Arjunic Acid

Arjunic Acid at a Glance

Arjunic acid is a pentacyclic triterpene acid of the oleanane type (2α,3β,19α-trihydroxyolean-12-en-28-oic acid) isolated from the bark of arjuna (Terminalia arjuna), the tree whose bark has been used for centuries in Ayurvedic medicine as a cardiac tonic. Structurally it is a trihydroxylated cousin of oleanolic acid and a close relative of arjunolic acid, the better-studied arjuna triterpene.

Its clearest isolated-molecule signal is as an antioxidant: in cell-free and red-blood-cell assays purified arjunic acid scavenges free radicals more strongly than ascorbic acid ^{1Reference 1Sun FY et al. · 2008In vitroArjunic acid, a strong free radical scavenger from Terminalia arjuna — in vitro studyView study →}. It also protects cultured heart-muscle cells from oxidative/hypoxic injury ^{2Reference 2Manu TM et al. · 2019In vitroTerminalia arjuna extract and arjunic acid mitigate cobalt chloride-induced hypoxia stress-mediated apoptosis in H9c2 cells — in vitro cardiomyocyte studyView study →} and triggers apoptosis in several cancer cell lines ^{3,4Reference 3Joo H et al. · 2016In vitroc-Jun N-terminal kinase-dependent endoplasmic reticulum stress pathway is critically involved in arjunic acid induced apoptosis in non-small cell lung cancer cells — in vitro studyView study →Reference 4Saxena M et al. · 2007In vitroCytotoxic agents from Terminalia arjuna — in vitro studyView study →} — a plausible mechanistic bridge to arjuna’s traditional cardiac reputation and to the plant’s anticancer literature.

The honest caveat runs through the whole page: all of arjuna’s human evidence is for the whole bark, and all of arjunic acid’s own evidence is preclinical — in-vitro assays and cell models, never a controlled human trial of the isolate. Like its triterpene siblings, it is a large, poorly water-soluble acid with limited expected oral bioavailability, so in-vitro potency should not be read as an oral-dose effect.

Arjunic Acid Among the Arjuna Triterpenes

The cardioactive reputation of Terminalia arjuna bark rests on a small suite of oleanane-type triterpene acids, of which the two headline molecules are arjunic acid and arjunolic acid. Both are trihydroxy derivatives of oleanolic acid sharing the molecular formula C₃₀H₄₈O₅, and they are in fact positional isomers — arjunic acid carries its third hydroxyl at the 19α position (2α,3β,19α-trihydroxy), while arjunolic acid carries it at C-23 (2α,3β,23-trihydroxy) ^{10Reference 10Amalraj A · 2017ReviewMedicinal properties of Terminalia arjuna (Roxb.) Wight & Arn.: a reviewView study →}. Alongside them sit the aglycone arjungenin, the saponin glycosides arjunetin and arjunin, and the related triterpene terminic acid; quantitatively the whole triterpene fraction is minor, under ~1% of the bark ^{9,10Reference 9Kalola J · 2006Extraction and TLC densitometric determination of triterpenoid acids (arjungenin, arjunolic acid) from Terminalia arjuna stem bark without interference of tannins — analytical studyView study →Reference 10Amalraj A · 2017ReviewMedicinal properties of Terminalia arjuna (Roxb.) Wight & Arn.: a reviewView study →}.

Within that set, arjunolic acid is the more mechanistically developed molecule — a PPAR-α agonist with anti-fibrotic cardiac data — and it is the one most often carried forward as arjuna’s “active.” Arjunic acid is the quieter sibling: grouped with arjunolic acid in the plant’s cardioprotective mechanism tables, but studied in its own right mainly as an antioxidant, a cardiomyocyte protectant, and an anticancer cytotoxin ^{1,2,3,4Reference 1Sun FY et al. · 2008In vitroArjunic acid, a strong free radical scavenger from Terminalia arjuna — in vitro studyView study →Reference 2Manu TM et al. · 2019In vitroTerminalia arjuna extract and arjunic acid mitigate cobalt chloride-induced hypoxia stress-mediated apoptosis in H9c2 cells — in vitro cardiomyocyte studyView study →Reference 3Joo H et al. · 2016In vitroc-Jun N-terminal kinase-dependent endoplasmic reticulum stress pathway is critically involved in arjunic acid induced apoptosis in non-small cell lung cancer cells — in vitro studyView study →Reference 4Saxena M et al. · 2007In vitroCytotoxic agents from Terminalia arjuna — in vitro studyView study →}. No dedicated human trial of isolated arjunic acid exists, so its contribution to the whole-bark cardiac effect is inferred, not demonstrated. the remainder is about what the isolated molecule does — a distinct question from what arjuna bark does in people.

What It's Used For

Arjunic acid’s evidence is entirely preclinical, and it splits into a genuinely strong antioxidant signal, a cardiomyocyte-protective signal that connects it to arjuna’s traditional use, and an anticancer signal from cell-line work — each on the isolated molecule, none confirmed in humans.

Evidence by IndicationStrength of support · Beta

Support is an experimental score — weighted by study type (human > animal > in vitro) and volume. A beta, not a validated metric. Every row here is isolate in vitro, with no human or whole-animal isolate data, so scores stay modest by design.

01Antioxidant / Free-Radical ScavengingShaky40%Cell-free + RBC assays, isolate more potent than ascorbate ^{1,2Reference 1Sun FY et al. · 2008In vitroArjunic acid, a strong free radical scavenger from Terminalia arjuna — in vitro studyView study →Reference 2Manu TM et al. · 2019In vitroTerminalia arjuna extract and arjunic acid mitigate cobalt chloride-induced hypoxia stress-mediated apoptosis in H9c2 cells — in vitro cardiomyocyte studyView study →}

02Cardiomyocyte ProtectionShaky34%Isolate (+ extract) protects H9c2 cells from CoCl₂ hypoxia ^{2Reference 2Manu TM et al. · 2019In vitroTerminalia arjuna extract and arjunic acid mitigate cobalt chloride-induced hypoxia stress-mediated apoptosis in H9c2 cells — in vitro cardiomyocyte studyView study →}

03Anticancer / CytotoxicShaky30%Isolate apoptosis in NSCLC + oral/ovarian/liver lines ^{3,4Reference 3Joo H et al. · 2016In vitroc-Jun N-terminal kinase-dependent endoplasmic reticulum stress pathway is critically involved in arjunic acid induced apoptosis in non-small cell lung cancer cells — in vitro studyView study →Reference 4Saxena M et al. · 2007In vitroCytotoxic agents from Terminalia arjuna — in vitro studyView study →}

04AntimicrobialShaky24%Isolate from T. sericea; MIC 1.9–15.6 µg/mL in vitro ^{5Reference 5Eldeen IM et al. · 2008In vitroIsolation and biological activities of termilignan B and arjunic acid from Terminalia sericea roots — in vitro studyView study →}

05Metabolic / FXR AgonismShaky18%Molecular docking + adipocyte markers only ^{7Reference 7Manu Mohan T et al. · 2020In vitroIn-silico therapeutic investigations of arjunic acid and arjungenin as an FXR agonist and validation in 3T3-L1 adipocytes — in vitro/in silico studyView study →}

Mechanisms

The antioxidant → anti-apoptotic axis is the load-bearing story: the same free-radical-quenching chemistry that raises antioxidant enzymes and protects heart cells also underlies its apoptosis-tuning in cancer lines. Every entry is in-vitro.

Pharmacokinetics

There is no dedicated pharmacokinetic dataset for arjunic acid — no measured oral bioavailability, Cmax or half-life for the isolate. What can be said is structural: arjunic acid is a large, lipophilic, poorly water-soluble pentacyclic triterpene acid, the same physicochemical class as oleanolic acid and ursolic acid, whose oral bioavailabilities are very low (oleanolic acid ~0.7%). By analogy, arjunic acid is expected to be poorly absorbed orally, which is the central reason its striking in-vitro potency should not be read as an oral-dose effect. One relevant interaction data point exists: in human liver microsomes, isolated arjunic acid produced no significant inhibition of CYP3A4, CYP2D6 or CYP2C9 — unlike the whole arjuna bark extract, which inhibited all three ^{6Reference 6Varghese A et al. · 2015In vitroIn vitro modulatory effects of Terminalia arjuna, arjunic acid, arjunetin and arjungenin on CYP3A4, CYP2D6 and CYP2C9 enzyme activity in human liver microsomes — in vitro studyView study →}.

Clinical Trials

There are no clinical trials of isolated arjunic acid. The human cardiovascular evidence attached to this molecule’s plant source belongs to whole Terminalia arjuna bark (chronic stable angina, heart failure), not to the isolate; arjunic acid appears in that literature only as one minor triterpene constituent of the tested extract ^{10Reference 10Amalraj A · 2017ReviewMedicinal properties of Terminalia arjuna (Roxb.) Wight & Arn.: a reviewView study →}.

Last checked: July 2026.

Isolate vs. Plant Studies

This is the crux of the arjunic-acid file. The mechanistic work is the isolated molecule — the antioxidant assays ^{1Reference 1Sun FY et al. · 2008In vitroArjunic acid, a strong free radical scavenger from Terminalia arjuna — in vitro studyView study →}, the H9c2 cardioprotection (extract and isolate, side by side) ^{2Reference 2Manu TM et al. · 2019In vitroTerminalia arjuna extract and arjunic acid mitigate cobalt chloride-induced hypoxia stress-mediated apoptosis in H9c2 cells — in vitro cardiomyocyte studyView study →}, the NSCLC and multi-line cytotoxicity ^{3,4Reference 3Joo H et al. · 2016In vitroc-Jun N-terminal kinase-dependent endoplasmic reticulum stress pathway is critically involved in arjunic acid induced apoptosis in non-small cell lung cancer cells — in vitro studyView study →Reference 4Saxena M et al. · 2007In vitroCytotoxic agents from Terminalia arjuna — in vitro studyView study →}, and the Terminalia sericea antimicrobial isolation ^{5Reference 5Eldeen IM et al. · 2008In vitroIsolation and biological activities of termilignan B and arjunic acid from Terminalia sericea roots — in vitro studyView study →} all test purified arjunic acid directly. As a preclinical isolate base that is a real strength.

The clinical evidence, by contrast, is entirely the plant. Arjuna’s randomised and controlled cardiovascular data are for whole stem-bark preparations, within which arjunic acid is one of several oleanane triterpenes (alongside arjunolic acid, arjungenin and the saponin glycosides) plus a large tannin and flavonoid fraction ^{9,10Reference 9Kalola J · 2006Extraction and TLC densitometric determination of triterpenoid acids (arjungenin, arjunolic acid) from Terminalia arjuna stem bark without interference of tannins — analytical studyView study →Reference 10Amalraj A · 2017ReviewMedicinal properties of Terminalia arjuna (Roxb.) Wight & Arn.: a reviewView study →}. Nothing in the human record isolates arjunic acid’s contribution, and its expected poor oral absorption means a whole-bark effect cannot be assigned to it. The correct framing: strong isolate mechanism + meaningful clinical evidence for the plant — but for the whole bark, not this molecule, and the two are not interchangeable.

Prevalence in Nature

Arjunic acid is a characteristic triterpene acid of arjuna (Terminalia arjuna) stem bark, the classical source, where it co-occurs with arjunolic acid, arjungenin, terminic acid and the saponin glycosides arjunetin and arjunin ^{9,10Reference 9Kalola J · 2006Extraction and TLC densitometric determination of triterpenoid acids (arjungenin, arjunolic acid) from Terminalia arjuna stem bark without interference of tannins — analytical studyView study →Reference 10Amalraj A · 2017ReviewMedicinal properties of Terminalia arjuna (Roxb.) Wight & Arn.: a reviewView study →}. Quantitatively it is a minor constituent: compositional analysis puts the bark’s total triterpenoid fraction under ~1%, and while arjunolic acid (~0.5%) and arjungenin (~0.3%) have been densitometrically quantified, a reliable isolated figure for arjunic acid itself is not well established in the literature ^{9Reference 9Kalola J · 2006Extraction and TLC densitometric determination of triterpenoid acids (arjungenin, arjunolic acid) from Terminalia arjuna stem bark without interference of tannins — analytical studyView study →}. It has also been isolated outside the genus’s flagship species — from the roots of Terminalia sericea — indicating it is shared across some Terminalia triterpene chemistry rather than unique to arjuna ^{5Reference 5Eldeen IM et al. · 2008In vitroIsolation and biological activities of termilignan B and arjunic acid from Terminalia sericea roots — in vitro studyView study →}. Analytical work has focused on efficient recovery of the acid from bark (microwave-assisted extraction with HPLC-PDA quantification) rather than on mapping its abundance across tissues and species ^{8Reference 8Verma SC et al. · 2012Microwave extraction and rapid isolation of arjunic acid from Terminalia arjuna stem bark and quantification of arjunic acid and arjunolic acid using HPLC-PDA — analytical studyView study →}.

Discovery & Synthesis

Arjunic acid entered the literature as one of the triterpene acids of Terminalia arjuna bark, catalogued alongside arjunolic acid and arjungenin in twentieth-century phytochemical surveys of the Ayurvedic cardiac tonic; a precise first-isolation date and author are not well documented. Its modern profile begins with the 2008 characterisation of the purified compound as a strong free-radical scavenger ^{1Reference 1Sun FY et al. · 2008In vitroArjunic acid, a strong free radical scavenger from Terminalia arjuna — in vitro studyView study →}, followed by the cytotoxicity, cardioprotection and mechanism studies above. Preparation today is by extraction from arjuna bark — the microwave-assisted / HPLC-PDA route is the representative modern method — rather than by total synthesis, which is not a documented commercial route for this molecule ^{8Reference 8Verma SC et al. · 2012Microwave extraction and rapid isolation of arjunic acid from Terminalia arjuna stem bark and quantification of arjunic acid and arjunolic acid using HPLC-PDA — analytical studyView study →}. Semi-synthetic derivatives (e.g. 2-O-acyl esters such as 2-O-palmitoyl arjunic acid) have been prepared from the natural acid to probe structure–activity relationships in cancer cells ^{4Reference 4Saxena M et al. · 2007In vitroCytotoxic agents from Terminalia arjuna — in vitro studyView study →}.

Patents: not yet researched.

Toxicity & Safety

Arjunic acid carries a low flag. It is a minor triterpene of a bark with a long Ayurvedic-use history; the isolated molecule was non-mutagenic in the Ames assay ^{5Reference 5Eldeen IM et al. · 2008In vitroIsolation and biological activities of termilignan B and arjunic acid from Terminalia sericea roots — in vitro studyView study →}, did not inhibit the major drug-metabolising CYP enzymes (3A4, 2D6, 2C9) in human liver microsomes ^{6Reference 6Varghese A et al. · 2015In vitroIn vitro modulatory effects of Terminalia arjuna, arjunic acid, arjunetin and arjungenin on CYP3A4, CYP2D6 and CYP2C9 enzyme activity in human liver microsomes — in vitro studyView study →}, and its expected poor oral absorption further limits systemic exposure. The safety record is thin because the isolate has never been given to humans — absence of harm here reflects absence of testing, not a clean bill of health.

Safety at a Glance

✅ Low / no toxicity

• Low-hazard triterpene of a food/medicine bark. Non-mutagenic in vitro, from a plant with long traditional cardiac use; the isolate showed a benign antioxidant profile ^{1,5Reference 1Sun FY et al. · 2008In vitroArjunic acid, a strong free radical scavenger from Terminalia arjuna — in vitro studyView study →Reference 5Eldeen IM et al. · 2008In vitroIsolation and biological activities of termilignan B and arjunic acid from Terminalia sericea roots — in vitro studyView study →}.
• No CYP inhibition by the isolate. Purified arjunic acid did not significantly inhibit CYP3A4/2D6/2C9 in human liver microsomes — note the whole bark did, so herb–drug interaction caution belongs to arjuna, not necessarily to this molecule ^{6Reference 6Varghese A et al. · 2015In vitroIn vitro modulatory effects of Terminalia arjuna, arjunic acid, arjunetin and arjungenin on CYP3A4, CYP2D6 and CYP2C9 enzyme activity in human liver microsomes — in vitro studyView study →}.
• No human safety data for the isolate. All findings are in-vitro; no repeat-dose, reproductive or clinical safety package exists for isolated arjunic acid.
• Poor oral bioavailability is unproven either way. As a poorly-soluble triterpene acid, systemic exposure from ordinary intake is likely low, which cuts both benefit and risk claims ^{8Reference 8Verma SC et al. · 2012Microwave extraction and rapid isolation of arjunic acid from Terminalia arjuna stem bark and quantification of arjunic acid and arjunolic acid using HPLC-PDA — analytical studyView study →}.

Any pregnancy, lactation or reproductive decision is a per-herb / per-supplement matter and is not adjudicated on this molecule page — no isolate-specific reproductive-toxicity data exist for arjunic acid, and the decision belongs to the arjuna monograph where intake is actually decided.

Dosage

There is no established or recommended human dose for isolated arjunic acid. The cited figures here are in-vitro research concentrations (µg/mL and µM), which are not convertible to a human oral dose. Human exposure to arjunic acid is indirect — as one minor triterpene within arjuna stem-bark preparations, whose cardiovascular research uses the whole bark, commonly around 500 mg three times daily of powder/extract or a standardised water extract near 750 mg twice daily ^{10Reference 10Amalraj A · 2017ReviewMedicinal properties of Terminalia arjuna (Roxb.) Wight & Arn.: a reviewView study →}. These are whole-bark research regimens, not doses of this molecule, and are not a personal recommendation.

References

1. Sun FY, Chen XP, Wang JH, Qin HL, Yang SR, Du GH (2008). Arjunic acid, a strong free radical scavenger from Terminalia arjuna — in vitro study. American Journal of Chinese Medicine. https://pubmed.ncbi.nlm.nih.gov/18306462/
2. Manu TM, Anand T, Pandareesh MD, Bhuvanesh Kumar P, Khanum F (2019). Terminalia arjuna extract and arjunic acid mitigate cobalt chloride-induced hypoxia stress-mediated apoptosis in H9c2 cells — in vitro cardiomyocyte study. Naunyn-Schmiedeberg’s Archives of Pharmacology. https://pubmed.ncbi.nlm.nih.gov/31069430/
3. Joo H, Lee HJ, Shin EA, Kim H, Seo KH, Baek NI, Kim B, Kim SH (2016). c-Jun N-terminal kinase-dependent endoplasmic reticulum stress pathway is critically involved in arjunic acid induced apoptosis in non-small cell lung cancer cells — in vitro study. Phytotherapy Research. https://pubmed.ncbi.nlm.nih.gov/26787261/
4. Saxena M, Faridi U, Mishra R, Gupta MM, Darokar MP, Srivastava SK, Singh D, Luqman S, Khanuja SP (2007). Cytotoxic agents from Terminalia arjuna — in vitro study. Planta Medica. https://pubmed.ncbi.nlm.nih.gov/18008199/
5. Eldeen IM, Van Heerden FR, Van Staden J (2008). Isolation and biological activities of termilignan B and arjunic acid from Terminalia sericea roots — in vitro study. Planta Medica. https://pubmed.ncbi.nlm.nih.gov/18484533/
6. Varghese A, Savai J, Pandita N, Gaud R (2015). In vitro modulatory effects of Terminalia arjuna, arjunic acid, arjunetin and arjungenin on CYP3A4, CYP2D6 and CYP2C9 enzyme activity in human liver microsomes — in vitro study. Toxicology Reports. https://pubmed.ncbi.nlm.nih.gov/28962416/
7. Manu Mohan T, Anand T, Bhuvanesh Kumar P, Fathima A, Khanum F (2020). In-silico therapeutic investigations of arjunic acid and arjungenin as an FXR agonist and validation in 3T3-L1 adipocytes — in vitro/in silico study. Computational Biology and Chemistry. https://pubmed.ncbi.nlm.nih.gov/31767507/
8. Verma SC, Jain CL, Padhi MM, Devalla RB (2012). Microwave extraction and rapid isolation of arjunic acid from Terminalia arjuna stem bark and quantification of arjunic acid and arjunolic acid using HPLC-PDA — analytical study. Journal of Separation Science. https://pubmed.ncbi.nlm.nih.gov/22761141/
9. Kalola J, Rajani M (2006). Extraction and TLC densitometric determination of triterpenoid acids (arjungenin, arjunolic acid) from Terminalia arjuna stem bark without interference of tannins — analytical study. Chromatographia. https://doi.org/10.1365/s10337-006-0772-3
10. Amalraj A, Gopi S (2017). Medicinal properties of Terminalia arjuna (Roxb.) Wight & Arn.: a review. Journal of Traditional and Complementary Medicine. https://pubmed.ncbi.nlm.nih.gov/28053890/

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