Song Xiang

Star

Pinus massoniana Lamb.

Not yet clinically reviewed

Pinyin: Song Xiang
Colophonium Pine Resin

Traditionally used for

  • Pain & joints
  • Skin
Moderate evidence · 5 studies

☯ TCM Properties

Category: external applications
Temperature: warm
Taste: sweet, bitter
Meridians: liver, spleen
Functions:

Dries Dampness, dispels Wind and alleviates pain; Discharges pus, removes toxins and generates flesh; Expels worms and other parasites

Traditional Chinese Uses

Song Xiang (Resina Pini) is the hardened rosin (colophony) tapped from pine trunks, chiefly Pinus massoniana. Sweet, bitter and warm, entering the Liver and Spleen channels, it is used mainly as an external-application medicinal. It dries Dampness, dispels Wind and alleviates pain, being applied to Wind-Damp rheumatic joint pain, scabies, ringworm (tinea) and weeping, itchy skin lesions. It also discharges pus, resolves toxin and generates flesh, so it is compounded into plasters and ointments for chronic non-healing sores, boils, abscesses, anal fistula and traumatic wounds; it can additionally expel parasites.

Song Xiang is primarily for external use, powdered into pastes, plasters or medicated oils. Internal use is small (roughly 0.5–1 g) and cautious, as the resin is warming and can irritate; unprocessed rosin is not swallowed in quantity.

Western Herbalism Properties

Actions:
analgesicantimicrobialvulnerarystimulant

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Botanical Description

Song Xiang is the hardened resin (rosin) tapped from the trunks of several Chinese pines (Pinaceae), chiefly Pinus massoniana and P. tabuliformis. The source trees are evergreen conifers 15–30 m tall with reddish-brown plate-fissured bark and bundles of two or three needles 8–25 cm long. Resin is collected by V-shaped scoring of the trunk, allowing the viscous oleoresin to flow into cups; upon distillation of the volatile turpentine fraction, the residue (colophony or rosin) sets as a translucent, brittle, glassy mass ranging from pale yellow to deep amber-brown. The fracture is conchoidal and lustrous; the substance is insoluble in water, soluble in ethanol, and softens readily on warming. It bears a faint terebinthine odour.

Active Constituents

Abietic acid

Abietane-type diterpene resin acid

Concentration: the principal resin acid of the drug; Chinese materia medica gives abietic acid plus its anhydride at roughly 80% of Song Xiang, and pharmacopoeial Resina Pini has been reported as more than 50% abietic acid

Abietic acid is the compound that carries most of the wound-healing activity attributed to pine resin. Isolated from Resina Pini, it increased migration and tube formation in human umbilical vein endothelial cells through ERK and p38 MAPK activation, and 0.8 microM abietic acid accelerated wound closure in a mouse cutaneous wound model. It is also a weak but real contact allergen in its own right, and inhibits testosterone 5-alpha-reductase in vitro.

Dehydroabietic acid and 7-oxodehydroabietic acid

Aromatic abietane-type diterpene resin acid

Concentration: minor in fresh resin; rises as the drug ages and oxidises in air

7-Oxodehydroabietic acid was the single most potent contact allergen recovered when unmodified rosin was fractionated and the fractions patch-tested on colophony-sensitive people. This is the chemistry behind the observation that old, air-exposed Song Xiang plasters sensitise more readily than freshly prepared ones.

15-Hydroperoxyabietic acid

Diterpene hydroperoxide (autoxidation product of abietic acid)

Concentration: absent from freshly tapped resin; generated on air exposure

Identified as the most potent contact allergen of colophony and used as a patch-test hapten. Its allergenic activity is unchanged by methyl esterification of the carboxyl group, showing that the hydroperoxide, not the acid, is the sensitising group.

Neoabietic, levopimaric and palustric acids

Abietane-type diterpene resin acid isomers

Concentration: together a substantial minority of the resin acid fraction

Labile conjugated-diene isomers that interconvert on heating and oxidise readily on standing. In their unoxidised state they contribute little individually to colophony dermatitis; their importance is as precursors of the oxidised allergens.

Pimaric and isopimaric acid

Pimarane-type diterpene resin acids

Concentration: the main non-abietane resin acids of pine rosin, a minor fraction of the total

Structurally more stable than the abietane isomers because they lack the conjugated diene. At their natural concentrations relative to abietic acid they were found to play an insignificant individual part in colophony dermatitis.

Resin hydrocarbons (resenes)

Neutral diterpene and sesquiterpene hydrocarbons

Concentration: about 5-6% of the drug

The neutral, non-acidic fraction that remains after the resin acids are accounted for. It contributes to the tackiness and film-forming behaviour that make Song Xiang useful as a plaster base.

Residual volatile oil (alpha-pinene, beta-pinene)

Bicyclic monoterpenes

Concentration: about 0.5% of the finished drug; Song Xiang is by definition the solid residue left after the turpentine has been distilled off

Song Xiang is defined as the resin of Pinus massoniana or Pinus tabuliformis after removal of the volatile oil, so only traces of pinene remain. These traces account for the residual pine odour and for some of the local irritancy of freshly melted resin.

⚠ Drug Interactions

Colophony-containing adhesive plasters, hydrocolloid dressings and topical medicaments

Major Evidence: Established

Colophony sensitises through oxidation products rather than through the fresh resin. Air exposure converts abietic acid to 15-hydroperoxyabietic acid, the most potent identified allergen, and to 7-oxodehydroabietic acid; both were confirmed by preparative fractionation combined with patch testing in colophony-sensitive patients. A patient already sensitised by sticking plaster, hydrocolloid dressing, depilatory wax or solder flux will react to a Song Xiang plaster, and the reverse is equally true.

Clinical note: Ask about sticking-plaster and wax-depilation rashes before prescribing a rosin-based plaster. Do not use Song Xiang topically in a patient with a known positive colophony patch test. Prefer freshly prepared resin over stock that has stood open, since allergenicity rises with air oxidation.

Heated rosin fume (solder flux, plaster manufacture, moxa-plaster work)

Major Evidence: Established

Fume generated when colophony is melted is a well-characterised cause of occupational asthma. In a follow-up of 39 electronics workers investigated by bronchial provocation to colophony-containing solder flux, non-specific histamine reactivity normalised in only about half of those who left the factory, and only 2 of 20 affected workers who left were symptom-free one to four years later; those merely moved to other work within the same factory did far worse, indicating that even indirect exposure sustains the disease.

Clinical note: Melting Song Xiang to make plasters is a fume-generating operation. Do it with ventilation, and keep asthmatic patients and staff away from the fume. Once colophony asthma is established, removal from exposure must be complete, not partial, and recovery may still be incomplete.

Finasteride, dutasteride and other 5-alpha-reductase inhibitors

Theoretical Evidence: Theoretical

Abietic acid isolated from Resina Pini was characterised as a testosterone 5-alpha-reductase inhibitor in a cell-based assay. Whether enough abietic acid crosses intact skin from a rosin plaster to affect systemic androgen metabolism has never been measured, so this remains a laboratory observation and not a demonstrated clinical interaction.

Clinical note: No action needed for ordinary topical use. Worth mentioning only if a patient is on a 5-alpha-reductase inhibitor and is using rosin preparations over large areas of broken skin.

Evidence Tier

Moderate evidence · 5 studies

Recorded 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.

Verified: design read from PubMed for a DOI that resolves to the cited paper Unverified: taken from the study's recorded description

Clinical Studies

Abietic acid isolated from pine resin (Resina Pini) enhances angiogenesis in HUVECs and accelerates cutaneous wound healing in mice

Park JY; Lee YK; Lee DS; Yoo JE; Shin MS; Yamabe N; Kim SN; Lee S; Kim KH; Lee HJ; Roh SS; Kang KS (2017) Journal of Ethnopharmacology animal

Abietic acid from Resina Pini increased migration and tube formation in human umbilical vein endothelial cells, with upregulation of ERK and p38 MAPK. In a mouse cutaneous wound model, groups treated with 0.8 microM abietic acid showed accelerated wound closure compared with controls. This is the best mechanistic support for the classical claim that Song Xiang generates flesh, but it tests the isolated constituent, not the crude resin, and there is no human trial.

Occupational asthma in electronics workers caused by colophony fumes: follow-up of affected workers.

Burge PS (1982) Thorax cohort

Thirty-nine electronics workers were investigated by bronchial provocation testing to colophony-containing solder flux and followed for one to four years. Histamine reactivity returned to normal in about half of those who left their factory but in only one of those relocated within it, and only 2 of 20 workers who left were symptom-free at follow-up. The study establishes that colophony fume causes asthma that often does not remit.

Identification of contact allergens in unmodified rosin using a combination of patch testing and analytical chemistry techniques

Sadhra S; Foulds IS; Gray CN (1996) British Journal of Dermatology cohort

Unmodified rosin was separated by preparative chromatography and the fractions patch-tested on colophony-sensitive individuals, with structures assigned by mass spectrometry, NMR and infrared. Oxidised resin acids proved to be stronger sensitisers than the parent acids, and 7-oxodehydroabietic acid was the most potent single allergen. At naturally occurring concentrations the unoxidised resin acids contributed little individually, except abietic acid, which was a weak but important allergen.

Methyl esterification of 15-hydroperoxyabietic acid does not affect the patch-test result in colophonium allergic patients

Karlberg AT; Bråred-Christensson J; Börje A; Harambasic E; Matura M (2007) Contact Dermatitis cohort

Patch testing in colophonium-allergic patients confirmed that converting the carboxyl group of 15-hydroperoxyabietic acid to its methyl ester does not reduce allergenic activity, supporting the conclusion that the hydroperoxide formed by air oxidation of abietic acid, and not the acid function, is the sensitising element of colophony.

Abietic Acid from Resina Pini of Pinus Species as a Testosterone 5.ALPHA.-Reductase Inhibitor

Roh SS; Park MK; Kim YU (2010) Journal of Health Science in vitro

Abietic acid obtained from Resina Pini of Pinus species inhibited testosterone 5-alpha-reductase in vitro. The finding is a laboratory characterisation of an isolated constituent; no systemic exposure from topical use of the crude resin has been demonstrated.

Historical Texts

Shen Nong Ben Cao Jing

Han dynasty
Lists song zhi, pine resin, in the upper class. It is given as bitter and warm, treating abscesses and malignant sores, head sores and bald patches, scabies and itching wind qi, settling the five viscera and removing heat, with the usual upper-class claim that long use lightens the body. This is the crude tapped oleoresin, the material from which the modern distilled drug Song Xiang is made.

Dian Nan Ben Cao

Ming dynasty
Cited as the source text for the drug under the name song xiang, that is the solid resin remaining after the volatile oil has been removed, as distinct from the crude song zhi of the earlier literature.

Ben Cao Gang Mu

Ming dynasty
Li Shizhen collects the synonyms song zhi, song gao, song fang, song jiao and song xiang under one entry, and records the purification of the crude resin by repeated melting in water before use in plasters and pastes.

References

  1. Karlberg AT; Bohlinder K; Boman A; Hacksell U; Hermansson J; Jacobsson S; Nilsson JLG. Identification of 15-Hydroperoxyabietic Acid as a Contact Allergen in Portuguese Colophony . Journal of Pharmacy and Pharmacology (1988) [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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