**Author details**

a mechanism that involves selective block of N‐type calcium channels. This action inhibits the discharge of pronociceptive neurochemicals such as glutamate, calcitonin gene‐con‐ nected peptide, and material P in the brain and spinal cord, ensuing in pain relief. It has been approved for the treatment of severe chronic pain in patients only when administered by the intrathecal route. Importantly, prolonged administration of ziconotide does not lead to the

Salvinorin A is the main active psychotropic molecule in *Salvia divinorum*, a Mexican plant that has a long history of use as an entheogen by indigenous Mazatec shamans. Salvinorin A is considered a dissociative. It can produce psychoactive experiences in humans with a typi‐ cal duration of action being several minutes to an hour [54, 55]. Furthermore, Salvinorin is a *trans*‐neoclerodane diterpenoid, which acts as a κ‐opioid receptor agonist. The mechanism of action of Salvinorin A on ileal tissue has been described as prejunctional, as it was able to adjust electrically made contraction, but not those of exogenous acetylcholine. A pharmaco‐ logically important feature of the contraction‐reducing properties of ingested Salvinorin A on gut tissue is that it is only pharmacologically active on inflamed and not normal tissue, thus reducing possible side effects. Salvinorin produce a conditioned place aversion and decreases

Pawhuskin A is a bioactive naturally occurring stilbene reported from *Dalea purpurea*. Pawhuskin A has recognized to function as an opioid receptor antagonist, with special bind‐ ing to the k receptor. Pawhuskin A is the most active natural compound making a small group

This chapter has focused on information and relevant literature pertaining to analgesic plants and their explored chemical constituents. Furthermore, unexplored medicinal plants reported to be used in folk medicine have been highlighted. This chapter also provides references to research carried out on analgesic drugs. Additionally, this chapter describes the main mecha‐

The authors are grateful to the Higher Education Commission of Pakistan and the University

of nonnitrogenous compounds with effect on the opiate receptor system [56].

nisms of action of natural products poisoning presenting analgesic properties.

development of addiction or tolerance [53].

346 Pain Relief - From Analgesics to Alternative Therapies

locomotors. It is able to modify dopaminergic pathway [55].

*2.7.4. Salvinorin*

*2.7.5. Pawhuskin A*

**3. Conclusions**

**Acknowledgements**

of Swabi, KPK, for financial support.

Abdur Rauf1 \*, Noor Jehan2 , Zarka Ahmad3 and Mohammad S. Mubarak4

\*Address all correspondence to: mashaljcs@yahoo.com

