| Congresso Brasileiro de Microbiologia 2023 | Resumo: 230-2 | ||||
Resumo:The drugs first-line in the treatment of Leishmaniasis are the pentavalent antimonials, used for more than 70 years. However, adverse side effects and drugs resistance of the parasites are being reported frequently. An alternative to the use of drugs for leishmaniasis is the use of photosynthetic microorganisms (microalgae and cyanobacteria) as a source of bioactive molecules that can be used as strong candidates for the development of new drugs. The aim was to evaluate the activity of the extract of Chlorella vulgaris microalgae against Leishmania braziliensis and the cytotoxicity on human cells. C. vulgaris (UTEX 1803) cultivated on Bold Basal medium supplemented with 1% corn steep liquor was concentrated, resuspended in 0.15M Tris-HCl-saline, pH 7.5 at 50 mg/mL sonicated using ten pulses of 1 min with a 1 min interval and liquid fraction was called C. vulgaris extract (CVE). L. braziliensis promastigotes (MHOM/BR/1975/M2903 strain) were cultured in Schneider’s medium, 10% FBS and streptomycin at 26 °C incubator and were grown to the log phase cells were treated with different CVE concentrations (39.06 to 1250 𝜇g/mL), and Glucantime® (7.8 to 250 𝜇g/mL), at 37 ºC for 48h to determined the cellular viability using a Neubauer chamber. Peripheral human blood mononuclear cells (PBMC) from healthy humans were cultured in RPMI 1640 medium at concentration of 1x106 cells/mL in 96-well plates and added CVE (140 to 2250 𝜇g/mL) and Glucantime® (25 to 400 𝜇g/mL) to evaluated the cytotoxicity. Each treatment was performed in triplicate with 24-hour incubation and the cell viability was analyzed by MTT method. The selectivity index (SI) of the CVE and Glucantime® were calculated from the ratio CC50 (cytotoxic concentration at 50% in PBMC) by IC50 against the promastigotes forms of L. braziliensis. CVE used on L. braziliensis promastigotes cells showed inhibition percentage of 40.65% at 156.25 𝜇g/mL and 51.34% at 312.5 𝜇g/mL, obtaining IC50 value of 297 µg/mL. The Glucantime® inhibited the growth of promastigotes with an IC50 value of 133.69 µg/mL. The cytotoxic concentration (CC50) of CVE was 891.76 µg/mL while that Glucantime® was >400 µg/mL, being considered more toxic than CVE. CVE and Glucantime® exhibited SI of 3 and >3, respectively. CVE showed an effect against promastigotes of L. braziliensis. The activity could be due to a synergistic action between the secondary metabolites and proteins, which may have altered the structure of the parasite's cell membrane. Thus, the use of the cell extract of C. vulgaris becomes a promising candidate to be explored. Palavras-chave: algae, antileishmanial, leishmaniasis, new treatment Agência de fomento:CAPES, CNPq, FACEPE | |||||