Immunomodulatory activity of methanolic leaf extract of Moringa oleifera in Wistar albino rats

Globally, Moringa oleifera is used by different communities to treat various ailments including modulation of the immune system though with limited scientific evidence. The aim was to study the immunomodulatory activity of M. oleifera methanolic leaf extract in Wistar albino rats.

An experimental laboratory-based study was done following standard methods and procedures. Nine experimental groups (I, II, III, IV, V, VI, VII, VIII, IX) each comprising of six animals were used. Group I received normal saline. Groups II to IX received 200 mg/kg bwt cyclophosphamide at the beginning of the study. Group III received 50 mg/kg bwt of an immunostimulatory drug levamisole. Groups IV to IX were dosed daily for 14 days with extract at doses of 250, 500, and 1000 mg/kg bwt, respectively, using an intragastric tube. Complete blood count (CBC), delayed-type hypersensitivity reaction (DTH), neutrophil adhesion test, and hemagglutination antibody titer were determined using standard methods and procedures. Statistical analysis was performed using GraphPad prism 5.0a Software.

There was an increment in WBC, lymphocyte, and neutrophil counts at a dose of 1000 mg/kg bwt similar to the levamisole-positive control group. The neutrophil adhesion was statistically significant (p≤0.05) for treatment groups that received 1000 mg/kg bwt (29.94%) and 500 mg/kg bwt at 17.28%. The mean percentage increment in footpad thickness was highest (26.9%) after 8 h of injection of antigen in the footpad of rats dosed 500 mg/kg bwt and this later reduced to 25.6% after 24 h. There was a dose-dependent increment in the mean hemagglutination antibody titer to sheep red blood cells (SRBC) from 10.73±0.57 HA units/μL for the 250 mg/kg bwt to 26.22±1.70 HA units/μL for the 1000 mg/kg bwt.

Methanolic leaf extract of M. oleifera caused a significant immunostimulatory effect on both the cell-mediated and humoral immune systems in the Wistar albino rats.