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The terpenoids, also known as isoprenoids, are a class of naturally occurring organic chemicals derived from the 5-carbon compound isoprene and its derivatives called terpenes, diterpenes, etc. While sometimes used interchangeably with "terpenes", terpenoids contain additional functional groups , usually containing oxygen. [ 1 ]
In general, carotenoids absorb wavelengths ranging from 400 to 550 nanometers (violet to green light). This causes the compounds to be deeply colored yellow, orange, or red. Carotenoids are the dominant pigment in autumn leaf coloration of about 15-30% of tree species, [3] but many plant colors, especially reds and purples, are due to polyphenols.
orange pigments . α-Carotene – to vitamin A carrots, pumpkins, maize, tangerine, orange.; β-Carotene – to vitamin A dark, leafy greens, red, orange and yellow fruits and vegetables.
Terpenoids (mono-, sesqui-, di-, etc.) have similar physical properties but tend to be more polar and hence slightly more soluble in water and somewhat less volatile than their terpene analogues. Highly polar derivatives of terpenoids are the glycosides, which are linked to sugars. These are water-soluble solids.
Tetraterpenoids (including many carotenoids) are tetraterpenes that have been chemically modified, as indicated by the presence of oxygen-containing functional groups. Phytoene is biosynthesized via the head-to-head condensation of two GGPP molecules. [2] One group of tetraterpenes, and possibly the most studied one, is the carotenoids pigments ...
Xanthophylls are carotenoids with molecules containing oxygen, such as lutein and zeaxanthin. Carotenes are carotenoids with molecules that are unoxygenated, such as α-carotene, β-carotene and lycopene. [22] In plants, carotenoids can occur in roots, stems, leaves, flowers, and fruits. Carotenoids have two important functions in plants.
Carotenes are produced in a general manner for other terpenoids and terpenes, i.e. by coupling, cyclization, and oxygenation reactions of isoprene derivatives. Lycopene is the key precursor to carotenoids. It is formed by coupling of geranylgeranyl pyrophosphate and geranyllinally pyrophosphate. [18]
Cucurbita fruits, including squash and pumpkin, typically have high content of the phytochemical pigments called carotenoids. Phytochemicals are chemical compounds produced by plants , generally to help them resist fungi, bacteria and plant virus infections, and also consumption by insects and other animals.