Development of a Capsicum Extract for large scale production and its pharmacological characterisation

Chili pepper fruits (Capsicum spp.) are not only consumed as a pungent spice but are also employed for medicinal purposes. Thus, the use of Capsicum extracts has a long tradition in folk medicine as rubefacient and topical analgesic for the treatment of various neuropathic and musculoskeletal pain conditions. In the European Pharmacopoeia (Capsici Fructus), the crude drug is defined as ripe fruits of C. annuum var. minimum Miller (Heiser) and small fruit varieties of C. frutescens L. Capsaicin, dihydrocapsaicin and further minor capsaicinoids are the main active ingredients of Capsicum fruits. It was the aim of our studies to develop a capsaicinoid-rich extract suitable for industrial scale production. Due to the rather lipophilic character of capsaicinoids, apart from ethyl acetate low-polar ethanol-water and acetone-water solvent mixtures were initially used for extraction. However, resulting extracts proved to be very inhomogeneous and required large quantities of excipients to yield dry and powdery materials. More polar extraction solvents were therefore tried and the best result was obtained with 70% (w/w) ethanol. The capsaicin content of such extracts amounts to about 2% of capsaicin and dihydrocapsaicin with an extract yield of ca. 20%.

The analgesic effect of capsaicin is due to a blockade of TRPV1 receptors on nociceptive sensory nerves. As it is known that TRPV1 receptors are important in the pathogenesis of overactive bladder diseases and their modulation can reduce symptoms, the ethanolic extract was tested in a cyclophosphamide-induced rat model of interstitial cystitis/painful bladder syndrome (IC/PBS). Oral administration (1, 3, 10 and 75 mg/kg) of the extract for 4 days reversed the induced visceral allodynia and hyperalgesia in a dose dependent-manner.

The obtained data indicate that this Capsicum extract may be an interesting oral treatment option for complex pain conditions for which no standard therapy is yet available.