Capsicum species: Chili pepper

Family

Solanaceae

Common Name

Chili pepper, pepper, chili

Plant Description

Consisting of approximately 22 species of tropical annuals or shrubs originating in tropical America, the genus Capsicum is universally recognized and grown for its hot, spicy fruits that are central to many of the world’s cuisine’s [1]. Such spices as cayenne pepper, paprika, chili powder, and Tabasco are derived from the fruits of Capsicum species.

In general Capsicum species are perennial or annual small shrubs with erect, spreading, branched stems and dark glossy green, glabrous leaves with narrow, lanceolate to elliptic blades with entire margins. Inflorescences are either solitary or clusters of star-shaped 5- lobed white, green or purplish flowers. Fruits are berries, glossy, and of various shapes and sizes. Depending on the species and variety of Capsicum, the fruits can be extremely irritating to the mucous membranes of the mouth eyes and nose.

Most cultivated species and varieties of Capsicum originate from 5 species:

• Capsicum annuum - sweet pepper, hot pepper, ornamental pepper, cayenne (Fig. 87 and Fig. 88)
• C. frutescens - hot pepper, Tabasco pepper, Thai pepper
• C. chinense - habenero pepper (scotch bonnet) (Fig. 89 and Fig. 90), red savina
• C. baccatum
• C. pubescens

Figure 87. Capsicum annuum.

Figure 88. Capsicum annuum.

Figure 89. Capsicum chinense (Habenero).

Figure 90. Capsicum chinense.

Within Capsicum annuum there are 5 main groups:

• Group 1 (Cerasiforme) – ornamental cherry peppers
• Group 2 (Conoides) - ornamental cone-shaped peppers
• Group 3 (Fasiculatum) – ornamental red chili
• Group 4 –(Grossum) – Bell peppers, sweet peppers, green or red wax peppers
• Group 5 (Longum) – spice peppers, cayenne pepper, chili pepper

Reputedly, the hottest pepper is the tepin (chiltecpin, chiltepin, chile de pajaro) C.annuum var. aviculare. The Pequin (chilipiquin, turkey pepper, grove pepper) that grows in Florida, Texas and Mexico is also very "hot". The degree of "hotness" of Capsicum species has been quantitated using the Scoville test, and correlates well to the quantity of capsaicinoids in the pepper as determined by high performance liquid chromatography [2,3].

Toxic Principle and Mechanism of Action

Capsaicin, and to a minor extent 4 other naturally occurring derivatives of capsaicin are the major irritants found in Capsicum species. Highest concentrations of the capsaicinoids are found in the fruits and especially in the seeds.

Capsaicin appears to block axons by depleting nerve terminals of the neuro-transmitter substance P. In so doing, capsaicin causes functional sensory nerve impairment, and has found medicinal use in helping modify chronic pain [4].

Capsaicin also acts on ion channels in cells causing depolarization and release of neurotransmitters which has an overall effect of stabilizing cell membranes [5,6].

Capsaicinoids are being investigated for the treatment of chronic arthritis pain, diabetic neuropathies, cystitis, and human immunodeficiency virus infection [7,8].

High doses of capsaicin can cause intense irritation to the mucous membranes of the mouth, gastrointestinal system, and may cause lethal convulsions [9].

Risk Assessment

Questions regarding the toxicity of hot peppers are the most frequent calls to poison control centers. This is because of the wide variety of colorful peppers that are sold for cooking and ornamental purposes, especially around holiday occasions, and are therefore readily accessible in many households. Although rarely a problem to household pets the hot peppers are irritants and are capable of affecting dogs and cats that chew and swallow the fruits. Sun dried peppers may be a source of aflatoxins and a variety of fungi [9].

Clinical Signs

As strong irritants the capsaicinoids cause a burning sensation in the mouth and eyes. Some species of Capsicum (Habenero peppers) may cause blistering of the mucous membranes in some individuals. In larger doses vomiting and diarrhea may occur. Experimentally very high doses cause convulsions, and rats fed 10% capsicum developed centrilobular necrosis of the liver [10]. The effects of the capsaicin are usually transitory, but can be relieved by irrigation of the mucous membranes with water.