Study On The Pharmacognosy Of Corn Silk

AIM: To provide reference for identifying Corn silk. Corn silk is Stigma of Zea mays Linne. It is a traditional Chinese medicine used for edema and dysuria, and it can be used to treat hypertension and jaundice also. It had been listed in Chinese Pharmacopeia (1977 ). Its further research about pharmacognosy has not been found by now. So we conducted the detailed research about its pharmacognosy. METHODS: (1)Three new identical characters of Corn silk have been found by microscopic study. The measurements of annular vessel, glandular hair, nonglandular hair and parenchyma cell had been finished. The horizontal section and vertical section of corn silk had been studied by paraffin section method. Glandular hair and nonglandular hair were also observed under the scanning electron microscope. (2) Corn silk of different habit and term(from 200.5.7 to 2004.8.11) had been collected in advance, and the accumulated quantities ofβ-sitosterol and allantoin in Corn silk of different growing term has been determined by HPLC method. (3)The basic constituents of corn silk had been tested by systematic pretest. RESULT: (1) Corn silk looked like a yellow-brown band, semi-transparent. There was one little brown strip near each margin of the band. By further magnified observation, there were many glandular hair and nonglandular hair on the surface of corn silk. Glandular hair looked like a long expanded balloon, which was composed of 3~9 cells. At the beginning of glandular hair, cells were oval. In the middle, swelling. Then cells became slim. At the bottom, the cell was a point handle. Nonglandular hair looked like a thread, which was composed of 2~4 cells. The trichome also distributed over the surface, which were composed of several rows of parenchyma cells. The whole outline of horizontal section was like a telephone handle, bended as the"C". The two ends were swelling, the middle was slim. Vascular bundles were found in the two swelling parts. (2) The accumulatedβ-sitosterol in Corn silk reached a maximum of 2.3256mg. g-1 in mid-July, then it would become little. The accumulated allantoin in corn silk of different term had increased from 0.1569 mg/g to 0.3038 mg/g in the first week(2004.7.5～2004.712),then it had kept steady in the next three weeks(2004.7.12～2004.8.2) ,and had reached a maximum of 0.7807 mg/g in the fifth week. (3) There were reductive carbohydrate, polysaccharides, steroidal saponins, tannin, amino acids, flavonoids and alkaloids distributed in the corn silk, which were testified by chemical experiments. CONCLUSION: (1) Corn silk has the typical characters under the microscope, which can be used as its identical reference. (2) The accumulated quantities ofβ-sitosterol and allantoin in Corn silk of different growing term was different from each other, which can give guidance to its usage. (3) The data achieved in chemical tests will have the reference value for the identical work of Corn silk.