Drynaria, just as its mandarin name Gu Sui Bu implied, is an herb that is commonly utilized for shattered bones. That is to say, its Chinese name, translated literally as “broken bone repairing” in English, says it all. However, as one of common Chinese herbs, it is more than just a broken-bone herb and it has what it takes to be more versatile medicinally.
What is Drynaria?
Medicinally it mainly refers to the roots of Drynaria fortunei (Kunze) J. Sm., Drynaria baronii (Christ) Diels, Drynaria propinqua (Wall.)J. Smith, or Pseudodrynaria coronans (Wall.) Ching. And other common names include Drynaria roosii, Drynaria Rhizome, and Rhizoma Drynariae. Among them Drynaria fortunei is a species of basket fern in the family Polypodiaceae. And the first one is mainly produced in Zhejiang, Hubei, Guangdong, Guangxi, and Sichuan; the second one is mainly produced in Shaanxi, Gansu, Qinghai and Sichuan. This herb can be harvested all year round but winter and spring are preferable. After the harvest, remove leaves and scales, wash clean, moisturize thoroughly, slice, and dry. It is used raw or sand-scorched.
Drynaria fortunei plant is an epiphytic herb, 20 to 40cm high. Fleshy, stout, and long rhizome grows horizontally and is covered densely with brown, linear chisel-shaped scales. Leaves come with two shapes. Foliage leaf is thick and leathery, reddish-brown or grayish brown, ovate, sessile, 5 to 6.5 cm long and 4 to 5.5 cm wide, and with pinnate lobed edges that looks like oak leaves. Sporophyll is green and with a short winged handle. Blade is oblong or oblong, 20 to 37cm long, 8 to 18.5cm wide, and pinnatipartite. 6 to 15 pairs of accessory pinna are broadly lanceolate or oblong, 4 ~ 10 cm long, and 1.5 to 2.5cm wide. Sori are round, brown, arranged with 2 to 4 lines on both sides of the middle vein. Each rectangular mesh harbors one 1 without indusia.
Root of Drynaria fortunei contains naringin, hop-21-ene, fern-9 (11) ene, ern-7-ene, filic-3-ene, β-sitosterol, stigmasterol, campesterol, and tetracyclic triterpenoids, such as cycloardenyl acetate, cyclomargenyl acetate, cyclolaudenyl acetate, 9, 10-cycloanost-25-en-3β-yl acetate, and so on. However, as far as the chemical constituents are concerned, it provides with no health benefits information, which instead can be revealed by its pharmacology.
Modern pharmacological actions of Drynaria
1. Its water decoction and Drynaria extract by alcohol can prevent the rising of serum cholesterol and triglycerides. In addition, they can prevent the formation of atherosclerotic plaques;
2. Its polysaccharides and flavanone glycosides can lower blood lipid and resist arteriosclerosis;
3. It can promote bone’s absorption of calcium, increase calcium and phosphorus levels, which is conducive to fracture healing;
4. It can improve cartilage cells and postpone degenerative lesions of bone cells;
5. The flavanone glycosides contained have significant sedative and analgesic effects.
Proven Drynaria herbal remedies
On the basis of related description on Chinese Materia Medica, this herb is considered bitter in flavor and warm in properties. And it goes to meridians of liver and kidney. Its fundamental functions are tonifying kidney to reinforce bones and promoting blood circulation to arrest pain. Basic medicinal uses and indications are lumbago due to the kidney deficiency, flaccid feet and knee, deafness, toothache, chronic diarrhea, enuresis, bone fractures, alopecia areata, and so on. Recommended dosage is from 10 to 20 grams in decoction, tea pills, or powder.
1. Gu Sui Bu San. This formula comes from Tai Ping Sheng Hui Fang (Taiping Holy Prescriptions for Universal Relief). It is basically used for incised wound and injury of the soft tissues and broken bones. Other major herbal ingredients are Zi Ran Tong (native copper), Hu Jing Gu (Tiger Shin), Bai Gui (Tortoise Plastron), Mo Yao (Myrrh), and more.
2. Shen Xiao Fang. This prescription is from Taiping Holy Prescriptions for Universal Relief too. It is mainly formulated for kidney deficiency induced low back pain, flaccidity of lower limbs, tinnitus and deafness, toothache, chronic diarrhea, and so on. Other primary herbs include Bu Gu Zhi (Psoralea Fruit), Niu Xi (Achyranthes Root), and so on.
Drynaria side effects and contraindications
It was reported that overdose of Drynaria herb might result in adverse reactions such as poisoning and stomachache. But so far no recognized drug interactions found clinically. TCM wise Gu Sui Bu herb should be used with cautions in cases of fire excess from yin deficiency and blood deficiency and wind-dry.