In Vitro Antitumor Activity of Sesquiterpene Lactones from Lychnophora trichocarpha / Atividade antitumoral in vitro de lactonas sesquiterpenicas de Lychnophora

The sesquiterpene lactones lychnopholide and eremantholide C were isolated from Lychnophora trichocarpha Spreng. (Asteraceae), which is a plant species native to the Brazilian Savannah or Cerrado and popularly known as arnica. Sesquiterpene lactones are known to present a variety of biological activities including antitumor activity. The present paper reports on the evaluation of the in vitro antitumor activity of lychnopholide and eremantholide C, in the National Cancer Institute, USA (NCI, USA), against a panel of 52 human tumor cell lines of major human tumors derived from nine cancer types. Lychnopholide disclosed significant activity against 30 cell lines of seven cancer types with IC100 (total growth concentration inhibition) values between 0.41 µM and 2.82 µM. Eremantholide C showed significant activity against 30 cell lines of eight cancer types with IC100 values between 21.40 µM and 53.70 µM. Lychnopholide showed values of lethal concentration 50% (LC50) for 30 human tumor cell lines between 0.72 and 10.00 µM, whereas eremantholide C presented values of LC50 for 21 human tumor cell lines between 52.50 and 91.20 µM. Lychnopholide showed an interesting profile of antitumor activity. The α-methylene-γ-lactone present in the structure of lychnopholide, besides two α,β- unsaturated carbonyl groups, might be responsible for the better activity and higher cytotoxicity of this compound in relation to eremantholide C.

As lactonas sesquiterpênicas licnofolida e eremantolida C foram isoladas de Lychnophora trichocarpha Spreng. (Asteraceae), espécie vegetal nativa do cerrado brasileiro e popularmente conhecida por arnica brasileira. As lactonas sesquiterpênicas são conhecidas por apresentarem variadas atividades biológicas, incluindo atividade antitumoral. O presente artigo relata a avaliação da atividade antitumoral in vitro de licnofolida e eremantolida C frente a um painel de 52 linhagens de células tumorais, provenientes de tumores humanos referentes a nove principais tipos de câncer. Os testes foram conduzidos no National Cancer Institute, USA (NCI, USA). Licnofolida apresentou atividade significativa frente a 30 linhagens de células tumorais referentes a sete tipos de câncer, com valores de CI100 (concentração que inibe 100% do crescimento celular) entre 0,41 µM e 2,82 µM. Eremantolida C mostrou atividade significativa frente a 30 linhagens de células tumorais referentes a oito tipos de câncer, com valores de CI100 entre 21,40 µM e 53,70 µM. Licnofolida apresentou valores de concentração letal 50% (CL50) para 30 linhagens de células tumorais humanas entre 0,72 e 10,00 µM, enquanto eremantolida C mostrou valores de CL50 para 21 linhagens entre 52,50 e 91,20 µM. Licnofolida apresentou um interessante perfil de atividade antitumoral. A presença na estrutura química da licnofolida de uma α-metileno-γ-lactona, além de dois grupos ésteres α,β-insaturados, podem ser responsáveis pela melhor atividade e maior citotoxicidade desta substância em relação à eremantolida C.

Biological activity of the aqueous extract of Lychnophora pinaster Mart.

Lyophilized aqueous extract (LAE) from Lychnophora pinaster Mart (Asteraceae) aerial parts was evaluated in the search of possible biological activities. LAE exhibited trypanocidal activity (113.62 mg/mL), but could not inhibit 5-lipoxygenase in vitro (17 percent of inhibition). LAE chemical characterization by HPLC with UV-Diode Array Detector showed the presence of caffeic acid, isochlorogenic acid, vitexin, isovitexin and quercetin, in comparison with authentic samples.

Atividade antibacteriana de furanoeliangólidos / Antibacterial activity of furanoeliangolides

As lactonas sesquiterpênicas licnofólido (1) e eremantólido C (2) e alguns derivados: 1 ,2 -epóxieremantólido C (3), 1 β -hidróxi-2,3-diidroeremantólido C (4), 3 - hidróxieremantólido C (5), cloreto de 4,5-diidroeremantólido-5-n-propilamônio (6) e 1 β -hidróxi- 2,3-diidrolicnofólido (7) foram testadas contra as bactérias Enterococus faecalis S48, Bacillus subtilis CECT 397, Staphylococus aureus ATCC 8, Salmonella typhymurium LT2, Escherichia coli U9 e Proteus sp. Os compostos 1, 4, 5 e 7 apresentaram atividade antibacteriana.

Sesquiterpene lactones lychnopholide (1) and eremantholide C (2) and some derivatives: 1 ,2 -epoxyeremantholide C (3), 1 β -hidroxy-2,3-dihydroeremantolide C (4), 3 -hydroxyeremantholide C (5), 5-n- propylamonium- 4,5-dihydroeremantholide C chloride (6) and 1 β -hydroxy-2,3- dihydrolychnopholide (7) were tested against Enterococus faecalis S48, Bacillus subtilis CECT 397, Staphylococus aureus ATCC 8, Salmonella typhymurium LT2, Escherichia coli U9 e Proteus sp. Compounds 1, 4, 5 and 7 showed activity.

Estudo quimico de Zeyheria montana M. (bolsa de pastor)

Do extrato hexânico das raízes de Zeyheria montana M., uma Bignoniácea conhecida como bolsa‑de‑pastor, empregada popularmente contra doenças de pele, foram isolados os seguintes compostos: lapachol, α‑lapachona, desidro‑α‑lapachona, 4‑hidróxi­-α‑lapachona, β‑sitosterol, ácido esteárico e uma mistura de ácidos graxos. Estas substancias foram identificadas por métodos espectrométricos usuais e/ou comparação com amostras autênticas. No cromatograma do extrato etanólico, obtido por CLAE, foram identificados os picos correspondentes às naftoquinonas isoladas e ao ácido esteárico. A ocorrência de naftoquinonas nas raizes de Z. montana e a atividade antimicrobiana comprovada para o lapachol e a α‑lapachona justificam o uso popular desta espécie.

Zeyheria montana M. (Bignoniaceae) is a widespread species in the Cerrado area of Minas Gerais, Brazil, and is popularly known as bolsa‑de‑pastor. In the Brazilian tradicional medicine its roots are used for the treatment of skin diseases. Several species of Bignoniaceae contain naphthoquinones, and lapachol was previously reported in the stem wood of Z. digitalis. This paper describes the isolation of three naphtoquinones from Z. montana stem barks, namely α‑lapachone, dehydro‑α‑lapachone and 4‑hydroxy‑α‑lapachone, besides lapachol, stearic acid and β‑sitosterol. Furthermore, we report the HPLC fingerprint for the species, which allowed the identification of the isolated compounds, except β‑sitosterol. Since the in vitro antimicrobial activity of lapachol and α‑lapachone has been previously described, the presence of these naphthoquinones in the roots of Z. montana corroborates its popular use for the treatment of skin diseases.

In vitro activity of natural and synthetic naphathoquinones against erythrocytic stages of Plasmodium falciparum

In an attempt to identify new antimalarial compounds we studied the blood schizonticide effect of chemically defined natural products which were isolated from plants (Bignoniaceae) or synthesized. Different concentrations of there drugs (up to 20 micronM) were incubated in vitro with blood forms of Plasmodium falciparum for 72 h. A total of 12 drugs of the naphtoquinones group were tested. Eight of them were isolated from plants (NP) and 4 synthesized (S). Three of the drugs (2 NP and one S) were very active and completely inhibited parasite growth at the higher concentrations used (20 micronM); 5 drugs were partially active (3S and 2NP) and 3 (NP) were totally inactive. Lapachol was among the drugs tested. Although it has been considered a potential antimalarial agent, it exhibited very low activity (20% inhibition of schizogony). The antimalarial activity of our naphthoquinones against drug-resistant strains was superior to that of chloroquine and quinine which were as controls. Two of the P. falciparum strains used for the tests were strongly chloroquine resistant. If these naphthoquinones prove to be active in vivo and are of low toxicity, they will be promising candidates for treatment of human malaria particularly since they are easily synthesized