Antiprotozoal Activities of Tiliroside and other Compounds from (Cav.) G. Don.

BACKGROUND

(Malvaceae) is extensively used in Mexican traditional medicine for the treatment of gastrointestinal disorders such as diarrhea and dysentery.

OBJECTIVE

The current study was to validate the traditional use of for the treatment of diarrhea and dysentery on biological grounds using antiprotozoal activity and computational experiments.

MATERIALS AND METHODS

The ethanol extract, subsequent fractions, flavonoids, phenolic acids, and a sterol were evaluated on and trophozoites. Moreover, molecular docking studies on tiliroside were performed; it was tested for its affinity against pyruvate:ferredoxin oxidoreductase (PFOR) and fructose-1,6-bisphosphate aldolase (G/FBPA), two glycolytic enzymes of anaerobic protozoa.

RESULTS

Bioassay-guided fractionation of extract of the aerial parts of gives tiliroside and apigenin, caffeic acid, protocatechuic acid, and β-sitosterol. The antiprotozoal assay showed that tiliroside was the most potent antiprotozoal compound on both protozoa with 50% inhibitory concentration values of 17.5 μg/mL for and 17.4 μg/mL for . Molecular docking studies using tiliroside showed its probable antiprotozoal mechanism with PFOR and G/FBPA. In both cases, tiliroside showed high affinity and inhibition constant theoretic for PFOR (lowest free binding energy from -9.92 kcal/mol and 53.57 μM, respectively) and G/FBPA (free binding energy from -7.17 kcal/mol and 55.5 μM, respectively), like to metronidazole, revealing its potential binding mode at molecular level.

CONCLUSION

The results suggest that tiliroside seems to be a potential antiprotozoal compound responsible for antiamoebic and antigiardial activities of . Its antiprotozoal activities are in good agreement with the traditional medicinal use of in gastrointestinal disorders such as diarrhea and dysentery.

SUMMARY

Bioassay-guided fractionation of extract of the aerial parts of gives: tiliroside and apigenin, caffeic acid, protocatechuic acid) and β-sitosterol. The antiprotozoal assay showed that tiliroside was the most potent antiprotozoal compound on both protozoa with IC50 values of 17.5 mg/mL for and 17.4 μg/mL for . Molecular docking studies using tiliroside showed its probable antiprotozoal mechanism with PFOR and /FBPA. In both cases tiliroside showed high affinity and inhibition constant theoretic for PFOR (lowest free binding energy from -9.92 kcal/mol and 53.57 mM, respectively) and G/FBPA (free binding energy from -7.17 kcal/mol, respectively and 55.5 μM), like to metronidazole, revealing its potential binding mode at molecular level. The results suggest that tiliroside seems to be a potential antiprotozoal compound responsible for antiamoebic and antigiardial activities of . PFOR: Pyruvate:ferredoxin oxidoreductase; G/FBPA: Fructose 1,6 bisphosphate aldolase.