Resiniferatoxin

[3][4] Resiniferatoxin activates transient vanilloid receptor 1 (TRPV1) in a subpopulation of primary afferent sensory neurons involved in nociception, the transmission of physiological pain.

Structure 6 contains all three rings of the RTX backbone and can then be converted to resiniferatoxin through additional synthesis steps attaching the required functional groups.

It is currently the most potent TRPV1 agonist known,[13] with ~500x higher binding affinity for TRPV1 than pure capsaicin, the active ingredient in hot chili peppers such as those produced by Capsicum annuum.

Sorrento Therapeutics has been developing RTX as a means to provide pain relief for forms of advanced cancer.

[16][17] The nerve desensitizing properties of RTX were once thought to be useful to treat overactive bladder (OAB) by preventing the bladder from transmitting "sensations of urgency" to the brain, similar to how they can prevent nerves from transmitting signals of pain; RTX has never received FDA approval for this use.

[4] RTX has also previously been investigated as a treatment for interstitial cystitis, rhinitis, and lifelong premature ejaculation (PE).

Figure 1. A partial synthesis of a resiniferatoxin derivative based on the method put forth by the Wender group of Stanford University. This partial synthesis shows how to create the three-ring backbone of RTX