Physicochemical and microscopic identification experiments of Rheum palmatum
The purpose of this experiment is to master the characteristics of raw drug properties of Rheum palmatum; to master the cross-sectional tissue characteristics and powder microscopic characteristics of Rheum palmatum as well as to master the physical and chemical identification characteristics of Rheum palmatum.
Operation method
microscopic observation
Materials and Instruments
Rhubarb Move I. Identification of traits For more product details, please visit Aladdin Scientific website.
Distilled water Chloral hydrate Sodium hydroxide Ethanol
Microscope Slides Coverslips Dropper Bottles Tweezers Alcohol Lamps Asbestos Mesh Alcohol Lamp Holders Beakers Evaporators Ultraviolet Analyzers Filter Paper
Take rhubarb specimens and describe rhubarb traits from the aspects of shape, surface features, sectional features, odor and so on.
Microscopic identification
1. examine the rhubarb rhizome cross-sectional tissue slices, and observe the main tissue characteristics from the outside to the inside
① cork layer and cortex have been removed, occasionally remaining.
② phloem rays l ~ 4 columns of cells, containing brown material.
③The formation layer is ring-like.
(iv) Xylem ducts are sparsely arranged radially.
⑤ Pith broad, scattered with most heteromorphic vascular bundles (star points), the complex vascular bundles, consisting of several exo-woody vascular bundles, the formation of the layer of rounded, rays in a stellate shoots.
2. rhubarb powder were distilled water and 10% chloral hydrate test solution mounted, alcohol lamp heating permeability, microscopic examination of the following features
① calcium oxalate cluster crystals are large and numerous, most of the angles are short and blunt.
②The ducts are mainly reticulated ducts, and there are ciliated pores and tiny threaded ducts, with a diameter of about 140 μm, non-woody.
(iii) The starch grains are spherical or oblong, the umbilical point is mostly stellate, and the complex grains are composed of 2~7 grains.
Physical and chemical identification
1. Sublimation test
A small amount of rhubarb powder added to a 50 ml beaker, placed on the alcohol lamp, evaporating dish water on the beaker, heating 20 min after the bottom of the evaporating dish with yellow needle-like or shuttle crystals, high temperature crystals were feathery (small molecules of anthraquinones sublimation).
2. Borntrager reaction
Drops of 10% NaOH solution on the surface of rhubarb tablets, can be seen from yellow to red (anthraquinone reddened by alkali).
3. Fluorescence
Take the dilute ethanol leachate of rhubarb powder, point it on filter paper, then add drops of dilute ethanol to diffuse it, it shows a yellow to light brown ring, put it under the UV lamp to observe, it shows a brown to brown-red fluorescence (anthraquinone derivatives), and it shall not show a bright blue-violet fluorescence (proving that there is no astragaloside and other astragaloids such as earth rhubarb glycosides).