Analgesic and anti-Inflammatory Activity of Diterpenoid Alkaloids Isolated from the Central Asian Species of Aconitum and Delphinium Plants

In different countries of Europe, Asia and America the plants containing diterpenoid alkaloids have been used on the folk medicine from ancient time. Aconitum and Delphinium plants (Ranunculaceae family) and their extracts are used in the Eastern medicine at present as antirheumatic, analgesic, anti-inflammatory and other remedies. More 50 species of Aconitum (300 worlwide) and 100 species of Delphinium (450 worldwide) are growing on the territory of Former Soviet Union countries, including Russia, Central Asia and Kazakhstan. 

We investigated analgesic and anti-inflammatory activity of individual diterpenoid alkaloids isolated from Aconitum and Delphinium species widespread in the Central Asia and revealed 25 promising substances. Analgesic activity was investigated in the conventional tests for displaying analgesics with central mechanisms of analgesia (hot plate) and peripheral mechanisms (acetic writhing). Anti-inflammatory activity was studied in rat formalin test. 

By comparison of analgesic activity of investigated alkaloids and underly mechanisms of their pharmacological action we divided them on the following types: activators of potential-gated Na⁺-channels of neurons cause shifting of the threshold of Na⁺-current towards membrane hyperpolarization and destroy neuronal conductivity; blockers of potential-gated Na⁺-channels cause inhibition of the fast intake Na⁺-current without changing of its activation threshold; blockers of N-cholinoreceptors.