Isolation and Characterisation of Antiviral and Immunomodulatory Constituents from Nigerian mistletoe, Loranthus micranthus

The avalanche of data on the immunomodulatory and anti-cancer activites of the European mistletoe, Viscum album especially with respect to its lectin constituents have been well documented [1]. These activities are always dependent on the season and host tree from which the plant material was harvested. The antimicrobial, antidiabetic and antimotility activities of the Eastern Nigeria mistletoe, Loranthus micranthus Hook. f. (Loranthaceae) have been reported [2,3,4]. Preliminary phytochemical evaluation showed presence of tannins, flavonoids, alkaloids, terpenoids, proteins, carbohydrates and saponins. Preliminary investigation with the crude aqueous (hot and cold extraction), methanolic (hot and cold extraction) and n-hexane (hot and cold extraction) extract of the mistletoe extract harvested in early January 2007 showed marked immunostimulatory activity using the total and differential leucocyte count, the delayed hypersensitivity reaction (DTH) and antibody titration models at three different dose levels of 50, 100, and 200mg/kg body weight in mice and rats. We observed a dose dependent increase in total and differential leukocyte count by well over 90% compared to the control (p<0.05, one-way ANOVA and Student t-test). Higher doses did not show any further benefit. The average increase in indurations in mice footpads in the presence of the extracts by 13, 47.8 and 56% followed similar trends as above. The mean antibody titre values increased by 100, 120, and 185% (p<0.05 compared to control) respectively at the tested dose levels of the extract. The results were all subjected to statistical analysis and no significant differences in respect to host tree variation were observed (P<0.001).

Acknowlegement: The authors are thankful to Mr. Ozioko of Bio resource Development and Conservation Centre, Nsukka, Enugu state for collection and authentication of the plant material from different host trees.

References: [1] Becker H, (1986) Oncology 43: 2–7. [2] Osadebe PO and Akabogu IC (2006) Fitoterapia 7; 54–56

3. Osadebe PO, Okide GB and Akabogu IC, (2004), J. Ethnopharmacol. 95: 133–138. 4. Osadebe PO and Uzochukwu IC (2006), J. Pharm. Allied Sci. 3: 263–268.