Capsanthin epoxides

Physiologically, violaxanthin is an important component of the xanthophyU cycle a high light stress-induced de-epoxidation of the violaxanthin pool to the more photoprotective zeaxanthin is mediated by violaxanthin de-epoxidase (VDE). Violaxanthin and neoxanthin, an enzymatically (NXS)-produced structural isomer, are the precursors for the abscisic acid (ABA) biosynthetic pathway (Figure 5.3.1, Pathway 4 and Figure 5.3.2). In non-photosynthetic tissues, namely ripe bell peppers, antheraxanthin and violaxanthin are precursors to the red pigments, capsanthin and capsorubin, respectively (Figure 5.3.3B). 

Fig. 2.3. Characteristic chromatogram of paprika paste. Detection at 450 nm. Peak identification 1 = Capsorubin 2 = 5,6-Diepikarpoxanthin 3 = Capsanthin-5,6-epoxide 4 = Capsanthin-3,6-epox-ide 5 = Violaxanthin 6 = Luteoxanthin 2 7 = Luteoxanthin 1 8 = Capsanthin 9 = Antheraxanthin 10 = Mutatoxanthin 11 = Cucurbitaxanthin A 12 = (9/9 Z)-Capsanthins 13 = (13/13 Z)-Capsanthins 14 = Zeaxanthin 15 = Nigroxanthin 16 = (9Z)-Zeaxanthin 17 = (13Z)-Zeaxanthin 18 = Cryptocapsin 19 = a-Cryptoxanthin 20 = /TCryptoxanthin 21 = (Z)-Cryptoxanthin 22 = /1-Carotene 23 = (Z)-jS-Carotene. Reprinted with permission from J. Deli et al. [27].

The structure of a new carotenoid, isolated from fruits of the red tomato-shaped paprika, was elucidated to be (3S,5f ,6S,59P)-3,6-epoxy-5,6-dihydro-5-hydroxy-P, carotenes, 6 -dione by spectroscopic analyses and mass spectrometry and was designated as capsanthone 3,6-epoxide. Capsanthone 3,6-epoxide is assumed to be an oxidative metabolite of capsanthin 3,6-epoxide in paprika (Maoka et al., 2001a). 

Fig. 9.7 Separation of carotenoids from red pepper with gradient. (Reproduced with permission from L. Almela, J. M. Lopez-Roca, M. E. Candela and M. D. Alcazar, J. Chromatogr., 502, 95 (1990).) Conditions sample, saponificated extract from red pepper fruit column, 25cm x 4.6mm i.d. stationary phase, Spherisorb 5 am mobile phase, 1mlmin petroleum ether-acetone, linear gradient from 5 to 25% acetone in 30 min visible-range detector 460 nm. Peaks 1 = j5-carotene 2 = cryptocapsin 3 = cryptoflavin 4 = j5-cryptoxanthin 5 = antheraxanthin 6 = capsolutein 7 = luteoxanthin 8 = zeaxanthin 9 = mutatoxanthin 10 = capsanthin 11 =capsanthin-5,6-epoxide ...

Rearrangement of these compounds leads to metabolites such as capsanthin [(3/ , 3 5, 5 / )-3,3 -dihydroxy-p,k-caro-ten-6 -one] (6), a red pigment from peppers Capsicum an-nuum, Solanaceae). This compound may be derived from rearrangement of an epoxide intermediate as shown (Fig. 26.10) (Riittimann, 1982). Capsanthin (6), capsorubrin (16), and cryptocapsin are the major pigments of red peppers (Riit-timann, 1982). 

Capsanthin a carotenoid, M, 584.85, m.p. 176 °C, [a]cd + 36° (CHQj). It possesses a terminal 5-mem-bered ring. The secondary OH-groups have R configuration on C3, and S configuration on C3. C is the main red pigment of paprika (Capsicum annum), where it is accompanied by Capsorubin (see), crypto-capsin and capsanthin-5,6-epoxide. Ripe fiiiits contain 9-10 mg C. per 100 g fresh weight. 

Capsanthin 5,6-epoxide [5,6-epoxy-3,3 -dihydroxy-5,6-dihydro-P,K-caroten-6 -one]... 

Seeds contain steroidal s onins (proto-dioscin, oligofurostanosides) large amounts of NaOH-soluble polysaccharides " carotenoids (mutatoxanthin epimers, antheraxanthin, P-carotene, P-cryptoxanthin, lutein, cap-santhin, capsanthin 5,6-epoxide, eapsorubin, neoxanthin, violaxanthin, zeaxanthin) and 15.3% oil composed of 43.47% arachidie, 22.16% oleic, 11.52% palmitic, 11.34% lino-leic, 5.78% behenic, 3.59% stearic, 2.14% linolenic acids, and 1.43% unsaponifiable matter consisted mostly of P-sitosterol. ... 

Antheraxanthin, capsanthin, capsanthin-5, 6-epoxide, capsorubin, fj-carotene, fJ-carotene-S, 6-epoxide, hydroxy-a-carotene, cryptocapsin, fj-cryptoxanthin, lutein, neoxanthin, violaxanthin, and zeaxanthin (3-Carotene, (3-cryptoxanthin, lutein, neoxanthin, violaxanthin, neocrome, auroxanthin, zeaxanthin, capsanthin, capsorubin, and cucurbitaxanthin A (3-Carotene, (3-cryptoxanthin, zeaxanthin, capsanthin, and capsorubin Lycopene, prolycopene, violaxanthin, neoxanthin, c -mutatoxanthin, and lutein... 

Capsorubin, violaxanthin, capsanthin-5,6-epoxide, capsanthin, 9-cw-capsanthin, 13-c -capsanthin, antheraxanthin, mutatoxanthin, cucurbitaxanthin A (capsolutein), zeaxanthin, 9-cis-zeaxanthin, 13-cis-zeaxanthin, p-apo-8 -carotenal, cryptoeapsin, P-cryptoxanthin, p-earotene, and cw-p-carotene Neoxanthin, violaxanthin, lutein, antheraxanthin, mutatoxanthin, P-carotene, neochrome, auioxanthin, luteoxanthin, and chltuophylls... 

Red paprika, Capsicum annum, contains a variety of carotenoid pigments among them capsanthin-5,6-epoxide, 103, and cucurbitaxanthin A, 104, that contain one 2-en io-hydroxy-3-exo,6,6-trimethyl-7-oxabicyclo[2.2.1]hept-l-yl end group [148]. Carotenoids 104 and 105 (cucurbitaxanthin B) are found in pumpkin, Cucurbita maxima [149]. Oxanorbomanone 106 (eutreptiellanone) has been isolated from the alga. Eutreptiella gymnastica [150-152] (Fig. 11). 

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