Antiproliferative, antimicrobial, antiplasmodial, and oral acute toxicity of Ficus elastica Roxb. Ex Hornem lianas

Abstract

Background: Ficus elastica is a plant used in traditional medicine for the treatment of allergies and skin infections. This study aimed to investigate the antimicrobial, antiplasmodial, and antiproliferative activities of the crude extract and fraction of F. elatica as well as the study of the in vivo oral acute toxicity of the most active fraction.

Methods: The antimicrobial activity of the total extract and the different fractions was evaluated by the determination of the inhibition diameter using the agar well diffusion method on 3 Gram (+) bacteria, 4 Gram (-) bacteria, and 2 fungi, by the determination of MIC using the micro-dilution method only on the strains that showed sensitivity on the agar and by the determination of MMC on Muller Hinton agar. The evaluation of antimalarial activity was done on Plasmodium falciparum 3D7 cells by measuring the parasite lactate dehydrogenase (pLDH) activity using the mixture of Malstat and NBS/PES. Extracts were afterward evaluated for their antiproliferative effect on 2 human cell lines (human oligodendroglioma and breast cancer) and mouse melanoma using colorimetric MTT assay.  The toxicity assessment of the most active fraction was performed in vivo according to the modified OECD 425 guidelines.

Results: Total extract and different fractions were not active on different strains because the MICs values are > 1024 µg/mL. Dichloromethane and hexane fractions were bactericidal with a ratio CMM/CMI of 2 and the total extract would be bacteriostatic. The antimalarial activity showed that the hexane fraction reduced the viability of P. falciparum 3D7 cells by 61.4% with an IC₅₀ value of 26.41 µg/mL. As for the antiproliferative activity, the dichloromethane fraction significantly inhibited different cell lines with IC₅₀ values between 13 and 16.5 µg/mL. The toxicity study conducted on the hexane fraction, being the most active fraction, resulted in no apparent signs of toxicity and no death at doses of 2000 mg/kg bw and 5000 mg/kg bw over a period of 14 days.

Conclusion: Methanolic crude extract of F. elastica lianas and its hexane as well as dichloromethane fractions possess low antibacterial activity. The dichloromethane fraction possesses antiproliferative activity while the hexane fraction possesses antiplasmodial activity and presented no signs of acute toxicity by the oral route. These results support the use of F. elastica in the treatment of several ailments such as skin infections.