Pyrrosia lingua, also called Tongue Fern or Shi Wei in Pinyin, is a less commonly used Chinese herb. And the leaves are its main medicinal part. As an endemic traditional Chinese medicine, the earliest known written record of its healing properties is the item in the “Shen Nong’s Herbal Classic” (Shen Nong Ben Cao Jing). From the point of view of TCM, its main medicinal uses are characterized as inducing diuresis for treating stranguria and clearing heat for stanching bleeding. Today it is often used to treat acute and chronic nephritis, pyelonephritis, cystitis, urethritis, urinary stones, bronchial asthma, lung-heat induced cough, and so on.
What is pyrrosia lingua?
This is a species of epiphytic fern that is a member in the family Polypodiaceae. However, in TCM it is not the only medicinal source of Shi Wei, which also refers to the dried leaves of Pyrrosia sheareri (Bak.) Ching, Pyrrosia petiolosa (Christ) Ching, Pyrrosia gralla (Gies.) Ching, Pyrrosia davidii (Bak.) Ching, and so on. And other common names of this herb include Tongue Fern, Pyrrosia Leaves, Folium Pyrrosiae, Japanese Felt Fern, and more. It grows wildly throughout China, especially in provinces of Taiwan, Zhejiang, Hubei, and Hebei. It can be harvested throughout the year. And the following process is to chop off the roots and rhizome, remove the impurities, wash away the sand and soil, dry in the sun or beside a fire, and cut into sections. Typically it is used raw medicinally.
Pyrrosia lingua plant is 10 to 30cm in height. Slender, crosswise rhizome is densely covered with brown lanceolate scales. Leaves grow sparsely; petiole is 6 to 15cm long, slightly 4-edged, and with base that has joints and is covered with stellate hairs; blade is lanceolate, linear-lanceolate or oblong-lanceolate, 7 to 20cm long, 1.5 to 3cm wide, and acuminate apex, attenuate base, and entire margin. Sori are oval and scattered in the whole lower surface or in upper surface. Main habitats include rocks in the wild or trees.
The whole plant contains diploptene, mangiferin, isomangiferin, chlorogenic acid, and β-sitosterol. And the isolated ingredients from pyrrosia leaf include kaempferol, quercetin, isoquercitrin, trifolin, chlorogenic acid, β-sitosterol acid, and sucrose.
Pyrrosia lingua health benefits
As mentioned above, this herb can be used for many different ailments. So, what is its mechanism? Now let’s take how it treats the upper urinary tract calculi as an example. This disease generally refers to the kidney or ureter stones, whose occurrence rate has increased in recent years, according to the reports. Its main clinical manifestations include activities-associated hematuria and pain, or renal colic caused by ureteral obstruction by stones. Currently, its leaf has been widely used in the treatment of the upper urinary tract calculi, thanks to its amazing ability of promoting diuresis to treat stranguria.
From point of view of Ben Cao Chong Yuan (The Esteemed Source of Materia Medica), pyrrosia herb bridges the intersection between the upward kidney essence and the downward lung essence. The upward water essence can help get though the upper and outside orifices; the descending lung qi can promote the circulation of waterway and thereby guide the urination back to normal.
Modern pharmacological actions of pyrrosia leaf
1) Its decoction has different degrees of inhibition on Staphylococcus aureus, Proteus, E. coli, and so on;
2) It has anti-viral, antitussive, and expectorant effects.
Sample pyrrosia recipes on herbal remedies
The Chinese Materia Medica concludes that it is bitter and sweet in flavor and cold in nature. It goes to meridians of lung, kidney, and bladder. Important function are alleviating water retention to relieve stranguria, clearing lung to eliminate phlegm, and cool blood to stop bleeding. Main pyrrosia uses and indications include stranguria, edema, urination difficulty, cough and asthma due to phlegm-heat, hemoptysis, nosebleed, metrorrhagia and metrostaxis, and traumatic bleeding. Recommended pyrrosia lingua dosage is from 9 to 15 grams in decoction or powder.
1) Shi Wei San from Qian Jin Fang (Thousand golden essential prescriptions). It is formulated with Dang Gui (Dong Quai), Pu Huang (cattails), and Shao Yao (Peony Root) to treat stranguria due to hematuria.
2) Shi Wei San from Gu Jin Lu Yan (Recorded Prescriptions in Ancient and Modern Times). It is coupled with Hua Shi (Talcum Powder) to make powder to cure urolithiasis.
3) Shi Wei San from Sheng Ji Zong Lu (Complete Record of Holy Benevolence). It is combined with Bing Lang (betel nut) and Sheng Jiang (Fresh Ginger Root) to heal cough.
4) Shi Wei San from Pu Ji Ben Shi Fang (Prescriptions for Universal Relief). It is matched with Mu Tong (Clematis Vine), Che Qian Zi (Plantain Seeds), Qu Mai (Dianthus), Talcum Powder, Gan Cao (Licorice Root), etc. to treat urolithic stranguria, dull abdominal pain, penis pain, urinary calculus, and all types of stranguria.
Clinical research of pyrrosia
It is reported that clinically it is widely used for the treatment of acute pyelonephritis, Chyluria, urolithiasis, chronic bronchitis, bronchial asthma, radiotherapy or chemotherapy-induced leukopenia, and the like.
a) Patients of acute pyelonephritis have been treated with decoction of about 20 tablets of Pyrrosia petiolosa. And most of them were cured.
b) The decoction, consisting of pyrrosia herb, Ji Xue Teng (Evergreen Wisteria), Tai Zi Shen (Pseudostellaria), Chen Pi (Citrus Peel), and E Jiao (Donkey-Hide Gelatin), could return the peripheral blood LINE-3 back to normal after taken 2 to 6 months.
Pyrrosia lingua side effects and contraindications
Overdose of pyrrosia lingua may lead to adverse reactions like dizziness and anxiety if it is taken by someone who is susceptible to it. The right remedy is to stop it immediately if the mentioned adverse reactions occur. TCM wise, it shouldn’t be used in cases of yin deficiency and no damp-heat.
a) The National Chinese herbal new medical method Exhibition technical information Selected (surgical diseases), 1970;65;
b) Zhong Xi Yi Jie He Za Zhi (Chinese journal of modern developments in traditional medicine), 1989; 9(1):9.