Properties of White Willow Bark Extract
Harvesting and Processing
White willow bark is usually harvested by stripping, air-drying or rapid drying.
Picture of White Willow Bark P.E/Powder
Color: 10-30% specifications are brown fine powder, 50-80% are light yellow or gray white powder, 95-99% specifications are gray to white crystalline powder.
Smell: Special smell, very strong bitter and astringent taste.
Solubility: Soluble in water, slightly soluble in methanol, ethanol, ethyl acetate, insoluble in benzene, petroleum ether.
Melting point: 197-200 Centidegree
Detection method: High performance liquid chromatography (HPLC).
Crude Drug Ingredients: Phenolic glycosides and flavonoid glycosides were the main active components of the extract from Salix alba, including Salicin, Salicortin, Tremulacin, Fragilin, Salicoysalicin, salireposide, and isorhamnetin and quercitrin.
Chemical Structural Formula of Salicylin
Quality of Medicinal Materials -Based on Dry bark of Salix alba L.
Characters: Changing in length, 1-2 cm in width and 1-2 cm in thickness, brown-green, smooth and slightly longitudinal wrinkles on the outer surface of tender willow bark; brown-yellow to brown-black, rough and irregular wrinkles on the outer surface; light yellow-brown to dark cinnamon-brown on the inner surface, grey-brown to red, with regular longitudinal stripes, and broken, short and insignificant fibers in the inner part. It is easy to split into longitudinal strips.
Microscopic identification: Thick epidermis and 2-3 rows of hypoplastic cork cells. The epidermis of horny tissue and soft tissue contains calcium oxalate crystalline clusters with a diameter of 20-25 um and tannic acid. The phloem is characterized by lignified fibers connected with crystalline sheaths containing prismatic calcium oxalate crystals, and fine soft tissues in phloem and medullary ray. There are single, round starch granules in the cells, with a diameter of 6-8 microns.
TLC identification: 1 g medicinal powder was extracted with 10 ml methanol in water bath for 10-15 minutes, then cooled and filtered to obtain the sample solution, and 0.05 mg/100 ml salicylic glycoside reference solution was prepared. The two solutions were separately placed on the same silica gel G thin-layer plate and expanded with a developer (96% ethanol solution of 1% iodine and 1% potassium iodide, respectively, added into the mixture of 96% ethanol and 8 M hydrochloric acid of the same volume). The two solutions were taken out, dried, heated at 105 C for 5-10 minutes, and examined under sunlight, relative to the main spots of salicin, Rf: red 2.0, red 1.1, brown. Green 0.7.
Foreign material: no more than 3%.
Total ash content: no more than 10%.
Acid insoluble ash: no more than 3%.
Water extract: not less than 10%.
Content Determination: The product is dried, and the content of salicin should not be less than 2.5%.
Uses of Extracts from White Willow Bark
1. In the field of cosmetics, it is mainly used to inhibit acne and acne, relieve swelling and pain.
2. In the field of medicine, it is mainly used to treat fever, cold and infection.
3. In the field of natural feed additives, it is mainly used for anti-inflammatory and digestive aid.