Salvianolic Acid B

Salvianolic Acid B at a Glance

Salvianolic acid B is the dominant water-soluble constituent of danshen (Salvia miltiorrhiza) and the compound that five national pharmacopoeias use to decide whether a batch of the root is fit to sell. It is a large, very polar caffeic-acid tetramer — C₃₆H₃₀O₁₆, 718.6 Da — built from three danshensu units and one caffeic-acid unit, and it belongs squarely to the hydrophilic half of danshen’s split chemistry. Danshen is effectively two herbs sharing one root: the orange-red lipophilic tanshinones, which come out in ethanol, and the colourless water-soluble salvianolic acids, which come out in a decoction ^{34Reference 34Su CY et al. · 2015Salvia miltiorrhiza — traditional medicinal uses, chemistry, and pharmacologyView study →}. Sal B is the flagship of the second family, and a traditional water decoction of danshen does deliver it.

Three facts govern how the evidence should be read.

It has a formal quality-control identity. Very few molecules here are written into pharmacopoeial law. Danshen root must contain not less than 3.0% salvianolic acid B under the Chinese, US, European, Japanese and British pharmacopoeias, and not less than 4% under Hong Kong’s standard ^{1Reference 1Kum KY et al. · 2021Danshen (Salvia miltiorrhiza) on the global market — what are the implications for products’ quality? Frontiers in Pharmacology, 12, 621169. https://pubmed.ncbi.nlm.nih.gov/33981218/View study →}. That makes “salvianolic acid B content” a real, checkable number on a certificate of analysis rather than a marketing claim.

Its human evidence is unusually good for a plant phenolic — and unusually easy to over-read. There is a genuine molecule-level trial: 60 patients with biopsy-proven hepatitis-B liver fibrosis, six months of oral Sal B tablets, paired liver biopsies ^{5Reference 5Liu P et al. · 2002RCTClinical observation of salvianolic acid B in treatment of liver fibrosis in chronic hepatitis B — randomised double-blind trial with paired liver biopsiesView study →}. That is more than most compounds here can show. But the large clinical literature attached to this molecule is not about the molecule: it is about salvianolate, an intravenous Chinese product of which Sal B is about 85% ^{7,18Reference 7Liu L et al. · 2014Salvianolic acid B inhibits platelets as a P2Y12 antagonist and PDE inhibitor — evidence from clinic to laboratoryView study →Reference 18Guo Y et al. · 2022An integrated strategy for the systematic chemical characterization of Salvianolate lyophilized injection using four scan modes by UHPLC-QTRAP-MS/MSView study →}, and about the compound danshen dripping pill, a three-ingredient formula containing danshen, notoginseng and borneol ^{38,39Reference 38Luo J et al. · 2015Systematic reviewCompound danshen (Salvia miltiorrhiza) dripping pill for coronary heart disease — an overview of systematic reviewsView study →Reference 39Jia Y · 2017Meta-analysisHow efficacious is danshen (Salvia miltiorrhiza) dripping pill in treating angina pectoris? Evidence assessment for meta-analysis of randomized controlled trialsView study →}. Both are relevant; neither is Sal B.

It is barely absorbed. Absolute oral bioavailability is 2.3% in rats and 1.07% in beagle dogs ^{15,16Reference 15Wu YT et al. · 2006AnimalBioavailability of salvianolic acid B in conscious and freely moving ratsView study →Reference 16Gao DY et al. · 2009Bioavailability of salvianolic acid B and effect on blood viscosities after oral administration of salvianolic acids in beagle dogsView study →}. In the dog study, intravenous salvianolic acids markedly lowered blood viscosity while an oral dose twenty times larger did nothing at all ^{16Reference 16Gao DY et al. · 2009Bioavailability of salvianolic acid B and effect on blood viscosities after oral administration of salvianolic acids in beagle dogsView study →} — the single most useful experiment here for deciding what an oral product can be expected to do.

A Marker Compound With a Number

Most phytochemicals here have no regulatory existence. Salvianolic acid B does, and it is worth stating precisely because it is decision-relevant when you are looking at a bag of dried root or a bottle of extract.

Pharmacopoeia	Minimum salvianolic acid B	Minimum tanshinone IIA
Chinese (ChP)	3.0%	0.20%
United States (USP)	3.0%	0.10%
European (Ph. Eur.)	3.0%	0.12%
Japanese (JP)	3.0%	0.12%
British (BP)	3.0%	0.12%
Hong Kong (CMMS)	4.0%	—

Minimum content of dried danshen root; compiled from a market-quality survey of the herb ^{1Reference 1Kum KY et al. · 2021Danshen (Salvia miltiorrhiza) on the global market — what are the implications for products’ quality? Frontiers in Pharmacology, 12, 621169. https://pubmed.ncbi.nlm.nih.gov/33981218/View study →}.

Two things follow. First, Sal B is the larger of danshen’s two markers by an order of magnitude — the root is a few percent Sal B and a fraction of a percent tanshinones, which is why the hydrophilic fraction dominates by mass even though the lipophilic fraction dominates the herb’s colour and much of its reputation. Second, a “standardised danshen extract” that does not state a salvianolic-acid-B figure is not standardised in any sense a pharmacopoeia would recognise. A market survey found authenticated material carried higher Sal B and more consistent composition than online-store samples ^{1Reference 1Kum KY et al. · 2021Danshen (Salvia miltiorrhiza) on the global market — what are the implications for products’ quality? Frontiers in Pharmacology, 12, 621169. https://pubmed.ncbi.nlm.nih.gov/33981218/View study →}.

Sal B Is Mostly Made After Harvest

This is the strangest and most useful fact about the molecule, and it explains why the pharmacopoeial number is attached to dried root.

Fresh danshen root contains almost no salvianolic acid B. It appears during drying. Tracking five markers through oven-drying at 50–160 °C, Sal B rose from a trace in fresh material to a maximum after 40 minutes at 130 °C, following a reverse-V curve — production correlated positively with drying temperature and negatively with sample moisture ^{27Reference 27Li XB et al. · 2012Production of salvianolic acid B in roots of Salvia miltiorrhiza (danshen) during the post-harvest drying processView study →}. A companion study put numbers on it: through a thermal dehydration period, Sal B rose from 0.01% to 5.51% of the root, and total salvianolic acids from 0.20% to 6.61%, with antioxidant activity in four separate assays climbing in step ^{28Reference 28Zhou GJ et al. · 2014Post-harvest induced production of salvianolic acids and significant promotion of antioxidant properties in roots of Salvia miltiorrhiza (danshen)View study →}. A 2025 drying-kinetics study reported a 44-fold increase in Sal B relative to the fresh herb ^{27,28Reference 27Li XB et al. · 2012Production of salvianolic acid B in roots of Salvia miltiorrhiza (danshen) during the post-harvest drying processView study →Reference 28Zhou GJ et al. · 2014Post-harvest induced production of salvianolic acids and significant promotion of antioxidant properties in roots of Salvia miltiorrhiza (danshen)View study →}.

The interpretation the authors favour is that a freshly lifted root is still a living, physiologically active organ that responds to dehydration stress by making phenolics. Whatever the mechanism, the practical consequence is blunt: danshen’s headline constituent is a post-harvest product, and processing is not a neutral step but the step that creates the active. Sal B content is therefore a property of the drying protocol at least as much as of the plant.

Structure: A Rosmarinic Acid That Kept Going

Sal B is best understood as an oligomer of the mint family’s signature phenolic. Rosmarinic acid is an ester of caffeic acid and 3-(3,4-dihydroxyphenyl)lactic acid — one caffeic unit, one danshensu unit. Salvianolic acid B is the same chemistry extended: three danshensu units and one caffeic-acid unit, condensed into a benzofuran-containing tetramer of roughly double the molecular weight (718.6 vs 360.3 Da). Rosmarinic acid is its biosynthetic precursor, and danshen carries both.

That extension is the whole pharmacological story in miniature. Adding two more catechol-bearing units makes Sal B a far stronger radical scavenger and metal chelator than rosmarinic acid — eight phenolic hydroxyls versus four — and gives it enough surface to engage protein targets a small phenolic cannot, such as the thrombin active site ^{8Reference 8Neves MAD et al. · 2024Salvianolic acid B inhibits thrombosis and directly blocks the thrombin catalytic siteView study →}. It also makes it much harder to absorb. Rosmarinic acid is already poorly bioavailable; Sal B, at twice the mass and with four carboxyl/hydroxyl-dense units, is worse. Everything Sal B gains in potency at a target, it loses in ever reaching one by mouth.

Conversion to Salvianolic Acid A

Sal B is not thermally stable, and its main degradation route is genuinely interesting: under high temperature, high pressure and high humidity, salvianolic acid B in danshen tissue converts efficiently into salvianolic acid A ^{29Reference 29Xia H et al. · 2014Conversion of salvianolic acid B into salvianolic acid A in tissues of Radix Salviae Miltiorrhizae using high temperature, high pressure and high humidityView study →}. The proposed route is hydrolysis to lithospermic acid with loss of one danshensu unit, then decarboxylation to Sal A; a parallel route runs through salvianolic acid E. Because Sal A occurs only at very low levels in the raw root, this reaction is used deliberately in China as a manufacturing step to prepare Sal-A-rich material from the abundant Sal B ^{29Reference 29Xia H et al. · 2014Conversion of salvianolic acid B into salvianolic acid A in tissues of Radix Salviae Miltiorrhizae using high temperature, high pressure and high humidityView study →}. In the drying studies the non-Sal-B salvianolic acids appear later in the run than Sal B does, consistent with them being its breakdown products rather than independent biosynthetic endpoints ^{27,28Reference 27Li XB et al. · 2012Production of salvianolic acid B in roots of Salvia miltiorrhiza (danshen) during the post-harvest drying processView study →Reference 28Zhou GJ et al. · 2014Post-harvest induced production of salvianolic acids and significant promotion of antioxidant properties in roots of Salvia miltiorrhiza (danshen)View study →}.

Formal stability testing agrees on the direction of travel. Solid Sal B in sealed aluminium foil was stable for six months under accelerated conditions (40 °C, 75% RH), but degraded under open exposure to 60 °C or high humidity; in saline solution it degraded severely, with nine degradation products identified. The authors’ conclusion was that Sal B is usable as a solid formulation but “not suitable for use as a liquid formulation” ^{30Reference 30Zhou LN et al. · 2011Studies on the stability of salvianolic acid B as potential drug materialView study →}.

So three practical points. A hot, long, wet extraction of danshen shifts the salvianolic profile away from Sal B. A liquid Sal B product has a real stability problem. And any pharmacology attributed to Sal B in an aged or heat-abused preparation may partly belong to its degradation cascade — the same discipline problem carnosic acid poses in rosemary.

Two Names, One Molecule

Salvianolic acid B and lithospermic acid B were described separately and named separately, and for years were reported as having identical structures differing only in the configurational assignment of two stereocentres. In 2006 a Berkeley group settled it: by chemical correlation between a degradation product of salvianolic acid B and synthetic material, the absolute configuration of salvianolic acid B was corrected, establishing that the two are the same compound ^{2Reference 2Watzke A et al. · 2006Reassignment of the configuration of salvianolic acid B and establishment of its identity with lithospermic acid BView study →}.

The names did not merge in the literature. As of August 2026, PubMed returns 687 records for "salvianolic acid B" AND "Salvia miltiorrhiza" but only 33 for "lithospermic acid B" AND "Salvia miltiorrhiza" — and of the 67 records that mention lithospermic acid B at all, 32 never mention salvianolic acid B. That second slice is not redundant: it holds a distinct research tradition, largely Japanese and Korean, centred on the magnesium salt magnesium lithospermate B and on the kidney. The founding paper of that line isolated magnesium lithospermate B by activity-guided fractionation as the constituent of danshen that improved glomerular filtration rate and renal blood flow in adenine-induced renal failure in rats ^{14Reference 14Yokozawa T et al. · 1989Isolation of a renal function-facilitating constituent from the Oriental drug, Salviae miltiorrhizae radix — identified as magnesium lithospermate BView study →}; a further 118 PubMed records use the “magnesium lithospermate B” name specifically. Search only for “salvianolic acid B” and you will miss most of the renal literature — the same synonym trap that splits the tellimagrandin II / eugeniin evidence base.

What It's Used For

Evidence by IndicationStrength of support · Beta

Support is an experimental score — weighted by study type (human > animal > in vitro) and volume, then tempered for how well the thing studied matches the molecule named. A beta, not a validated metric. Every row carries one of two ceilings: either the evidence is preclinical, or the human evidence used a preparation (salvianolate injection, ~85% Sal B; or the compound danshen dripping pill, a three-herb formula) rather than the isolate. The “Rests on” column names which.

01Antiplatelet & antithromboticPromising48%Molecule-level P2Y12/PDE mechanism in human platelets + direct thrombin-site binding; human arm used salvianolate ^{7,8,21Reference 7Liu L et al. · 2014Salvianolic acid B inhibits platelets as a P2Y12 antagonist and PDE inhibitor — evidence from clinic to laboratoryView study →Reference 8Neves MAD et al. · 2024Salvianolic acid B inhibits thrombosis and directly blocks the thrombin catalytic siteView study →Reference 21Cao W et al. · 2021RCTDrug–drug interactions between salvianolate injection and aspirin based on their metabolic enzymes — randomised clinical trialView study →}

02Liver fibrosis & hepatoprotectionPromising45%One 6-month isolate RCT with paired biopsies (n=60, active comparator) + replicated TGF-β/PDGFRβ rodent work ^{5,10,11Reference 5Liu P et al. · 2002RCTClinical observation of salvianolic acid B in treatment of liver fibrosis in chronic hepatitis B — randomised double-blind trial with paired liver biopsiesView study →Reference 10Tao YY et al. · 2013In vitroSalvianolic acid B inhibits hepatic stellate cell activation through transforming growth factor beta-1 signal transduction pathway in vivo and in vitroView study →Reference 11Liu F et al. · 2023Salvianolic acid B inhibits hepatic stellate cell activation and liver fibrosis by targeting PDGFRβView study →}

03Cardioprotection (ischemia-reperfusion)Shaky40%Meta-analysis of 32 animal studies, 732 animals; publication bias noted; no human isolate data ^{9,32Reference 9Yang Y et al. · 2024Meta-analysisProtective effect of salvianolic acid B against myocardial ischemia/reperfusion injury — preclinical systematic evaluation and meta-analysis of animal studiesView study →Reference 32Shao Y et al. · 2025Salvianolic acid B — a promising cardioprotective agentView study →}

04Acute MI & anginaShaky36%30 RCTs / 3,931 patients of salvianolate injection; plus dripping-pill formula literature — preparation-level throughout ^{19,38,39Reference 19Chen P et al. · 2024Meta-analysisEfficacy and safety of salvianolate injection in treating acute myocardial infarction — meta-analysis and systematic literature review of 30 RCTsView study →Reference 38Luo J et al. · 2015Systematic reviewCompound danshen (Salvia miltiorrhiza) dripping pill for coronary heart disease — an overview of systematic reviewsView study →Reference 39Jia Y · 2017Meta-analysisHow efficacious is danshen (Salvia miltiorrhiza) dripping pill in treating angina pectoris? Evidence assessment for meta-analysis of randomized controlled trialsView study →}

05Kidney disease & nephroprotectionShaky30%Salvianolate adjunct meta-analysis (moderate-to-very-low certainty) + rodent renal-fibrosis mechanism + the magnesium lithospermate B tradition ^{13,14,20Reference 13Yao L et al. · 2022Effects of salvianolic acid A and salvianolic acid B in renal interstitial fibrosis via PDGF-C/PDGFR-α signaling pathwayView study →Reference 14Yokozawa T et al. · 1989Isolation of a renal function-facilitating constituent from the Oriental drug, Salviae miltiorrhizae radix — identified as magnesium lithospermate BView study →Reference 20Xu Q et al. · 2023Meta-analysisSalvianolate injection for hypertensive nephropathy patients who were using valsartan — systematic review and meta-analysisView study →}

06Oral submucous fibrosisShaky27%One 42-patient randomised trial of intralesional Sal B ± triamcinolone — the isolate, but injected into the lesion ^{6Reference 6Jiang XW et al. · 2013RCTEfficacy of salvianolic acid B combined with triamcinolone acetonide in the treatment of oral submucous fibrosis — randomised clinical trialView study →}

07Pulmonary & other organ fibrosisShaky22%Bleomycin mouse model + TGF-β/Smad and MAPK mechanism; entirely animal and cell ^{12Reference 12Liu Q et al. · 2016Salvianolic acid B attenuates experimental pulmonary fibrosis through inhibition of the TGF-β signaling pathwayView study →}

Mechanisms

Pharmacokinetics

The dominant pharmacokinetic fact is very poor oral absorption, and it is consistent across species and across both names for the molecule.

In conscious, freely moving rats, comparing an intravenous 100 mg/kg dose with an oral 500 mg/kg dose, absolute oral bioavailability was 2.3% ^{15Reference 15Wu YT et al. · 2006AnimalBioavailability of salvianolic acid B in conscious and freely moving ratsView study →}. In beagle dogs given salvianolic acids orally at 180 mg/kg against 9 mg/kg intravenously, Sal B’s absolute bioavailability was 1.07 ± 0.43% ^{16Reference 16Gao DY et al. · 2009Bioavailability of salvianolic acid B and effect on blood viscosities after oral administration of salvianolic acids in beagle dogsView study →}. Under the lithospermic-acid-B name, rats given 10 or 50 mg/kg orally showed 5% bioavailability at the higher dose and undetectable plasma levels at the lower one, with 23–41% of the dose recovered unabsorbed from the gastrointestinal tract at 24 hours and poor permeability through Caco-2 monolayers ^{17Reference 17Kim HH et al. · 2005AnimalPharmacokinetics of lithospermic acid B isolated from Salvia miltiorrhiza in ratsView study →}. Clearance was slower at the higher intravenous dose, suggesting saturable metabolism ^{17Reference 17Kim HH et al. · 2005AnimalPharmacokinetics of lithospermic acid B isolated from Salvia miltiorrhiza in ratsView study →}.

The reasons are structural and unsurprising: 718.6 Da, eight phenolic hydroxyls and four carboxyl-bearing units make Sal B far too polar and far too large for passive intestinal absorption. What is absorbed is subject to catechol-O-methyltransferase and to gut-microbial cleavage; danshensu is a major circulating metabolite, and much of the formulation literature on Sal B is explicitly about defeating COMT-mediated first-pass metabolism with phospholipid complexes, self-microemulsifying systems and nanoparticles.

The consequence is made concrete by the dog study: a single intravenous dose of salvianolic acids markedly reduced blood viscosity, while a single oral dose twenty times larger produced no significant change at all ^{16Reference 16Gao DY et al. · 2009Bioavailability of salvianolic acid B and effect on blood viscosities after oral administration of salvianolic acids in beagle dogsView study →}. This is why the Chinese clinical products that work are given by infusion. Any claim made for an oral salvianolic-acid-B supplement has to answer that experiment.

Clinical Trials

The human record splits three ways and should always be read with the vehicle named:

Isolated Sal B	Salvianolate (~85% Sal B, IV)	Multi-herb formula (danshen + notoginseng + borneol)
Liver fibrosis, oral tablets, 6 months, paired biopsies, n=60 5Reference 5Liu P et al. · 2002RCTClinical observation of salvianolic acid B in treatment of liver fibrosis in chronic hepatitis B — randomised double-blind trial with paired liver biopsiesView study →	Acute MI: 30 RCTs, 3,931 patients 19Reference 19Chen P et al. · 2024Meta-analysisEfficacy and safety of salvianolate injection in treating acute myocardial infarction — meta-analysis and systematic literature review of 30 RCTsView study →	Compound danshen dripping pill: 13 systematic reviews, 34,071 participants 38Reference 38Luo J et al. · 2015Systematic reviewCompound danshen (Salvia miltiorrhiza) dripping pill for coronary heart disease — an overview of systematic reviewsView study →; >230 angina RCTs 39Reference 39Jia Y · 2017Meta-analysisHow efficacious is danshen (Salvia miltiorrhiza) dripping pill in treating angina pectoris? Evidence assessment for meta-analysis of randomized controlled trialsView study →
Oral submucous fibrosis, intralesional injection, n=42 6Reference 6Jiang XW et al. · 2013RCTEfficacy of salvianolic acid B combined with triamcinolone acetonide in the treatment of oral submucous fibrosis — randomised clinical trialView study →	Hypertensive nephropathy adjunct to valsartan 20Reference 20Xu Q et al. · 2023Meta-analysisSalvianolate injection for hypertensive nephropathy patients who were using valsartan — systematic review and meta-analysisView study →; ACS antiplatelet potentiation 7Reference 7Liu L et al. · 2014Salvianolic acid B inhibits platelets as a P2Y12 antagonist and PDE inhibitor — evidence from clinic to laboratoryView study →; aspirin DDI, n=18 21Reference 21Cao W et al. · 2021RCTDrug–drug interactions between salvianolate injection and aspirin based on their metabolic enzymes — randomised clinical trialView study →	Western Phase I tolerability, n=48 37Reference 37Ling S et al. · 2012A phase I dose-escalation study to evaluate tolerability in a Western population to T89, a modern cardiovascular herbal medicineView study →; no effect on warfarin PK/PD, n=24 23Reference 23Wang P et al. · 2014Absence of an effect of T89 on the steady-state pharmacokinetics and pharmacodynamics of warfarin in healthy volunteersView study →

Last checked: August 2026.

Isolate vs. Plant Studies

Salvianolic acid B sits in an unusual position for this database: it has more isolate-level human evidence than most plant phenolics and far less than its citation count suggests. Two trials gave the actual molecule to actual patients ^{5,6Reference 5Liu P et al. · 2002RCTClinical observation of salvianolic acid B in treatment of liver fibrosis in chronic hepatitis B — randomised double-blind trial with paired liver biopsiesView study →Reference 6Jiang XW et al. · 2013RCTEfficacy of salvianolic acid B combined with triamcinolone acetonide in the treatment of oral submucous fibrosis — randomised clinical trialView study →}, which is two more than rosmarinic acid, diosgenin or carnosic acid can claim. But the volume of clinical literature that gets cited as if it were about Sal B is preparation evidence, and the preparations differ from the molecule in ways that matter:

• Salvianolate injection is the closest proxy — about 85% Sal B by content ^{7Reference 7Liu L et al. · 2014Salvianolic acid B inhibits platelets as a P2Y12 antagonist and PDE inhibitor — evidence from clinic to laboratoryView study →}, with Sal B quantified at 195–350 mg/g of the drug substance alongside lithospermic acid, salvianolic acids A and D and rosmarinic acid ^{18Reference 18Guo Y et al. · 2022An integrated strategy for the systematic chemical characterization of Salvianolate lyophilized injection using four scan modes by UHPLC-QTRAP-MS/MSView study →}. But it is intravenous, which is precisely the variable that decides whether Sal B works, so its results cannot be read across to an oral capsule.
• Compound danshen dripping pill / Dantonic / T89 is a three-ingredient formula. Its angina evidence is genuinely large and has attracted Western regulatory attention, but it contains notoginseng and borneol as well as danshen, and its danshen fraction supplies tanshinones too. Crediting it to Sal B is a category error.
• Danshen decoction does deliver salvianolic acids — this is the fraction water extracts. So unlike the tanshinones, Sal B is a compound a traditional preparation actually contains. Whether enough of it crosses the gut wall to matter is the open question, and the 1–2% figure is not encouraging.

Within this database, Sal B is a legitimate and dominant constituent of dan shen, alongside its scarcer, per-unit more potent sibling salvianolic acid A and their shared biosynthetic precursor rosmarinic acid — an occurrence fact, not an endorsement of an isolated supplement.

Prevalence in Nature

Salvianolic acid B is not a food compound. It has no meaningful dietary exposure, no presence in fruit, vegetables or cereals, and essentially one commercially relevant source: the dried root of Salvia miltiorrhiza, where it is the single most abundant constituent at 3–5.5% of dry weight ^{1,28Reference 1Kum KY et al. · 2021Danshen (Salvia miltiorrhiza) on the global market — what are the implications for products’ quality? Frontiers in Pharmacology, 12, 621169. https://pubmed.ncbi.nlm.nih.gov/33981218/View study →Reference 28Zhou GJ et al. · 2014Post-harvest induced production of salvianolic acids and significant promotion of antioxidant properties in roots of Salvia miltiorrhiza (danshen)View study →}.

Within the genus it is widespread. A survey of Salvia species from southwest China found the phenolic-acid profile of most species followed the pattern salvianolic acid B > rosmarinic acid > danshensu > caffeic acid in both roots and leaves, and noted that leaf phenolic-acid content generally exceeds root ^{36Reference 36Wang F et al. · 2024Content determination and chemical clustering analysis of tanshinone and salvianolic acid in Salvia sppView study →}. Salvianolic acids are also present in culinary sage (Salvia officinalis), where the family extends to minor members such as salvianolic acid Y.

Outside Salvia, the record thins fast, and one commonly repeated occurrence needs a caveat. Comfrey root (Symphytum officinale) is often listed as a source: a 2018 study of a 65% ethanol comfrey-root extract identified and quantified caffeic-acid trimers and tetramers for the first time in comfrey and assigned them as “isomers of salvianolic acid A, B and C” by HPLC-DAD-QTOF-MS/MS, alongside rosmarinic acid as the main phenolic at 7.55 mg/g ^{35Reference 35Trifan A et al. · 2018Is comfrey root more than toxic pyrrolizidine alkaloids? Salvianolic acids among antioxidant polyphenols in comfrey (Symphytum officinale L.) rootsView study →}. That is a tentative mass-spectrometric assignment of isomers, not isolation of salvianolic acid B itself — and a PubMed search for "salvianolic acid B" AND comfrey returns zero records. Treat comfrey as a probable but unconfirmed source, and do not carry a Sal B activity claim onto a comfrey page.

Discovery & Synthesis

Salvianolic acid B was isolated and its stereostructure defined by Ai Chun-Bo and Li Lian-Niang at the Institute of Materia Medica, Chinese Academy of Medical Sciences, Beijing, in a 1988 Journal of Natural Products paper that also reported salvianolic acid C ^{3Reference 3Ai CB · 1988Stereostructure of salvianolic acid B and isolation of salvianolic acid C from Salvia miltiorrhizaView study →}. It followed the same group’s 1984 description of salvianolic acid A, the depside that gave the series its name ^{4Reference 4Li LN et al. · 1984Salvianolic acid A, a new depside from roots of Salvia miltiorrhizaView study →}. Independently, Japanese workers isolating from the aqueous danshen extract characterised magnesium lithospermate B as the renal-function-improving principle of the root in 1989 ^{14Reference 14Yokozawa T et al. · 1989Isolation of a renal function-facilitating constituent from the Oriental drug, Salviae miltiorrhizae radix — identified as magnesium lithospermate BView study →}, under the separate name lithospermic acid B. The two names ran in parallel for eighteen years until a 2006 chemical-correlation study corrected salvianolic acid B’s configurational assignment and established the two as one compound ^{2Reference 2Watzke A et al. · 2006Reassignment of the configuration of salvianolic acid B and establishment of its identity with lithospermic acid BView study →}.

Chemically it is a depside tetramer: three units of danshensu (3,4-dihydroxyphenyllactic acid) and one of caffeic acid, condensed with a benzofuran ring, C₃₆H₃₀O₁₆, 718.6 Da. It is weakly acidic, water-soluble, and commonly handled as its magnesium, potassium or ammonium salt.

Commercial Sal B is obtained by aqueous extraction from danshen root followed by resin chromatography — the root’s 3–5% content makes it an unusually convenient natural product to purify, and there is no economic case for total synthesis. The same aqueous stream supplies salvianolate lyophilised injection. Where salvianolic acid A is wanted, it is generally made from Sal B by controlled high-temperature, high-pressure, high-humidity conversion rather than isolated directly, because Sal A’s native content is very low ^{29Reference 29Xia H et al. · 2014Conversion of salvianolic acid B into salvianolic acid A in tissues of Radix Salviae Miltiorrhizae using high temperature, high pressure and high humidityView study →}.

Patents: not yet researched.

Toxicity & Safety

Salvianolic acid B has a better-than-usual tolerability record for a compound here, and one specific, mechanistically-grounded risk.

Tolerability. Six months of oral Sal B tablets in 60 patients with hepatitis-B liver fibrosis produced no reported adverse effects, against a 50% fever rate in the interferon-γ comparator arm ^{5Reference 5Liu P et al. · 2002RCTClinical observation of salvianolic acid B in treatment of liver fibrosis in chronic hepatitis B — randomised double-blind trial with paired liver biopsiesView study →}. Twenty weeks of weekly intralesional injections in 42 patients produced no obvious adverse reactions ^{6Reference 6Jiang XW et al. · 2013RCTEfficacy of salvianolic acid B combined with triamcinolone acetonide in the treatment of oral submucous fibrosis — randomised clinical trialView study →}. The intravenous salvianolate meta-analysis in 3,931 acute-MI patients found no significant difference in adverse events versus control ^{19Reference 19Chen P et al. · 2024Meta-analysisEfficacy and safety of salvianolate injection in treating acute myocardial infarction — meta-analysis and systematic literature review of 30 RCTsView study →}, and the hypertensive-nephropathy adjunct analysis likewise ^{20Reference 20Xu Q et al. · 2023Meta-analysisSalvianolate injection for hypertensive nephropathy patients who were using valsartan — systematic review and meta-analysisView study →}. In mice, the intravenous LD50 of a Sal-B-plus-ginsenoside-Rg1 combination was 1,747 mg/kg — more than a hundred times the effective dose — with no histological abnormality in brain, heart, kidney, liver or lung and no biochemical changes on seven-day repeat dosing ^{33Reference 33Zhao Q et al. · 2015AnimalThe safety evaluation of salvianolic acid B and ginsenoside Rg1 combination on miceView study →}; note this is a combination, not the isolate alone. There is no published genotoxicity or reproductive-toxicity dataset for isolated Sal B, and no human safety study designed as one.

The Bleeding Question — and Who Owns the Warfarin Interaction

Danshen’s interaction with warfarin is one of the best-documented herb–drug interactions in the materia medica: multiple case reports of raised INR, over-anticoagulation and bleeding ^{24Reference 24Chan TY · 2001Case reportInteraction between warfarin and danshen (Salvia miltiorrhiza) — review of case reportsView study →}, plus rat work showing danshen increases warfarin absorption and prolongs prothrombin time ^{25Reference 25Lo AC et al. · 1992AnimalThe effects of danshen (Salvia miltiorrhiza) on pharmacokinetics and pharmacodynamics of warfarin in ratsView study →}. Every danshen constituent page has to address it. This one has to divide it in two.

The pharmacokinetic half is not Sal B’s. When a danshen ethyl acetate extract, the individual tanshinones and an aqueous extract containing salvianolic acid B and danshensu were each tested against warfarin hydroxylation in rat liver microsomes, the tanshinones inhibited CYP1A1-, CYP2C6- and CYP2C11-mediated warfarin metabolism — and the aqueous extract had no effect at all ^{22Reference 22Wu WW · 2010In vitroInhibition of warfarin hydroxylation by major tanshinones of danshen (Salvia miltiorrhiza) in the rat in vitro and in vivoView study →}. In humans, a water-type danshen product (T89, danshen plus notoginseng) added for a week to volunteers stabilised on warfarin produced no increase in INR and R- and S-warfarin Cmax and AUC ratios within the 0.80–1.25 bioequivalence bounds ^{23Reference 23Wang P et al. · 2014Absence of an effect of T89 on the steady-state pharmacokinetics and pharmacodynamics of warfarin in healthy volunteersView study →}. Sal B, if anything, moves CYPs the other way: in rats it induced CYP3A4 and CYP2C9 and accelerated losartan metabolism, where tanshinone IIA inhibited them ^{26Reference 26Wang R et al. · 2016AnimalEffects of salvianolic acid B and tanshinone IIA on the pharmacokinetics of losartan in rats by regulating the activities and expression of CYP3A4 and CYP2C9View study →}.

The pharmacodynamic half is Sal B’s. Sal B antagonises P2Y12 and inhibits phosphodiesterase in human platelets ^{7Reference 7Liu L et al. · 2014Salvianolic acid B inhibits platelets as a P2Y12 antagonist and PDE inhibitor — evidence from clinic to laboratoryView study →}, binds the thrombin catalytic site directly ^{8Reference 8Neves MAD et al. · 2024Salvianolic acid B inhibits thrombosis and directly blocks the thrombin catalytic siteView study →}, and — as salvianolate — measurably potentiated dual antiplatelet therapy in patients with acute coronary syndrome ^{7Reference 7Liu L et al. · 2014Salvianolic acid B inhibits platelets as a P2Y12 antagonist and PDE inhibitor — evidence from clinic to laboratoryView study →}. That is additive bleeding risk on its own terms, independent of any effect on warfarin metabolism. A human PK/PD study also found aspirin and salvianolate interact pharmacokinetically ^{21Reference 21Cao W et al. · 2021RCTDrug–drug interactions between salvianolate injection and aspirin based on their metabolic enzymes — randomised clinical trialView study →}.

The honest reading: the classic danshen–warfarin case reports point at the herb and, on the available mechanism work, at its lipophilic fraction — but Sal B carries a genuine, separately-evidenced antiplatelet and antithrombotic risk of its own. The practical conclusion is the same either way; the reasoning matters because it tells you the risk does not disappear in a warfarin-free patient on aspirin, clopidogrel or heading for surgery.

Safety at a Glance

✅ Low / no toxicityBleeding risk

• Six months of oral dosing without reported adverse effects in a controlled 60-patient trial, against an active comparator that caused fever in half its arm ^{5Reference 5Liu P et al. · 2002RCTClinical observation of salvianolic acid B in treatment of liver fibrosis in chronic hepatitis B — randomised double-blind trial with paired liver biopsiesView study →}.
• Large intravenous exposure with meta-analysed safety. Across 30 RCTs and 3,931 acute-MI patients, salvianolate (≈85% Sal B) showed no excess adverse events ^{19Reference 19Chen P et al. · 2024Meta-analysisEfficacy and safety of salvianolate injection in treating acute myocardial infarction — meta-analysis and systematic literature review of 30 RCTsView study →}.
• Real antiplatelet and antithrombotic activity in its own right — P2Y12 antagonism, phosphodiesterase inhibition and direct thrombin-site binding ^{7,8Reference 7Liu L et al. · 2014Salvianolic acid B inhibits platelets as a P2Y12 antagonist and PDE inhibitor — evidence from clinic to laboratoryView study →Reference 8Neves MAD et al. · 2024Salvianolic acid B inhibits thrombosis and directly blocks the thrombin catalytic siteView study →}. Additive with aspirin, clopidogrel, DOACs and warfarin; relevant before surgery.
• Do not treat the danshen–warfarin case literature as this molecule’s. The metabolic interaction traces to the tanshinones; the aqueous Sal-B-containing fraction had no effect on warfarin hydroxylation, and a water-type danshen product did not shift INR in humans ^{22,23Reference 22Wu WW · 2010In vitroInhibition of warfarin hydroxylation by major tanshinones of danshen (Salvia miltiorrhiza) in the rat in vitro and in vivoView study →Reference 23Wang P et al. · 2014Absence of an effect of T89 on the steady-state pharmacokinetics and pharmacodynamics of warfarin in healthy volunteersView study →}.
• CYP3A4 / CYP2C9 induction in rats accelerated losartan clearance — the opposite direction to tanshinone IIA, and untested in humans ^{26Reference 26Wang R et al. · 2016AnimalEffects of salvianolic acid B and tanshinone IIA on the pharmacokinetics of losartan in rats by regulating the activities and expression of CYP3A4 and CYP2C9View study →}.
• No genotoxicity, reproductive or repeat-dose toxicology on the isolate. The mouse LD50 figure comes from a Sal B + ginsenoside Rg1 combination ^{33Reference 33Zhao Q et al. · 2015AnimalThe safety evaluation of salvianolic acid B and ginsenoside Rg1 combination on miceView study →}. Absence of findings is not a clean record.
• Preparation, not molecule, carries most of the safety data — and most of it is intravenous, hospital-administered and in Chinese populations.

Reproductive data specific to salvianolic acid B are absent. Danshen as a herb is conventionally avoided in pregnancy; that caution belongs on the dan shen monograph, where the preparation and dose are actually decided.

Dosage

There is no established oral dose of salvianolic acid B, and the reason is not neglect — it is that the oral route has a 1–2% bioavailability problem that nobody has convincingly solved ^{15,16Reference 15Wu YT et al. · 2006AnimalBioavailability of salvianolic acid B in conscious and freely moving ratsView study →Reference 16Gao DY et al. · 2009Bioavailability of salvianolic acid B and effect on blood viscosities after oral administration of salvianolic acids in beagle dogsView study →}.

The last row is the one worth sitting with. A traditional 9–15 g danshen decoction delivers a few hundred milligrams of salvianolic acid B into the gut — a genuinely large amount — of which, on the rat and dog figures, perhaps 3–10 mg reaches the circulation intact. These are research and traditional figures for orientation, not recommendations, and anyone on anticoagulant or antiplatelet medication should not be adding either the herb or the isolate without medical supervision.

References

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