Leishmanicidal activity and cytotoxicity of compounds from two Annonacea species cultivated in Northeastern Brazil.
BACKGROUND
Visceral leishmaniasis is endemic in 88 countries, with a total of 12 million people infected and 350 million at risk. In the search for new leishmanicidal agents, alkaloids and acetogenins isolated from leaves of Annona squamosa and seeds of Annona muricata were tested against promastigote and amastigote forms of Leishmania chagasi.


METHODS
Methanol-water (80:20) extracts of A. squamosa leaves and A. muricata seeds were extracted with 10% phosphoric acid and organic solvents to obtain the alkaloid and acetogenin-rich extracts. These extracts were chromatographed on a silica gel column and eluted with a mixture of several solvents in crescent order of polarity. The compounds were identified by spectroscopic analysis. The isolated compounds were tested against Leishmania chagasi, which is responsible for American visceral leishmaniasis, using the MTT test assay. The cytotoxicity assay was evaluated for all isolated compounds, and for this assay, RAW 264.7 cells were used.


RESULTS
O-methylarmepavine, a benzylisoquinolinic alkaloid, and a C37 trihydroxy adjacent bistetrahydrofuran acetogenin were isolated from A. squamosa, while two acetogenins, annonacinone and corossolone, were isolated from A. muricata. Against promastigotes, the alkaloid showed an IC50 of 23.3 µg/mL, and the acetogenins showed an IC50 ranging from 25.9 to 37.6 µg/mL; in the amastigote assay, the IC50 values ranged from 13.5 to 28.7 µg/mL. The cytotoxicity assay showed results ranging from 43.5 to 79.9 µg/mL.


CONCLUSIONS
These results characterize A. squamosa and A. muricata as potential sources of leishmanicidal agents. Plants from Annonaceae are rich sources of natural compounds and an important tool in the search for new leishmanicidal therapies.
Faculdade de Medicina Veterinária, Universidade Estadual do Ceará, Fortaleza, CE.
Nadja Soares
NS
Vila-Nova
Selen Maiade
SM
Morais
Maria José Cajazeiras
MJ
Falcão
Lyeghyna Karla Andrade
LK
Machado
Cláudia Maria Leal
CM
Beviláqua
Igor Rafael Sousa
IR
Costa
Nilce Viana Gramosa Pompeu de Sousa
NV
Brasil
Heitor Francode
HF
Andrade Júnior
D015107:4-Butyrolactone / Q000031:analogs & derivatives / Q000302:isolation & purification / Q000494:pharmacology / Q000633:toxicity; D054378:Acetogenins / Q000302:isolation & purification / Q000494:pharmacology / Q000633:toxicity; D031041:Annona / Q000737:chemistry*; D044182:Benzylisoquinolines / Q000302:isolation & purification / Q000494:pharmacology / Q000633:toxicity; D002850:Chromatography, Gel; D005663:Furans / Q000302:isolation & purification / Q000494:pharmacology / Q000633:toxicity; D018314:Leishmania infantum / Q000187:drug effects*; D007928:Lethal Dose 50; D009152:Mutagenicity Tests; D021261:Parasitic Sensitivity Tests; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D012639:Seeds / Q000737:chemistry; D014344:Trypanocidal Agents / Q000302:isolation & purification / Q000494:pharmacology* / Q000633:toxicity
D054378:Acetogenins; D044182:Benzylisoquinolines; D005663:Furans; D010936:Plant Extracts; D014344:Trypanocidal Agents; C570175:annonacinone; C455172:corossolone; D015107:4-Butyrolactone; C064689:armepavine