In vitro Anthelmintic activity of ethanolic extracts combinations of the stem barks of <i>Lannea kerstingii</i> and <i>Ficus thonningii</i> on <i>Heligmosomoides polygyrus</i> and <i>Caenorhabditis elegans</i>

Abstract

Background: Neglected tropical diseases, in particular helminthiasis, constitute a public health problem worldwide. This study was aimed at evaluating the anthelmintic activity of the therapeutic combination of Lannea kerstingii and Ficus thonningii in order to justify their use in combination by traditional healers for the treatment of intestinal worms. Methods: The anthelmintic tests using combinations of L. kerstingii and F. thonningii were carried out using the combination protocol. Combination 1 corresponding to 75% F. thonningii and 25% L. kerstingii; combination 2 corresponding to 50% F. thonningii and 50% L. kerstingii; and combination 3 corresponding to 25% F. thonningii and 75% L. kerstingii. Two nematodes were used: Heligmosomoides polygyrus and Caenorhabditis elegans. The effect of the combinations was evaluated invitro on L3 larvae of H. polygyrus and L4 stage of Caenorhabditis elegans. The most active combination was used for the hemolysis test on red blood cells and the antioxidant effects using 2,2- diphenyl-1-picryl hydrazyl (DPPH) radical scavenging, iron power reduction (FRAP test), NO radical inhibition and H2O2 scavenging methods. The phytochemical screening was conducted using both qualitative and quantitative methods. The analysis aimed to identify and measure the bioactive compounds present. Results: The IC50 of the combinations of extracts on H. polygyrus L3 are 0.13, 0.55, and 0.05 mg/mL for combinations 1, 2, and 3, respectively. Combination 3 (25% F. thonningii and 75% L. kerstingii) was found to have a greater larvicidal effect on the L3 form of H. polygyrus than the other combinations. The IC50 of the combinations on C. elegans L4 were 17.84, 16.54, and 2.60µg/ml, respectively, for combinations 1, 2, and 3. Combination 3 (25% F. thonningii and 75% L. kerstingii) with an IC50 of 2.60 µg/mL had a greater larvicidal effect on the L4 larvae of C. elegans, followed by combination 2 and finally combination 1. Combination 3 with an IC50 of 2.02e-005 showed a greater effect than vitamin C for DPPH radical scavenging activity. While in all other antioxidant tests, the effects of combination 3 are inferior, with IC50 of 285.9, 717.1, and 497175 for iron (III) power reduction, nitric oxide radical inhibition, and hydrogen peroxide scavenging, respectively, to those of vitamin C. Combination 3 also had a low haemolytic effect on red blood cells. Combination 3 shows the presence of polyphenols, flavonoids, alkaloids, tannins, saponins, and triterpenes and the absence of quinones. Combination 3 contains polyphenols (3130±128.6) and flavonoids (1746±22.63). Conclusion: This study provides scientific evidence supporting the traditional use of combined extracts from the two plants in treating helminthiasis. However, further studies need to be carried out, in particular on in vivo anthelmintic activity and acute toxicity.