Comparative acute toxicities and immunomodulatory potentials of five Eastern Nigeria mistletoes.

BACKGROUND

Traditionally, mistletoes of Eastern Nigeria origin, Loranthus micranthus Linn. have been used as immunostimulant for the management of certain diseases with high profile immune depleting potentials. This practice has remained till date without scientific validation.

OBJECTIVE

To obtain and validate evidence for or against its continued use as immunostimulant and afford data for further studies on this specie of mistletoe. The present work is an in vivo proof of ethnopharmacological concept of the age long immunomodulatory use of our local mistletoe.

METHODS

Aqueous-methanol extracts of the plant leaves from five different host trees were evaluated for immunomodulatory activity using four in vivo models in mice or rats, namely; total and differential leukocyte count (TLC and DLC), the cellular mediated delayed-type hypersensitivity reaction (DTHR) test, the humoral mediated antibody titration (AT) test and the cyclophosphamide-induced myelosuppression (CIM) test at different dose levels (100, 200 and 400 or 50, 100 and 250 mg kg(-1); depending on model) against standard controls. Phytochemical and acute toxicity tests were equally carried out on all the extracts.

RESULTS

Results obtained indicate that all the mistletoes contained the same phytochemical constituents, although in varying amounts. The mistletoes exhibited statistically significantly different (p < 0.05 or p < 0.001, ANOVA) immunomodulatory (up-regulatory) activities in the overall order of that from Kola acuminata > Citrus spp > Persia americana > Parkia biglobosa > Pentaclatra macrophylla. LD(50) values were generally greater than 5000 mg/kg.

CONCLUSIONS

The present study confirms the Eastern Nigeria mistletoe as a potent and safe alternative or complementary medicine for the management of immunodeficiency diseases.