Secretory Structure And Their Relationship To Accumulation Of Furanocoumarins In Psoralea Corylifolia

Bu-Gu-Zhi [Psoralea corylifolia L], which belongs to Papilionoideae, under Leguminosae, is an annual herbage growing wild throughout South African, South America, North America and Australia. Psoralen and Isopsoralen are the major medicinal components that are extracted from vhe leaf, stem, flower and fruit of this herb. After reviewing distribution, morphorlogy and structure, growth and development, physiology and ecology, chemical component, pharmacology, medical exploitation and comprehensive use, the technique of propagation and cultivation, we investigated the secretory structures of different organs of Psoralea corylifolia and its correlation with medical components, and a linear relationship between furanocoumarins content and secretory cavities index on leaf by using anatomy, histochemistry and phytochemistry. After the young leaves were dealt with UV-B radiation, psoralen and isopsoralen content were determined. Some important results were listed below:The secretory structures of Psoralea corylifolia have two types: secretory cavities and glandular trichomes. Light and scanning electron microscope examination of fixed plant material revealed that secretory cavities show a schizo-lysigenous development and origin from protodermal cells, The protodermal cells undergoes an anticlinal divisions and prolong to form a small mound that resembles a surface gland. Sinking of the cavity to its subsurface position occurs with dorsiventral expansion of the mesophyll. As the mesophyll expands, the hypodermal cells flatten and curve forming a sheath-like layer surrounding an increasingly large depression. In the mature cavity, the hypodermal sheath cells appear vacuolated, while the trabeculae can be seen crossing cavities. The glandular trichomes originate from a single protodermal cell that suffers a periclinal division to form two celled trichomes. Then the two celled trichomes were divided into four celled by one periclinal division. The lower two cells corresponds to the trichome basal cell and stalk cell. The upper two cell of this four celled divides asymmetrically to give rise to the trichome head.Histochemistry test in the secretory cavities showed that vanillin and 10ï¼…KOH Methanol reacted with furanocoumarins substance to produce characteristic colors. The secretion in cavities showed intense red autofluorescence under 432nm UV light. We used these as the tests methods to locate furanocoumarins and deduce its contents. Furthermore, there was a linear relationship between furanocoumarins contents and secretory cavities index on leaf in Psoralen corylifolia. The results showed that furanocoumarins were primarily accumulated in secretory cavities of stems, leaves and fruits.The contents of two furanocoumarins in different organs and developmental stages from Psoralea corylifolia were analyzed by HPLC. The analysis indicated that psoralen and isopsoralen were accumulated in roots, stems, leaves, and seeds of Psoralea corylifolia. The highest content appeared in fruits and the lowest in roots. The contents of the two furanocoumarins in young shoots and leaves were higher than that in mature shoots and leaves, and the contents of the two furanocoumarins in rape fruits were higher than in young fruits.There are influences on psoralen and isopsoralen contens by UV-B radiation. Under the UV-B radiation, the contents of psoralen and isopsoralen were higher than control group. The contents of psoralen and isopsoralen changed with UV-B radiation in continuous days. It showed a changing trend from low to high, then to low.