Effect of some plant extracts from Egyptian herbal plants against Toxoplasma gondii tachyzoites in vitro

Nowadays, herbal extracts are considered to be a potential source for developing new drugs that will overcome resistance to conventional chemotherapeutic agents. This study was aimed to explore the efficacy of several Egyptian plant extracts against Toxoplasma gondii infection in vitro for future development of a new, safe, and effective compound for T. gondii. Methanol extracts from Matricaria chamomilla (German chamomile), Laurus nobilis, Citrullus colocynthis, Cinnamum camphora, Boswellia scara, and Melissa officionalis plants and oil extracts (either essential or fixed oils) of some plants such as: lemon grass (Cymbopogon citratus), marjoram (Origanum majorana), watercress (Nasturtium officionale), wheat germ (Triticum aestivum), sesame (Sesamum indicum), rosemary (Salvia rosmarinus), citronella (Cymbopogon nardus), clove (Syzygum aromaticum), jojoba (Simmondsia chinesis), and basil (Ocimum basilicum) were investigated for their anti-Toxoplasma activities. The methanol extracts from C. colocynthis and L. nobilis and the oil extracts from lemon grass and marjoram were active against T. gondii with half maximal inhibitory concentrations (IC(50)) of 22.86 µg/ml, 31.35 µg/ml, 4.6 µg/ml, and 26.24 µg/ml, respectively. Their selectivity index (SI) values were <10. Interestingly, the methanol extract from M. chamomilla and oil from citronella had the lowest IC(50) values for T. gondii (3.56 µg/ml and 2.54 µg/ml, respectively) and the highest SI values (130.33 and 15.02, respectively). In conclusion, methanol extract from M. chamomilla and oil from citronella might be potential sources of novel therapies for treating toxoplasmosis.