DOSE-RESPONSE OF LOW TO MODERATE LEVELS OF AQUEOUS EXTRACTS OF THE LEAVES OF Erythrophleum suaveolens ON RABBITS

The native African medicinal plant, Erythrophleum suaveolens, is frequently used by tradi-medical practitioners to treat a variety of human diseases in sub-Saharan Africa. However, knowledge on adequately safe dose levels and health implications associated with prolonged exposure is limited. This paper reports on dose-response and associated health implications of E. suaveolens leaves aqueous extracts on rabbits following sub-chronic exposures to low to moderate dose levels. Accordingly, low (2.5 mg/kg b.w./day) and moderate (5.0 mg/kg b.w./day) dose levels of extract were separately administered by gavage to test rabbit groups on daily basis for a total of 56 days, with daily weighing and observations for clinical signs and or mortality. Baseline and post-treatment biochemical and hematological parameters were determined. Rabbits were sacrificed (day 57) for gross and histopathological examinations. Generally, body weights increased with neither noticeable clinical signs nor mortality cases. With exceptions of average levels of urea (from low dose males and moderate dose females) and ALP (from low dose females), no significant differences in biochemical parameters were observed. All studied hematological parameters in males, likewise RBC, Hb and PCV in females in the moderate dose groups, in addition to Platelets for low dose female group, revealed significant differences (p<0.05). Liver and brain lesions and mild hepato-cellular infiltration speculated during gross examination were further confirmed by histopathological examination mainly in females. Biochemical, haematological and histopatological observations suggest mild dose-dependent toxicity at low but more at moderate dose levels with female rabbits more susceptible. Notwithstanding higher dose studies are required to confirm the speculated dose-dependent effect, likewise, very low dose level studies to determine the NOAEL as foundation for drug or vaccine candidate/development from this widely consumed medicinal plant.