Endophytic bacteria, such as Streptomyces, have the potential
to act as a source for novel bioactive molecules with medicinal
properties. The present study was aimed at assessing
the antimalarial activity of crude extract isolated from various
strains of actinobacteria living endophytically in some
Malaysian medicinal plants. Using the four day suppression
test method on male ICR strain mice, compounds produced
from three strains of Streptomyces (SUK8, SUK10, and SUK27)
were tested in vivo against Plasmodium berghei PZZ1/100 in
an antimalarial screen using crude extracts at four different
concentrations. One of these extracts, isolated from Streptomyces
SUK10 obtained from the bark of Shorea ovalis tree,
showed inhibition of the test organism and was further tested
against P. berghei-infected mice for antimalarial activity at
different concentrations. There was a positive relationship between
the survival of the infected mouse group treated with
50 μg/kg body weight (bw) of ethyl acetate-SUK10 crude extract
and the ability to inhibit the parasites growth. The parasite
inhibition percentage for this group showed that 50%
of the mice survived for more than 90 days after infection
with the parasite. The nucleotide sequence and phylogenetic
tree suggested that Streptomyces SUK10 may constitute a new
species within the Streptomyces genus. As part of the drug
discovery process, these promising finding may contribute
to the medicinal and pharmaceutical field for malarial treatment.