The effect of Plantago ovata on humoral immune responses in experimental animals

The effect of the aqueous extract of Plantago ovata (PO) (Plantaginaceae) consisting of a mixture of polysaccharides and glycoside on humoral immune responses was studied. In rabbits, after oral administration of PO (0.5 g/kg) a significant decrease in anti-HD antibody titre was observed in primary response. Intraperitoneal injection of 0.25 g/kg of PO in mice prior to immunisation with sheep red blood cells (SRBC) resulted in a significant decrease in hemagglutinating antibody (HD) titre. Oral administration and intraperitoneal injection of 0.25 and 0.5 g/kg of PO resulted in a significant increase in white blood cells (WBC) and spleen leukocytes counts. The spleen weight also increased with intraperitoneal injection (0.25 and 0.5 g/kg) and oral administration of 0.5 g/kg of PO. Present results indicate that PO can suppress the humoral immune responses, especially in primary immune response.