CAROTENOIDS IN LAND PLANTS 



Scybold and Egle have confirmed this in both spores and seeds. * * * 

 Lutein (xanthophyll) is the principal component of wheat » a «. 2 « «. 2 3 ? 

 and flavoxanthin and zeaxanthin have been reported in canary seed and 

 millet ; * * * cryptoxanthin, however, appears to be absent from most 

 seeds but may be present in peppers, a 3 7, 2 3 s 



Pumpkin seeds contain both carotenes and xanthophylls ^ ^ ^ but 

 annatto seeds {Bixa orellana) contain neither carotene, lycopene nor 

 cryptoxanthin ; ^ ^ • as might be expected {see p. 32), red pepper seeds 

 contain capsorubin and capsanthin.^^^ Lycopene has been isolated 

 from chaura {Maytenus disticha) seeds. * * ^ 



Maize has long been known to contain p-carotene, cryptoxanthin 

 and zeaxanthin, 2 4 1 and it was from this source that zeaxanthin was 

 first isolated. Earlier workers reported a preponderance of crypto- 

 xanthin, but it seems from recent work that maize contains about equal 

 amounts of ^-carotene and cryptoxanthin although the exact relative 

 amounts do vary somewhat with varieties. ^ **• ^ * '^^ ** ^ The total 

 carotenoid content of maize also varies with variety, limiting values 

 reported are 0-1-4-8 pig./g. (fresh wt.).^**'^*^"''** Other pigments 

 reported in maize are a-carotene, ^-carotene, (reported as x-carotene 

 and "unknown carotene I,"i*» although it should be noted that 

 x-carotene is reported to have vitamin A activity whilst ^-carotene is 

 inactive ; see p. 27). y-carotene, 1 ». 2 * « lutein (xanthophyll) and 

 probably cw-isomers of p-carotene. ^ * ' Sorghum has about one-half 

 the carotene content of maize. ^ * ® 



Considering bean and pea seeds, it is found that green (ready for 

 picking) soya beans {Soja glycine),^ *^ cow peas {Vigna sinensis)y^^* 

 Lima beans (Phaseolus lunatus\^^^ Thomas Laxton peas {Pisum 

 sativum), 2 s 0, 2 6 1 ^nd French (snap) beans {Phaseolus vulgaris) 2 e a, 2 6 » 

 contain between 2 and 7 ^Ag./g- (wet wt.) of carotene. Carotene has 

 also been reported in cotton seeds. ^ * * The belief that the carotene 

 content of peas depends considerably on the variety is apparently 

 firmly based a e 3, 2 s 6, 2 6 e (^^^ Table 6) although it has been disputed. ^ * ' 

 Table 6 shows the varietal differences encountered during one inves- 

 tigation. 



In developing pea seeds the accumulation of carotenoids parallels 

 the synthesis of starch until just before maturation when the pigments 

 begin to disappear, a 6 s. 2 e 9 At maturation the values drop precipitately; 

 for example, typical values for peas and beans are 0-2-0-5 

 M'g'/g- ; 2 46,256,259 some samples actually show no vitamin A activity 

 when tested biologically. ^^ « <> One cannot, however, ignore reports 

 that the carotene content of peas does not vary greatly during matura- 

 tion, a 6 7, a • 1 



43 



