Capsaicin in the context of Amide

Pungency (/ˈpʌndʒənsi/ PUN-jən-see), commonly referred to as spiciness, hotness or heat, is a sensation that contributes to the flavor of certain foods such as chili peppers. Highly pungent foods may be experienced as unpleasant. The term piquancy (/ˈpiːkənsi/ PEEK-ən-see) is sometimes applied to foods with a lower degree of pungency that are "agreeably stimulating to the palate". In addition to chili peppers, piquant ingredients include wasabi, horseradish and mustard. The primary substances responsible for pungency are capsaicin (in chilis), piperine (in peppercorns) and allyl isothiocyanate (in radishes, mustard and wasabi).

Chili peppers, also spelled chile or chilli (from Classical Nahuatl chīlli [ˈt͡ʃiːlːi] ), are varieties of berry-fruit plants from the genus Capsicum, which are members of the nightshade family Solanaceae, cultivated for their pungency (spicy heat). They are used as a spice to add pungency in many cuisines. Capsaicin and the related capsaicinoids give chili peppers their intensity when ingested or applied topically. Chili peppers exhibit a range of heat and flavors. This diversity is the reason behind the availability of different types of chili powder, each offering its own taste and heat level.

Chili peppers originated in Central or South America and were first cultivated in Mexico. European explorers brought chili peppers back to the Old World in the late 16th century as part of the Columbian Exchange, which led to the cultivation of multiple varieties across the world for food and traditional medicine. Five Capsicum species have been widely cultivated: annuum, baccatum, chinense, frutescens, and pubescens.

Black pepper (Piper nigrum) is a flowering vine in the family Piperaceae, cultivated for its fruit (the peppercorn), which is usually dried and used as a spice and seasoning. The fruit is a drupe (stonefruit) which is about 5 mm (1⁄4 in) in diameter (fresh and fully mature), dark red, and contains a stone which encloses a single pepper seed. Peppercorns and the ground pepper derived from them may be described simply as pepper, or more precisely as black pepper (cooked and dried unripe fruit), green pepper (dried unripe fruit), or white pepper (ripe fruit seeds).

Black pepper is native to Southeast or South Asia. Ground, dried, and cooked peppercorns have been used since antiquity, both for flavour and as a traditional medicine. Black pepper is one of the most commonly traded spices in the world. Its spiciness is due to the chemical compound piperine, which is a different kind of spiciness from that of capsaicin characteristic of chilli peppers. It is ubiquitous in the Western world as a seasoning and is often paired with salt and available on dining tables in shakers or mills.

Group C nerve fibers are one of three classes of nerve fiber in the central nervous system (CNS) and peripheral nervous system (PNS). The Group C fibers are unmyelinated and have a small diameter and low conduction velocity, whereas Groups A and B are myelinated. Group C fibers include postganglionic fibers in the autonomic nervous system (ANS), and nerve fibers at the dorsal roots (IV fiber). These fibers carry sensory information.

Damage or injury to nerve fibers causes neuropathic pain. Capsaicin activates C fibre vanilloid receptors, providing the burning sensation associated with chili peppers.

In physiology, nociception /ˌnəʊsɪˈsɛpʃ(ə)n/, also nocioception; from Latin nocere 'to harm/hurt') is the sensory nervous system's process of encoding noxious stimuli. It deals with a series of events and processes required for an organism to receive a painful stimulus, convert it to a molecular signal, and recognize and characterize the signal to trigger an appropriate defensive response.

In nociception, intense chemical (e.g., capsaicin present in chili pepper or cayenne pepper), mechanical (e.g., cutting, crushing), or thermal (heat and cold) stimulation of sensory neurons called nociceptors produces a signal that travels along a chain of nerve fibers to the brain. Nociception triggers a variety of physiological and behavioral responses to protect the organism against an aggression, and usually results in a subjective experience, or perception, of pain in sentient beings.

Whether invertebrates can feel pain is a contentious issue. Although there are numerous definitions of pain, almost all involve two key components. First, nociception is required. This is the ability to detect noxious stimuli which evokes a reflex response that moves the entire animal, or the affected part of its body, away from the source of the stimulus. The concept of nociception does not necessarily imply any adverse, subjective feeling; it is a reflex action. The second component is the experience of "pain" itself, or suffering—i.e., the internal, emotional interpretation of the nociceptive experience. Pain is therefore a private, emotional experience. Pain cannot be directly measured in other animals, including other humans; responses to putatively painful stimuli can be measured, but not the experience itself. To address this problem when assessing the capacity of other species to experience pain, argument-by-analogy is used. This is based on the principle that if a non-human animal's responses to stimuli are similar to those of humans, it is likely to have had an analogous experience. It has been argued that if a pin is stuck in a chimpanzee's finger and they rapidly withdraw their hand, then argument-by-analogy implies that like humans, they felt pain. It has been questioned why the inference does not then follow that a cockroach experiences pain when it writhes after being stuck with a pin. This argument-by-analogy approach to the concept of pain in invertebrates has been followed by others.

The ability to experience nociception has been subject to natural selection and offers the advantage of reducing further harm to the organism. While it might be expected therefore that nociception is widespread and robust, nociception varies across species. For example, the chemical capsaicin is commonly used as a noxious stimulus in experiments with mammals; however, the African naked mole-rat, Heterocephalus glaber, an unusual rodent species that lacks pain-related neuropeptides (e.g., substance P) in cutaneous sensory fibres, shows a unique and remarkable lack of pain-related behaviours to acid and capsaicin. Similarly, capsaicin triggers nociceptors in some invertebrates, but this substance is not noxious to Drosophila melanogaster (the common fruit fly).Criteria that may indicate a potential for experiencing pain include:

Irritation, in biology and physiology, is a state of inflammation or painful reaction to allergy or cell-lining damage. A stimulus or agent which induces the state of irritation is an irritant. Irritants are typically thought of as chemical agents (for example phenol and capsaicin) but mechanical, thermal (heat), and radiative stimuli (for example ultraviolet light or ionising radiations) can also be irritants. Irritation also has non-clinical usages referring to bothersome physical or psychological pain or discomfort.

Irritation can also be induced by some allergic response due to exposure of some allergens for example contact dermatitis, irritation of mucosal membranes and pruritus. Mucosal membrane is the most common site of irritation because it contains secretory glands that release mucus which attracts the allergens due to its sticky nature.

The Scoville scale is a measurement of spiciness of chili peppers and other substances, recorded in Scoville heat units (SHU). It is based on the concentration of capsaicinoids, among which capsaicin is the predominant component.

The scale is named after its creator, American pharmacist Wilbur Scoville, whose 1912 method is known as the Scoville organoleptic test. The Scoville organoleptic test is a subjective assessment derived from the capsaicinoid sensitivity by people experienced with eating hot chilis.

Liniment (from Latin: linere, meaning "to smear, anoint"), also called embrocation and heat rub, is a medicated topical preparation for application to the skin. Some liniments have a viscosity similar to that of water; others are lotion or balm; still, others are in transdermal patches, soft solid sticks, and sprays. Liniment usually is rubbed into the skin, which the active ingredients penetrate.

Liniments are typically sold to relieve pain and stiffness, such as from muscular aches and strains, and arthritis. These are typically formulated from alcohol, acetone, or similar quickly evaporating solvents and contain counterirritant aromatic chemical compounds, such as methyl salicylate, benzoin resin, menthol, and capsaicin. They produce a feeling of warmth within the muscle of the area they are applied to, typically acting as rubefacients via a counterirritant effect.

Pepper spray, oleoresin capsicum spray, OC spray, capsaicin spray, mace, or capsicum spray is a lachrymator (tear gas) product containing as its active ingredient the chemical compound capsaicin, which irritates the eyes with burning and pain sensations and so causes them to close, bringing temporary blindness. This blindness allows officers to more easily restrain subjects and permits people in danger to use pepper spray in self-defense for an opportunity to escape. It also causes temporary discomfort and burning of the lungs which causes shortness of breath. Pepper spray is used as a less lethal weapon in policing, riot control, crowd control, and self-defense, including defense against dogs and bears.

Pepper spray was engineered originally for defense against bears, cougars, wolves, and other dangerous predators, and is often referred to colloquially as bear spray.

PAVA spray is an incapacitant spray similar to pepper spray. It is dispensed from a handheld canister, in a liquid stream. It contains a 0.3% solution of pelargonic acid vanillylamide (PAVA), also called nonivamide, a synthetic capsaicinoid (analogue of capsaicin), in a solvent of aqueous ethanol. The propellant is nitrogen. This solution has been selected because this is the minimum concentration which will fulfill the purpose of the equipment: namely, to minimise a person's capacity for resistance, without unnecessarily prolonging their discomfort.

PAVA is significantly more potent than CS gas. The liquid stream is a spray pattern and has a maximum effective range of up to four metres (13 ft). Maximum accuracy, however, will be achieved over a distance of 1.25–2 metres (4.1–6.6 ft). The operating distance is the distance between the canister and the subject's eyes, not the distance between the user and the subject.

Nonivamide, also called pelargonic acid vanillylamide or PAVA, is an organic compound and a capsaicinoid. It is an amide of pelargonic acid (n-nonanoic acid) and vanillyl amine. It is present in chili peppers, but is commonly manufactured synthetically. It is more heat-stable than capsaicin.

Nonivamide is used as a food additive to add pungency to seasonings, flavorings, and spice blends. It is also used in the confectionery industry to create a hot sensation, and in the pharmaceutical industry in some formulations as a cheaper alternative to capsaicin.