Pimolpan PithayanukulBunmun LapettRapepol BavovadaNarumol PakmaneeRutt SuttisriMahidol UniversityChulalongkorn UniversityThai Red Cross Agency2018-08-242018-08-242007-04-01Pharmaceutical Biology. Vol.45, No.4 (2007), 282-28817445116138802092-s2.0-34347387551https://repository.li.mahidol.ac.th/handle/20.500.14594/24223The ethyl acetate extract of Eclipta prostrata L. (Asteraceae) was evaluated for its antivenom potential against Calloselasma rhodostoma Kuhl (Viperidae) (Malayan pit viper; MPV) venom. The partially purified ethyl acetate extract (PEE) was found to contain 47% wedelolactone as its major constituent. PEE and wedelolactone demonstrated strong antiproteolytic and antihemorrhagic activities against MPV venom in a dose-dependent manner. The extract, at 5 mg/mL, could inhibit proteolytic activity of 100 μg of the venom and hemorrhagic activity of 3 minimum hemorrhagic doses (MHD) to 95% and 68%, respectively. At the same concentration, wedelolactone could neutralize the proteolytic activity at around 76% and, at doses of 0.25-1 mg/mL, offered protection against hemorrhagic activity of the venom in the range 3-35%. Both PEE and wedelolactone displayed partial anti-phospholipase A2 activity (21% for PEE and 7% for wedelolactone) and could not neutralize the lethal effect of either 2LD50 or 4LD50 of MPV venom. © 2007 Informa Healthcare.Mahidol UniversityBiochemistry, Genetics and Molecular BiologyMedicinePharmacology, Toxicology and PharmaceuticsArticleSCOPUS10.1080/13880200701214805