These are tender annuals or perennials which are found extensively in South America. They have straight, woody stems and single, star-shaped, white flowers in the axils of the leaves. The flowers are followed by juiceless berries or pods, which vary in shape and size. They are green at first and change to red, yellow or purple. They contain many flat, kidney-shaped, white seeds, which are very hot tasting.
Kinds that are commonly grown are varieties of C. frutescens, which are the Peppers grown in the vegetable garden and include those from which red pepper, cayenne pepper, Tabasco and paprika are made.
In tropical countries it is a perennial and will form a shrub as high as 8 feet, but when it is grown in gardens it is treated as an annual and is raised from seeds every year.
Capsicum species (Solanaceae) including C. annum L., C. baccatum L., C. chinense Jacq., C. frutescens L., C. pubescens Ruiz & Pavon, C. minimum Roxb.
Synonyms and Part Used
Cayenne, Chilli Pepper, Hot Pepper, Paprika, Red Pepper, Tabasco Pepper.
Up to 1.5%, usually 0.11%. Major components capsaicin (48.6%), 6,7–dihydrocapsaicin (36%), nordihydrocapsaicin (7.4%), homodihydrocapsaicin (2%) and homocapsaicin (2%).
Trace. Over 125 components have been isolated with at least 24 characterised.
Carotenoid pigments (capsanthin, capsorubin, carotene, lutein), proteins (12–15%), fats (9–17%), vitamins including A and C.
Other plant parts
The plant material contains solanidine, solanine and solasodine (steroidal alkaloidal glycosides) and scopoletin (coumarin).
Capsicum (chilli) peppers are widely used as a spice. Capsicum is listed by the Council of Europe as a natural source of food flavouring (category N2). This category indicates that capsicum can be added to foodstuffs in small quantities, with a possible limitation of an active principle (as yet unspecified) in the final product.
Capsicum is stated to possess stimulant, antispasmodic, carminative, diaphoretic, counterirritant, antiseptic and rubefacient properties. Traditionally, it has been used for colic, flatulent dyspepsia without inflammation,chronic laryngitis (as a gargle), insufficiency of peripheral circulation and externally for neuralgia including rheumatic pains and unbroken chilblains (as a lotion/ointment). This can also be used externally for treatment of painful muscle spasms in shoulder, arm and spine; arthritis, rheumatism, lumbago and chilblains.
Fruit : 30–120 mg three times daily.
Capsicum Tincture : 0.3–1.0 mL; capsaicin content 0.005–0.01%.
Stronger Tincture of Capsicum : 0.06–2.0 mL.
Oleoresin : 0.6–2.0 mg.
Oleoresin, internal : 1.2 mg (maximum dose), 1.8 mg (maximum daily dose).
Oleoresin, external : 2.5% maximum strength.
Creams, ointments : 0.02–0.05%.
The action of capsaicin on nervous, cardiovascular, respiratory, thermoregulatory and gastrointestinal systems has been reviewed.Capsaicin has been used as a neurochemical tool for studying sensory neurotransmission.
In vitro and animal studies
Infusion of capsaicin (200 μg/kg, by intravenous injection) has been reported to evoke dose–dependent catecholamine secretion (adrenaline, noradrenaline) from the adrenal medulla of pentobarbitone–anaesthetised rats.
The addition of capsaicin (0.014%) to a high–fat (30%) diet fed to rats was found to reduce serum–triglyceride concentrations but to have no effect on serum cholesterol or pre-β-lipoprotein concentrations.Capsaicin was thought to stimulate lipid mobilisation from adipose tissue. Lipid absorption was unaffected by capsaicin supplementation.
Activities of two hepatic enzymes, glucose–6–phosphate dehydrogenase and adipose lipoprotein lipase, were elevated in rats when capsaicin was added to the diet.Capsicum extracts fed orally to hamsters have been reported to significantly decrease hepatic vitamin A concentrations. Serum vitamin A concentrations were not affected.
Both the gastric and duodenal mucosae are thought to contain ‘capsaicin–sensitive’ areas which afford protection against acid- and drug–induced ulcers when stimulated by hydrochloric acid or by capsaicin itself. Stimulation causes an increase in mucosal blood flow and/or vascular permeability, inhibits gastric motility, and activates duodenal motility.Desensitisation of these areas, using a regimen involving subcutaneous or oral administration of capsaicin, is thought to remove the protection.However, capsaicin desensitisation was found to have little effect on peripheral responses to stress (i.e. ulcer formation) but did enhance central responses (increase in plasma corticosterone concentration) in rats.The increase in plasma corticosterone concentration observed in capsaicin–desensitised rats was similar in stressed and non–stressed animals.
Capsaicin was found to influence adrenal cortical activity independently of the presence of a stress factor and may represent a stressor in itself.Capsaicin desensitisation was not found to influence basal gastric acid secretion in non–stressed rats, but did lower pentagastrin–stimulated gastric output.However, other results have reported that capsaicin desensitisation does increase acid secretion.
Capsicum (leaf and stem) has been reported to exhibit uterine stimulant activity in animal studies.
Pharmacokinetic studies in rats have reported that capsaicin is readily transported via the gastrointestinal tract and absorbed through non–active transport into the portal vein.Capsaicin is partly hydrolysed during absorption and the majority is excreted in the urine within 48 hours.Dihydrocapsaicin–hydrolysing enzyme is present in various organs of the rat but principally in the gastrointestinal tract and the liver. The biotransformation pathway of dihydrocapsaicin in the rat has been studied.Metabolites are mainly excreted as glucuronide conjugates in the urine.
Ingestion of red chillies (10 g in wheatmeal) by controls and duodenal ulcer sufferers has been reported to have no significant effect on acid or pepsin secretion, or on sodium, potassium and chloride concentrations in the gastric aspirate.There was reported to be no apparent change (qualitative or quantitative) in mucous and no gastric mucosal erosion was evident.In contrast, capsicum has been shown to increase acid concentration and DNA content (indicating exfoliation of epithelial cells) of gastric aspirates in both control subjects and patients with duodenal ulcers.A study involving 18 healthy volunteers suggested that chilli (20 g in 200 mL water) protected against aspirin–induced gastroduodenal mucosal injury, compared with control (water).
Capsicum is applied externally as a counter– irritant in many preparations used for rheumatism, arthritis, neuralgia and lumbago. Clinical studies of topical preparations containing capsaicin have investigated its effectiveness in the treatment of chronic post–herpetic neuralgia, shingles, diabetic neuro pathy, rhinopathy and neuropathic pain in cancer patients.
A systematic review of randomised, double–blind, placebo–controlled trials of topical capsaicin included 13 trials involving patients with diabetic neuropathy, osteoarthritis, post–herpetic neuralgia, postmastectomy pain and psoriasis.All the included trials reported that capsaicin was superior to placebo. However, the review drew cautious conclusions because blinding may have been compromised by the irritant effects of capsaicin.
Capsicum contains pungent principles (capsaicinoids) that are strongly irritant to mucosal membranes. Inhalation of paprika can produce a form of allergic alveolitis.
Chronic administration of capsicum extract (0.5 μg capsaicin/kg body weight) to hamsters has been reported to be toxic.Treated animals did not survive beyond 17 months whereas all untreated controls survived beyond this period. In addition, eye abnormalities were observed in the treated animals. This effect was attributed to the depletion of substance P in primary afferent neurons by capsaicin, causing a loss of corneal pain sensation and subsequently the loss of protective corneal reflexes.
It is thought that metabolism of capsaicin and related analogues may reduce their acute toxicity.LD50 values stated for capsaicin in mice include 0.56 mg/kg (intravenous), 7.56 mg/kg (intraperitoneal), 9.00 mg/kg (subcutaneous) and 190 mg/kg (oral). In rats, an intraperitoneal LD50 of 10 mg/kg has been reported for capsaicin.The toxicity of capsaicinoids has reportedly not been ascribed to any one specific action but may be due to their causing respiratory failure, bradycardia and hypotension.
Capsicum may cause gastrointestinal irritation, although it has been stated that capsicum does not influence the healing of duodenal ulcers and does not need to be avoided by patients with this condition.Excessive ingestion may cause gastroenteritis, hepatic or renal damage.Capsicum may interfere with monoamine oxidase inhibitors (MAOIs) and antihypertensive therapy (increased catecholamine secretion), and may increase the hepatic metabolism of drugs (glucose–6–phosphate dehydrogenase and adipose lipoprotein lipase activity elevated).
Pregnancy and lactation
There are no known problems with the use of capsicum during pregnancy, although it may cause gastrointestinal irritation and should therefore be used with caution. Doses should not greatly exceed amounts normally ingested in foods. It is not known whether the pungent components in capsicum are secreted into the breast milk.
Capsicum is commonly used in both foods and in medicinal products. The capsaicinoids are principally responsible for the biological activity of capsicum. These pungent principles are thought to stimulate and aid digestion and to act as a counter– irritant when applied externally. Capsaicin has also been used as a neurochemical tool for studying sensory neurotransmission.
Conflicting reports have been documented concerning the effect of capsicum on acid secretion and on ulcer healing. Capsaicin–sensitive areas of the gastric and duodenal mucosa are thought to provide protection against mucosal damage. It has been suggested that this protection is lost if the sensory fibres are desensitised. Whether oral consumption of capsicum by humans can cause desensitisation is unclear. The toxicity of capsicum extracts observed in animals is considered to be due to the capsaicinoid components. However, ingestion of capsicum in the diet is not thought to represent a health risk. Capsicum should not be ingested in doses greatly exceeding amounts normally used in foods.