The leaves of Erigeron floribundus
(Kunth) Sch. Beep. or (syn: Conyza sumatrensis
(Retz) E.K. Walker) (Asteraceae) are used by some traditional healers in West Africa in HIV/AIDS therapy. The purpose of this study was to assess the immune-boosting properties of the aqueous leaf extract of Erigeron floribundus (Ef) by monitoring blood markers of cellular immunity in rabbit.
Two sets each of five groups (six rabbits per group) were used in this study. The groups in the first set each received intraperitoneally a single dose of Ef (25, 50, 75 or 100 mg/kg) or 0.9 % NaCl (control). The groups in the second set received methylprednisolone (15 mg/kg, MP15) and mixtures of MP15 with Ef (50, 75 or 100 mg/kg), MP15 or isoprinosine 50 mg/kg (Ip50, reference standard). Whole blood was collected in EDTA tubes from the marginal vein of the rabbit ear on Days 0, 3, 9, 15 and 21 after administration for the determination of CD4+ count by flow cytometry, and also of neutrophils and total lymphocytes in the blood.
: Each plant extract dose tested (50, 75 and 100 mg/kg) induced a significant increase in neutrophils (p < 0.001), total lymphocytes and TCD4+ (p < 0.0001) from the 3rd to 15th day after administration, compared to control (0.9 % NaCl). Furthermore, the same test extract doses significantly reversed the immunosuppressive effect of methylprednisolone (p < 0.001) to the same extent as isoprinosine.
The aqueous extract of the leaves of Erigeron floribundus stimulated the increase of neutrophils, total lymphocytes and TCD4+ in rabbit blood and thus provides some justification for its use in the traditional treatment of AIDS.