Capsicum Peppers



The Capsicum peppers vary considerably in shape, size, color, and pungency, with over 20 different species. The very pungent, hot-tasting peppers, indigenous to more tropical habitats, are often called chile, chili, or Cayenne pepper, whereas the milder European varieties are known as sweet peppers, bell peppers, or paprika. Capsicum peppers are distinct from black pepper (Piper nigrum), a vine native to India that is the source of peppercorns, mainly used as a condiment spice.

Uses and Benefits:

Various members of the Capsicum pepper family have been used traditionally in Central and South America and in Asia to treat many diseases, Common indications include cardiovascular, circulatory, and respiratory problems; bowel disorders; wounds; burns; joint pains; and headaches. Currently, extracts of Capsicum species are commonly employed for local analgesia in acute and chronic pain syndromes, and capsaicin is available in a variety of pharmaceutical products. Pepper extracts are also used in sprays for defense against wild animals, humans, and garden pests.

Pharmacology:

Peppers contain over 125 volatile oils, as well as glycosides and vitamins. The main component of capsicum peppers is the glycoside capsaicinoid, or capsaicin (N-vanillyl-8­methyl-6-[E]-nonenamide).This chemical is related to eugenol (a major component of cloves) and vanillin (a major component of vanilla). Pure capsaicin and the related dihydrocapsaicin are ex­traordinarily pungent; they can be detected in a dilution of 1 in 17 million.The "hotness" of peppers is measured on the Scoville Organoleptic scale. Sweet bell peppers usually have zero Scoville units; habaneras measure over 200,000 units; and pure capsaicin rates over 15,000,000 units.The capsaicinoids are insoluble in water but readily dissolve in alcohol and vegetable oils.

A great deal is known about capsaicin. This molecule has proved to be a valuable tool for evaluating physiological mecha. nisms of cough, bronchospasm, and mucus production in humans and animals.However, its most important use is as a treatment for pain. Capsaicin is a lipophilic vanilloid that acts on receptors in the peripheral terminals of the nocioceptors that respond to painful stimuli. The stimulated receptor opens specific cation channels, resulting in transmission of sensory input through unmyelinated C-fibers. The transmitted impulse produces release of a neuropeptide, substance P, from sensory nerves that mediate pain.It has been shown that repeated or prolonged stimulation by capsaicin-which initially causes pain-gradually inactivates the nocioceptors and sensory nerve fibers, and they eventually degenerate. Pain may return, however, as receptors and nerve fibers regenerate over several weeks.

Clinical Trials:

An accepted value of capsaicin is its use as a topical rubefacient, counter-irritant, and analgesic for various forms of arthritis,11,12 and it is considered to be beneficial for neuropathic pain syndromes, such as fibromyalgia, peripheral neuropathy, causalgia, post-mastectomy pain, and trigeminal neuralgia.10,15,16 There is also some evidence supporting its use for pruritic disor­ders such as psoriasis, and for circulatory impairment that causes cold extremities,?,11

In spite of the acceptance of capsaicin as a pharmaceutical drug, there is controversy about its clinical value for pain relief. A meta-analysis evaluated randomized, double-blind, placebo­controlled trials of capsaicin for painful conditions in a total of patients. For diabetic neuropathy, of four trials totaling 309 patients, only two trials showed significant benefit. For osteoarthritis, of three trials totaling 382 patients, only one trial using either 0.025% or 0.075% capsaicin showed significant benefit. For post­herpetic neuralgia and for post-mastectomy pain, single small trials found no significant benefits. For psoriasis, four trials total­ing 245 patients were analyzed, and significant improvement was found in all trials. However, despite being of some benefit, topical capsaicin does not offer the most effective treatment when used in a concentration of 0.025% or 0.075%, although these are the strengths commonly marketed.

Adverse Effects:

People who are not conditioned to using peppers in large amounts will find oral or topical exposure to be unpleasant. Topical use causes increased pain for the first few days of use; patients must be counseled about this effect. Oral intake of peppery preparations can lead to gagging, coughing, inability to speak, dyspnea, and vomiting. Some patients with dyspepsia may find oral capsaicin increases discomfort and can induce gastroenteritis, diarrhea, and proctitis. Smaller doses of enteric capsules can prevent these dose-dependent consequences of capsaicin ingestion. It is still unclear whether peppery products can cause stomach ulcers, and some studies have lound chili peppers to be protective.

Side Effects and Interactions:

ACE inhibitor pretreatment may enhance the cough induced by inhaled capsaicin; one patient on an ACE inhibitor only coughed when she applied topical capsaicin to her nxtremities. Oral capsicum pepper was found to enhance the absorption characteristics of a sustained release form of theophylline in a European controlled study. These reports have not been confirmed.

Cautions:

Topical solutions, extracts, and creams should not be allowed to contact the eyes or broken skin because they could cause intense irritation. If capsaicin gets onto the fingers, the hands should be washed with soapy water to avoid inadvertently bringing capsaicin into or around the eyes. Some individuals are allergic to peppers. Alveolitis can occur in paprika packers who inhale its dust, and asthma or chronic cough can be precipitated in susceptible individuals who work with pepper products. Pepper remedies should always be used with caution if the tolerance of the patient is unknown. Small doses or concentrations should be initiated, and increases made as indicated and tolerated.

Preparations & Doses:

Oral dosages of 30-120 mg of cayenne pepper or 1-2 mg of the oleoresin up to three times a day are usually recommended, although larger doses may be tolerated. Oral products are usually available as capsules. Capsaicin can be used in topical products; commercial creams that are well known (e.g., Zostrix) contain 0.025% or 0.075% capsaicin. Some patients tolerate and require higher concentrations, which they can make themselves. Cayenne powder can be mixed into vegetable oil or a topical cream to give concentrations of 0.1 % to 0.5% for application several times a day. If tolerated, higher concentrations up to 5% can be tried. In all cases, small or dilute amounts should be used initially, because excessive amounts will irritate the skin and cause pain.

Summary Evaluation:

Capsicum peppers, which contain capsaicinoids, are of importance as research tools and as medications. Topical capsaicin creams and oils produce a sense of warmth and burning; repeated applications cause less discomfort, and the analgesic effect becomes predominant. Such application to painful muscle, skin, or joint areas has been shown to be therapeutic. Capsicum products are well accepted in orthodox medical practice for treating arthritic, musculoskeletal, and neuropathic pain, although clinical trial results are mixed. Other potential uses, such as for treating sinusitis and bronchitis, have not been studied and have not gained equal recognition. A major problem is that the pungent, burning qualities make sham treatment or double-blind assessment impossible.