Violacein is a bacterial metabolite originally isolated from C. violaceum that has antibacterial and antiprotozoal activities.[1] [2] It is produced by C. violaceum as a purple pigment in response to N-hexanoyl homoserine lactone , a property that has been modified to create a strain of C. violaceum used in detecting quorum-sensing molecules.[3] Violacein is active against Gram-positive bacteria, including B. subtilis and S. aureus (MICs = 0.8 and 1.6 µM, respectively). It is also active against P. falciparum, including chloroquine-susceptible and -resistant strains (IC50s = 0.85 and 0.63 µM, respectively).[2] It reduces parasitemia in a mouse model of nonlethal P. chabaudi chabaudi infection when administered at a dose of 7.5 mg/kg and increases survival in a mouse model of lethal P. chabaudi chabaudi infection. Violacein permeabilizes the cytoplasmic membrane of bacterial cells but does not affect the cell wall.[1]
Butyrolactone V is a fungal metabolite that has been found in A. terreus and has antiprotozoal, antioxidant, and anticancer activities.1,2,3 It is active against the P. falciparum strain K1 (IC50 = 7.9 μg/ml) and L. amazonensis promastigotes (IC50 = 23.7 μM).2,1 Butyrolactone V (227 and 454.1 μM) is also active against adult S. mansoni worms.1 It scavenges 2,2-diphenyl-1-picrylhydrazyl and ABTS radicals with IC50 values of 20.7 and 3.7 μM, respectively, in cell-free assays.3 Butyrolactone V also inhibits proliferation of MDA-MB-231 and MCF-7 breast cancer cells (IC50s = 22.2 and 31.9 μM, respectively).1
Canophyllal shows antiplasmodial activity against the W2 strain of Plasmodium falciparum which is resistant to chloroquine and other antimalarial drugs.
Garcinone E is active constituents in the anticomplement assay used. Garcinone E exhibits potent activity in vitro against Plasmodium falciparum chloroquine-resistant strain W2, with IC50 values below 3 µM. It has potent cytotoxic effect on all hepatocellular carcinomas cell lines as well as on the other gastric and lung cancer cell lines included in the screen, may be potentially useful for the treatment of certain types of cancer.
Longistylin A and longistylin C show some cytotoxic effects, with IC(50) values of 0.7-14.7 microM against the range of cancer cell lines. Longistylin A and longistylin C, and betulinic acid show a moderately high in vitro activity against the chloroquine