Proteolytic-independent cobra neurotoxin inhibiting activity of Curcuma sp. (Zingiberaceae).

The 1: 1 (w/v) aqueous extract of Curcuma sp. (Zingiberaceae) was shown to antagonize the toxic action of Naja naja siamensis neurotoxin possibly via direct inactivation of the toxin. The plant extract possessed proteolytic activity which could be separated from the neurotoxin inhibiting activity. The mechanism of antagonism between the plant extract and the neurotoxin was shown not to be involved with the existence of proteolytic activity in the plant extract.

The absence of antagonism between extracts of Clinacanthus nutans Burm. and Naja naja siamensis venom.

Clinacanthus nutans Burm, a herb reputed in Thailand and Malaysia to be "snakebite antidote" has been tested in vitro and in vivo for antivenin activity. The aqueous extract of C. nutans leaves has been found to have no effect on the inhibition of neuromuscular transmission produced by purified Naja naja siamensis neurotoxin in isolated rat phrenic-nerve diaphragm preparations. The extract of C. nutans, when given orally or intraperitoneally, are ineffective in prolonging the survival time of experimental mice receiving lethal doses of N.n. siamensis crude venom. Oral administrations of the herb extracts pretreated with alpha-amylase or beta-amylase also fail to protect the animal. It is concluded that the extract of C. nutans can not antagonize the action of cobra venom.