Screening of Morinda lucida leaf extract for antimalarial action on Plasmodium berghei berghei in mice.

The leaf extract of Morinda lucida collected in August was administered subcutaneously to albino Swiss mice infected with P. berghei berghei. The schizontocidal activity on early infection was assessed by administering chloroquine (standard) distilled water or Morinda lucida as single daily dose on day 0-3 to infected mice. On day 4 the degree of parasitaemia and percentage was determined in relation to control. Its schizontocidal activity was also observed on an established infection by administering the drugs 72 h after infecting the mice and the degree of parasitaemia was determined daily. The repository action of pyrimethamine was also compared with Morinda lucida. On the early infection, the chloroquine equivalent of Morinda lucida was found to be 1.0 mg/kg. In established infection a daily increase in parasitaemia was observed in control group while the animals that received chloroquine (5 mg/kg) and 1/6 dilution of the stock of Morinda lucida extract showed a sharp fall in parasitaemia from the second day of treatment. For the prophylactic test, 1.2 mg/kg of pyrimethamine and 1/6 dilution of stock of extract produced 80.5% and 70% chemosuppression respectively. It is interesting to note that Morinda lucida leaves extract appears to have schizontocidal and repository effects in mice infected with P. berghei berghei.