Immunomodulatory activities of n-hexane and methanol extracts of Loranthus micranthus Linn. parasitic on Parkia biglobosa

Abstract

Loranthus micranthus, a species of mistletoe peculiar to the Eastern province of Nigeria has been shown to possess anti-diabetic, antimotility, antimicrobial and antihypertensive activities which are host-tree dependent [1–3]. The antimicrobial activity was found to vary with the season of harvest. We reported immune stimulating activity of extracts of mistletoe harvested from Kola acuminata [4]. In our efforts to establish the bio-activities and active principles in our local mistletoe, the immunomodulatory activity of the n-hexane and methanol extracts from Loranthus micranthus parasitic on Persea americana was assessed at three dose levels ranging from 100 to 400mg/kg body weight using delayed type hypersensitivity reaction (DTHR) and cyclophosphamide-induced myelosuppression models in mice. This was compared with responses from a standard immunostimulatory drug, levamisole. Preliminary phytochemical analysis of the extracts showed the presence of tannins, flavonoids, alkaloids, terpenoids, carbohydrates, proteins and saponins. Regression analysis indicated a dose-dependent response relationship in the parameters measured with over 170% increase for both extracts at the highest dose level. The one way ANOVA test showed significant variation in the parameters between the controls and the different dose levels. However, at a 95% confidence level, (P<0.05), there was no statistically significant difference between the two extracts, an indication that the active immunomodulant(s) could be both in the polar and non-polar crude extract. Thus, these extracts from Loranthus micranthus possess pronounced immune stimulating action comparable to Levamisole in mouse-based models.