OBJECTIVETo compare the crystal form with the toxicity intensitity of raphides in four poisonous herbs of Araceae family.

METHODThe four kinds of raphides were extracted and isolated from Pinellia ternate, P. pedatisecta, Arisaema amurense and Typhonium giganteum. These raphides were observed with scanning electron microscopy (SEM), and the elements were analyzed with X-ray photoelectron spectroscopy. Infrared spectrum was used for detecting the functional groups. Toxic intensities of the four kinds of raphides were detected by mice acute toxicity experiment, and the value of LD0 were from caculated by Bliss rule.

RESULTThe raphides in the four plants have the similar crystal form. Observation with SEM showed a pointed and blunt end, and a long groove and barbs on a raphide. The raphides in P. ternate and P. pedatisecta were sharper than that in other two, respectively. The results of X-ray diffraction, photoelectric spectra showed that the major component of raphides was calcium oxalate monohydrate, and also showed the elements of N and S existing. Infrared spectra showed the raphides contained functional groups of -COOH and -NH2. These results illustrated that the calcium oxalate monohydrate was not the only component of the raphide. The raphides could produce severe toxic reactions. LD50 values of P. ternate, P. pedatisecta, A. amurense and T. giganteum were 14.78, 14.11, 16.02 and 18.90 mg x kg(-1) (ip), respectively. The corresponding LD50 values of crude drugs were all above 3000 mg x kg(-1) (ip). The toxicity of raphides was 200 times of crude drugs'.

CONCLUSIONThe raphides in P. ternate and P. pedatisecta, A. amurense and T. giganteum were their common poisonous factor.