# Exploring the Anthelmintic, Antioxidant, and Cytotoxic Potential of Khaya grandifoliola and Faidherbia albida Extract Combinations: In Vitro Studies on Heligmosomoides polygyrus and Caenorhabditis elegans

## TL;DR

This study tests plant extract combinations from Khaya grandifoliola and Faidherbia albida for their ability to kill parasitic worms in lab settings, showing promising results.

## Contribution

The study demonstrates the synergistic anthelmintic potential of combining two traditional plant extracts for treating soil-transmitted helminth infections.

## Key findings

- Combination 2 (50% F. albida and 50% K. grandifoliola) showed the highest nematocidal activity with low IC50 values on H. polygyrus and C. elegans.
- Combination 2 exhibited strong antioxidant activity, particularly in iron reduction and hydrogen peroxide inhibition, though less than ascorbic acid.
- The combination showed weak DPPH and NO scavenging activity compared to ascorbic acid.

## Abstract

Soil‐transmitted helminth infection is endemic in Chad and constitutes a public health problem, particularly among school‐age children. The aim of this study was to evaluate the synergistic anthelmintic activity of the combined extracts of Khaya grandifoliola and Faidherbia albida used in Chad by traditional practitioners for the treatment of soil‐transmitted helminth infection.

The anthelmintic tests using combinations of K. grandifoliola and F. albida followed standard protocol. Combination 1 corresponding to 75% F. albida and 25% K. grandifoliola, Combination 2 corresponding to 50% F. albida and 50% K. grandifoliola, and Combination 3 corresponding to 25% F. albida and 75% K. grandifoliola. The nematocidal activity was assessed on Heligmosomoides polygyrus and Caenorhabditis elegans using the WMicroTracker. L3 larvae of H. polygyrus were obtained after 7 days of coproculture, and L4 of C. elegans. One hundred microliter concentrations of extracts, albendazole, and distilled water were brought into contact with 100 μL of H. polygyrus suspension in a 96‐well microplate incubated for 20 h at 28°C in the WMicroTracker. The same procedure was adopted for C. elegans, but 180 μL of OP50 and 19 μL of C. elegans suspension were mixed with 1 μL of extracts and incubated at 20°C in the WMicroTracker. The antioxidant activity was assessed by 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical, iron reducing power (Frap), hydrogen peroxide (H2O2), and nitric oxide (NO). Cytotoxicity was tested on red blood cells. The phytochemical screening was conducted using both qualitative and quantitative methods. Standard procedures were followed to ensure accuracy and reliability. The analysis was aimed at identifying and measuring the bioactive compounds present.

Combination 2 (50% F. albida and 50% K. grandifoliola) was the most promising, with an IC50 of 0.26 and 0.003 mg/mL, respectively, on H. polygyrus and C. elegans. This was followed by Combination 3 with an IC50 of 0.43 mg/mL for H. polygyrus. Combination 2 and Combination 3 with percentage inhibitions of 98.61 ± 0.98 and 99.14 ± 0.60, respectively, for H. polygyrus and C. elegans did not show a significant difference with respect to albendazole and levamisole. Combination 2 has the capacity to reduce iron with an IC50 of 2170 ± 3.73  μg/mL. Ascorbic acid (46.19 ± 0.18  μg/mL) used as a reference molecule shows a greater capacity than that of combination 2. With regard to H2O2, Combination 2 inhibited H2O2 slightly less (IC50: 0.114 ± 0.02  μg/mL) than ascorbic acid (IC50: 0.108 ± 0.03  μg/mL). As for DPPH, the combination had a moderately low scavenging activity (17.64 ± 0.18  μg/mL) compared with ascorbic acid, which had a good scavenging activity (7.23 ± 3.73  μg/mL). Combination 2 had a very weak effect on NO (IC50: 103.5 μg/mL) compared with ascorbic acid (54.22 ± 3.74  μg/mL).

This study provides scientific evidence supporting the traditional use of combined extracts from the two plants in treating helminthiasis. However, nematodes differ in structure, composition, and physiology. Further in vivo studies are needed to understand how Combination 2 affects nematode larvae.