Evaluation of antioxidant, antimicrobial, toxicological, and larvicidal activity of Psychotria fractistipula L.B. Sm., Klein Delprete

The objective of this study was to assess the potential antioxidant, antimicrobial, and toxicological properties of crude extracts and fractions obtained from the leaves and stem of Psychotria fractistipula L.B. Sm., Klein & Delprete. The content of phenolic compounds varied significantly between samples (783.70 – 78.22 GAE mg/g), with the highest concentrations being in the ethyl acetate fraction of the leaves and stem (679.39 and 783.70 GAE mg/g, respectively). The latter yielded also the best IC 50 of the DPPH radical, which amounted to 9.48 and 4.75 µg/mL, respectively; whereas other samples ranged up to 156.64 µg/mL. Similarly, phosphomolybdenum activity varied between 90.17% and 16.00%, with the ethyl acetate fractions of the leaves and stem corresponding to 90.17% and 87.37%, respectively. Antimicrobial activity was elevated in the leaves crude extract ( Staphylococcus aureus , 62.5 µg/mL), leaves ethyl acetate fraction ( S. aureus , 31.25 µg/mL; Enterococcus faecalis , 62.4 µg/mL), and the stem ethyl acetate fraction ( S. aureus , 31.25 µg/mL; Pseudomonas aeruginosa , 62.5 µg/mL). Hemolytic activity was high in the chloroform fractions of the leaves (1000 µg/mL) and stem (500 µg/mL). Larvicidal activity against Aedes aegypti was observed in the hexane fraction of the stem (LC 50 , 297.44 µg/mL). The ethyl acetate fractions of the stem and leaves were toxic to Artemia salina , with LC 50 values of 277.91 and 933.89 µg/mL, respectively. These results indicate that P. fractistipula may constitute an unexplored source of natural antioxidants and antimicrobials with low toxicity. clorofórmio das folhas (1000 µg/mL) e caule (500 µg/mL). Observou-se atividade larvicida contra Aedes aegypti na fração hexano do caule (CL 50 , 297,44 µg/mL). As frações de acetato de etila do caule e das folhas foram tóxicas para Artemia salina , com valores de CL 50 de 277,91 e 933,89 µg/mL, respectivamente. Esses resultados indicam que P. fractistipula pode constituir uma fonte inexplorada de antioxidantes e antimicrobianos naturais com baixa toxicidade. Palavras-chave Psychotria