Identification of Chemical Component Cantharidin from Chinese Blister Beetle by LC-MS/MS / 世界科学技术-中医药现代化

This study was aimed to verify the chemical component cantharidin from Chinese blister beetle by LC-MS/MS. Components were first processed by HPLC to choose the appropriate separation conditions before LC/MS/MS analysis. Through the positive and negative ions pre-scan, positive ions scanning way was selected in the scanning of each separate component. The scanned maps were obtained and the relative molecular mass was deduced. The results showed that 8 types of cantharidin compounds were identified, including three isomers. It was concluded that LC-MS/MS was able to determine the chemical component cantharidin from Chinese blister beetle rapidly and accurately, which was existed in the body by the form of combined amino acid.

Origin, transfer and distribution of cantharidin-related compounds in the blister beetle Hycleus scabiosae

Cantharidin provides chemical protection for the coleopteran families Meloidae and Oedemeridae. In the present study, it was observed that cantharidin concentration in Hycleus scabiosae was slightly decreased from mated females (mean = 0.011 mg/mg of dry weight) to males (mean = 0.010 mg/mg) and considerably diminished in relation to virgin females (mean = 0.005 mg/mg). Significant concentrations of palasonin (21.69 ng/mg among virgins and 17.49 ng/mg in mated females) and palasoninimide (14.62 ng/mg in virgins and 9.17 ng/mg in mated females) were found in H. scabiosae. Palasonin, palasoninimide and cantharidinimide content of eggs were measured as 5.61, 7.69 and 7.80 ng/mg respectively. Surprisingly, males showed no trace of cantharidin-related compounds (CRCs); therefore CRCs in H. scabiosae could not be transferred from males to females and based on experiments employing its deuterated form, cantharidin is probably independently synthesized in females from the male nuptial transfer. An inseminated female incorporates about 38.5 ng of cantharidin (0.34 percent of the maternal content), 196.35 ng of palasonin (91.82 percent of maternal content) and 269.15 ng of palasoninimide (96.70 percent maternal content) into each egg mass during oviposition. It seems that eggs of this meloid species exploit a different array of protective chemicals by increasing the ratio of CRCs versus cantharidin. CRCs are less toxic than cantharidin; therefore, such compounds might have been deposited in eggs as a safer substitute for cantharidin to provide effective protection, but does not simultaneously harm the susceptible embryo.(AU)