishmaniasis (Ferreira et al 2004) and A. nitidum is used for treating uterus and ovary inflammation, diabetes, cancer, fever and rheumatism (Weniger et al 2001). The family Apocynaceae, which includes the genus Aspidosperma, is characterized by the frequent presence of alkaloids with extensive structural diversity (Allen and Holmstedt 1980).…”