Pyrola

Other Names

alpine shinleafAmerican shinleafAmerican wintergreenbog wintergreencommon shinleafelliptic-leaved shinleafgreen-flowered pyrolagreen-flowered wintergreenHerba Pyrolaelarge wintergreenlarge-leaved shinleaflarger wintergreenliverleaf wintergreenLu An ChaLu Han CaoLu Shou ChaLu Ti CaoLu Xian Caopink shinleafpink wintergreenPirola rotundifoliaPyrola americanaPyrola angustifoliaPyrola aphyllaPyrola asarifoliaPyrola atropurpureaPyrola callianthaPyrola chloranthaPyrola compactaPyrola confertaPyrola dahuricaPyrola decorataPyrola ellipticaPyrola grandifloraPyrola groenlandicaPyrola hopeiensisPyrola incarnataPyrola japonicaPyrola magnaPyrola majorPyrola minorPyrola monophylaPyrola obovataPyrola pictaPyrola pumilaPyrola renifoliaPyrola rotundifoliaPyrola subaphyllaPyrola unifloraPyrola virensPyrolaceaePyrolae HerbaPyrole à feuilles d'asaretpyrolorround-leaf wintergreenround-leaved pyrolaround-leaved wintergreenrounded shinleafshinleafshiny-leaf pyrolavintergrønnslektavintergrønslektawax-flower wintergreenwaxflower shinleafwild lily of the valleywintergreen常绿茶破血丹紫背金牛草罗汉茶鹿含草鹿晗草鹿衔草鹿蹄草

Synopsis

Pyrola: A Comprehensive Reference Article

1. Identity: Botanical Classification, Nomenclature, and Natural Sources

Pyrola is a genus of approximately 30 species of small, evergreen perennial herbs in the heath family (Ericaceae), characterized by basal rosettes of leathery, ovate to orbicular leaves and slender, erect stems bearing terminal racemes of nodding, urn- or bell-shaped flowers that are typically white, greenish, or pinkish-red. Under the old Cronquist system the genus was placed in its own family Pyrolaceae, but genetic research showed it belonged in the family Ericaceae. The genus Pyrola was established by Carl Linnaeus in his Species Plantarum in 1753, with the name derived from the Latin pyrus (pear tree).

With over 40 species worldwide, the Pyrola genus represents one of the most taxonomically complex elements in Ericaceae. China hosts 26 species, including 15 endemics unique to its flora. These plants, commonly known as shinleaf or wintergreen, are primarily autotrophic but some species or forms are partially or fully mycoheterotrophic, deriving carbon and nutrients from mycorrhizal fungi associated with their roots. Native to northern temperate, boreal, and arctic regions of North America, Europe, and Asia, with extensions to high-elevation montane habitats in Central America (Guatemala) and Southeast Asia (Sumatra), Pyrola species thrive in moist, shaded woodlands, bogs, and alpine meadows.

Medically Relevant Species

Although multiple species have been studied, the two officially recognized sources of the traditional Chinese medicine drug known as Pyrolae herba are Pyrola calliantha H. Andres and Pyrola decorata H. Andres. Pyrolae herba (P. herba) is a kind of traditional Chinese medicine with extensive medicinal value, which is derived from the dried whole plant of Pyrola calliantha or Pyrola decorata (Pyrolaceae), as recognized by the State Pharmacopoeia Committee. Other species that have attracted scientific attention include Pyrola rotundifolia L. (round-leaved wintergreen), Pyrola japonica, Pyrola incarnata, and Pyrola renifolia.

Pyrola rotundifolia, the round-leaved wintergreen, is a plant species of the genus Pyrola found in Europe, Japan, Mongolia, Myanmar, Vietnam, and Russia. It typically grows about a foot tall and blooms from May to August with bell-shaped, fragrant white flowers. The plant prefers moist, alkaline soils—often thriving in sandy or loamy environments such as bogs, fens, and beech woods.

Geographic Distribution

The genus Pyrola L. (Ericaceae), comprising about 40 species, is mainly spread in the Circumboreal floristic region of the Holarctic. The species occur throughout Europe, western and central Asia, China, and North America. In Europe, their range extends from the parallel of 68° N passing through northern Scandinavia, reaching as far as northern Spain and Italy, through Bulgaria, Crimea, and the Caucasus.

Common Names and Synonyms

Chinese (TCM): Luxiancao (鹿衔草); also Luticao
Korean: Nok-Je-Cho
English: Shinleaf, Wintergreen, Round-leaved Wintergreen, Round-leafed Pyrola
Pharmaceutical name (TCM): Pyrolae Herba (P. herba)

Pyrolae herba, known as Nok-Je-Cho in Korea and Luxiancao in China, is the whole dried plant of Pyrola japonica Klenze (Pyrolaceae) in Korean tradition, while in China the official source plants are P. calliantha and P. decorata.

Common Dosage Forms and Preparations

Pyrolae herba is prepared from the dried whole plant of Pyrola calliantha or Pyrola decorata. It is known as "Luxiancao" in Chinese and has a long history of medicinal use in China. Preparations in both traditional and modern contexts include dried whole herb (for decoctions), ethanolic extracts, aqueous extracts, volatile oils obtained by hydrodistillation, and standardized fractions isolating total flavonoids or phenolic glycosides. Scientific preparations include ethanol, petroleum ether, ethyl acetate, n-butyl alcohol, and aqueous extracts prepared by solvent sequential process, then isolated and purified to obtain phytochemicals.

2. Traditional and Historical Use

Traditional Chinese Medicine

Pyrola (Pyrolaceae), also known as Luxiancao/鹿衔草 in China, was recorded in Sheng Nong's Herbal Classic listed in top grade. Pyrola herbs were used as medicinal plants for a long history with wide-ranging activities of nourishing kidney-yang, strengthening muscles and bones, activating blood, stopping bleeding, dispelling rheumatism, and eliminating dampness.

As a Yang-tonic agent, Pyrola decorata H. Andres, also known as Luxiancao or Luticao, has been extensively used as a valuable tonifying agent for more than 2000 years in China. It has been included in Shengnong's herbal classic and came out of the top grade lists. According to traditional Chinese medicine (TCM) theory, tonic herbs have been used for various patterns of body deficiency and anti-aging.

Pyrolae herba has a long history of medicinal use in China. In ancient times, it was often used to treat pain in tendons and bones, swollen sores, cough, expectoration, bleeding, and other diseases. In modern times, it is widely used clinically for the treatment of rheumatic arthritis, rheumatoid arthritis, bone hyperplasia, sciatica, cervical spondylosis, lumbar spondylosis, acute and chronic bronchitis, mammary gland hyperplasia, tumor, hypertension, coronary heart disease, and bleeding diseases.

More than 100 compounds have been identified from the Pyrola plants. A total of 33 prescriptions containing Pyrola plants are compiled in the broader genus literature.

Korean and East Asian Traditional Use

The Pyrolae herba extract contains chimaphilin, acetovanillon, and toluhydroquinone, and has been used traditionally as a folk remedy in Korea and China to treat cancer, excessive menstrual flow, chronic phthisical cough, and various inflammatory diseases including rheumatoid arthritis and arthralgia.

Traditional Use in East-Central Europe

Many Pyrola L. species are used in traditional Eastern medicine due to their high nutritional value and valuable biological activities. The aerial parts of P. calliantha, P. decorata, P. incarnata, P. japonica, P. rotundifolia, and other species have been used to treat pulmonary hemorrhage, gastric hemorrhage, rheumatic arthritic diseases, kidney deficiency, and urogenital diseases in traditional Chinese medicine. In eastern European folk medicine, P. rotundifolia leaves have historically been used medicinally, as documented in Carpathian ethnobotanical surveys.

North American Indigenous Use

Native Americans and empirics employed Pyrola species as sudorific, astringent, anodyne, and nervine, in diseases of the breast, colds, wounds, ophthalmia, bad humours, and weak nerves, and externally as blisters. This account was recorded by the botanist C. S. Rafinesque in his Medical Flora of 1830, covering P. rotundifolia, P. elliptica, and P. uniflora.

Traditional Preparations

Traditional preparations in Chinese medicine have taken the form of decoctions of the dried whole herb, tinctures, and powdered formulations combined with other herbs in classical prescriptions for kidney deficiency, rheumatic complaints, and hemorrhagic disorders. Pyrola decorata, as a tonifying agent, is a valuable element in many Chinese prescriptions for Alzheimer's, Parkinson's, and other neurodegenerative diseases.

3. Key Constituents and Active Compounds

Overall Phytochemical Profile

At present, more than 70 compounds have been identified from Pyrolae herba, including flavonoids, phenolic glycosides, quinones, terpenoids, volatile oils, and other compounds. When the entire genus Pyrola is considered, collectively, more than 100 compounds have been isolated from the Pyrola plants.

Flavonoids

Flavonoids constitute a major and pharmacologically active class of compounds in Pyrolae herba. Key identified members include hyperoside (hyperin; quercetin-3-O-galactoside), 2′′-O-galloylhyperin, quercetin, kaempferol glycosides, and formononetin. From Pyrola calliantha (whole plant), two new tetralones — pyrolones A (1) and B (2) — and a new flavonol glycoside, 2′′-O-(4-hydroxybenzoyl)hyperin (3), were isolated, together with six structurally related compounds, including 2′′-O-galloylhyperin (4), hyperin (5), formononetin (6), quercetin 3-O-α-L-arabinopyranoside (7), quercetin 3-O-α-L-arabinofuranoside (8), and kaempferol 3-O-β-D-galactopyranoside (9).

A high content of phenols (208.35 mg GAE/g of dry extract), flavonoids (38.90 mg QE/g of dry extract), and gallotannins (722.91 GAE/g of dry extract) was obtained from P. rotundifolia leaves. The tannin, hyperoside, and quercetin contents of samples across three species were determined by reverse-phase HPLC and varied within the ranges 9.77–34.75, 0.34–2.16, and 0.062–0.147 mg/g dry weight, respectively. Total flavonoid content varied within the range 16.22–37.82 mg/g dry weight.

Phenolic Glycosides

From the water-soluble constituents of the whole herb of Pyrola rotundifolia (Pyrolaceae), one novel phenolic glycoside dimer, pyrolaside A, and one novel phenolic glycoside trimer, pyrolaside B, together with two known phenolic glycosides homoarbutin and isohomoarbutin, were isolated. These novel compounds are unique to the genus and have been identified as significant contributors to antimicrobial activity.

Quinones and Naphthalene Derivatives

Chimaphilin (5,8-dimethoxy-1,4-naphthoquinone) is one of the most studied and characteristic bioactive compounds of the genus. A new naphthoquinone and a new tetralone derivative, together with known chimaphilin, acetovanillon, and toluhydroquinone, were isolated as active constituents. The active components of Pyrolae herba such as chimaphilin, ursolic acid, and hyperoside had previously been shown to possess anti-inflammatory, antioxidant, and antibacterial properties.

Terpenoids

Ten compounds were isolated and identified from Pyrola calliantha, including chimaphilin (1), uvaol (2), ursolic acid (3), 2beta,3beta,23-trihydroxy-12-ene-28-ursolic acid (4), daucosterol (5), 2alpha,3beta,23,24-tetrahydroxy-12-ene-28-ursolic acid (6), emodin (7), gallic acid (8), monotropein (9), and adenosine (10). Ursolic acid is a pentacyclic triterpenoid with well-documented anti-inflammatory and cytotoxic activities. Monotropein is an iridoid glycoside identified in several species.

Volatile Oils

The volatile oil from Pyrolae herba was prepared by hydrodistillation and characterized by gas chromatography-mass spectroscopy (GC-MS). A total of 12 components in PHVO were identified representing 81.62% of the total integrated chromatographic peaks. The major compounds were found to be n-hexadecanoic acid (29.29%), cedrol (17.08%), 6,10,14-trimethyl-2-pentadecanone (9.59%), and cis-9-octadecadienoic acid (8.23%).

Other Compounds

Additional identified compounds include gallic acid, protocatechuic acid, betulin, adenosine, phytosterols, and fatty acids. Pyrola decorata H. Andres has been a source of traditional Chinese herbal medicine Luxiancao for more than 2000 years. Five phenolic components — protocatechuic acid, gallic acid, hyperoside, 2′′-O-galloylhyperin, and quercetin — have been evaluated for antioxidant and cytoprotective effects.

4. Mechanisms of Action

Anti-inflammatory Mechanisms

The extract of Pyrolae herba (PH), which has been used as an anti-inflammatory folk remedy in Korea and China, was investigated for its anti-inflammatory action using arachidonic acid-, 12-O-tetradecanoylphorbol 13-acetate-, or carrageenan-induced edema assays. The anti-nociceptive activity of PH was also tested in mice using the acetic acid-induced writhing model. PH showed dose-dependent and significant (P < 0.05 at 100–400 mg/kg) anti-inflammatory and anti-nociceptive activities in the animal assays.

The mechanism of the activities of PH was examined by testing the extract to determine if it inhibits the expression of inducible nitric oxide synthase (iNOS) and the production of nitric oxide (NO) from the murine macrophages, RAW 264.7 cells. Both the iNOS expression and NO production were significantly suppressed by PH in a dose-dependent manner. PH also inhibited the activating phosphorylation of p38 MAP kinase and NF-κB in these cells.

Antiplatelet and Cardiovascular Mechanisms

The chloroform-soluble and n-butyl alcohol-soluble fractions of water extract of Pyrolae herba inhibited platelet aggregation induced by arachidonic acid and showed a positive inotropic effect. Pyrola plants have confirmed pharmacological activities such as antibacterial, analgesic, anti-inflammatory, inhibitory effects of platelet aggregation, as well as vasodilating effects.

Antioxidant Mechanisms

In five antioxidant assays, the lyophilized aqueous extract of P. decorata and its five phenolic components dose-dependently increased the radical-scavenging (or reducing power) activities. However, the IC₅₀ values of hyperoside were consistently higher than those of 2′′-O-galloylhyperin. The primary antioxidant mechanisms involve direct scavenging of free radicals, metal chelation (particularly of ferrous ions), and inhibition of lipid peroxidation.

Antitumor Mechanisms

The antiproliferative activity of volatile oil from Pyrolae herba (PHVO) against SW1353 cells was investigated using MTT assay, flow cytometry, and western blot analysis. Results demonstrated that PHVO inhibited SW1353 cell viability in a dose- and time-dependent manner. PHVO treatment decreased the number of cells entering the S phase and caused a reduction in the expression of cyclin D1, cyclin-dependent kinase (CDK)4 and CDK6, whereas it caused an increase in the expression of p21.

Antimicrobial Mechanisms

In vitro tests for antimicrobial activity showed pyrolaside B to possess significant activity against two Gram-positive organisms, Staphylococcus aureus and Micrococcus luteus. Chimaphilin has also been identified as an active antifungal compound in the genus. Antifungal activity of multiple compounds from Pyrola was evaluated; chimaphilin showed the strongest activity.

5. Scientific Evidence by Area of Use

5.1 Inflammation and Pain

Evidence type: Animal and in vitro studies; no published randomized controlled human trials identified.

The most rigorously mechanistic data come from a published preclinical study (Lee et al., 2007, Journal of Ethnopharmacology). The extract of Pyrolae herba was investigated for its anti-inflammatory action using arachidonic acid, 12-O-tetradecanoylphorbol 13-acetate, or carrageenan-induced edema assays. The anti-nociceptive activity was also tested in mice using the acetic acid-induced writhing model. PH showed dose-dependent and significant (P < 0.05 at 100–400 mg/kg) anti-inflammatory and anti-nociceptive activities. The mechanism was examined by testing inhibition of iNOS expression and NO production from murine macrophages, RAW 264.7 cells; both were significantly suppressed in a dose-dependent manner. PH also inhibited the activating phosphorylation of p38 MAP kinase and NF-κB in these cells.

Isolation and identification of anti-inflammatory and analgesic principles from the whole herb of Pyrola rotundifolia L. were performed based on bioassays of the inhibitory activities on carrageenan-induced hind paw edema in rats and on acetic acid-induced writhing in mice.

Strength of evidence: Preclinical (animal and cell-based) only. No controlled human clinical trials have been identified in the peer-reviewed literature. The traditional use for rheumatic diseases is extensive, but robust clinical confirmation is lacking.

5.2 Antioxidant Activity

Evidence type: In vitro studies with standardized assays.

The extract from leaves of P. rotundifolia was analyzed for antioxidant capacity using DPPH•, ABTS•+, metal chelating power, and β-carotene-linoleic acid bleaching assays. The examined extract showed moderate radical scavenging and chelating activity, and good inhibiting ability of linoleic acid oxidation (EC₅₀ = 0.05 mg/mL) in comparison to standards.

The EC₅₀ value for the extract of the leaves of P. rotundifolia for DPPH• scavenging (0.2 ± 0.01 mg/mL) was almost three times higher than the one for ascorbic acid. Among studied species, the highest DPPH• ability was reported for P. calliantha (IC₅₀ = 9.66 μg/mL), followed by P. renifolia (IC₅₀ = 24.80 μg/mL) and P. decorata (IC₅₀ = 37.11 μg/mL). Antioxidant activity determined by DPPH assay across multiple Pyrola samples showed IC₅₀ ranging from 7.96 to 50.33 µg/mL, ABTS•+ within the range 612.66–1021.05, and FRAP 219.64–398.12 µmol equiv. Trolox/g, respectively.

Strength of evidence: Moderate at the in vitro level across multiple studies and species; no human trials on antioxidant endpoints.

5.3 Bone Health and Osteoblast Proliferation

Evidence type: Animal studies and cell-based experiments; no independent human clinical trials identified.

Pyrola herbs are extensively used clinically in China for bone-related conditions. Pharmacological studies have shown that Pyrolae herba has a variety of pharmacological activities, including promoting osteoblast proliferation. Studies by Liu et al. (2012, BMC Complementary and Alternative Medicine, as cited in the literature) evaluated the therapeutic effects of Pyrola herb on bone metabolism in ovariectomized rats in combination with other herbs. The constituent hyperoside, which is present in high amounts in Pyrola, has been studied specifically for bone-related effects. Hyperoside is capable of treating many diseases such as cancer, cerebral and cardiac ischemic reperfusion injury, high glucose-induced inflammation, neurotoxicity, and hepatitis. Data demonstrate that hyperoside has potential applications as a drug for osteoporosis treatment.

Strength of evidence: Preclinical (animal models, in vitro osteoblast systems); promissory but not yet confirmed in human clinical trials specific to Pyrola.

5.4 Cardiovascular and Cerebrovascular Protection

Evidence type: Animal and in vitro studies.

The protective effect of total flavonoid of Herba Pyrolae on acute myocardial ischemic injury induced by isoproterenol in rats was investigated to understand primary mechanisms. Modern pharmacological studies have revealed that P. herba exhibits an extensive range of biological activities, including protective activity on cardiovascular and cerebrovascular systems. The platelet aggregation inhibitory activity observed in arachidonic acid assays (see Section 5.1) has also been proposed as a mechanism for cardiovascular benefits.

Strength of evidence: Preclinical only. No human clinical trials on cardiovascular outcomes specifically from Pyrola preparations have been identified.

5.5 Antimicrobial Activity

Evidence type: In vitro studies.

From the water-soluble constituents of the whole herb of Pyrola rotundifolia, novel phenolic glycoside dimers and trimers (pyrolaside A and B) together with known phenolic glycosides homoarbutin and isohomoarbutin were isolated. In vitro tests for antimicrobial activity showed pyrolaside B to possess significant activity against two Gram-positive organisms, Staphylococcus aureus and Micrococcus luteus.

Antifungal activity of multiple compounds from Pyrola was evaluated; chimaphilin showed the strongest activity.

Strength of evidence: In vitro only. No clinical antimicrobial studies identified.

5.6 Antitumor Activity

Evidence type: In vitro and cell-line studies only; no human trials.

The antitumor and antioxidant activities of volatile oils from Pyrolae herba were demonstrated to work against various types of tumor cells, including SW1353 human chondrosarcoma cells. PHVO inhibited SW1353 cell viability in a dose- and time-dependent manner. PHVO treatment decreased the number of cells entering the S phase and caused a reduction in the expression of cyclin D1, CDK4 and CDK6, whereas it caused an increase in the expression of p21. PHVO demonstrated potent antitumor activity against SW1353 cells, suggesting its potential use as a therapeutic agent in the treatment of chondrosarcoma.

The volatile oil is a complex combination of a variety of chemical components, any of which may play a role in inhibiting cell growth. It is not clear as to which of the components contribute most significantly to antitumor activity. Therefore, components of volatile oil from Pyrolae herba should be further investigated in order to elucidate the individual antitumor activity of each component.

The cytotoxic effect in increasing concentration on five types of leukemic cell lines was also investigated using trypan blue vital staining. It was found that the analyzed extract induced the apoptosis of all the tested cell lines. These findings suggest that the leaves of P. rotundifolia are a source of valuable compounds providing protection against oxidative damage, hence their use in traditional medicine is justified.

Strength of evidence: Preliminary. All data are in vitro or cell-line based. No animal tumor models or human clinical trials for cancer have been identified in the peer-reviewed literature. The chimaphilin compound has separately shown activity against multidrug-resistant osteosarcoma cell lines via insulin-like growth factor-I receptor (IGF-IR) signaling in preclinical settings.

5.7 Lipid-Lowering Activity

Evidence type: Preclinical (animal models).

Pharmacological studies have shown that Pyrolae herba has variety of pharmacological activities, including reducing blood lipids. The evidence for lipid-lowering effects is cited in review literature as having been demonstrated in animal studies, though the specific mechanistic details remain under investigation and no human clinical trial data on lipid outcomes from Pyrola specifically have been identified.

5.8 Neuroprotective / Cognitive Function

Evidence type: Preclinical; very preliminary.

Pyrola decorata, as a tonifying agent, is a valuable element in many Chinese prescriptions for Alzheimer's, Parkinson's, and other neurodegenerative diseases. A recent study cited in ResearchGate databases referenced work examining whether Pyrolae herba alleviates cognitive impairment via TREM2 signaling to modulate neuroinflammation. This line of research is very early stage. The available evidence remains preclinical.

6. Body Systems and Health Areas Associated with Pyrola

Musculoskeletal system: Rheumatic arthritis, rheumatoid arthritis, bone hyperplasia, sciatica, cervical and lumbar spondylosis, promotion of osteoblast proliferation.
Cardiovascular system: Coronary heart disease, hypertension, platelet aggregation inhibition, cardioprotective effects on ischemic myocardium.
Respiratory system: Acute and chronic bronchitis, cough, expectoration, pulmonary hemorrhage.
Hematological system: Bleeding disorders, gastric hemorrhage, excessive menstrual flow.
Urogenital system: Kidney deficiency (TCM concept), urogenital diseases.
Immune/inflammatory system: Anti-inflammatory effects via iNOS/NO and NF-κB pathways.
Oncology (preclinical only): Antitumor activity in chondrosarcoma, leukemic, and other cell lines.
Neurological system (very preliminary): Prescriptions for Alzheimer's and Parkinson's diseases in TCM; neuroprotective effects under investigation.

It is used clinically in modern times to treat rheumatic arthritis, rheumatoid arthritis, bone hyperplasia, sciatica, cervical spondylosis, lumbar spondylosis, acute and chronic bronchitis, mammary gland hyperplasia, tumor, hypertension, coronary heart disease, and bleeding diseases.

7. Dosage Forms and Dosages Reported in Studies

The following dosages are reported as they appeared in the cited scientific literature; they do not represent standardized clinical recommendations.

Animal anti-inflammatory studies: PH showed dose-dependent and significant (P < 0.05 at 100–400 mg/kg) anti-inflammatory and anti-nociceptive activities in the animal assays.
In vitro antioxidant studies (P. decorata leaves): PC12 cells were pretreated for 24 h with different extractions of P. decorata leaves at concentrations of 0.1, 0.5, 1, 5, and 10 mg/mL, then H₂O₂ of 0.4 mM was added in all samples for an additional 2 h.
Antioxidant assay comparisons (P. rotundifolia): The EC₅₀ value for the extract of the leaves of P. rotundifolia (DPPH•) was 0.2 ± 0.01 mg/mL.
Linoleic acid oxidation inhibition (P. rotundifolia): The examined extract showed good inhibiting ability of linoleic acid oxidation at EC₅₀ = 0.05 mg/mL in comparison to standards.

The existing studies on chemical constituents and pharmacological activities have not fully revealed the medicinal value of P. herba, and there is also a lack of systematic literature research on quality control. No standardized human clinical dosing regimens for Pyrola as a dietary supplement have been established by regulatory agencies such as the NIH Office of Dietary Supplements, NCCIH, EMA, or EFSA.

8. Safety Considerations and Known Interactions

General Toxicological Status

Pyrolae herba is rich in chemical constituents, diverse in pharmacological activities, and abundant in resources, and is widely used in clinics from traditional to modern. However, there is a lack of research on the relationship between chemical constituents and pharmacodynamics of Pyrolae herba.

The existing clinical applications suggest that Pyrolae herba has a certain therapeutic potential in the treatment of hemorrhagic diseases, but there is a lack of information on experimental studies. Formal systematic toxicology studies specifically addressing Pyrola safety in humans are not available in the peer-reviewed literature reviewed. The genus review compiled by Yang et al. (Bentham Science, 2019) includes safety as one of its review parameters, aiming to sum up the updated and comprehensive information about botany and traditional use, phytochemistry, pharmacological activities, and safety by analyzing information available on Pyrola plants via internationally accepted scientific databases.

Antiplatelet and Anticoagulant Potential

The chloroform-soluble and n-butyl alcohol-soluble fractions of water extract of Pyrolae herba inhibited platelet aggregation induced by arachidonic acid. This documented antiplatelet effect, observed in preclinical models, raises a theoretical concern about interactions with antiplatelet drugs (e.g., aspirin, clopidogrel) and anticoagulants (e.g., warfarin), although no human pharmacokinetic or drug interaction studies have been published.

Cardiovascular Effects

Water extracts of Pyrolae herba showed a positive inotropic effect in preclinical testing, meaning they may influence heart contractility. This effect has not been characterized in human subjects.

Quality and Standardization Concerns

Results revealed that there were significant variations in phytochemical profiles and antioxidant activity among all Pyrola samples. This inter-species and geographical variability in chemical composition means that the biological potency and safety profile of any given preparation may differ substantially depending on the source species, growing region, and extraction method. The absence of established international quality standards or pharmacopeial monographs outside of the Chinese Pharmacopoeia represents a practical limitation.

Evidence Gaps

There is a lack of research on the relationship between chemical constituents and pharmacodynamics of Pyrolae herba. The existing clinical applications suggest therapeutic potential in the treatment of hemorrhagic diseases, but there is a lack of information on experimental studies. It is worthwhile to further investigate Pyrolae herba in depth in the hope of making discoveries and breakthroughs.

Further work should be developed on the elucidation of structure-function relationships, understanding of multi-target pharmacological effects, as well as developing its application both in clinical usage and functional food for research and development of Pyrola plants.

9. Summary of Evidence Quality

The research base for Pyrola is substantial at the phytochemical and preclinical level but remains thin at the level of human clinical evidence. Pharmacological studies have shown that P. herba has a variety of pharmacological activities, including anti-inflammatory, anti-bacterial, anti-viral, anti-tumor, anti-oxidation, reducing blood lipids, protective on cardiovascular and cerebrovascular, promoting osteoblast proliferation, and so on. However, nearly all of these findings derive from animal models, cell culture experiments, or traditional clinical observations — not from rigorous randomized controlled trials in human populations. The absence of human clinical trial data is the single most significant limitation of the current evidence base, and all pharmacological claims must be interpreted with that constraint firmly in mind.

References

Health Conditions

Health conditions that Pyrola may help support.

No conditions available.

Body Systems

Body systems that Pyrola may help support.

No body systems available.