Investigating in Vivo and in Vitro Effects of Ethanolic and Aqueous Extracts of Myrtle (Myrtus communis) on Leishmania major

The extract of myrtle plant contains polyphenolic compounds that show antibacterial, antiviral, and anti-parasitic properties. We aimed to investigate the therapeutic effect of aqueous and ethanolic myrtle extract against leishmaniasis caused by L. major in vivo and in vitro conditions.

This study was carried out in Tarbiat Modares University, Tehran, Iran in 2018. Aqueous and ethanolic extract of myrtle plant at 6.25 to 400 mg/ml concentrations were tested on Leishmania major promastigotes, non-infected macrophages, and macrophages infected with amastigotes in vitro using counting, MTT and flow cytometry techniques. Then, BALB/c mice were treated with ethanolic, aqueous and a mixture of both extracts of myrtle plant. The treatment was carried out for four weeks. Then, the effectiveness of the herbal medicine was assessed by measuring wounds diameters, mice weights and their mortality rate on weekly basis.

The IC50 values of aqueous and ethanolic extracts for promastigotes were 7.86 and 11.66 μg/mL respectively. The IC50 values of the aqueous and ethanolic extracts for amastigotes were 12.5 and 47.2 μg/mL respectively. Flow cytometry indicates 62.88% and 60.16% apoptosis induced by ethanolic and aqueous extract of myrtle plant respectively. The lowest parasitic load was seen in the group treated with ethanolic extract.

The lesion sizes for treated groups with extracts were similar to those treated with glucantime. Oral administration instead of injection is another advantage of myrtle plant over glucantime, which makes the herb easy and more practical.