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Useful plants of dermatology. V. Capsicum and capsaicin
SPECIAL ARTICLE Useful plants of dermatology. V. Capsicum and capsaicin Scott A. Norton, MD, MSc Fort Huachuca and Tucson, Arizona
Capsaicin is more than a medication; it provides the essential fieriness to the world’s most valuable spice, hot pepper. Capsaicin is found in the hot pepper’s placenta, the white fibrous material that holds the seeds. Some capsaicin rubs off onto the seeds, making them pungent as well, but it is not present in the pepper’s flesh. Capsaicin’s medical usefulness comes from its ability to deplete unmyelinated sensory neurons of Substance P, a neurotransmitter involved in cutaneous itch and burning.1 In pure form, capsaicin has virtually no flavor or odor. Capsaicin is a mixture of five closely related vanillyl amides of isodecenoic acid (Fig 1). A pepper’s fieriness is measured by the Scoville Organoleptic Test devised in 1912.2 Scores range from 0 Scoville units for bell peppers, 2500 to 4000 units for jalapeno and cayenne peppers, to 70,000 units for tabasco peppers.3 The heat of a pepper is unrelated to color (which is determined by a separate gene for carotenoid content). Certainly not all hot peppers are red. Peppers are members of the genus Capsicum (Fig 2) from which the name capsaicin is derived. Capsicum was described and named by the preLinnean botanist de Tournefort.3 The Latin capsa or box may refer to the boxy shape of the fruit. Linnaeus maintained the name in the original Species Plantarum in 1753. The flowers of Capsicum species resemble those of the closely related tomato, potato, eggplant, and tobacco—all members of the Solanaceae or nightshade family. From the Dermatology Service, Raymond W. Bliss Health Clinic, Fort Huachuca, and the University of Arizona College of Medicine, Tucson. The opinions and assertions in this article are those of the author and not of the Department of Defense. Reprints are not available from the authors. J Am Acad Dermatol 1998;39:626-8. 16/1/91010
626
Fig 1. Molecular formula for capsaicin. There are at least five vanillyl amides found in natural capsaicin.
Early European consumers appreciated the gustatory similarities between capsicum and the botanically unrelated black pepper (Piper nigrum of the Piperaceae), so they conferred the name pepper. Many botanists and cooks prefer to call the subjects of this essay capsicums to avoid confusion. In this quinquicentennary of Columbus’s second voyage, we recall Diego Alvarez Chanca, physician on that expedition, who observed Arawak Indians of the Caribbean using capsicums as both a spice and a medicine (Fig 3). Chanca brought capsicums back to Iberia from where they spread eastward rapidly, reaching India by 1498 via Portuguese voyages of discovery.4 Although we think of red pepper as an essential spice in the cuisine of many regions worldwide, capsicum was unknown in the Old World until shortly after Columbus. When one enjoys the pungent flavors of Old World cuisines such as Szechwan, Thai, Indian, Hungarian, and Ethiopian, remember that capsicums have been present in them for only a few hundred years. Medicinal uses of topical capsaicin include treatment of the pain and burning of postherpetic neuralgia, diabetic neuropathy, reflex sympathetic dystrophy, Raynaud’s phenomenon, notalgia paresthetica, arthralgias, plantar warts, pharyngitis, diabetic neuralgia, and hemodialysis-related pruritus.5 Other formulations are used as throat
Journal of the American Academy of Dermatology Volume 39, Number 4, Part 1
Norton 627
Fig 2. Jalapeno peppers. There are five domesticated species of peppers of which C annuum var annuum includes most of the economically important varieties. The Tabasco pepper is C frutescens var tabasco. (From Andrews J. Peppers: the domesticated capsicums. New ed. Plate 14. Copyright © 1995. Courtesy of Jean Andrews and the publisher, The University of Texas Press [Austin]).3
Fig 3. Peppers for sale at Tarascan Indian market, Patzcuaro, Mexico. The genus Capsicum probably evolved in central Bolivia and contains 20 to 30 species. The greatest differentiation of the cultivated species occurs in Mexico. There are possibly several hundred varieties of edible peppers.3,4
balms. Capsaicin is not a rubifacient because it does not induce reddening of the skin. Albert von Szent-Gyorgyi, a Hungarian researcher raised on food spiced with paprika, derived Vitamin C from paprika peppers; for this, he received the Nobel Prize in Medicine and Physiology in 1937.3,6 Recently the capsaicin receptor VR1 (vanilloid receptor 1) was identified. It appears that prolonged exposure of these receptors to capsaicin causes injury and death of neuronal pain fibers, thereby stopping transmission of the noxious stimulus. This explains why the transmission of pain stops upon continuous exposure to capsaicin.7,8
Capsaicin has a number of nonculinary, nonmedicinal uses also. Its recorded use as a repellent dates to the 15th century when Caribbean islanders used irritating smoke from burning capsicums in an attempt to repel the Spanish invaders.6 It is now used as a personal defense spray by police, military forces, and private citizens. Other repellent uses include the treatment of ship hulls to deter barnacle aggregation and on the neck of sheep to deter coyote attacks. REFERENCES 1. Cordell GA, Araujo OE. Capsaicin: identification, nomenclature, and pharmacotherapy. Ann Pharmacother 1993;27:330-6.
628 Norton 2. Scoville WL. Note on capsicums. J Am Pharm Assoc 1912;1:453-4. 3. Andrews J. Peppers: the domesticated capsicums, new edition. Austin (TX): University of Texas Press; 1995. p. 5-117. 4. Govindarajan VS. Capsicum: production, technology, chemistry, and quality. I. History, botany, cultivation, and primary processing. Crit Rev Food Sci Nutrition 1985; 22:109-76. 5. Markovits E, Gilhar A. Capsaicin: an effective topical treatment in pain. Int J Dermatol 1997;36:401-4.
Journal of the American Academy of Dermatology October 1998
6. Heiser CB Jr. Nightshades: the paradoxical plants. San Francisco: WH Freeman; 1969. p. 7-27. 7. Caterina MJ, Schumacher MA, Tominaga M, Rosen TA, Levine JD, Julius D. The capsaicin receptor: a heat-activated ion channel in the pain pathway. Nature 1997; 389:816-24. 8. Clapham DE. Some like it hot; spicing up ion channels. Nature 1997;389:783-4.
Capsaicin is more than a medication; it provides the essential fieriness to the world’s most valuable spice, hot pepper. Capsaicin is found in the hot pepper’s placenta, the white fibrous material that holds the seeds. Some capsaicin rubs off onto the seeds, making them pungent as well, but it is not present in the pepper’s flesh. Capsaicin’s medical usefulness comes from its ability to deplete unmyelinated sensory neurons of Substance P, a neurotransmitter involved in cutaneous itch and burning.1 In pure form, capsaicin has virtually no flavor or odor. Capsaicin is a mixture of five closely related vanillyl amides of isodecenoic acid (Fig 1). A pepper’s fieriness is measured by the Scoville Organoleptic Test devised in 1912.2 Scores range from 0 Scoville units for bell peppers, 2500 to 4000 units for jalapeno and cayenne peppers, to 70,000 units for tabasco peppers.3 The heat of a pepper is unrelated to color (which is determined by a separate gene for carotenoid content). Certainly not all hot peppers are red. Peppers are members of the genus Capsicum (Fig 2) from which the name capsaicin is derived. Capsicum was described and named by the preLinnean botanist de Tournefort.3 The Latin capsa or box may refer to the boxy shape of the fruit. Linnaeus maintained the name in the original Species Plantarum in 1753. The flowers of Capsicum species resemble those of the closely related tomato, potato, eggplant, and tobacco—all members of the Solanaceae or nightshade family. From the Dermatology Service, Raymond W. Bliss Health Clinic, Fort Huachuca, and the University of Arizona College of Medicine, Tucson. The opinions and assertions in this article are those of the author and not of the Department of Defense. Reprints are not available from the authors. J Am Acad Dermatol 1998;39:626-8. 16/1/91010
626
Fig 1. Molecular formula for capsaicin. There are at least five vanillyl amides found in natural capsaicin.
Early European consumers appreciated the gustatory similarities between capsicum and the botanically unrelated black pepper (Piper nigrum of the Piperaceae), so they conferred the name pepper. Many botanists and cooks prefer to call the subjects of this essay capsicums to avoid confusion. In this quinquicentennary of Columbus’s second voyage, we recall Diego Alvarez Chanca, physician on that expedition, who observed Arawak Indians of the Caribbean using capsicums as both a spice and a medicine (Fig 3). Chanca brought capsicums back to Iberia from where they spread eastward rapidly, reaching India by 1498 via Portuguese voyages of discovery.4 Although we think of red pepper as an essential spice in the cuisine of many regions worldwide, capsicum was unknown in the Old World until shortly after Columbus. When one enjoys the pungent flavors of Old World cuisines such as Szechwan, Thai, Indian, Hungarian, and Ethiopian, remember that capsicums have been present in them for only a few hundred years. Medicinal uses of topical capsaicin include treatment of the pain and burning of postherpetic neuralgia, diabetic neuropathy, reflex sympathetic dystrophy, Raynaud’s phenomenon, notalgia paresthetica, arthralgias, plantar warts, pharyngitis, diabetic neuralgia, and hemodialysis-related pruritus.5 Other formulations are used as throat
Journal of the American Academy of Dermatology Volume 39, Number 4, Part 1
Norton 627
Fig 2. Jalapeno peppers. There are five domesticated species of peppers of which C annuum var annuum includes most of the economically important varieties. The Tabasco pepper is C frutescens var tabasco. (From Andrews J. Peppers: the domesticated capsicums. New ed. Plate 14. Copyright © 1995. Courtesy of Jean Andrews and the publisher, The University of Texas Press [Austin]).3
Fig 3. Peppers for sale at Tarascan Indian market, Patzcuaro, Mexico. The genus Capsicum probably evolved in central Bolivia and contains 20 to 30 species. The greatest differentiation of the cultivated species occurs in Mexico. There are possibly several hundred varieties of edible peppers.3,4
balms. Capsaicin is not a rubifacient because it does not induce reddening of the skin. Albert von Szent-Gyorgyi, a Hungarian researcher raised on food spiced with paprika, derived Vitamin C from paprika peppers; for this, he received the Nobel Prize in Medicine and Physiology in 1937.3,6 Recently the capsaicin receptor VR1 (vanilloid receptor 1) was identified. It appears that prolonged exposure of these receptors to capsaicin causes injury and death of neuronal pain fibers, thereby stopping transmission of the noxious stimulus. This explains why the transmission of pain stops upon continuous exposure to capsaicin.7,8
Capsaicin has a number of nonculinary, nonmedicinal uses also. Its recorded use as a repellent dates to the 15th century when Caribbean islanders used irritating smoke from burning capsicums in an attempt to repel the Spanish invaders.6 It is now used as a personal defense spray by police, military forces, and private citizens. Other repellent uses include the treatment of ship hulls to deter barnacle aggregation and on the neck of sheep to deter coyote attacks. REFERENCES 1. Cordell GA, Araujo OE. Capsaicin: identification, nomenclature, and pharmacotherapy. Ann Pharmacother 1993;27:330-6.
628 Norton 2. Scoville WL. Note on capsicums. J Am Pharm Assoc 1912;1:453-4. 3. Andrews J. Peppers: the domesticated capsicums, new edition. Austin (TX): University of Texas Press; 1995. p. 5-117. 4. Govindarajan VS. Capsicum: production, technology, chemistry, and quality. I. History, botany, cultivation, and primary processing. Crit Rev Food Sci Nutrition 1985; 22:109-76. 5. Markovits E, Gilhar A. Capsaicin: an effective topical treatment in pain. Int J Dermatol 1997;36:401-4.
Journal of the American Academy of Dermatology October 1998
6. Heiser CB Jr. Nightshades: the paradoxical plants. San Francisco: WH Freeman; 1969. p. 7-27. 7. Caterina MJ, Schumacher MA, Tominaga M, Rosen TA, Levine JD, Julius D. The capsaicin receptor: a heat-activated ion channel in the pain pathway. Nature 1997; 389:816-24. 8. Clapham DE. Some like it hot; spicing up ion channels. Nature 1997;389:783-4.