Rubia cordifolia

Rubia cordifolia L.: A Comprehensive Reference

1. Identity and Botanical Characterization

Taxonomy and Nomenclature

Rubia cordifolia (family: Rubiaceae) L. is a perennial botanical drug climbing vine. It is a branched climber with small, greenish-white flowers that are arranged in a cluster of round, fleshy, purple fruits. The species name "cordifolia" refers to its heart-shaped leaves. It has the following botanical synonyms: Galium cordifolium (L.) Kuntze and Rubia cordifolia subsp. pratensis (Maxim.) Kitam., among others.

Common Names

In India, R. cordifolia is often known as Madder or Indian Madder. Locals in India call it "Manjistha," and its dried samples are sold in the market under the name "Manjith." In Traditional Chinese Medicine (TCM) it is known as Qiancao. Its root and rhizome, referred to in TCM as Rubiae Radix et Rhizoma, is used for hematemesis, epistaxis, flooding and spotting, traumatic bleeding, amenorrhea caused by obstruction, joint impediment pain, and swelling caused by injuries from falls.

Geographic Distribution

It is found throughout India, ascending to an altitude of 3,750 m from the North-West Himalayas eastwards. Growing at altitudes of 570–1,800 m, R. cordifolia is found along roadsides, riversides, on hillsides, and in valleys. The plant also occurs across East Asia, parts of Africa, and in tropical regions throughout the Indo-Pacific zone.

Botanical Description and Plant Parts Used

Its roots have a brownish-red bark from which a red dye is obtained. The plant grows well in hilly districts, and the root has medicinal value. Generally, the root and rhizome are collected in spring or autumn in the third or fourth year after cultivation. Its dried roots and rhizomes are used in medicine; the traditional Chinese medicine name for this material is RUBIAE RADIX ET RHIZOMA.

Common Dosage Forms and Preparations

The powdered root is used at 1–3 g; decoction at 56–112 ml. In modern supplement contexts, it is often taken as a powder, decoction, or capsule, and frequently combined with other herbs such as neem or turmeric for synergistic effects. Classical Ayurvedic dosage forms include tablets, capsules, powders (churna), syrups, decoctions, and fermented preparations (Asava–Arishta). Well-known classical Ayurvedic recipes include Maha Manjishtadi Kashaya, Manjisthadi taila, Pinda taila, Manjishthadya ghrita, and Manjishthadi arka.

2. Traditional and Historical Use

Ayurveda (India)

Manjistha is considered to be one of the most valuable herbs in Ayurveda, the world's oldest health care system that originated in India. In Ayurveda, it is one of the chief "rakta shodhana" (blood purifiers) and is categorized under "varna prasadaka" herbs—agents that enhance complexion and skin tone. Ancient Ayurvedic texts like the Charaka Samhita and Sushruta Samhita describe its application in treating chronic skin diseases, ulcers, jaundice, and gynecological imbalances.

Rubia cordifolia (Sanskrit: mañjiṣṭhā) is used in Ayurveda to promote skin care and enhance the beauty of the skin (varṇya). Ayurvedic texts enumerate its qualities as: Varṇya, rakta-prasādaka, rakta-śodhaka (blood purifier).

In Ayurveda, Manjistha is classified as a "rasayana," or rejuvenating herb, prized for its ability to promote overall health and vitality. In Ayurveda, R. cordifolia has been used as a coloring agent for medicinal oils, and applied externally to inflamed areas, ulcers, and fractures. It was also used topically to heal wounds and bruises, given its capacity to dissolve stagnant blood and improve microcirculation.

In ancient India, it also served a dual purpose: medicinal herb and dye source. Its roots produced a red pigment used to color textiles and also as a cosmetic.

Traditional Chinese Medicine

R. cordifolia has been used in medicine for thousands of years. It was first published in the "Shennong's Herbal Classic" during the Qin and Han Dynasties and was classified as a high-quality product. It is mainly used in TCM to treat hematemesis, epistaxis, hemorrhage, trauma bleeding, stasis of amenorrhea, joint arthralgia pain, swelling, and pain relief.

A great number of literary studies have reported that it can be used for the improvement of blood circulation, hemostasis, and activation of collaterals. The plant water decoction can be taken orally to treat diarrhea, and it is also a main ingredient of a formula named "Er-Xie-Ting granule," which is used to treat acute infantile diarrhea in China.

Use in Other Traditional Systems

This drug is used to treat Shi Feng Bi (rheumatism), menstrual pain, urinary system diseases, dropsy, paralysis, amenorrhea, and jaundice in India. In addition, it serves as a pigment utilized as a food additive and a dye for wool or fiber.

3. Key Chemical Constituents

Overview of Phytochemical Classes

Studies have found that R. cordifolia is rich in more than 100 compounds, mainly including anthraquinones, naphthoquinones, anthraquinone glycosides, naphthoquinone glycosides, bicyclic hexapeptides, triterpenoids, and polysaccharides.

Anthraquinones

Anthraquinone is a well-known category of phytochemicals. Alizarin, munjistin, purpurin, rubiadin, tectoquinone, and xanthopurpurin are the common ones.

• Purpurin (1,2,4-trihydroxyanthraquinone): Purpurin is a trihydroxy derivative of anthraquinone, first isolated in pure form in 1827 from the roots of Rubia cordifolia. Purpurin is the major anthraquinone present in Rubia cordifolia. Purpurin has been used in the Chinese pharmacopeia to evaluate the quality of herbal medicine.
• Alizarin (1,2-dihydroxyanthraquinone): Alizarin, otherwise called mordant red, is the red dye derived from the root of R. cordifolia.
• Manjistin (xanthopurpurin-2-carboxylic acid): Trihydroxy anthraquinone (purpurin) and xanthopurpurin-2-carboxylic acid (manjistin) are the two main components present in the root of R. cordifolia, in addition to 1,2-dihydroxyanthraquinone (alizarin).
• Rubiadin: A hydroxymethylanthraquinone derivative identified as contributing to the plant's antimicrobial and anti-inflammatory profile. The roots contain quinones like glycosides including rubiadin, 1-hydroxy-2-methoxy anthraquinone, 3-dimethoxy-2-carboxy anthraquinone, rubiprasin A, B, C, mangistin, alizarin, garancin, mollugin, and furomollugin.
• Pseudopurpurin: Pseudopurpurin (an anthraquinone) is a characteristic natural red-color compound present in the roots of R. cordifolia. It is a derivative of purpurin (purpurin 3-carboxylic acid). It improves bone geometry and selectively exhibits tumor inhibitory potential.

Naphthoquinones

• Mollugin: The two main secondary metabolites in the root of R. cordifolia belong to quinone compounds; mollugin belongs to naphthoquinone compounds. Mollugin, one of the major active constituents of Rubia cordifolia, has been well-studied for its pharmacological properties, demonstrating potent anti-inflammatory properties by suppressing the TAK-1-mediated activation of NF-κB/MAPK and enhancing the Nrf2/HO-1-mediated antioxidant response.

Bicyclic Hexapeptides

Bicyclic hexapeptides are commonly considered among the most important bioactive compounds in R. cordifolia. So far, 19 bicyclic peptides have been found in R. cordifolia. Fractionation of R. cordifolia root extract has yielded three anthraquinones (alizarin, purpurin, and emodin), two lignans, and two cyclic hexapeptides, namely deoxybouvardin RA-V and RA-XXI.

Other Constituents

Various chemical constituents like anthraquinones, iridoid glycosides, naphthoic acid esters, bicyclic hexapeptides, and triterpenes have been isolated and identified from Rubia cordifolia Linn. Chemically, it contains glucosides known as Manjisthin and Purpurine, along with resins, lime salts, and coloring agents.

Standardization per Pharmacopoeia

Purpurin and mollugin are the two main active ingredients specified in the Chinese Pharmacopoeia. The Chinese Pharmacopoeia requires that the contents of these two secondary metabolites in the roots of R. cordifolia be up to standard before they can be used as medicines.

4. Mechanisms of Action

Anti-inflammatory Mechanisms

Mollugin inhibits pro-inflammatory chemocytokine production. Mollugin demonstrates potent anti-inflammatory properties by suppressing the TAK-1-mediated activation of NF-κB/MAPK signaling and enhancing the Nrf2/HO-1-mediated antioxidant response. Alizarin, 6-hydroxyrubiadin, purpurin, and rubiadin are expected to be key constituents responsible for analgesic and anti-inflammatory properties.

Purpurin showed a significantly anti-inflammatory effect by reducing the content of IL-6, TNF-α, and IL-1β and increasing IL-10. Compared with controls, quinones from R. cordifolia (alizarin, purpurin, and mollugin) significantly reduced cytokine/chemokine overexpression in TNF-α-activated keratinocytes, and this reduction was also detected in imiquimod-stimulated macrophages.

Antioxidant Mechanisms

Purpurin is an anthraquinone that gives R. cordifolia antioxidant properties. Purpurin has anticancer, antibacterial, and neuromodulatory effects owing to its strong antioxidant activity.

Anticancer Mechanisms

Mollugin was proven to potentiate autophagic activity, as well as induce growth inhibition and apoptosis of HN4 human oral cancer cells and SK-BR-3 breast cancer cells. Mollugin was reported to possess anti-cancer activity in HER2-overexpressing cancer cells in a dose- and time-dependent manner. Further study demonstrated that mollugin inhibited cell proliferation and promoted apoptosis of breast and ovarian cancer cells by suppressing FAS expression through modulation of a HER2/Akt/SREBP-1c signaling pathway. In addition, mollugin could inhibit HER2 expression by suppression of NF-κB activation.

MTT detection and AnnexinV-FITC/PI double fluorescence staining showed that mollugin inhibited the proliferation and induced apoptosis of nasopharyngeal carcinoma (NPC) cells. Western blotting indicated that the molecular mechanism of mollugin against NPC was related to the regulation of the expression of Survivin and XIAP.

Extracts of Rubia cordifolia significantly inhibited the incorporation of [3H]-thymidine, induced by fetal bovine serum, in a dose-dependent manner. They also inhibited the PMA-induced expression of c-fos genes in A-431 cells, suggesting that inhibition of DNA synthesis underlies the mechanism for its antiproliferative properties.

Topoisomerase Inhibition

Topoisomerase I and II inhibitory activities and cytotoxicities have been measured from constituents of the roots of Rubia cordifolia.

5. Scientific Evidence by Area of Health Use

5.1 Inflammation and Rheumatoid Arthritis

Preclinical evidence: Rubia cordifolia was studied for anti-inflammatory effect in rats with carrageenan paw edema. The plant showed significant anti-inflammatory activity at doses of 10 and 20 ml/kg of water extracts. The activity was comparable to that of phenylbutazone (100 mg/kg).

Results indicated that the ethanol extract of Rubia cordifolia (RCE) suppressed foot swelling and alleviated joint damage, and also had anti-inflammatory properties by inhibiting the expression of tumor necrosis factor and other inflammatory markers in an adjuvant-induced arthritis rat model.

The effect of purpurin on inflammation was investigated using macrophage RAW264.7 inflammatory cells induced by lipopolysaccharide (LPS), and an adjuvant-induced arthritis (AIA) rat model was established to explore the effect of purpurin on joint damage and immune disorders. Purpurin obviously improved joint injury and reduced toxicity in the liver and spleen and regulated the level of FOXP3 and CD4+/CD8+. Furthermore, purpurin reduced the MMP3 content of AIA rats.

Clinical evidence: Direct human clinical trials isolating R. cordifolia as a monotherapy for rheumatoid arthritis are largely absent in the peer-reviewed literature. The ancient Indian Ayurvedic medicinal system uses herbomineral drugs to treat arthritis, but despite centuries of use, very few have been tested by formal drug trials. The available data remain preclinical.

5.2 Anticancer Activity

Preclinical evidence (in vitro and in vivo): Isolated compounds from R. cordifolia root (alizarin, purpurin, emodin, and cyclic hexapeptides) were tested against a panel of luciferase reporter genes that assesses the activity of a wide range of cancer-related signaling pathways.

In macrophage culture assays, bioassay-guided fractionation yielded 1-hydroxytectoquinone from R. cordifolia; anti-inflammatory activity was tested through the carrageenan-induced rat-paw edema model, and the compounds were then tested against murine tumors (Ehrlich ascites carcinoma) and three human cancer cell lines: A375 (malignant skin melanoma), Hep2 (epidermoid laryngeal carcinoma), and U937 (lymphoma).

Clinical evidence for RA-700: The maximum tolerated dose of RA-700, an antitumor compound from R. cordifolia, was established at 1.4 mg/M² in clinical trials. RA-700 inhibited Lewis tumor growth in the early stage after tumor implantation. However, the evidence from RA-700 clinical work is limited; no published randomized controlled trials in oncology patients using R. cordifolia extract as a primary treatment were identified in peer-reviewed sources as of the latest reviews.

Most studies are preclinical. The pharmacological mechanism of R. cordifolia has not been thoroughly studied. Findings suggest that R. cordifolia and its ingredients may be clinically useful as anti-cancer agents, but the in vivo activities against cancers should be explored further using cancer animal models before clinical translation.

5.3 Antimicrobial Activity

R. cordifolia was found to be more specific towards gram-positive strains, although gram-negative P. aeruginosa was also inhibited by the methanol extracts in a dose-dependent manner. R. cordifolia was significantly active against B. subtilis and S. aureus compared with streptomycin and penicillin G used as standards.

Extract of R. cordifolia showed a significant inhibitory activity against Propionibacterium acnes standardized culture. These findings are entirely preclinical (in vitro). No published human trials of R. cordifolia for infectious disease were identified.

5.4 Skin Disorders and Dermatology

Rubia cordifolia is a medicinal herb with anti-inflammatory activity. The key active ingredients of R. cordifolia responsible for its antipsoriatic activity and the underlying mechanisms are not fully understood. Studies have been designed to investigate the anti-inflammatory activity of quinones in R. cordifolia against psoriasis.

It offers potential benefits for the cosmetic industry due to its antioxidant (bioflavonoid) properties for protecting skin from damage, anti-inflammatory effects (purpurin) for soothing and calming irritated skin, and skin-brightening qualities (anthraquinones) promoting an even complexion.

Evidence for dermatological applications in humans is largely traditional or derives from in vitro investigations. Well-controlled clinical trials of R. cordifolia in skin conditions (acne, eczema, psoriasis) as a standalone therapy are not reported in the peer-reviewed literature identified by this review.

5.5 Anti-diarrheal and Gastrointestinal Activity

An aqueous extract of the aerial part of R. cordifolia delayed the onset of semi-solid feces, reduced the evacuation index in senna leaf-induced diarrhea in mice, and inhibited propulsive movement in castor oil-induced intestinal transit but not in the normal intestinal transit test. The results were compared with the standard anti-diarrheal drug loperamide. Oral treatment also significantly decreased macroscopic damage area, improved microscopic structure, and reduced malondialdehyde (MDA) content, IL-1β, and TNF-α levels in colonic tissue compared with the TNBS control group in rats. These findings are preclinical (rodent models).

5.6 Antioxidant and Immunomodulatory Activity

Modern pharmacological studies have revealed that R. cordifolia and its derived components have anti-tumor, anti-oxidative, anti-platelet aggregation, and anti-inflammatory effects.

In a preclinical antioxidant study, ethanol-treated rats (2 g/kg of 20% w/v, orally, daily for four weeks) concurrently received either R. cordifolia extract (RC) or a combination of vitamin E and C (each 100 mg/kg, orally). Parameters including phagocytosis, total leukocyte count, humoral and cell-mediated immune responses, lipid peroxidation, reduced glutathione content, superoxide dismutase, and catalase activities were assessed. Chronic ethanol administration decreased the humoral and cell-mediated immune response, phagocytosis, phagocytosis index, total leukocyte count, reduced glutathione, catalase, and superoxide dismutase activities, and increased lipid peroxidation. RC treatment countered these changes, with effects comparable to the vitamin combination.

5.7 Neuroprotection

Mollugin has a variety of pharmacological effects, including neuroprotective, anti-inflammatory, anticancer, and antiviral effects. Anti-inflammatory, anti-mutagenic, anti-cancer, anti-microbial, and neuroprotective potential have been reported for its main constituent purpurin, based on results from both in vitro and in vivo experiments in rodents. No human clinical trials of R. cordifolia for neurological conditions were identified.

6. Body Systems Associated with Rubia cordifolia

• Hematological / Circulatory system: Traditionally used as a blood purifier, hemostatic agent, and to activate blood circulation and dissolve blood stasis.
• Dermatological system: Used topically and internally for skin diseases, acne, eczema, and wound healing. Purpurin and anthraquinones studied for anti-psoriatic and skin-brightening activities.
• Musculoskeletal / Immune system: Used for rheumatism, joint pain, and arthritis; studied for anti-inflammatory and immunomodulatory effects.
• Gastrointestinal system: Traditionally used for diarrhea and dysentery; preclinical evidence of anti-diarrheal and anti-colitic activity.
• Oncology: Constituents studied in vitro and in some animal models for antitumor activity; RA-700 evaluated in early-phase clinical studies.
• Reproductive and gynecological system: Traditionally used for amenorrhea, dysmenorrhea, and gynecological imbalances.
• Urinary system: Traditional use for urinary tract disorders and as an ingredient in polyherbal formulations for urolithiasis.
• Neurological system: Preclinical neuroprotective activity of mollugin and purpurin in rodent models.

7. Dosage Forms and Reported Study Dosages

From classical pharmacognosy sources: powdered root 1–3 g; decoction 56–112 ml. In animal studies, Rubia cordifolia at 100–300 mg/kg (oral) showed significant (p<0.05) reduction in paw edema produced by carrageenan.

For the cyclic hexapeptide antitumor fraction, the maximum tolerated dose of RA-700 was established at 1.4 mg/M² in clinical trials.

Research has found that R. cordifolia grows better in sunny environments and that triennial plants have better biomass and higher concentrations of the primary components purpurin and mollugin compared to biennial plants. This has implications for the consistency of the active constituent content in commercial preparations.

8. Safety Considerations

General Safety Status

There are few pharmacokinetic and toxicity studies of R. cordifolia; therefore, the clinical safety data for R. cordifolia is lacking. Its toxic dose cannot be determined by animal toxicity studies alone, and clinical trials are needed to evaluate its safety in humans.

Genotoxicity and Carcinogenicity Concerns: The Lucidin Question

Lucidin is a genotoxic and mutagenic hydroxyanthraquinone that has been identified primarily in Rubia tinctorum L. (European or common madder root). It reacts with exocyclic amino groups of DNA nucleobases and forms adducts/lesions leading to carcinogenesis.

Madder color (MC), a food coloring extracted from roots of Rubia tinctorum L., has been proven to exert carcinogenicity in the rat kidney and liver. Furthermore, it induces DNA adducts in the kidney, liver, and colon. MC is composed of anthraquinones such as lucidin-3-O-primeveroside and alizarin.

In a rat medium-term multi-organ carcinogenesis bioassay, male rats were fed a diet containing either 0.008% or 0.04% alizarin or rubiadin. Treatment with 0.04% rubiadin significantly increased atypical renal tubules/hyperplasias and induced renal cell adenomas and carcinomas. Renal cell tumors were also increased with 0.04% alizarin, although at lower incidence than with rubiadin.

An important distinction: purpurin (1,2,4-trihydroxyanthraquinone) is a minor component in European madder (Rubia tinctorum) roots, but is the main dye (along with munjistin) extracted from Indian madder (Rubia cordifolia). Lucidin, the primary genotoxic concern, is associated with Rubia tinctorum. However, anthraquinones from the Rubia genus exhibited potential genotoxicity by implanting into the DNA of Escherichia coli, blocking gene expression and inducing cell death. The genotoxic activity of lucidin was tested in a battery of short-term tests. The compound was mutagenic in five Salmonella typhimurium strains without metabolic activation, and its mutagenicity was increased after addition of rat liver S9 mix. In V79 cells, lucidin was mutagenic at the hypoxanthine-guanine phosphoribosyl transferase gene locus and active in inducing DNA single-strand breaks and DNA-protein cross-links.

Researchers note that the presence of purpurin in bacterial mutagenicity assays was found responsible for a marked inhibition of mutagenicity induced by food-derived heterocyclic amines, and four anthraquinone pigments, among them alizarin and purpurin, showed significant antigenotoxic activities on DNA damage induced by carcinogens in Drosophila. This illustrates a complex, dual profile: certain anthraquinones appear antimutagenic at low concentrations, while high-dose and long-term exposure raises carcinogenicity concerns.

Lack of Human Pharmacokinetic Data

Most studies are preclinical. The pharmacological mechanism of R. cordifolia has not been thoroughly studied. In addition, there are few pharmacokinetic and toxicity studies, therefore the clinical safety data for R. cordifolia is lacking.

Urine Discoloration

The anthraquinone pigments, particularly purpurin and alizarin, are known to impart a red or orange color to urine following ingestion. Roots of madder and extracts thereof have been used as a food colorant and red or yellow clothing dye since ancient times. This chromogenic property of the root's anthraquinones means that urinary discoloration may be observed in users and is a known effect rather than a pathological finding.

Pregnancy

Traditional Ayurvedic sources note that use during pregnancy warrants particular caution due to the plant's historical use for menstrual regulation and its emmenagogue properties. No adequate human safety data for pregnancy is available in the peer-reviewed literature identified.

Quality and Adulteration

The Chinese Pharmacopoeia requires that the contents of purpurin and mollugin be up to standard before products can be used as medicines; however, the products of R. cordifolia on the market are uneven, and improving quality during cultivation has been identified as a problem.

9. Summary of Evidence Strength

R. cordifolia has multiple pharmacological activities, including neuroprotective, anti-tumor, antibacterial, anti-inflammatory, anti-oxidant, and immunosuppressive effects. However, the vast majority of this evidence derives from in vitro cell studies and rodent models. Most studies are preclinical. Human clinical trials are sparse: one early-phase clinical study of the isolated compound RA-700 (a cyclic hexapeptide) established a maximum tolerated dose, and some Ayurvedic polyherbal formulations containing R. cordifolia have been studied, but rigorous randomized controlled trials of R. cordifolia as a standalone intervention in human subjects are largely absent from the published literature. The mode of action of the exhaustive list of compounds has not been elucidated completely, as many compounds are solvent-specific and are not available in large quantities. Quantified research directing the therapeutic usage of specific extraction solvents for different plant organs is still lacking.

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