2.5.2.3 Cantharides Beetles
Synonyms Spanish fly; Blistering fly; Blistering beetles.
Biological Sources Cantharides comprises of the dead and dried insects of Cantharis vesicatoria Linn., (Lyatta vesicatoria) belonging to the family Meloidae. Cantharides contains the
furanocoumarin derivatives cantharidin ranging from 0.6 to 1%.
Geographical Sources These beetles are invaribaly found in the Southern and Central Europe residing on the plants belonging to the family Oleaceae and Caprifoliaceae. The various countries that are commercially engaged in the collection of cantharides are namely: Russia (now known as CIS countries), Rumania, Italy, Spain, Sicily and India.
Preparation The fully developed insects, that are brilliant green in apprearance with a distinct metallic lusture, are invariably collected in the early morning on a large spread cloth by vigorously shaking the branches of the shrubs. The beetles are sacrificed either by exposing them to the vapours of chloroform, sulphur dioxide and ammonia in a closed chamber or dipping them into vinegar. The dead beetles are dried artificially at a controlled temperature not exceeding 40oC.
Description
Colour : Brilliant green or Bronze green
Odour : Characteristic odour
Size : Length = 10-20 mm: Width = 3-6 mm.
Chemical Constituents Cantharides essentially contains an important vesicating* principle termed as canthraridin, which is nothing but the anhydride of cantharidic acid, located in the soft portions of beetles.
Besides, cantharides also contains resin, formic, acetic, uric acids and fat (12-15%)
Substituents/Adulterants Cantharides beetles are mostly substituted by Mylabris species, the well known Chinese cantharis having a close resemblance to the former ones. Mylabris essentially comprises of the dried beetles of Mylabris cichorii or Mylabris pustulata abundantly found in China and India, and contains cantharidin ranging between 1 to 1.2%.
Uses
1. Cantharidin has proved to a hair growth stimulant and hence used in hair oil.
2. Cantharides beetles, in general, is a vesicant, rubefacient and counter irritan
