Du Zhong (Eucommia Bark) (First grade) (Flat sheets, grayish-brown exterior, rough, with longitudinal fissures and transverse lenticels)
Du Zhong (Eucommia Bark) (Second grade) (Smooth, dark purple interior, broken surface with connected white rubbery threads)
Du Zhong (Eucommia Bark) (First grade, 4mm thick)
Du Zhong (Eucommia Bark) rubbery threads
Du Zhong (Eucommia Bark) sliced
Du Zhong (Eucommia Bark) and stir-fried Du Zhong (Eucommia Bark) three grades (4, 3, 2mm thick)
Du Zhong (Eucommia Bark) silk roll
Salt-fried Du Zhong (Eucommia Bark) charred
Sand and salt-fried Du Zhong (Eucommia Bark)
Sand and salt-fried Du Zhong (Eucommia Bark)
Rotary drum salt-fried Du Zhong (Eucommia Bark)
Fake stir-fried Du Zhong (Eucommia Bark) dyed with caramel coloring
【Naming】
【Source】
Shen Nong’s Classic of Materia Medica, Upper Class
【Common Usage Level】
A
【Botanical Origin】
Dried bark of the Eucommiaceae plant Eucommia ulmoides Oliv.
【Characteristics】
The dried bark is in flat sheets or rolled pieces, varying in size and thickness, generally about 3-10mm thick and 40-100cm long. The outer surface is grayish-brown, rough, with irregular longitudinal fissures and oblique transverse lenticels, sometimes with light gray lichen spots. However, most commercial products have had part of the rough outer bark removed, so the outer surface is light brown and relatively smooth. The inner surface is smooth and dark purple. It is brittle and easily broken, and the broken surface has interwoven silvery-white thread-like substances that are dense and slightly elastic. It has a faint odor, a slightly bitter taste, and leaves a gelatinous residue when chewed.
Most prepared slices are cut into squares, approximately 1-3cm square, or into thin strips about 3mm wide, which are light brown or grayish-brown and have obvious longitudinal lines and fissures. The cut surface has interwoven silvery-white thread-like substances. The odor is faint, and the taste is slightly bitter. After stir-frying to charcoal, it is brownish-black and slightly salty.
【Processing】
Salt-processed Du Zhong (Eucommia Bark).
【Identification】
《Annotations to the Materia Medica》: “White threads are best.”
《Newly Revised Materia Medica》: “The more white threads when broken, the better.”
《Classified Materia Medica》: “The more white cotton-like material when broken, the better.”
《Essentials of Materia Medica》: “Moist is good.”
《Compendium of Materia Medica》: “[Hong Jing says] It looks like Magnolia officinalis, and the more white threads when broken, the better.”
《Essentials of Materia Medica for Preparation》: “That which comes from Hanzhong, thick and moist, is good.”
《Discriminating Good from Bad》: “Thick and flat, with abundant and moist oily quality, when broken transversely and pulled apart with both hands, one sees countless silvery threads, like cotton, which is a good product.”
The best is large and complete without breaks, with fine bark and thick flesh, and when broken the threads are abundant and stretch long, and are not easily broken, the inner surface is dark purple, and the body is dry and hard. A dry body is light, with a crisp sound when broken, and the inner surface is smooth and glossy. If the body is heavy and the inner surface shows a watery color with black spots, it indicates dampness and does not meet the standards. Among different parts of the plant that produce Du Zhong (Eucommia Bark), the trunk bark is the best, the bark near the root is second, and the thin branch bark is the worst.
【Identification Terms】
1. Flat sheets: Refers to bark-type medicinal materials that, after being peeled from large tree trunks, do not easily shrink and curl during drying, and are in the shape of wide and thick boards or thick pieces. Such as Du Zhong (Eucommia Bark), Huang Bai (Phellodendron Bark).
2. Rough bark: Mainly refers to dead tree bark, which refers to the cork layer in botany. Such as the outer bark of Du Zhong (Eucommia Bark).
3. Rubber threads (glue threads): Refers to the unique white colloidal threads inside the bark of the Du Zhong (Eucommia Bark) tree, the white rubber threads that connect after breaking.
【Section】
Bark Category