Cyanthillium cinereum (Little Ironweed): A Comprehensive Reference
1. Identity, Taxonomy, and Nomenclature
1.1 Accepted Scientific Name and Taxonomic History
Cyanthillium cinereum (L.) H. Rob., commonly known as little ironweed or ash-colored fleabane, is a species of flowering plant in the family Asteraceae. The genus name Cyanthillium is derived from the Greek kyanos (blue) combined with ilium (flank), alluding to the purplish margins of the involucral bracts. The specific epithet cinereum originates from the Latin cinereus, meaning ash-gray, describing the grayish pubescence covering the leaves and stems of the plant.
The species was first described by Carl Linnaeus as Conyza cinerea in Species Plantarum in 1753. It was subsequently transferred to the genus Vernonia by Christian Friedrich Lessing in 1829, becoming Vernonia cinerea. In 1990, Harold E. Robinson reassigned it to the newly recognized genus Cyanthillium in Proceedings of the Biological Society of Washington, volume 103. The species has accumulated over 20 junior synonyms, reflecting its complex taxonomic history and variable morphology across regions.
A critically important note for researchers: taxonomic confusion is widespread in the literature; IPNI lists Cyanthillium cinereum and Vernonia cinerea as totally different plants, while The Plant List lists Cyanthillium cinereum as a synonym of Vernonia betonicaefolia. Because no plant name database has been found that indicates Vernonia cinerea as a synonym of Cyanthillium cinereum, it is very likely that studies citing the folk uses of Cyanthillium cinereum may in fact be associated with Vernonia cinerea and not Vernonia betonicaefolia. Despite this, the 2024 MDPI review treated the two names as synonymous: Vernonia cinerea (L.) Less. has the synonym Cyanthillium cinereum (L.) H. Rob. and is usually known as "Sahadevi" in Indian or "Bach dau ong" in Vietnamese traditional medicine. Throughout the scientific literature — including clinical trials — the names Vernonia cinerea and Cyanthillium cinereum are used interchangeably, and this article follows that convention while acknowledging the nomenclatural uncertainty.
1.2 Common Names
Common names include ash-colored fleabane and common vernonia; kuksim (Bangladesh); kbal ruy (Cambodia); cenderong hari, concong hari, bujong semalam (Malaysia); devida, sahadevi, naichottepoonde, uttamkanyaka (India); lidah anjing (Indonesia); yambaru higotai (Japan); nya phaen din yen (Laos); byaing-chay-pin (Myanmar); agas moro (Philippines); yaa-saam-wan (Thailand); bach dau ong (Vietnam). It is also known as poovamkurunnal or poovamkurunnila in Malayalam, and monara kudumbiya in Sinhalese.
1.3 Botanical Description and Distribution
Cyanthillium cinereum is an annual herb up to 120 cm tall. It produces flat-topped arrays of numerous flower heads, each with pinkish or purplish disc florets but no ray florets. It usually flowers and fruits as an herb but can grow to about 1 m tall and resemble a shrub. Leaves, stems, and petioles are covered with woolly hairs; leaves are alternate, between 3–4 cm long and 1.5–3 cm wide, tapering gradually into a short petiole; each flower head contains 20–30 flowers approximately 5 mm long.
The species is native to tropical Africa and tropical Asia (India, Sri Lanka, Indochina, Indonesia, etc.) and has become naturalized in Australia, Mesoamerica, tropical South America, the West Indies, and the US State of Florida. It is an annual or perennial and grows primarily in the seasonally dry tropical biome. C. cinereum commonly occurs in upland crop areas, gardens, waste places, and along roadsides.
1.4 Common Preparations and Dosage Forms
The plant is harvested from the wild for local use as a food and medicine. Traditional preparations described in ethnobotanical literature include whole-plant decoctions (kashayam), leaf infusions, seed oil, root pastes, and flower-derived poultices. In clinical research settings, the plant has been evaluated as a standardized herbal tea infusion (infusion bag), pastilles, and lozenges. In one clinical trial, 3 grams of crushed dried whole plant of V. cinerea was prepared in an infusion tea bag; sixty-four subjects were equally randomized to receive the 14-day tea taken three times daily or placebo. In another trial, the V. cinerea group received two pastilles three times daily. A multicenter trial assigned patients to take one lozenge three times a day for three months. C. cinereum is the herbal tea specified in the Thai National List of Essential (Herbal) Medicines as the most efficacious tea for smoking cessation; however, herbal tea is noted to be inconvenient, and no standardized extraction method was known at the time of the review.
2. Traditional and Historical Use
2.1 Ayurveda (India)
In its ethnobotanical applications, V. cinerea is one of the most widely used species of the Vernonia genus, with a long history of traditional usage in Ayurveda, traditional Asian medicine, and Western herbalism. Ayurveda was developed approximately 6,000 years ago in India and is considered the earliest record of scientific medicine. In the Ayurvedic Pharmacopoeia of India, V. cinerea is commonly called "Sahadevi." Sahadevi has been widely utilized for collyrium preparation since ancient times.
The plant has great medicinal value in diverse traditional usage in different nations and is recognized in the Ayurvedas. The whole plant is used in decoction or infusion to treat fever. It provides remedy for spasms of the urinary bladder and strangury, and is often combined with quinine to treat malaria. The seeds are used as a source of alexipharmic and anthelmintic drugs, and as an alterative in leprosy and chronic skin diseases. Leaves have analgesic, antipyretic, and anti-inflammatory effects. Paste of stem/bark is used to heal cuts, while flowers are traditionally used to treat conjunctivitis, arthritis, and rheumatism. Root infusion is used as an antidote to scorpion sting and snake venom.
Cyanthillium cinereum, known as Sahadevi in Ayurveda, is used traditionally to treat fevers, colds, and urinary disorders, as well as for its anti-inflammatory effects through decoctions of the whole plant. Various parts of the plant, including leaves, roots, seeds, and flowers, are employed; seed oil addresses skin ailments, while root paste is applied topically for wound healing.
2.2 Traditional Thai Medicine
The plant holds cultural significance in Indian, Thai, and African folk medicine. In Thai traditional practices, it is known as Ya Dok Khao and brewed into teas for pain relief and diuresis. Thailand is well known for the traditional application of aerial-parts extracts of C. cinereum for immune-related remedies and anti-inflammation. The plant has been used for smoking cessation in Thailand and other countries, and as relief for the common cold. It has been included in Thailand's National List of Essential Medicines since 2012 for smoking cessation.
2.3 Traditional Southeast Asian and African Use
A decoction is used in some traditions to treat kidney disorders, swellings, inflammation, lower abdominal pains, and menstrual pains; also to expel the placenta and as an abortifacient. It is considered a more potent abortifacient and better treatment for menstrual pains when combined with Justicia secunda. An infusion of the leaves combined with Stachytarpheta jamaicensis is used for treating albuminuria and sprains. A poultice of the leaves is applied to the forehead in the treatment of headaches.
Among the Subanen healers of the Philippines, pounded leaves are applied to venomous bites, and the whole plant boiled in water is drunk three times a day for cough.
Vernonia cinerea is reportedly used in folk medicine in East and West Africa as well as in India and South America. There are cross-continental similarities in some of the uses, especially against ailments such as malaria, infertility, skin conditions, and worms. In Madagascan folk medicine, it is used as a febrifuge.
2.4 Siddha Medicine (India)
In the Siddha system of medicine, an Indian traditional medical system, physicians use Vernonia cinerea whole-plant kashayam (crude aqueous extract) to reverse metal-related toxic effects during metal-based therapies.
2.5 Broader Ethnobotanical Record
Cyanthillium cinereum has documented therapeutic uses in traditional contexts against asthma, cancer, cholera, colic pain, cough, diarrhea, dysentery, impotency, and night-blindness. Known as "Sahadevi," "Naichette," or "Mukuthipundu" in India, in folklore medicine it is used in malaria, fever, gastrointestinal tract worms, pain, inflammation, and nervous disorders. This species has also been claimed to have antidepressant action.
3. Key Phytochemical Constituents and Active Compounds
3.1 Overview of Phytochemical Classes
Studies on phytochemical constituents of C. cinereum have shown the presence of glycosides, flavonoids, aliphatic acids, terpenoids, sterols, saponins, tannins, fatty oils, triterpenoids, alkaloids, esters, and sesquiterpenes on extraction with different solvents. Analysis of phytochemicals revealed the presence of steroids, alkaloids, flavonoids, phenols, cardiac glycosides, saponins, phlorotannins, and tannins.
3.2 Sesquiterpene Lactones
Previous phytochemical investigations on C. cinereum have revealed the existence of sesquiterpenoids, triterpenoids, flavonoids, and steroids. Among them, hirsutinolide-type sesquiterpenoids are the most characteristic components of the genus Cyanthillium, and they have shown promising biological activities including anti-cancer, anti-inflammatory, and anti-parasitic effects.
At least 34 sesquiterpene lactones from the Vernonia genus have been reported to possess anticancer and other biological activities including antimalarial, antibiotic, antileishmania, antioxidant, anti-inflammatory, anti-platelet, and insecticidal activities. Notable among these with anticancer activity is Vernolide-A.
Flavonoids and the sesquiterpene vernolide-A are considered the principal bioactive compounds of V. cinerea. The potential sesquiterpene lactone groups from the Vernonia genus — namely vernolide-A, vernolide-B, and vernodalin — have been reported for anticancer effects by downregulating cancer promoter proteins. Vernolide-A, vernolide-B, and vernodalin are predicted to have the most selective and attractive interactions with candidate target proteins such as p38α, PGEP2R, and HSP90α, respectively.
3.3 Major Identifiable Phytoconstituents
The major phytoconstituents present in the ethanolic extract of C. cinereum are lupeol, lupeol acetate, luteolin-7-O-glucoside, stigmasterol-β-D-glucopyranoside, stigmasterol, and dotriacontanoic acid, along with several other minor phytochemicals. The plant has also been reported to contain luteolin 7 mono beta-D-glucopyranoside and triterpene compounds such as lupeol acetate and beta-amyrin acetate.
The majority of characterized compounds are sesquiterpene lactones, but triterpenes, flavonoids, steroids, phenolics, and other compounds are present as well.
3.4 Presence of Nicotine
The leaves of V. cinerea have been reported to contain nicotine. This finding is of particular relevance to the plant's proposed mechanism of action in smoking cessation applications (see Section 5.1).
3.5 Essential Oil Composition
Studies aimed at investigating the therapeutic potential of polar (methanolic and aqueous) and nonpolar (hexane and chloroform) crude extracts of the whole plant have examined multiple parameters including free-radical scavenging (DPPH•, ABTS•+, H₂O₂, and •OH), reducing power, protection of DNA against oxidative damage, cytotoxicity, inhibition of oxidative hemolysis in erythrocytes, total phenolic content, and inhibition of lipid peroxidation.
4. Pharmacological Mechanisms of Action
4.1 Antioxidant and Free-Radical Scavenging
All free-radical generating assay models demonstrated positive scavenging efficiency with differential but considerable magnitudes for the four extract types. Only the hexane extract showed significant H₂O₂ scavenging effect. Lipid peroxidation estimated by thiobarbituric acid-malondialdehyde (MDA) reaction showed a high degree of inhibition for all extracts. C. cinereum has shown antioxidant protective effects against oxidative damage to biological molecules such as lipids and DNA. Extracts of C. cinereum could sustain equilibrium between free radicals and antioxidant systems, inhibiting the oxidative damage cascade in cells.
4.2 Anti-inflammatory Mechanisms
The alcoholic extract of the flowers of C. cinereum caused a reversal of the inflammatory processes in adjuvant arthritic rats. Leaf extracts have been reported with significant analgesic, anti-inflammatory, and antipyretic properties.
4.3 Monoamine Oxidase (MAO) Inhibition — Smoking Cessation
It relieves nicotine addiction by inhibiting monoamine oxidase (MAO). This mechanism, combined with the plant's reported endogenous nicotine content, is hypothesized to underlie its utility as a smoking cessation aid.
4.4 Immunomodulatory Effects
The levels of IFN-γ, IL-2, and GM-CSF were significantly increased by V. cinerea extract. The level of TNF-α was reduced by V. cinerea extract administration in immunosuppressed mice. These results demonstrate that V. cinerea has an ameliorating effect on cyclophosphamide-induced immunosuppression in animal models.
4.5 Anticancer Mechanisms
Vernolide-A, a sesquiterpene lactone from Vernonia cinerea, induces apoptosis in B16F-10 melanoma cells by modulating p53 and caspase-3 gene expressions and regulating NF-κB-mediated bcl-2 activation. The inhibition of multi-drug resistance transporters or drug efflux pump and STAT3-STAT2 phosphorylation has been mentioned as an interesting mechanism. V. cinerea possesses both cytotoxic and antimetastatic effects on lung cancer cells.
4.6 Nephroprotective Mechanism
Petroleum ether, ethyl acetate, and alcoholic extracts from the aerial parts of V. cinerea (500 mg/kg, oral) have a protective effect on cisplatin-induced nephrotoxicity in albino rats without any deteriorative effects on the kidney. Pretreatment with V. cinerea extract decreased blood urea nitrogen, serum creatinine, serum total proteins, and urinary proteins in vivo.
5. Scientific Evidence by Area of Use
5.1 Smoking Cessation
This is the best-studied clinical application of the plant and the one for which human trial data are most available.
Systematic Reviews and Meta-Analyses:
Several randomized controlled trials have investigated V. cinerea for smoking cessation, but there remained no critical summary of overall findings until a systematic review and meta-analysis was conducted, searching nine databases through November 2017. Randomized controlled trials reporting the smoking cessation effect of V. cinerea were included. Estimates of pooled effects were calculated as relative risk with 95% CI using a random-effects model. Five trials with 347 smokers were included. That meta-analysis demonstrated that V. cinerea has potential efficacy for smoking cessation, but concluded that further well-designed RCTs of standardized V. cinerea compared with standard treatment should be conducted to strengthen this evidence.
The V. cinerea treatment group was associated with a significantly higher cessation rate than the control group, with no evidence of heterogeneity for both continuous abstinence rate (CAR) (week 8 risk ratio [RR]: 1.69, 95% CI [1.00, 2.86]; week 12 RR: 2.18, 95% CI [1.17, 4.04]).
Individual Randomized Controlled Trials:
A 24-week, randomized, single-blind, placebo-controlled, parallel trial was conducted at an outpatient smoking cessation clinic at Thanyarak Institute, Pathumthani, Thailand. A 3-gram dose of crushed dried whole plant was prepared in infusion tea bags. Sixty-four subjects were equally randomized to receive a 14-day tea taken three times daily or placebo. Primary outcomes were continuous abstinence rate (CAR) and the 7-day point prevalence abstinence rate (PAR), confirmed by urine cotinine.
A randomized double-blinded controlled trial was conducted at a community pharmacy among subjects aged 18–60 years with intention to quit smoking and low to moderate level of nicotine addiction. Previous studies examining four-to-eight-week treatments using V. cinerea had found it to be ineffective; this study aimed to evaluate smoking cessation effects over a longer treatment duration with pastilles. The V. cinerea group received two pastilles three times daily; the control group received placebo for 12 weeks. Outcomes were CAR and point abstinence rate at 4 and 12 weeks. This study was reported as the first to show that V. cinerea is effective for smoking cessation.
A randomized, active-comparator, open-label trial compared V. cinerea with nortriptyline for smoking cessation. A total of 84 patients participated in the study, equally randomized with 42 participants in each group. Overall, there was no statistically significant difference in CAR between the V. cinerea and nortriptyline groups (Odds ratio 0.68, 95% CI 0.25–1.85, P = 0.451). After week 12, CAR between both groups was not different (44.44% vs. 45.95%). After follow-up at week 24, CAR in both groups was not different (41.67% vs. 43.24%). Relapse rate between V. cinerea and nortriptyline groups was also not different (13.89% vs. 10.81%, P = 0.923).
A multicenter randomized, paralleled, double-blind, controlled trial (ClinicalTrials.gov NCT06268002) was conducted at five hospitals and two community pharmacies in Thailand between September 2017 and December 2021. Patients were assigned to either a Vernonia cinerea group (n = 130) or a placebo group (n = 130), both instructed to take one lozenge three times a day for three months. Both groups received individual counseling about smoking cessation techniques. The primary outcome was continuous abstinence rate defined as self-report of no cigarette smoking since target quit date, plus biochemical validation for 1 month.
Evidence Strength Assessment: The evidence for smoking cessation represents the strongest clinical evidence base for this plant. The pooled meta-analysis is encouraging, but individual trial results have been mixed, earlier short-duration trials found non-significant effects, and the evidence base remains limited by small sample sizes, variable dosage forms, and few well-standardized extracts. Several studies showed non-significant results on smoking cessation by V. cinerea. The evidence is therefore described as preliminary to moderate, with sufficient justification for Thailand's inclusion of the plant on its national essential medicines list, but insufficient for definitive conclusions pending larger, standardized trials.
5.2 Antimalarial and Antiparasitic Activity
Sesquiterpene lactones, which possess antimalarial activity, have been isolated from the plant. The plant is traditionally often combined with quinine to treat malaria. Sesquiterpene lactones with antimalarial activity have been isolated. The cited isolation study (Chea et al., 2006) isolated sesquiterpenes from Vernonia cinerea; it should be noted this work was conducted under the Vernonia cinerea name, not Cyanthillium cinereum specifically. All available antimalarial evidence is preclinical (in vitro and animal models); no human clinical trials specifically for malaria have been identified in authoritative databases. Evidence is classified as very preliminary.
5.3 Anticancer Activity
The most in-depth studies on the pharmacology of this plant in the cancer context were carried out by Pratheeshkumar and Kuttan (2009–2012), evaluating both the crude extract and the sesquiterpene vernolide-A, focusing on the possible cytotoxic effect on cancer cells.
In a bioassay-guided fractionation of ethanol extract, vernolide-A was isolated as an active principle with anticancer activity. Vernolide-A inhibited lung metastasis of melanoma cells in mice and increased the animals' life span. The inhibitory effect of vernolide-A (C₂₁H₂₈O₇) on lung metastasis induced by B16F-10 melanoma cells was studied using C57BL/6 mice. Vernolide-A was administered in three modalities: simultaneously with tumor, prophylactically to tumor, and after tumor development. Maximum inhibition in metastasis was observed when vernolide-A was administered simultaneously with tumor. There was 89.39% inhibition of lung tumor nodule formation and 88.51% increase in the life span of metastatic tumor-bearing animals. These are preclinical (animal model) findings.
In vitro studies of VC ethanol extract exhibited cytotoxicity to both colorectal cancer cell lines tested. Sesquiterpene lactone, especially vernolide-A, may be one of the bioactive compounds active against cancer cells that is better extracted by ethanol. Suitable concentrations of VC-EtOH extract (25–50 μg/mL) were suggested for use in future in vivo studies and pharmaceutical development.
Hirsutinolide-type sesquiterpenoids from Cyanthillium cinereum specifically have shown anti-prostate cancer activity in prior studies. In a study assessing the effect of V. cinerea on mice infected with several cancer types, after receiving 2000 mg/kg BW of crude extract, the animals did not exhibit any toxic symptoms or death, living for up to 14 days.
Evidence Strength: All anticancer evidence for Cyanthillium cinereum is currently in vitro and animal-based only. No human clinical trials for cancer treatment have been identified. The mechanistic work with vernolide-A and hirsutinolide-type sesquiterpenoids is scientifically interesting but translational gaps remain large. Evidence is classified as very preliminary.
5.4 Anti-inflammatory and Antipyretic Activity
The alcoholic extract of flowers of C. cinereum caused a reversal of inflammatory processes in adjuvant arthritic rats. Leaf extracts have been reported with significant analgesic, anti-inflammatory, and antipyretic properties. These studies are preclinical animal models. No human clinical trials specifically for inflammation or fever reduction have been identified in authoritative databases for this plant alone. Evidence is in vitro/animal only and classified as very preliminary.
5.5 Antioxidant Activity
Whole-plant hexane, chloroform, methanolic, and aqueous crude extracts bear potent antioxidant properties. Furthermore, C. cinereum has shown antioxidant protective effects against oxidative damage to biological molecules such as lipids and DNA. Flavonoids and phenols, recognized for their potent antioxidant properties, play a significant role and are identified in this plant. All such evidence is in vitro; evidence strength is very preliminary with respect to human health outcomes.
5.6 Renoprotective (Kidney-Protective) Activity
Petroleum ether, ethyl acetate, and alcoholic extracts from aerial parts of V. cinerea (500 mg/kg oral) have demonstrated a protective effect on cisplatin-induced nephrotoxicity in albino rats without any deteriorative effects on the kidney. Pretreatment with V. cinerea extract decreased blood urea nitrogen, serum creatinine, serum total proteins, and urinary proteins in vivo.
Cyanthillium cinereum is also an ingredient in the commercial polyherbal Ayurvedic formula Cystone. Cystone is a marketed polyherbal Ayurvedic antiurolithic medicine whose ingredient list includes Cyanthillium cinereum (L.) H. Rob. (whole plant). This polyherbal formula preparation has been validated as an antiurolithic medicine in experimental animal models. In rats, oral Cystone treatment at 250, 500, and 750 mg/kg b.w. for 42 days revealed a dose-related effect in the reduction of lithogenic substances following glycolic acid–induced urolithiasis; the 500 and 750 mg/kg b.w. doses showed better protective effects.
The renoprotective evidence is animal-based for C. cinereum extracts in isolation; the Cystone polyherbal product has been evaluated in human subjects, but the contribution of C. cinereum specifically cannot be isolated from that combination formula. Overall renoprotective evidence strength for the standalone plant in humans is very preliminary.
5.7 Antimicrobial and Antibacterial Activity
A wide range of pharmacological activities — including antioxidant, antibacterial, antifungal, anti-inflammatory, hepatoprotective, cardiovascular, antidepressant, antidiarrheal, hypolipidemic, diuretic, and hypoglycemic actions — have been ascribed to various parts of C. cinereum. All available evidence for antimicrobial activity is in vitro. Evidence strength is very preliminary.
5.8 Antiepileptic Activity
Investigations into the anti-epileptic activity of Cyanthillium cinereum leaves against pentylenetetrazole (PTZ)-induced epileptic models in mice found that, amongst all extracts tested, only the ethanol extract significantly (p < 0.05) inhibited generalized tonic-clonic seizures in PTZ-induced epilepsy in a dose-dependent manner (100 or 200 mg/kg, p.o.). This evidence is animal-based only and classified as very preliminary.
5.9 Hepatoprotective Activity
The liver is the principal organ involved in the metabolism of drugs and hazardous chemicals. Carbon tetrachloride (CCl₄), a strongly hepatotoxic chemical capable of inducing both acute and chronic liver injury in animals, has been employed to induce hepatic necrosis. Animals exposed to CCl₄ display elevated levels of liver marker enzymes in their serum, thus indicating hepatic cell damage. Acute toxicity induced by CCl₄ results in enhanced cellular leakage and increased permeability of hepatocyte membranes. However, elevated activities of liver marker enzymes were suppressed by V. cinerea extract. This hepatoprotective evidence is animal-based. Evidence strength is very preliminary.
6. Body Systems and Health Areas Associated with the Plant
- Respiratory system: Traditional use for cough, asthma, cold; in vitro evidence for anti-inflammatory effects in airway cells (smokers' lozenge clinical trials).
- Nervous system / addiction medicine: Smoking cessation via proposed MAO inhibition; clinical trial evidence (moderate, mixed).
- Immune and inflammatory system: Anti-inflammatory and antipyretic effects in animal models; immunomodulation in cyclophosphamide-treated animals.
- Oncology (pre-clinical): Cytotoxic sesquiterpene lactones; in vitro and animal anticancer data.
- Urinary/renal system: Traditional use for urinary disorders; animal evidence for nephroprotection; ingredient in clinical polyherbal urolithiasis formula (Cystone).
- Gastrointestinal system: Traditional use for diarrhea, dysentery, colic pain, worm infestations.
- Skin and wound healing: Traditional topical use; seed oil for skin ailments; paste for wound healing.
- Liver (hepatic system): Animal-model hepatoprotective activity; traditional use for liver diseases.
- Infectious diseases / parasitology: Traditional and in vitro evidence for antimalarial and antimicrobial effects.
- Reproductive system: Traditional use in menstrual complaints and as an abortifacient in some cultures.
- Neurology/psychiatry: Claimed antidepressant action (evidence very limited); animal antiepileptic data.
7. Dosage Forms and Reported Study Dosages
The following dosages are reported exactly as stated in source documents. They represent study-specific protocols, not clinical recommendations.
- Herbal infusion (tea): 3 grams of crushed dried whole plant prepared in an infusion tea bag, taken three times daily for 14 days (randomized controlled trial, Thailand).
- Pastilles: Two pastilles three times daily for 12 weeks (randomized double-blinded controlled trial, community pharmacy setting).
- Lozenges: One lozenge three times a day for three months (multicenter RCT, NCT06268002).
- Animal study (nephroprotection): Petroleum ether, ethyl acetate, and alcoholic extracts at 500 mg/kg oral dose in albino rats.
- Animal study (antiepileptic): Ethanol extract at 100 or 200 mg/kg (p.o.) in mice.
- In vitro (colorectal cancer cells): VC-EtOH extract at 25–50 μg/mL.
- Animal Cystone study (urolithiasis): The polyherbal Cystone formulation at 250, 500, and 750 mg/kg b.w. orally for 42 days in rats.
8. Safety Considerations and Known Interactions
8.1 Acute Toxicity
A toxicity study of the methanol extract of Vernonia cinerea found no apparent toxicity. In an acute toxicity study using mice, the median lethal dose (LD₅₀) of the extract was greater than 2000 mg/kg, and no pathological changes were found in macroscopic examination by necropsy. Brine shrimp test LC₅₀ values were 3.87 mg/mL (at 6 hours) and 2.72 mg/mL (at 24 hours), exhibiting no significant toxicity. In conclusion, the methanol extract did not produce toxic effects in mice and brine shrimp.
In a study assessing the effect of V. cinerea on mice infected with several cancer types, after receiving 2000 mg/kg BW of crude extract, the animals did not exhibit any toxic symptoms or death, living for up to 14 days.
8.2 In Vitro Cytotoxicity
Cyanthillium cinereum has been reported to have very low cytotoxic effects and also has potential to serve as a good anti-inflammatory and antioxidant agent.
8.3 Hepatotoxicity and Nephrotoxicity Concerns
Studies have examined hepatotoxic and nephrotoxic effects of chronic exposure to Vernonia cinerea crude extract on Wistar rats. The specific results of this chronic toxicity study in rats were not fully retrievable in publicly available sources during research for this article, but the existence of such safety research indicates that chronic exposure considerations have been explored in preclinical models. Researchers and practitioners are directed to consult the primary literature directly.
8.4 Abortifacient Properties
A decoction is used in some traditional contexts as an abortifacient, and is considered a more potent abortifacient and better treatment for menstrual pains when combined with Justicia secunda. This traditional use has documented pharmacological plausibility and is a significant safety consideration for use during pregnancy.
8.5 Asteraceae Family Sensitization
As a member of the Asteraceae family, Cyanthillium cinereum carries the potential for cross-reactivity in individuals sensitized to other Asteraceae species (e.g., chamomile, ragweed, chrysanthemum). This is an established class-level consideration for all Asteraceae botanical products, though specific data for C. cinereum-specific allergic reactions was not retrieved from the searched sources.
8.6 Taxonomic Identification Concerns
A major identification problem exists in the literature: IPNI lists Cyanthillium cinereum and Vernonia cinerea as totally different plants. Because no plant name database has confirmed Vernonia cinerea as a synonym of Cyanthillium cinereum, it is very likely that some studies citing folk uses of Cyanthillium cinereum may in fact be associated with Vernonia cinerea and not Vernonia betonicaefolia. It is thus recommended that future studies on the species pay particular attention to its identification. This taxonomic ambiguity means that the safety profile established in studies conducted under the Vernonia cinerea name may not be fully applicable to a product labeled as Cyanthillium cinereum without careful botanical authentication.
8.7 Regulatory Status
Vernonia cinerea (L.) Less. — a synonym of Cyanthillium cinereum (L.) H. Rob. — is used in numerous traditional Thai medicines and for the cessation of smoking; Thailand's National List of Essential Herbal Drugs placed the whole plant extract under the indication for smoking cessation. This represents a formal regulatory recognition in Thailand. No equivalent formal listing was found for North American, European (EMA, EFSA), or WHO-level monograph recognition in available sources.
References
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