Chen Xiang (Agarwood, Aloeswood, or Aquilariae Lignum Resinatum)

Chen Xiang (Agarwood, Aloeswood, or Aquilariae Lignum Resinatum)

What Is Chen Xiang

Chen Xiang commonly known as Agarwood, Aloeswood, Eaglewood, or Aquilariae Lignum Resinatum is the resinous wood of Aquilaria sinensis (Lour.) Gilg, which is an evergreen tree belonging to the family Thymelaeceae. It is a relatively rare and precious Chinese herbal medicine, which first appeared in <Mingyi Bie Lu> during the Northern and Southern Dynasties (420-589 CE).

There are approximately 21 species of Aquilaria, most of which are distributed in southern China, eastern India, and Southeast Asian countries. Among them, the plants known to produce fragrant resin include A. malaccensis, A. sinensis, A. rugosa, A. filaria, A. subintegra, and A. beccariana.

A. sinensis has high economic and medicinal value. This plant grows well in low-altitude mountainous areas, hills, and sparsely wooded areas on sunny roadsides. They are distributed in various provinces of China, including Guangdong, Guangxi, Hainan, Yunnan, and other regions.

The formation of agarwood occurs slowly and infrequently in nature. Agarwood plants may produce various secondary metabolites at the site of damage caused by natural factors such as lightning, chopping, burning, insect infestation or microbial invasion, or human factors such as cutting, digging holes, chemical reagent invasion, and bacterial inoculation. After a complex resin production process, these metabolites are deposited in the heartwood to form agarwood. It is the world’s most expensive non-building timber, widely used in cosmetics, incense, perfumes, handicrafts, religious and medicinal fields.

A. sinensis can be gathered in any season. People cut their resinous wood, remove the part without resin, dry them in the shade, chop them into small pieces, crush or grind them into powder, and make them into Chinese herbal medicines.

Chen Xiang contains bornyl ferulate, baimuxinic acid, agarospirol, 4-epi-15-hydroxyacorenone, vetaspira-2, 6-dien-14-al, (4R,5R,7R)-1(10)-spirovetiven-11-ol-2-one, baimuxinol, β-agarofuran, baimuxifuranic acid, 8α,12-dihydroxy-selina-4,11-dien-4-al, 9β-hydroxy-selina-4,11-dien-14-al, 9β-hydroxy-selina-3,11-dien-14-al, 12,15-dioxo-α-selinen, selin-11-en-4α-ol, eudesma-4-en-11,15-diol, 12-epoxy-8-oxoeremophilane, valerianol, 11-hydroxy-valenc-1(10)-en-2-one, neopetasane, longifolene, 3-Oxo-7-hydroxylholosericin A, qinanlactone, qinanol A~E, sinenofuranol, malacinone A~B, aquilarene A~J, aquilarin B, aquilariperoxide A, diterpenes, triterpenes, sterols, flavonoids, chromones, benzylacetones, phenolic acids, and aliphatic compounds.

Generally, Chen Xiang that is rich in resin and has a strong fragrance is preferred.

According to the Chinese Pharmacopoeia, the medicinal nature of Chen Xiang is slightly warm, with a pungent and bitter taste. It has a certain therapeutic effect on the pathological changes of the spleen, stomach, and kidney meridians.

In traditional Chinese medicine, it is often used to promote qi circulation and relieve pain, warm middle energizer and arrest vomiting, promote inspiration to relieve asthma, and treat distending pain in the chest and abdomen, cold pain in the abdomen, nausea, vomiting, belching, loss of appetite, coughing, breathing difficulties, asthma, chronic bronchitis, childhood pneumonia, chronic obstructive pulmonary disease (COPD), stomachache, chronic gastritis, gastroesophageal reflux disease (GERD), intestinal obstruction, peptic ulcer, functional constipation, unstable angina, heart stabbing pain, urinary stone, and urinary retention.

There are more than 100 kinds of traditional Chinese medicine prescriptions that contain it, such as Chen Xiang Hua Qi Wan, Su Zi Jiang Qi Tang, and Si Mo Tang.

Benefits

  • Anti-inflammation, inhibiting LPS-induced nitric oxide production in RAW 264.7 macrophages and carrageenan-induced paw swelling in mice [1, 2].
  • Anti-oxidation, scavenging DPPH radicals and ABTS radicals [3].
    Promoting qi circulation and dispelling cold, treating distending pain in the chest and abdomina caused by qi stagnation due to congealing cold.
  • Warming middle energizer to descend qi, treating vomiting and hiccup caused by stomach cold.
  • Warming the kidney to promote the reception of qi, treating dyspnea of deficiency type caused by deficiency of kidney-qi, insufficiency of the kidney yang, or renal dysfunction.
  • Its extract can inhibit the activity of acetylcholinesterase and α-glucosidase [3].
  • The inhalation administration of agarwood can significantly improve the learning and memory impairment caused by scopolamine in mice [4].
  • Multiple tests have shown that its essential oil can improve anxiety symptoms in mice. In the elevated plus maze test, its volatile oil significantly increased the time, distance, and frequency of mice opening their arms. In the light-dark exploration test, its volatile oil increased the time that mice spent in the light chamber. Additionally, in the open field test, the effectiveness of its volatile oil at a dose of 40 mg/kg was comparable to the positive drug diazepam (2.5 mg/kg) [5].
  • The tail suspension test and forced swimming test have demonstrated that its essential oils can significantly reduce immobility time in mice, indicating good anti-depressive effects [5]. Additionally, grouping treatment of 40 depressed patients found that agarwood fumigation therapy can effectively improve clinical symptoms of depression [6].
  • It can shorten the sleep latency and prolong the sleeping time of mice at a suprathreshold dose of pentobarbital. In addition, grouping treatment of 120 insomnia patients showed that agarwood fumigation therapy significantly improved sleep quality, reduced the severity of insomnia, and improved emotional disorders. It has a significant sedative-hypnotic effect [6].
  • Its 2-(2-phenylethyl)chromone-enriched extract can inhibit gastric epithelial cell death induced by taurocholic acid [7].
  • Aquilariperoxide A inhibits cell proliferation and migration in human cancer cells. Besides, it also has an anti-malaria effect [8].
  • Its essential oil has a good inhibitory effect on both gram-negative and gram-positive bacteria, and its bacteriostatic effect on gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis) is particularly significant.
  • Its alcohol extracts alleviate the occurrence and development of gastric ulcers by inhibiting oxidation and inflammation [9].
  • Research has found that its alcohol extract can significantly reduce the frequency of asthma attacks in a mouse model induced by ovalbumin and aluminum hydroxide, alleviate its pathological damage, improve peripheral blood white cell count and eosinophil count, decrease the levels of inflammatory cytokines IL-1β and IL-17, increase the level of anti-inflammatory cytokine IL-10, while downregulating the expression of IL-1R, tumor necrosis factor receptor R (TNFR), nuclear transcription factor-kappaB (NF-κB), Bax, and caspase-3 mRNA [10].

Combinations

Side Effects

  • A small percentage of patients using it may cause allergic skin rashes.

Precautions and Warnings

  • The dosage of Chen Xiang should be controlled between 1-5g.
  • It can be prepared into decoctions, pills, and powders.
  • When preparing a decoction containing Chen Xiang, it is recommended to first decoct the other herbs and then add them toward the end of the boiling process.
  • People who are allergic to Chen Xiang should not take it.
  • Patients with hyperactivity of fire due to yin deficiency should not take it.
  • Patients with visceral prolapse due to qi deficiency of spleen and stomach should not take it.