Studies on the cobra neurotoxin inhibiting activity in an extract of Curcuma sp. (Zingiberaceae) rhizome.

A study was carried on the mode of action and some properties of a cobra neurotoxin inhibitor found in the extract of Curcuma sp. (Zingiberaceae). When the principal postsynaptic neurotoxin (STX) of the Thai cobra (Naja naja siamensis) was mixed with an aqueous extract of Curcuma sp.

Effects of piperine on bioenergetic functions of isolated rat liver mitochondria.

The in vitro effects of piperine on three bioenergetic reactions namely, oxidative phosphorylation, ATPase activity and calcium transport by isolated rat liver mitochondria have been investigated. Piperine was found to inhibit state 3 and DNP-stimulated respiration by mitochondria respiring with glutamate plus malate or succinate as substrates. The I50 values of piperine on oxidative phosphorylation in the presence of glutamate plus malate and succinate were 22 and 12 micrograms/mg mitochondrial protein respectively.

Inhibition of mitochondrial ATPase by 2,4,3',5'-tetrahydroxystilbene.

2,4,3',5'-tetrahydroxystilbene (THS) wa s found to inhibit rat liver mitochondrial adenosine triphosphatase (ATPase) activity induced by various concentrations of 2,4-dinitrophenol (DNP). The I50 was found to be 17 nmoles/mg mitochondrial protein. The maximum inhibitory effects of oligomycin and atractyloside on the DNP-activated mitochondrial ATPase activity can be enhanced by adding THS.