Studies on pharmacognosy of Taxus Ramulus et Folium

摘要

Taxus Ramulus et Folium (TRF) is the branchlet and leaf of Taxus cuspidata Sieb. et Zucc, which showed action of diuresis and unblock the meridian and was used to treat renal disease and diabetes. Previous studies showed that mainly active components in TRF are taxanes such as taxinine, taxol and brevifoliol, and biflavonoids like sciadopitysin and ginkegetin. Modern pharmacological research showed that taxanes have unique function of anticancer and anti-oxidant, the biflavonoids have anticancer, hepatoprotection, anti-free radical and so on. There is no quality standard, nor are any reports on pharmacognosy for TRF. So it is essential to carry out systemic studies on microscopic and TLC identification, main constituents assay and the pharmacological function to preferably develop and utilize resources of TRF. 1. Optical microscopy was used to observe the powder of TRF. The epidermal cells with slightly thickened walls were kind of square or rectangle and arranged closely. The suberization cells were yellowish-brown and sometimes the spiral vessels were obviously observed. The stoma scatted on fragment of the epidermal cell, composed of two dumbbell-shaped guard-cells. The brown or redish-brown contents focused or distributed in the cell. 2. The TLC identification methods were established, and chemical reference substances of taxinine, sciadopitysin and ginkegetin were used as control. To test taxinine, using the silica gel GF254 as the coating substance and petroleum ether - ethyl acetate - acetone - methanol (8 : 2 : 2 : 1) as the mobile phase. To identify diflavonoids, using polyamide film as the coating substance and petroleum ether - ethyl acetate -methanol ( 4 : 2 : 1 ) as the mobile phase. The result showed that the methods are simple and fast, which can be used as identification methods of TRF. 3.The separation and quantification of taxinine and sciadopitysin were performed on a Diamonsil ODS C18 (200 mm × 4.6 mm, 5 μm ) and mobile phase consisted of methanol (A) - water (B) with gradient program of 0 - 5 min, 35% - 25% B; 5 - 45 min, 25% B; 45 - 65 min, 25% to 0% B; 65 - 75 min, 0% B, with a flow rate of 0.8 mLmin"1 and the wavelength was set at 272 nm. And the method had good linear relationship within the ranges of 15.15-161.6 ug / mL ( r = 0.9999) for taxinine and 12.06-160.8 ug / mL (r= 0.9998) for sciadopitysin. The average recoveries were 100.9 % and 100.4 %, with RSD 1.6 % and 2.5%, respectively. The established method is accurate and simple, which could be the quality control method of TRF. 4. The effects of TRF extracts on the hypoglycemic activity in diabetes mice induced Alloxan was studied. In this paper, metformin was used as the positive control medicine. Compared with the model group, different doses of TRF extracts could significantly depress the blood glucose and improve the symptom for diabetic mice (P < 0.05).