Ru Xiang
StarBoswellia carterii Birdw.
Traditionally used for
- Cough & breathing
- Menstrual & women's health
- Pain & joints
- Skin
Cautions & contraindications
- Bleeding disorders
- Before surgery
☯ TCM Properties
Invigorates Blood and Moves Qi; Alleviates Pain; Reduces Swelling; Promotes Tissue Regeneration and Heals Sores; Relaxes the Sinews and Unblocks the Collaterals
Traditional Chinese Uses
Ru Xiang (frankincense resin, boswellia) is a warm, acrid herb that moves Blood and Qi to relieve pain and reduce swelling. It is a primary herb for pain from Blood and Qi stagnation — including joint pain from Wind-Cold-Damp bi obstruction, traumatic injuries with bruising and swelling, and menstrual pain from Blood stasis. Applied topically, it promotes wound healing and reduces the pain and swelling of carbuncles and abscesses. It is frequently combined with Mo Yao (myrrh) for synergistic Blood-moving and pain-relieving effects.
Western Herbalism Properties
Relationships
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Botanical Description
Boswellia carterii (often considered synonymous with B. sacra) is a small deciduous tree in the family Burseraceae, native to arid scrublands of Somalia, Yemen, and Oman. It typically grows 2-8 meters tall, with papery, peeling bark and a contorted trunk often anchored directly to bare limestone. The leaves are pinnately compound with 7-15 lance-shaped, finely toothed, slightly hairy leaflets clustered toward branch tips. Small white to pale-yellow five-petaled flowers are borne in axillary racemes and develop into small reddish-brown capsular fruits. When the bark is incised, the tree exudes a milky oleo-gum-resin that hardens on contact with air into pale-yellow to amber teardrop-shaped pieces known as frankincense, the aromatic resin used medicinally and ritually.
Active Constituents
Total boswellic acids
Pentacyclic triterpenic acidsConcentration: 491.20 g/kg dry weight (about 49%) in resin identified as Boswellia sacra Flueck, treated by those authors as a synonym of B. carteri Birdw, against 295.25 g/kg (about 30%) in Boswellia serrata
The defining acidic fraction of the oleogum resin and the reason frankincense is not interchangeable between Boswellia species. In the one study that assayed both species side by side, the B. sacra/B. carteri material carried roughly two-thirds more total boswellic acid than Indian B. serrata.
3-O-acetyl-11-keto-beta-boswellic acid (AKBA)
Pentacyclic triterpenic acidConcentration: 70.81 g/kg dry weight (about 7.1%) in B. sacra/B. carteri resin, against 7.35 g/kg (about 0.7%) in B. serrata - close to a tenfold difference
The most potent boswellic acid. It is a specific, non-redox inhibitor of 5-lipoxygenase, blocking leukotriene biosynthesis by a mechanism distinct from the redox and iron-chelating inhibitors, and it also interferes directly with COX-1. Its oral bioavailability is poor and strongly food-dependent. The tenfold AKBA gap between B. carterii and B. serrata is the single most important reason not to read B. serrata trial data straight across to Ru Xiang.
11-keto-beta-boswellic acid (KBA)
Pentacyclic triterpenic acidConcentration: 35.50 g/kg dry weight (about 3.6%) in B. sacra/B. carteri resin, and 34.62 g/kg in B. serrata - essentially equal between the two species
A 5-lipoxygenase inhibitor in its own right and, unlike AKBA, the boswellic acid that reaches usable plasma concentrations after oral dosing of a resin extract.
beta-boswellic acid and alpha-boswellic acid
Pentacyclic triterpenic acids (non-keto)Concentration: 186.19 g/kg and 184.34 g/kg dry weight respectively (about 18.6% and 18.4%) in B. sacra/B. carteri resin
Together the bulk of the boswellic acid fraction. They are less potent than the keto forms against 5-lipoxygenase, and alpha-boswellic acid becomes detectable in plasma only when the extract is taken with a high-fat meal.
Volatile oil, principally alpha-pinene
Monoterpene hydrocarbonsConcentration: alpha-pinene averaged 37.3% of the essential oil of B. carterii, with alpha-thujene 7.9%, myrcene 7.3%, limonene plus beta-phellandrene 14.4% and sabinene 4.9%; the corresponding oil of B. sacra averaged 68.2% alpha-pinene
The aromatic fraction responsible for the resin's qi-moving character in traditional use. It also settles a live taxonomic question: chiral GC-MS gave enantiomeric (+)/(-) alpha-pinene ratios of 0.68 for B. carterii against 8.24 for B. sacra and optical rotations of -13.3 degrees against +30.1 degrees, on the basis of which those authors argued the two are distinct species rather than synonyms - directly contradicting the synonymy assumed by the boswellic acid quantification above.
beta-caryophyllene oxide
Sesquiterpene oxideConcentration: not quantified; present as a marker spot on TLC
A TLC marker specific to B. carterii/B. sacra resin. B. papyrifera instead shows incensole and incensole acetate, and B. serrata shows serratol and 3-oxo-tirucallic acid, so the three olibanums can be told apart in a minimally equipped laboratory. This matters because the cheaper African olibanums are substituted for Ru Xiang.
⚠ Drug Interactions
Warfarin, direct oral anticoagulants, heparin and low-molecular-weight heparins
This is a real antiplatelet interaction, not a theoretical one. Water and hydroalcoholic gum resin extracts at 3 mg dry weight per mL completely inhibited ADP-induced platelet aggregation, an effect the authors judged comparable to 20 micrograms per mL of heparin. The same extracts extended prothrombin time from about 13 seconds to over 60 and activated partial thromboplastin time from about 32 seconds to over 90, and the hydroalcoholic extract inhibited clotting factors Xa and XIa markedly at 6 micrograms while about 10 micrograms of heparin was needed for comparable inhibition. Boswellic acids also inhibit 5-lipoxygenase and interfere directly with COX-1, the same COX-1 route by which aspirin suppresses platelet thromboxane. The species tested in the coagulation study was Boswellia serrata, whose resin carries roughly one tenth the AKBA of B. carterii, so the effect is unlikely to be smaller with Ru Xiang. No human interaction study has been done in either species.
Clinical note: Do not add Ru Xiang to a stable anticoagulated patient without a plan to monitor. Check INR one to two weeks after starting or stopping, and watch for bruising and gum bleeding in patients on DOACs where INR gives no warning. Stop at least one to two weeks before elective surgery, dental extraction or neuraxial anaesthesia.
Antiplatelet drugs (aspirin, clopidogrel, ticagrelor, prasugrel) and NSAIDs
Boswellic acids are specific non-redox 5-lipoxygenase inhibitors and also interfere directly with COX-1. Adding a COX-1-active resin to an antiplatelet agent or an NSAID stacks two mechanisms of platelet suppression and two routes to gastric injury. The effect has been demonstrated in vitro with B. serrata extracts; no clinical event series exists.
Clinical note: Prefer to avoid the combination in patients on dual antiplatelet therapy. Where Ru Xiang is used with an NSAID, consider gastric protection and review the need for both.
Mo Yao (Commiphora myrrha), the classical paired drug
Ru Xiang and Mo Yao are so habitually co-prescribed that prescriptions abbreviate the pair, and the pairing has a measured pharmacological basis. In a study that used Boswellia carterii itself rather than B. serrata, the combined water extract suppressed carrageenan-induced paw oedema more strongly than either resin alone at 2 and 3 hours, inhibited PGE2 production, and significantly reduced writhing and prolonged latency in oxytocin-induced dysmenorrhoea in mice where frankincense extract alone had no effect on writhing. Twelve candidate active compounds were identified in the combination extract by UPLC-MS/MS. Since both resins are blood-moving drugs used together at full dose, the antiplatelet caution above applies to the pair rather than to Ru Xiang alone.
Clinical note: When the Ru Mo pair is prescribed, apply the anticoagulant and perioperative cautions to the combination. Both resins are also common causes of gastric upset, which is the usual dose-limiting effect in practice.
High-fat food and fat-containing vehicles (dosing condition)
In a randomised, open, single-dose, two-way crossover study in healthy male volunteers, giving a Boswellia serrata gum resin dry extract with a standardised high-fat meal produced several-fold higher AUC and peak concentrations of beta-boswellic acid, KBA and AKBA than the fasted state, and alpha-boswellic acid and acetyl-alpha-boswellic acid became detectable in plasma only when given with the fat. This is a properly conducted human pharmacokinetic study, though with B. serrata extract rather than B. carterii resin.
Clinical note: Keep dosing consistent with respect to food. If a patient is stable on Ru Xiang taken with meals, a change to fasted dosing can cut exposure several-fold and look like loss of efficacy, and the reverse can look like a new adverse effect.
Boswellia papyrifera, Boswellia frereana and Boswellia serrata resins substituted for Ru Xiang
Olibanum reaches the market from several Boswellia species and they are not equivalent. B. serrata resin carries about 0.7% AKBA against about 7% in B. sacra/B. carteri material. B. papyrifera is distinguished by incensole and incensole acetate, which B. carterii/B. sacra does not show, while B. carterii/B. sacra shows beta-caryophyllene oxide and B. serrata shows serratol - a TLC method exists that separates all three. A further layer of confusion is that major botanical references have treated B. carterii and B. sacra as synonyms while chiral GC-MS data have been used to argue they are distinct species, so even a correctly labelled sample may not be the material a given study used.
Clinical note: Specify the species when ordering and expect the supplier to be able to name it. Do not assume that a clinical dose derived from a standardised B. serrata extract translates to an equivalent weight of B. carterii crude resin, or the reverse.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| decoction, or powder/pills | 3–5 g | Daily | — | — | 中国药典 2020 【用法与用量】煎汤或入丸、散，3～5g；外用适量，研末调敷。 【注意】孕妇及胃弱者慎用。 【性味与归经】辛、苦，温。归心、肝、脾经。 — Chinese Pharmacopoeia 2020, quoted verbatim; route and cautions preserved. Replaces a cleared category-filler value. |
Dui Yao — Herb Pairs
The classical two-herb combinations this herb appears in, each with an action neither herb has alone.
Together they move blood and qi more strongly than either alone, dispersing stasis, reducing swelling and relieving pain; one leans to moving qi, the other to breaking blood stasis.
Classic for traumatic injury, painful swellings and stasis pain of the chest, abdomen and limbs; both are also core to Huo Luo Xiao Ling Dan (Zhang Xichun). Hard on the stomach; avoid in pregnancy.
Named pairing — Lü Jingshan, Shi Jinmo Dui Yao
Evidence Tier
Strong evidence · 6 studiesRecorded studies by study design, strongest design at the top. This is a study-design tier only, not a GRADE rating: it does not weigh risk of bias, consistency or precision.
Systematic review / meta-analysis
1
1 verified · 0 unverified
Randomized controlled trial
2
2 verified · 0 unverified
Other clinical trial
0
Observational / case report
0
In vitro / animal
3
1 verified · 2 unverified
Show 3 studies
- Gum resin of Boswellia serrata inhibited human monocytic (THP-1) cell activation and platelet aggregation
- Evaluation of the anti-inflammatory and analgesic properties of individual and combined extracts from Commiphora myrrha, and Boswellia carterii
- Boswellic acids: novel, specific, nonredox inhibitors of 5-lipoxygenase.
Other / unclassified
0
Verified: design read from PubMed for a DOI that resolves to the cited paper Unverified: taken from the study's recorded description
Clinical Studies
Gum resin of Boswellia serrata inhibited human monocytic (THP-1) cell activation and platelet aggregation
Water and hydroalcoholic gum resin extracts at 3 mg dry weight per mL completely inhibited ADP-induced platelet aggregation, comparably to 20 micrograms per mL of heparin. Both extracts extended prothrombin time from about 13 to over 60 seconds and APTT from about 32 to over 90 seconds. The hydroalcoholic extract inhibited factors Xa and XIa strongly at 6 micrograms, where about 10 micrograms of heparin was needed for around 30% inhibition. HPLC put AKBA at 9% w/w in the hydroalcoholic and 7.8% in the water extract. The species is Boswellia serrata, not B. carterii.
Evaluation of the anti-inflammatory and analgesic properties of individual and combined extracts from Commiphora myrrha, and Boswellia carterii
One of the few pharmacological studies that used Boswellia carterii itself. Myrrh water extract and the combined myrrh-frankincense extract inhibited formalin-induced paw oedema by 30.44% and 23.50% at 3.9 and 5.2 g/kg, all samples significantly suppressed PGE2, and the combination suppressed carrageenan-induced oedema more strongly at 2 and 3 hours than either alone. In oxytocin-induced dysmenorrhoea, frankincense extract alone did not reduce writhing while the combination significantly reduced writhing and prolonged latency, supporting the classical Ru Xiang and Mo Yao pairing.
Effect of Food Intake on the Bioavailability of Boswellic Acids from a Herbal Preparation in Healthy Volunteers
A randomised, open, single-dose, two-way crossover study in healthy male subjects given three capsules equivalent to 786 mg of Boswellia serrata gum resin dry extract fasted or with a standardised high-fat meal. The fed state produced several-fold greater AUC and Cmax for beta-boswellic acid, KBA and AKBA, and alpha-boswellic acid and acetyl-alpha-boswellic acid were detectable only in the fed state. The authors call the food effect profound and important for any therapeutic use of boswellic acids.
Efficacy and tolerability of Boswellia serrata extract in treatment of osteoarthritis of knee – A randomized double blind placebo controlled trial
A randomised double-blind placebo-controlled crossover trial in 30 patients with knee osteoarthritis, eight weeks per arm with a washout. All patients on active treatment reported reduced knee pain, increased knee flexion and increased walking distance, and less frequent knee swelling; radiographs were unchanged. Tolerability was good apart from minor gastrointestinal adverse effects. Small, and conducted with a standardised Boswellia serrata extract rather than B. carterii resin.
Effectiveness of Boswellia and Boswellia extract for osteoarthritis patients: a systematic review and meta-analysis
Seven randomised trials with 545 osteoarthritis patients. Boswellia and its extracts reduced pain (VAS weighted mean difference -8.33, 95% CI -11.19 to -5.46; WOMAC pain -14.22, 95% CI -22.34 to -6.09), reduced WOMAC stiffness (-10.04, 95% CI -15.86 to -4.22) and improved WOMAC function (-10.75) and the Lequesne index (-2.27), with at least four weeks of treatment recommended. The included trials used Boswellia serrata, so the result supports the genus rather than Ru Xiang specifically.
Boswellic acids: novel, specific, nonredox inhibitors of 5-lipoxygenase.
The foundational mechanistic paper: boswellic acids inhibit 5-lipoxygenase and therefore leukotriene biosynthesis by a specific, non-redox mechanism, distinguishing them from redox-active and iron-chelating inhibitors. This is the pharmacology that underlies both the anti-inflammatory use of frankincense and its interaction profile with antiplatelet and anti-inflammatory drugs.
Historical Texts
Ming Yi Bie Lu
Six DynastiesBen Cao Gang Mu
Ming dynastyReferences
- Mannino G, Occhipinti A, Maffei M. Quantitative Determination of 3-O-Acetyl-11-Keto-βBoswellic Acid (AKBA) and Other Boswellic Acids in Boswellia sacra Flueck (syn. B. carteri Birdw) and Boswellia serrata Roxb . Molecules (2016) [DOI]
- Woolley CL, Suhail MM, Smith BL, Boren KE, Taylor LC, Schreuder MF, Chai JK, Casabianca H. Chemical differentiation of Boswellia sacra and Boswellia carterii essential oils by gas chromatography and chiral gas chromatography–mass spectrometry . Journal of Chromatography A (2012) [DOI]
- Huang K, Chen Y, Liang K, Xu X, Jiang J, Liu M, Zhou F. Review of the Chemical Composition, Pharmacological Effects, Pharmacokinetics, and Quality Control of Boswellia carterii . Evidence-Based Complementary and Alternative Medicine (2022) [DOI]
This information is for educational purposes only and is not intended to replace professional medical advice. Always consult a qualified healthcare provider before using any herbal remedy, especially if you are pregnant, nursing, or taking medications.
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