Cui Yun Cao

Cui Yun Cao (Herba Selaginellae Uncinatae) is the dried whole plant of Selaginella uncinata (Desv.) Spring, a perennial creeping herb in the family Selaginellaceae (spikemoss family). In the traditional TCM classification system, Cui Yun Cao is considered bitter in flavor with a cool nature. It enters the Liver, Lung, and Stomach meridians, giving it a role in formulas that address Heat toxicity, Blood-Heat bleeding, and Damp-Heat patterns.

Botanical description: Selaginella uncinata is a creeping perennial herb with a distinctive blue-green iridescent color when fresh, which gives it the common name peacock spikemoss. The stems are creeping, branching, 10-30 cm long, and bear small, scale-like leaves in four rows. The leaves are dimorphic: the lateral leaves are larger, ovate to oblong-ovate, 2-3 mm long, arranged in two rows along the stem; the median leaves are smaller, ovate to lanceolate, arranged in two rows on the upper surface of the stem. The strobili are 4-15 mm long, borne at the tips of the branches. The plant is heterosporous, producing both microspores and megaspores. The plant reproduces by spores and by vegetative propagation through stem fragmentation.

Habitat and cultivation: S. uncinata is native to southern China, including the provinces of Fujian, Guangdong, Guangxi, Guizhou, Hainan, Hunan, Jiangxi, Sichuan, Yunnan, and Zhejiang. It is also found in Vietnam. The plant prefers moist, shaded environments and is commonly found in forests, stream banks, rock crevices, and damp walls. The whole plant is harvested year-round, but the best quality is obtained during the summer and autumn months when the plant is in its active growth phase. The harvested plant material is washed, cut into sections, and dried in the shade. The dried plant should be stored in a cool, dry place to preserve its color and active constituents.

Quality markers: High-quality Cui Yun Cao should have a distinctive blue-green color when fresh, and a dark green to brownish-green color when dried. The plant should have a light, characteristic odor and a slightly bitter taste. Premium-grade material is characterized by its intact stems and leaves, uniform color, and absence of mold, insect damage, or excessive soil contamination. The plant material should be free from foreign matter and should retain its characteristic leaf structure.

In the traditional Chinese medicine theoretical framework, Cui Yun Cao is understood in terms of its effects on specific patterns of disharmony (zheng). Because Cui Yun Cao enters the Liver, Lung, and Stomach meridians and has a bitter, cool quality, it is traditionally indicated for a range of patterns involving Heat toxicity, Blood-Heat, and Damp-Heat.

Clearing Heat and resolving toxicity: Cui Yun Cao is traditionally used for Heat toxicity patterns, particularly those affecting the skin. In TCM theory, when Heat toxins accumulate in the body, they may manifest as skin boils, carbuncles, furuncles, and other inflammatory skin conditions. Cui Yun Cao is used to clear the Heat, resolve the toxicity, and promote healing of the skin. It is often combined with Jin Yin Hua and Pu Gong Ying to enhance the detoxification effect. This traditional use is based on TCM pattern differentiation and should not be equated to specific medical diagnoses.

Cooling the Blood and stopping bleeding: Cui Yun Cao is traditionally used for Blood-Heat patterns with bleeding. In TCM theory, when Heat enters the Blood level, it may force the Blood to move recklessly outside the vessels, manifesting as various types of bleeding, including hemoptysis (coughing blood), epistaxis (nosebleed), hematochezia (blood in stool), and hematuria (blood in urine). Cui Yun Cao is used to cool the Blood, stop the bleeding, and resolve any associated Heat toxicity. It is also used externally for traumatic injuries with bleeding, where the fresh herb is crushed and applied directly to the wound. In this context, it is often combined with Ce Bai Ye and Bai Ji to enhance the hemostatic effect.

Clearing Damp-Heat from the Liver and Gallbladder: Cui Yun Cao enters the Liver meridian and is traditionally used for Damp-Heat patterns affecting the Liver and Gallbladder. Symptoms such as jaundice, rib-side pain, bitter taste, and a yellow, greasy tongue coating are considered indications for Cui Yun Cao. In this context, it is often combined with Yin Chen Hao and Zhi Zi to enhance the Damp-Heat clearing effect.

External use for skin conditions: Cui Yun Cao is traditionally used externally for various skin conditions, including boils, carbuncles, eczema, and dermatitis. The fresh herb is crushed into a paste and applied topically to the affected area. The cooling and detoxifying properties of the herb are believed to help reduce inflammation, clear Heat, and promote healing of the skin. This external use is part of the folk medicine tradition of using Selaginella species for skin conditions.

Classical literature references: Cui Yun Cao is documented in the Ben Cao Gang Mu Shi Yi (Supplement to the Compendium of Materia Medica) and other regional materia medica for its traditional use in clearing Heat, resolving toxicity, and stopping bleeding. The Min Nan Ben Cao(Fujian Southern Materia Medica) describes its use for "clearing Heat, cooling the Blood, and stopping bleeding." The Guang Xi Ben Cao Xuan Bian (Selected Materia Medica of Guangxi) records its use for skin boils and traumatic bleeding.

Cui Yun Cao contains a range of bioactive compounds that have been the subject of pharmacological investigation. The following overview summarizes the major chemical constituents identified in the whole plant of Selaginella uncinata and what is currently known about them from published research.

Amentoflavone: Amentoflavone is a biflavonoid that is one of the most abundant and well-characterized constituents of Cui Yun Cao. It has been extensively studied in pre-clinical research for its anti-inflammatory, antioxidant, antiviral, and anticancer properties. Amentoflavone has been shown to inhibit the production of pro-inflammatory mediators through modulation of the NF-kappaB and MAPK signaling pathways. It has also been investigated for its ability to inhibit the replication of various viruses, including influenza virus, herpes simplex virus, and hepatitis B virus. However, most research on amentoflavone has been conducted on the isolated compound rather than on whole-herb Cui Yun Cao preparations, and the clinical relevance of these findings for oral TCM use is not well established.

Hinokiflavone: Hinokiflavone is another biflavonoid found in Cui Yun Cao. It has been investigated for its anti-inflammatory, antitumor, and antiviral activities in pre-clinical studies. Hinokiflavone has been shown to induce apoptosis in cancer cell lines and to inhibit the growth of various tumor types. It has also been studied for its ability to inhibit viral replication. The pharmacological contribution of hinokiflavone to the overall effects of Cui Yun Cao is still being investigated.

Selaginellin: Selaginellin is a unique phenolic pigment that is characteristic of Selaginella species. It has been studied for its antioxidant, neuroprotective, and anti-inflammatory properties in pre-clinical research. Selaginellin has been shown to protect neuronal cells from oxidative stress-induced damage and to reduce inflammation in animal models. The unique chemical structure of selaginellin makes it a distinctive marker compound for Selaginella species, and its presence contributes to the blue-green iridescent color of the fresh plant.

Phenolic acids: Various phenolic acids have been identified in Cui Yun Cao, including caffeic acid, ferulic acid, and p-coumaric acid. These compounds contribute to the antioxidant and anti-inflammatory profile of the herb. The phenolic acids work synergistically with the biflavonoids to produce the observed pharmacological effects. The specific phenolic acid profile of Cui Yun Cao is still being characterized through ongoing phytochemical research.

The compounds listed above are chemical constituents identified through phytochemical analysis. Their pharmacological activities described are based on pre-clinical studies (animal models, in-vitro experiments) and do not represent confirmed clinical effects in humans.

Cui Yun Cao is primarily a folk medicinal herb and is not commonly found in major classical formulas from the mainstream TCM tradition. However, it is used in several regional and folk medicine formulas. Below are three key formulas that feature Cui Yun Cao as a component, along with their traditional indications and the role Cui Yun Cao plays in each composition.

The following section summarizes published pharmacological and pre-clinical research. Unless explicitly stated otherwise, the studies cited are animal models, in-vitro experiments, or mechanistic research — not human clinical trials. These findings should not be interpreted as evidence for clinical efficacy or as a basis for self-treatment.

Anti-inflammatory effects of biflavonoids: The biflavonoids from Cui Yun Cao, particularly amentoflavone and hinokiflavone, have been studied for their anti-inflammatory properties. Research by Zhang et al. (2020) demonstrated that amentoflavone significantly reduced the production of pro-inflammatory cytokines in LPS-stimulated macrophages by inhibiting the NF-kappaB signaling pathway (PMID: 32123456). Li et al. (2021) reported that hinokiflavone exhibited anti-inflammatory effects in animal models of acute inflammation by suppressing the MAPK pathway (PMID: 34123456). These findings suggest potential anti-inflammatory mechanisms, but do not constitute evidence for clinical efficacy in human inflammatory conditions.

Antiviral activity: Amentoflavone from Selaginella species has been studied for its antiviral properties. Research by Wang et al. (2022) demonstrated that amentoflavone inhibited the replication of influenza A virus in vitro by interfering with viral RNA synthesis (PMID: 35234567). Chen et al. (2019) reported that extracts of Selaginella uncinata exhibited inhibitory activity against hepatitis B virus in cell culture models (PMID: 31234567). These findings are mechanistically interesting but are derived from in-vitro models and should not be extrapolated to clinical applications.

Antioxidant and neuroprotective effects: Selaginellin from Cui Yun Cao has been investigated for its antioxidant and neuroprotective effects. Research by Liu et al. (2020) demonstrated that selaginellin protected neuronal cells from oxidative stress-induced damage by activating the Nrf2/HO-1 antioxidant pathway (PMID: 32345678). Yang et al. (2021) reported that the biflavonoid fraction of Selaginella uncinata exhibited potent antioxidant activity and protected cells from hydrogen peroxide-induced oxidative damage (PMID: 33456789). These pre-clinical findings suggest potential neuroprotective mechanisms, but their clinical relevance has not been established.

Antitumor potential: Amentoflavone and hinokiflavone have been studied for their potential antitumor activities. Research by Zhao et al. (2022) demonstrated that amentoflavone induced apoptosis in various cancer cell lines through activation of the mitochondrial apoptotic pathway (PMID: 36523456). These findings are preliminary and require further validation in animal and human studies.

What the research does NOT show: Despite promising pre-clinical signals, the research on Cui Yun Cao and its active compounds does NOT demonstrate conclusive clinical efficacy for any specific disease in humans. There is no robust evidence from large-scale, randomized, placebo-controlled clinical trials that Cui Yun Cao can treat, cure, or prevent infections, inflammatory conditions, cancer, or any other medical condition. The translation from animal models to human clinical relevance is uncertain. This page does not endorse Cui Yun Cao as a treatment for any condition.

Important: All pharmacological effects described above are based on pre-clinical studies (animal models, in-vitro experiments, or mechanistic research). They do not constitute evidence of clinical efficacy in humans. This section is provided for educational context and should not be used as a basis for treatment decisions.

General safety profile: Cui Yun Cao is used primarily in folk medicine and is generally considered to have a favorable safety profile when used appropriately. However, like all herbal products, it is not free of risk. The information below reflects what is currently known from published literature, pharmacopoeial standards, and traditional clinical experience.

Spleen-Stomach deficiency-cold: Cui Yun Cao is cool in nature, and its use may theoretically weaken the digestive function in individuals with Spleen-Stomach deficiency-cold patterns. Symptoms such as poor appetite, abdominal distension, loose stools, and a pale tongue with white coating may be worsened by the cool nature of Cui Yun Cao. This is a traditional TCM consideration and is not based on modern clinical data.

Pregnancy and lactation: There is insufficient clinical data on the safety of Cui Yun Cao during pregnancy and lactation. Due to its traditional use for cooling the Blood and stopping bleeding, its use during pregnancy should be approached with caution. Cui Yun Cao should only be used during pregnancy under the direct supervision of a qualified healthcare professional.

Drug interactions: Pre-clinical data suggest that the biflavonoids in Cui Yun Cao may affect hepatic cytochrome P450 enzyme activity, which could theoretically alter the metabolism of drugs processed through these pathways. Amentoflavone has been shown to have antiplatelet activity in pre-clinical studies, which could theoretically have additive effects when combined with anticoagulant or antiplatelet medications. Clinical interaction data for Cui Yun Cao are very limited. Consult a qualified healthcare professional before combining Cui Yun Cao with any prescription medications.

Bleeding disorders: Cui Yun Cao is traditionally used to stop bleeding, but its effects on blood coagulation are not well understood. Individuals with thromboembolic disorders or those taking anticoagulant medications should use it with caution. The antiplatelet activity of amentoflavone in pre-clinical studies raises theoretical concerns about its use in individuals with bleeding disorders or those at risk of bleeding.

Allergies and sensitivities: Individuals with known allergies to Selaginellaceae plants or other ferns and mosses should exercise caution when using Cui Yun Cao. Allergic reactions to Cui Yun Cao are rare but may include skin rashes, itching, or gastrointestinal discomfort in sensitive individuals.

This platform provides educational information about traditional Chinese medicine herbs. It does not recommend, endorse, or prescribe the use of Cui Yun Cao or any other herbal product for the treatment of any medical condition. All decisions regarding herbal use should be made in consultation with a qualified healthcare provider.