vii] OXIDIZING ENZYMES 95 



The flowers of the following species can be used : Snowdrop (Galanthus nivalis}, 

 Narcissus (Narcissus poeticus), white variety of Lilac (Syringa vulgaris\ Hawthorn 

 (Crataegus OxyacantJia\ White Lily (Lilium candidum], white var. of Phlox, double 

 white Pink, white Stock (Matthiola) etc., etc., in fact almost any species with white 

 flowers* or a white variety. 



Expt. 96. Demonstration of the presence of Jlavone or flavonol pigments in tissues 

 containing chlorophyll. Make a hot water extract of the leaves of any of the under- 

 mentioned species. Make with it the same tests as in the previous experiment. 



The following plants may be used : Snowdrop (Galanthus nivalis\ Dock (Rumex 

 obtusifolius}, Goutweed (Aegopodium Podagraria), Dandelion (Taraxacum, ojficinale}, 

 Violet ( Viola odoratd), Ribwort Plantain (Plantago lanceolata}^ Elder (Sambucus 

 nigra}. 



The most important flavone pigments are apigenin, chrysin and 

 luteolin. 



Apigenin has not yet been found to be widely distributed. Its 

 formula is : 



OH 



It occurs in the Parsley (Carum Petroselinum) (Perkin, 18) and in 

 the flowers of the ivory-white variety of Snapdragon (Antirrhinum 

 majus) (Wheldale and Bassett, 30). 



Expt. 97. Extraction of apiin, the glucoside of apigenin, from the Parsley (Carum 

 Petroselinum). Take some Parsley leaves and boil in as little water as possible. 

 Filter off the extract and make the following tests for apigenin : 



(a) Add alkali. A lemon yellow coloration is given. 



(6) Add basic lead acetate solution. A lemon yellow precipitate is formed. 



(c) Add ferric chloride solution. A brown colour is produced. 



(d) Add ferrous sulphate solution. A reddish-brown colour is produced. 



Apiin frequently separates out in a gelatinous condition from aqueous 

 and dilute alcoholic solutions. 



Chrysin is a flavone occurring in the buds of various species of 

 Poplar (Populus). It has the formula : 



