Phytochemistry and in vitro growth inhibitory action of Corchorus olitorius leaves against Leishmania tropica

Corchorus olitorius L. (Malvaceae) is a nutritional, edible vegetable, as its leaves have a high mineral content, including calcium and iron, as well as vitamins such as thiamine (B1), riboflavin (B2), folic acid, ascorbic acid (C) and tocopherol (E). Also, it is rich with essential phytochemicals such as cardiac glycosides, flavonoids, phenolics, fatty acids and terpenes, which are known for their pharmacological importance, like antioxidant, anti-inflammatory, antibacterial activities, antiviral, analgesic, antidiabetic and antitumor. This study aimed to evaluate the antileishmanial activity of C. olitorius hexane extract towards cutaneous leishmaniasis prepared by the extraction of 20 g of dried powdered leaves, followed by preliminary phytochemical analysis by GC-MS and TLC. Six different concentrations were assessed (1000, 500, 250, 125, 62.5 and 31.25 µg/mL) and compared with Pentostam®, a commonly prescribed antileishmanial medication. The GC-MS chromatogram demonstrated that the hexane extract is rich in terpenes (Phytol) and fatty acids (linolenic and palmitic acid) and TLC confirms the presence of β-sitosterol as having an RF value similar to the standard. IBM software's one-way analysis of variance (ANOVA) test was used to calculate the rate of inhibition for the 6 concentrations. The inhibition rate was more significant in the first 3 concentrations, 1000, 500 and 250 μg/mL, giving 78.96 %, 76.99 % and 68.88 % inhibition rate respectively, proving the anti-antileishmanial effect, as compared to positive control′s inhibition value, which was 67.23 % and the hexane fraction used to treat L. tropica was effective at low concentration of 0.127 mg/mL. The hexane extract contains a good percentage of linolenic, palmitic acid and phytol. TLC and GC-MS confirm the presence of β-sitosterol and the antileishmanial qualities are similar to Pentostam® treatment.