Chili Pepper Capsaicin and Capsaicinoids
Chili peppers (Capsicums) are different in taste, turn up, aroma, pungency, color, origin, growing course of action, DNA structure and toxicity levels. Capsicum consists of 38% pericarp, 2% inner sheath, 56% seeds, and 4% stalks. The character that separates the Capsicum family from other plant groups and the quintessence of the chili pepper is an alkaloid called Capsaicin (kap-sa-I-sin), an unusually powerful and pungent crystalline substance found in no other plant. Capsaicin is the source of pungency and heat in Capsicums.
Capsaicin is a colorless, crystalline, bitter compound present in capsicum [Previously referred to as capsicine]. It has a molecular weight of 305.46. Capsaicin has a Melting Point of 65_C, Boiling Point of 81_C, Vapor Pressure of 40 and a Vapor Density of 1.59 (Air=1). The range in capsaicin content in the pericarp of an average capsicum is about 0.17% to 0.58% and the inner sheath is 6.6% to 7.7%; color is concentrated mostly in the pericarp. Chili seeds contain 19% oil with 0.024% capsaicin content. The percentage of capsaicin in the capsicum plant depends on the species, geographical origin and the climatic conditions.
Capsaicin is produced by glands at the juncture of the placenta and the pod wall. The capsaicin spreads unevenly throughout the inside of the pod and is concentrated mostly in the placental tissue. The seeds are not supplies of heat, as commonly believed. From one Kg. of cayenne pepper for example, approximately 2.13 g. of crude capsaicin can be secluded, which is about 20 times the amount found in paprika.
The potent active ingredient, considered early as a single substance, Capsaicin was soon shown to be a combination of two unsaturated and three saturated homologs. This combination is now called Capsaicinoids.
Capsaicinoids are produced by glands in the peppers placenta, which is the top of the partition just below the stem. The placenta is about 16 times more pungent than the flesh.
Upon contact with the human mucous membranes, Capsaicin produces inflammation causing an immediate closing of the eyes and difficulty in breathing and burning sensation of the skin. Capsaicin causes the irritation of the trigeminal cells. These cells are pain receptors located in the mouth, nose, stomach and the mucous membrane. They release Substance P (SP), a chemical messenger that communicates any pain or skin inflammation to the brain. SP is a neurotransmitter. Neurotransmitters are inter-cellular chemical messengers that are secreted by neurons (nerve cells) across specialized structures (synapses) to transmit chemical information to one or more target cells. Capsaicin stimulation of sensory nerves not only produces central transmission of sensory signals but also releases SP from central and peripheral sensory nerve terminals. Substance P (SP) belongs to the Tachykinin family, which represents a group of biologically active peptides with a similar ordern of amino acids in the C-terminal vicinity. SP was the first peptide of the tachykinin family to be found in mammals.
Substance P: Arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-Gly-Leu-Met-NH2
The natural release of SP is consequently likely to represent a direct action on postcapillary venules or smooth muscle cells. Both Capsaicinoids and SP act as Spasmogens on certain viscera containing smooth muscle causing contractions. Substance P is one of the meaningful causes of contraction of the oesophagus, trachea, respiratory track and iris muscles of the eyes.