Tong Cao (Medulla Tetrapanacis or Rice Paper Pith)

What Is Tong Cao

Tong Cao commonly known as Medulla Tetrapanacis or Rice Paper Pith is the stalk pith of Tetrapanax papyrifer, which is an evergreen shrub or small tree belonging to the family Araliaceae. It is a relatively practical and common Chinese herbal medicine, which first appeared in <Ben Cao Shi Yi> (Supplements to Newly Revised Materia Medica) in the 27th year of Kaiyuan in the Tang Dynasty (739 AD).

Tetrapanax papyrifer also called Rice Paper Plant is the sole species in this genus. They like warmth and humidity and are not tolerate drought and waterlogging. They are often grown on sunny, rich soils below 2,800 meters above sea level or cultivated in gardens.

They are native to China and have been introduced to South Korea, Japan, New Zealand, the United States, and Brazil. Their stalk pith can be made into paper flowers and small crafts.

Tetrapanax papyrifer (Rice Paper Plant)

In autumn, people gather the stems of Tetrapanax papyrifer, cut them into pieces, take out their stalk pith, straighten them, dry them in the sun, cut them into thick slices, and make them into Chinese herbal medicines.

Tong Cao contains papyriogenin A, papyriogenin C~M, papyriogenin A1, papyriogenin A2, papyrioside L-Ⅱa, papyrioside L-Ⅱb, papyrioside L-Ⅱc, papyrioside L-Ⅱd, papyrioside La, papyrioside Lb, papyrioside Lc, papyrioside Ld, papyrioside LA, papyrioside LB, papyrioside LC, papyrioside LD, papyrioside LE, papyrioside LF, papyrioside LG, papyrioside LH, β-sitosterol, daucosterol, 7-oxostigmasterol-3-O-B-D-glucopyranoside, 7-oxositosterol-3-O-B-D-glucopyranoside, afzelin, astragalin, kaempferol, 3,7,4′-tri-O-acetylkaempferol, kaempferol 7-O-(2-E-p-coumaroyl-α-rhamnoside), kaempferol 7-O-(2,3-di-E-coumaroyl-α-rhamnoside), cinnamyl alcohol, trans-cinnamic acid, 5-formylbenzofuran, coumarin, dihydrocoumarin, N-(2′,3′-dihydroxytetracosanol)-2-amino-8-octadecene-1,3,4-trio, N-(2′-hydroxytetracosanol)-2-amino-8-octadecene-1,3,4-trio, araliacerebroside, polysaccharides, amino acids, and some trace elements.

Generally, the white, thickset, and elastic Tong Cao is preferred.

According to <Ri Hua Zi Zhu Jia Ben Cao>, the medicinal property of Tong Cao is slightly cold, with a sweet and bland taste. It has a certain therapeutic effect on the pathological changes of the lung and stomach meridians.

In traditional Chinese medicine, it is often used to clear heat and induce diuresis, ventilate qi and promote lactation, and treat dysuria, stranguria, hematuric strangury, edema, oliguria, postpartum hypogalactia, agalactia, chronic rhinitis, nasal polyps, acute intestinal obstruction, urinary calculus, and jaundice hepatitis.

There are about 130 kinds of traditional Chinese medicine prescriptions containing it, such as Dang Gui Si Ni Tang, San Ren Tang, and Cui Ru Wan.

Benefits

  • Anti-inflammation, inhibiting carrageenan-induced paw swelling and cotton ball-induced granulomas in mice [1].
  • Anti-oxidation, scavenging DPPH free radicals, and delaying aging [2].
  • Anti-hepatotoxicity, reducing CCL4 and galactosamine-induced hepatocyte injury in rats [3].
  • Inducing diuresis and increasing urine output and K+ excretion in rats.
  • Clearing heat and treating dysuria, stranguria, hematuric strangury, edema, oliguria, and urolithiasis.
  • Ventilating stomach qi and promoting lactation, and treating postpartum hypogalactia and agalactia.
  • Studies have found that its methylene chloride and methanol extracts have significant antithrombin activity [4].
  • Studies have found that papyriogenin A exhibited anti-HIV activity and low cytotoxicity in acutely infected H9 lymphocytes [5].

Combinations

  • It can be used in combination with Dong Kui Guo (Fructus Malvae), Hua Shi (Talcum), and Shi Wei (Folium Pyrrosiae) to treat dysuria and stranguria due to heat.
  • It can be used in combination with Jin Qian Cao (Lysimachia Christinae), Hai Jin Sha (Spora Lygodii), and Shi Wei (Folium Pyrrosiae) to treat urolithiasis.
  • It can be used in combination with Zhu Ling (Polyporus) and Di Long (Earthworm) to treat edema and oliguria caused by retention and accumulation of water-dampness.
  • It can be used in combination with Chuan Shan Jia (Squama Manitis), Wang Bu Liu Xing (Semen Vaccariae), and Mu Tong (Caulis Akebiae) to treat postpartum hypogalactia and agalactia.
  • It can be used in combination with Yi Yi Ren (Semen Coicis), Bai Dou Kou (Fructus Amomi Rotundus), Ku Xing Ren (Bitter Apricot Seed), and Hua Shi (Talcum) to treat headache, aversion to cold, heavy body, body pain, fatigue, chest tightness with not easy hunger, fever in the afternoon caused by damp-warm diseases in the early stage, or warm diseases mingled with dampness in summer.

Side Effects

At present, there is no literature report that Tong Cao has toxic effects, and no data is showing that taking it at the prescribed dose can cause serious adverse reactions.

Overdose of it may cause nausea, vomiting, or upper abdominal pain.

It may cause hypokalemia when taken in high doses over a long period of time.

Precautions and Warnings

  • The dosage of Tong Cao should be controlled at 3-5g.
  • It can be made into decoctions, pills, or granules.
  • People who are allergic to Tong Cao should not take it.
  • It should not be taken with medicines containing penicillin.
  • Patients without damp-heat syndrome should not take it.
  • Patients without a deficiency of both qi and yin should not take it.
  • Pregnant women should not take it.
  • Breastfeeding women should take it under medical supervision.