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Description

Oud (Agar wood, Gaharu, Jinko, Aloeswood, Eaglewood & many more names to be added) is the king of all aromas. More valuable than precious gemstones, oud’s natural wealth is derived from large evergreen trees of the Aquilaria family that are native to Bangladesh, India, Malaysia, Indonesia, Cambodia & many more southeast Asian countries. Normally the heartwood of these trees is relatively light and pale in color. However, sometimes the trees are attacked by a special type of fungus. They become infected, and in response to the attack they produce a dense, dark, aromatic resin. This embedded resin is called Oud (Agar wood), which is valued in many cultures for its distinctive, rich and beautiful natural fragrance. Oud is used in medicines, incense, perfume, cosmetics and religious practices. In some countries sculptures fashioned out of oud are held in especially high esteem. In Japan and China it is believed that wearing a necklace or bracelet made of oud brings good luck and keeps devils away.

One of the reasons for the relative rarity and high cost of oud (Agar wood) is the continuing depletion of this unique, wild resource. To prevent its extinction, in 1995 the Convention on International Trade in Endangered Species of Wild Fauna and Flora listed Aquilaria malaccensis, as a potentially threatened species in Appendix II. In 2004 all Aquilaria species were listed in Appendix II; however, a number of countries are disputing this listing.

Oud (Agar wood) comes in a few colors & many grades. Pricing varies according to grade and country of origin.

History

The natural odour of Oud (Agar wood) is complex, aromatic and pleasing, with no similar, natural herbal analogues. As a result, Oud (Agar wood) and its extracted oil, have gained great cultural and religious significance amongst the rich and elite in ancient civilizations around the world. The Middle Eastern Gulf countries value oud for traditional reasons: history says that Adam carried a stick of oud (Agar wood) in his hand when he came to earth, and Eve was dressed in the leaves of the Agar wood trees. Japanese, Taiwanese, Chinese and Vietnamese people attach religious significance to oud, and also use it as a natural, medicinal remedy. The Chinese chronicle Nan zhou yi wu zhi, written by Wa Zhen of the Eastern Wu Dynasty, mentions Agar wood produced in the Rinan commandery (now Central Vietnam), and how people collected it in the mountains:

Starting in 1580 after Nguyen Hoang took control over the central provinces of modern Vietnam, he encouraged trade with other countries, specifically China and Japan. Oud (Agar wood) was exported in three varieties: Calambac (kỳ nam in Vietnamese), trầm hương (very similar but slightly harder and slightly more abundant), and oud or Agar wood proper. A pound of Calambac bought in Hoi An for 15 taels could be sold in Nagasaki for 600 taels. The Nguyen Lords soon established a Royal Monopoly over the sale of Calambac. This monopoly helped fund the Nguyen state finances during the early years of the Nguyen rule.

Xuanzang's travelouges and the Harshacharita, written in 7th century A.D. in the Northern part of the Indian subcontinent, mentions use of Agar wood products such as 'Xasipat' (writing-material) and 'aloe-oil' in ancient Assam (Kamarupa) & Sylhet (Bangladesh). The tradition of making writing-materials from its bark still exists in Assam & Sylhet.

Benefits of Oud (Agar wood)

Oud (Agar wood) possesses a salient mystery that has captured the hearts of pious Devotees, royal elites & elegant peoples for many centuries. Oud- this earthly, natural and unique gift of God- has the rare ability to ground our inner being. As an intangible essence, it has the power to inspire our hearts & souls that we may glimpse the Divine realms.

Oud (Agar wood) is not only therapeutic to the mind and body- it is also an exercise in sensory refinement of the heart and soul. Experiencing the fine aroma of each distinct strand of Oud, you will discover an art form that is at once subtle and deeply powerful- an aroma that is both penetrating and naturally relaxing.

Elite and elegant clientele from nations around the globe employ this most rich, natural aroma to compliment their personalities; others offer it to their God when they go to pray. Today the biggest consumers are Middle Eastern Gulf Arabs (UAE., KSA., Bahrain, Qatar, Kuwait & Oman are the biggest), followed by Japanese, Chinese, Taiwanese and Vietnamese, with growing interest being shown by Americans and Canadians.

The benefit of using this natural aroma is that once you apply this rich aroma to your clothes, a unique and heavenly scent will pervade your surroundings and will create a remarkable scented aura among others, bringing coolness to the heart and mind.

You can avail yourself of the unique, rich, spiritual, mental and physical benefits of oud (Agar wood) by visiting any of the showrooms listed on this website, or many other showrooms around the globe!

Be aware of :

Etymology

Name of Oud (Agar wood) in different cultures:

Formation

There are fifteen species in the Aquilaria genus and eight are known to produce Oud (Agar wood). In theory Oud (Agar wood) can be produced from all members; however, until recently it was primarily produced from Aquilaria malaccensis. Aquilaria agallocha and Aquilaria secundaria are synonyms for Aquilaria malaccensis. Aquilaria crassna and Aquilaria sinensis are the other two members of the same genus that are usually harvested.

Formation of Oud (Agar wood) occurs in the trunk, branch and roots of the trees that have been infected by a parasitc ascomycetous mold, Phaeoacremonium parasitica, a dematiaceous (dark-walled deep infected) fungus. As a response, the tree produces a resin high in volatile organic compounds that aids in suppressing or retarding the fungal growth. While the unaffected wood of the tree is relatively light in color & almost useless, the resin dramatically increases the mass and density of the affected wood, changing its color from a pale beige to dark brown or black. In natural forest only as rare as 7% of the trees are infected by the fungus in natural way. A common method in artificial forestry is to inoculate all the trees with the fungus, but no sustainable result has yet been noted.

High quality resin comes from a tree's natural immune response to a fungal attack. It is commonly known as Oud (Agar wood) Super (King quality). An inferior resin is created using forced methods where aquilaria trees are deliberately wounded, leaving them more susceptible to a fungal attack. This has not yet produced Agar wood of valuable.

Conservation of Agar wood-producing Species

Overharvesting and habitat-loss threatens some populations of agarwood-producing species. Concern over the impact of the global demand for Oud (Agar wood) has thus led to the inclusion of the main taxa on CITES Appendix II, which requires that international trade in Oud (Agar wood) is subject to controls designed to ensure that harvest and exports are not to the detriment of the survival of the species in the wild (I must remember here my friend Mr. James Compton from Australia who has worked hard as an regional director to regulate these).

We thank Almighty that our company, “OUD LINE”, is an active member of the Malaysian Timber Industry Board and that our Cites permit allows us to legally export oud (Agar wood). In Malaysia 59% of the land is occupied by forests & rain forests.

In addition, Oud (Agar wood) plantations have been established in a number of countries. The success of these plantations depends on the stimulation of Oud (Agar wood) production in the trees. Numerous inoculation techniques have been developed, with varying degrees of success, but so far no sustainable report has been found.

Journal on Aquilaria species that produces Oud (Agar wood)

See: Ng, L.T., Chang Y.S. and Kadir, A.A. (1997) "A review on agar (gaharu) producing Aquilaria species" Journal of Tropical Forest Products 2(2): pp. 272-285.^[6]

A Journal of the Bangladesh Pharmacological Society (BDPS) Bangladesh J Pharmacol 2009; 4: 24-28
Journal homepage: www.banglajol.info; www.bdjpharmacol.com
Indexed in Bangladesh Journals Online, Directory of Open Access Journals, Google Scholar and HINARI
ISSN: 1991-007X (Print); 1991-0088 (Online); DOI: 10.3329/bjp.v4i1.851

Analysis of essential oil of eaglewood tree (Aquilaria agallocha Roxb.) by gas chromatography mass spectrometry

Md. Nazrul Islam Bhuiyan, Jaripa Begum and Md. Nurul Huda Bhuiyan
BCSIR Laboratories, P.O. Chittagong Cantonment, Chittagong 4220, Bangladesh.

The study was carried out to find out the differences in composition of oils obtained from healthy, naturally infected and artificially screws wounds eaglewood (Aquilaria agallocha Roxb.) using gas chromatography mass spectrometry analysis. Natural healthy plants agar contained octacosane (19.83%), naphthalene, 1,2,3,5,6,7,8,8a-octahydro-1,8a-dimethyl-7-(1-methylethenyl)-, [1R- (1.alpha.,7.beta.,8a.alpha.)]- (12.67%), 5-isobutyramido-2-methyl pyrimidine (13.52%), caryophyllene oxide (11.25%) and (.+-.)-cadinene (5.46%). Natural infected plants agar (super agar) contained cycloheptane, 4-methylene-1-methyl -2-(2-methyl-1-propen-1-yl)-1-vinyl- (46.17%), caryophyllene oxide (33.00%) and 7-isopropenyl-4a-methyl-1-methylenedecahydronaphthalene (20.83%). Artificially screw injected plants agar contained diisooctyl phthalate (71.97%), 1H-cycloprop[e]azulen-4-ol, decahydro-1,1,4,7-tetramethyl-, [1ar- (1a.alpha.,4.beta.,4a.beta., 7.alpha., 7a.beta., 7b.alpha.)]- (9.16%), hexadecanoic acid (7.05%), naphthalene, 1,2,3,5,6,7,8,8a-octahydro-1,8a-dimethyl-7-(1- methylethenyl)-, [1R-(1.alpha.,7.beta.,8a.alpha.)]- (6.45%) and aristolene (5.36%). This study showed a marked difference in the oil compositions among the treatmentswith regards to their quality.

Introduction

Agar, a valuable aromatic oleoresinous deposit found in the stems of Aquilaria agallocha Roxb. (syn. Acquilaria malaccensis Lamk., family: Thymelaeaceae) is available in Bangladesh, East India and other parts of South East Asia (Gibson, 1977). The present investigation includes essential oils and identification of fungal isolates from three samples of agar collected in the Sylhet region of Bangladesh. The eaglewood tree A. agallocha is a precious floral wealth of Indian subcontinents like Bangladesh (Anonymous., 1948). The resinous patches of fragrant wood of the plant known as 'agar' is used as incense in Egypt, Arabia and throughout the northeast part of Bangladesh where it can be found. The oil obtained from agar is described as a stimulant, cardiac tonic and carminative. It is also used in the cosmetic and pharmaceutical industries. Agarwood (jinkoh in Japanese) is an oriental medicine for use as a sedative (Okugawa et al., 1993). Agar is considered to be a pathological product produced by fungal invasion of the host (Qi Shu-Yuan et al., 1992). Since 1938, few workers have been studying about agar formation and reported the agar zones to be associated with mold and decay fungi (Bose, 1938; Bhattacharyya et al., 1952; Jalaluddin, 1977; Venkataramanan et al., 1985; Beniwal, 1989; Tamuli et al., 2000ab; Mitra and Gogoi, 2001). Among different fungal species reported to be associated with agar zones, few could exhibit pathogenesis with the development of disease symptoms while others seem to be of saprophytic nature in different eco-geographical conditions. Studies on the oil of infected A. agallocha were made by various workers (Maheshwari et al., 1963; Varma et al., 1965; Paknikar and Naik, 1975; Thomas and Ozainne, 1976; Pant and Rastogi, 1980; Bhandari et al., 1982; Nagashima et al., 1983; Ishihara et al., 1991, 1993). Maheshwari et al., (1963) isolated three new sesquiterpenic furanoids of the selinane group from agarwood oil, obtained from the fungus infected plant and their structures and absolute configurations determined by degradative studies and physical measurements. Varma et al., (1965) examined that degradative studies and physical measurements supported by an unambiguous synthesis of the derived ketone have led to the assignment of a novel spiroskeleton to agarospirol, a sesquiterpene alcohol isolated from the essential oil of infected agarwood. Paknikar and Naik (1975) reported that on hydrogenation of α- agarofuran and β-agarofuran the same dihydroagarofuran was obtained. Thomas and Ozainne (1976) reported some naturally occurring dihydroagarofuran and isodihydroagarofuran to unequivocally show that the dihydroagarofuran found was indeed dihydro- β-agarofuran and isodihydroagarofuran was isodihydro-β-agarofuran; two separate compounds. Pant and Rastogi (1980) and Bhandari et al,. (1982) isolated a new sesquiterpene, agarol and a couinarinolignan, aquillochin, respectively, from the oil of agarwood. Nagashima et al. (1983) further characterized the presence of two more sesquiterpene alcohols, jinkohol II and jinkoheremol, from the Indonesia agar wood oil. Nakanishi et al. (1984) again reported that a benzene extract of an Indonesian sample of 'Jinkoh' agarwood was found to contain α-agarofuran, 10-epi-γ-eudesmol and oxoagarospirol. Ishihara et al. (1991) characterized seven new sesquiterpenes based on the guaiane skeleton in a sample of agarwood oil. Five new eudesmane sesquiterpenes and three other compounds further characterized by Ishihara et al. (1993) in a sample of agarwood extract produced in the laboratory from A. agallocha of Vietnamese origin. Vesicular-arbuscular myccorhizal association in the tree species and changes in amino acid composition due to pathogenesis were also studied by Tamuli et al. (2002a, 2002b). Tamuli et al., (2005) investigate the difference in composition of oils obtained from healthy, naturally infected and artifically inoculated eaglewood using GC and GC-MS analyses. This investigation shows a marked difference in the oil compositions among the treatments with regards to their quality. Valerianol (3.0%) and tetradecanoic acid (7.1%) contents were recorded higher in the oils of naturally infected plants than in that of healthy ones (0.1% and 6.9% respectively). Pentedecanoic acid was totally absent in the oils of healthy plants, whereas it was found in a greater amount (6.8%) in the oil of naturally infected plants. In contrast dodecanoic acid (3.1%), pentedecanoic acid (6.2%), hexadecanoic acid (31.5%) and octadecanoic acid were found in the oils of healthy plants, while the oils obtained from naturally infected plants contained lower amounts of these components (2.3%, 4.8%, 20.0% and 1.0% respectively). The oils obtained from the inoculated plants showed almost similar distribution of the components with healthy plants. So far the qualitative study of the oils of healthy and wounds eaglewood has yet to be investigated. The present investigation was, therefore, undertaken to study the qualitative differences in the oils obtained from healthy, naturally infected and artificially screw wounds eaglewood. This paper reports the results obtained by GC-MS on A. agallocha oils.

Materials and Methods

Plant material: A. agallocha was collected from the Sylhet of Bangladesh during November 2007. The specimen was identified by Dr. Mohammad Yusuf (Taxonomist), BCSIR Labs. Ctg. One-voucher specimen (Y-699) was deposited in the herbarium of BCSIR Laboratory,Chittagong. Extraction of essential oil: Essential oils were extracted from healthy plants, natural fungal inoculated plants (super agar) and artificial screws injected plants. All those three types of plant materials were collected from Sylhet, crashed and dried and then grinned individually. The grinded materials were soak in distilled water up to 14 days and filtered them separately. The filtrate water mixtures were placed with Clevenger-type apparatus individually for isolation of oils by hydrodistillation (Clevenger, 1928). After 72 hours essential oils were collected separately and dried over anhydrous sodium sulfate. The oils were then stored in sealed container under refrigeration prior to analysis. GC-MS analysis: The three types of essential oil in different types of woods from A. agallocha were analyzed by GC-MS electron impact ionization (EI) method on GC-17A gas chromatograph (Shimadzu) coupled to a GC-MS QP 5050A mass spectrometer (Shimadzu); fused silica capillary column (30 m x 2.5 mm; 0.25 mm film thickness), coated with DB-5 ms (J&W); column temperature 100oC (2 min) to 250oC at the rate of 3oC/min; carrier gas, helium at constant pressure of 90 Kpa. Acquisition parameters full scan; scan range 40-350 amu. Identification of the compounds: Compound identification was done by comparing the NIST library data of the peaks with those reported in literature, mass spectra of the peaks with literature data. Percentage composition was computed from GC peak areas on with DB-5 ms column without applying correction factors.

Results and Discussion

Plant material: A. agallocha was collected from the Sylhet of Bangladesh during November 2007. The specimen was identified by Dr. Mohammad Yusuf (Taxonomist), BCSIR Labs. Ctg. One-voucher specimen (Y-699) was deposited in the herbarium of BCSIR Laboratory,Chittagong. Extraction of essential oil: Essential oils were extracted from healthy plants, natural fungal inoculated plants (super agar) and artificial screws injected plants. All those three types of plant materials were collected from Sylhet, crashed and dried and then grinned individually. The grinded materials were soak in distilled water up to 14 days and filtered them separately. The filtrate water mixtures were placed with Clevenger-type apparatus individually for isolation of oils by hydrodistillation (Clevenger, 1928). After 72 hours essential oils were collected separately and dried over anhydrous sodium sulfate. The oils were then stored in sealed container under refrigeration prior to analysis. GC-MS analysis: The three types of essential oil in different types of woods from A. agallocha were analyzed by GC-MS electron impact ionization (EI) method on GC-17A gas chromatograph (Shimadzu) coupled to a GC-MS QP 5050A mass spectrometer (Shimadzu); fused silica capillary column (30 m x 2.5 mm; 0.25 mm film thickness), coated with DB-5 ms (J&W); column temperature 100oC (2 min) to 250oC at the rate of 3oC/min; carrier gas, helium at constant pressure of 90 Kpa. Acquisition parameters full scan; scan range 40-350 amu. Identification of the compounds: Compound identification was done by comparing the NIST library data of the peaks with those reported in literature, mass spectra of the peaks with literature data. Percentage composition was computed from GC peak areas on with DB-5 ms column without applying correction factors.

Results and Discussion

The oil of healthy, naturally infected and artificially screws injected plants of A. agallocha contained 0.15% (w/v), 0.80% (w/v) and 0.35% (w/v) oil respectively.

The oils were colorless, having pleasant smell. The oil of healthy, naturally infected and artificially screws injected plant agar was analyzed by GC-MS. Twenty nine compounds in the healthy oil, three compounds in the super oil and five compounds in the artificial screws infected oil were identified. The data are shown in Table I, II and III respectively. Investigation showed a marked difference between the oils obtained from naturally infected and healthy plants with regards to their quality. Healthy plants oil contained octacosane (19.83%), naphthalene, 1,2,3,5,6,7,8,8a-octahydro-1,8adimethyl- 7-(1-methylethenyl)-, [1R (1.alpha.,7.beta., 8a.alpha.)]- (12.67%), 5-isobutyramido-2-methyl pyrimidine (13.52%), caryophyllene oxide (11.25%) and (.+-.)-cadinene (5.46%). Natural infected plants (super agar) contained cycloheptane, 4-methylene-1-methyl-2- (2-methyl -1-propen-1-yl ) -1-vinyl- (46.17%), caryophyllene oxide (33.00%) and 7-Isopropenyl-4amethyl- 1-methylenedecahydronaphthalene (20.83%). Artificially screw injected plants contained diisooctyl phthalate (71.97%), 1H-cycloprop[e]azulen-4-ol, decahydro 1,1,4,7-tetramethyl-, [1ar-(1a.alpha.,4.beta., 4a.beta., 7.alpha., 7a.beta., 7b.alpha.)]- (9.16%), hexadecanoic acid (7.05%), naphthalene, 1,2,3,5,6,7,8,8aoctahydro- 1,8a-dimethyl-7-(1-methylethenyl)-, [1R- (1.alpha.,7.beta.,8a.alpha.)]- (6.45%) and aristolene (5.36%). The oils obtained from the inoculated plants showed almost similar distribution of the components. But some of the components were found in the oils of artificially inoculated plants including naturally infected whereas those are totally absent in the oil of healthy plants. 7-Isopropenyl-4a-methyl-1- methylenedecahydronaphthalene and cycloheptane, 4- methylene-1-methyl-2-(2-methyl-1-propen-1-yl)-1-vinyl - were totally absent in the oil of healthy plants and natural infected plants oil. It was observed that the characteristic components of agarwood oil were found to be lower in the oils obtained from healthy samples. The oils obtained from artificially inoculated agarwood have no such differences with the oils of healthy wood though little changes were observed. This may indicate that naturally infected type of agarwood would not be achieved by artificially screws injected plants oil. The observations made by us showed that the microflorais of great importance in production of specialized type of agarwood for best quality agar oil. However, there may exist variants or eco-types within the agarwood plant species. If natural variant or type exists within the plant species, the fungal pathogens might be host type specific or variant specific. If it is so, there may exist specific host variant pathogen/host type-pathogen relationship, which determines the success of artificial inoculation. Therefore, identification of natural variant or eco-type and the specific host-pathogen relationship under different ecological conditions is expected to give clue for unraveling the secret of agar formation. Then only artificial supplement of inoculum to the specific host might give positive result for induction of disease in the plant. On the basis of above fact it may be concluded that A. agallocha, may be utilized as a source of natural octacosane, cycloheptane, 4-methylene-1- methyl-2-(2-methyl-1-propen-1-yl)-1-vinyl- and diisooctyl phthalate respectively.

References

Anonymous. The wealth of India: Raw materials. Vol 1. New Delhi, Publication and Information Directorate, CSIR, 1948, pp 88-90. / Beniwal BS. Silvical characteristics of Aquilaria agallocha Roxb. Indian Forest. 1989; 115: 17-21. Bhandari P, Pant R, Rastogi RP. Aquillochin: A coumarinolignan from Aquilaria agallocha. Phytochemistry 1982; 21: 2147-49. http://dx.doi.org/10.1016/0031-9422(82)83075-6 / Bhattacharyya B, Datta A, Baruah HK. On the formation and development of agaru in Aquilaria agallocha. Sci Cult. 1952; 18: 240- 41. / Bose SR. The nature of 'Agaru' formation. Sci Cult. 1938; 4: 89- 91. / Clevenger JF. Apparatus for determination of volatile oil. J Amer Pharm Assoc. 1928; 17: 346. / Gibson IAS. The role of fungi in the origin of oleoresin deposits (Agaru) in the wood of Aquillaria agallocha (Roxb.). Bano Biggyn Patrika. 1977; 6: 16-26. / Ishihara M, Tsuneya T, Uneyama K. Fragrant sesquiterpenes from agarwood. Phytochemistry 1993; 33: 1147-55. http:// dx.doi.org/10.1016/0031-9422(93)85039-T / Ishihara M, Tsuneya T, Uneyama K. Guaiene sesquiterpenes from agarwood. Phytochemistry 1991; 30: 3343-47. http://dx.doi.org/10.1016/0031-9422(91)83206-Z http://dx.doi.org/10.1016/0031-9422(91)83727-3 / Jalaluddin M. A useful pathological condition agarwood. Econ. Bot. 1977; 31: 222-24. / Maheshwari ML, Jain TC, Bates RB, Bhattacharyya SC. Structure and absolute configuration of α-agarofuran, β- agarofuran and dihydroagarofuran. Tetrahedron. 1963; 19 1079-90. http://dx.doi.org/10.1016/S0040-4020(01)99363-9 / Mitra J, Gogoi P. Fungi associated with the diseased wood (agarwood/agaru) of Aquilaria agallocha Roxb. (Family: / Thymelaeaceae) grown in Assam. Proceedings of seminar on scope and dimension of agarplantation in NE region Ahmed M, Gogoi P, Ahmed GU, Hojai AATMA (eds). India, 2001, pp 61-69. / Nagashima T, Kawasaki I, Yoshida T, Nakanishi T, Yoneda K, Miura I. New Sesquiterpenoids from agarwood. Paper IXth International essential oil congress. Singapore, 1983, pp 12- 16. / Nakanishi T, Yamagata E, Yoneda K, Nagashima T, Kawasaki I, Yoshida T, Mori H, Miura I. Three fragrant sesquiterpenes of agarwood. Phytochemistry 1984; 22: 2066-67. http:// dx.doi.org/10.1016/S0031-9422(00)84975-4 / Okugawa H, Ueda R, Matsumoto K, Kawanishi K, Kato A. Effect of Agarwood on the central nervous system in mice. Planta Medica. 1993; 59: 32-36. http://dx.doi.org/10.1055/s -2006-959599 PMid:8441779 / Paknikar SK, Naik CG. Stereochemistry of dihydroagaro furans and evidence in support of the structure of 4,11- epoxy-ciseudesmane. Tet Lett. 1975; 15: 1293-94. http://dx.doi.org/ 10.1016/S0040-4039(00)72652-9 / Pant P, Rastogi RP. Agarol, a new sesquiterpene from Aquilaria agallocha. Phytochemistry 1980; 19: 1869-70. http:// dx.doi.org/10.1016/S0031-9422(00)83839-X / Qi Shu-Yuan, Lu Bi-Yau, Zhu Liang-Feng, Li Bao-Ling. Formation of oxoagarospirol in Aquilaria sinensis. Plant Physiol Commun. 1992; 28: 336-39. / Tamuli P, Boruah P. Changes in amino acids in agarwood plant under pathological condition. Geobios. 2002a; 29: 241- 43. / Tamuli P, Boruah P. Vesicular-arbuscular mycorrhizal (VAM) association of agarwood tree in Jorhat district of the Brahmaputra Valley. Indian Forest. 2002b; 128: 991-94. / Tamuli P, Boruah P, Nath SC. Essential oil of eaglewood tree: A product of pathogenisis. J Essent Oil Res. 2005; 17: 601-04. / Tamuli P, Boruah P, Nath SC, Samanta R. Fungi from diseased agarwood tree (Aquilaria agallocha Roxb.): Two new records. Adv Forest Res India 2000a; 22: 182-87. / Tamuli P, Boruah P, Nath SC, Samanta R. Mycofloral study on the phyllosphere and soil of agarwood tree plantation. U.G.C. Sponsored seminar on conservation of biodiversity, Assam, 2000b; p 5. / Thomas AF, Ozainne M. The stereochemistry of the dihydroagarofurans. Tet Lett. 1976; 20: 1717-18. http://dx.doi.org/10.1016/S0040-4039(00)92932-0 Varma KR, Maheshwari ML, Bhattacharyya SC. The constitution of agarospisol, a sesquiterpenoid with a new skeleton. Tetrahedron 1965; 21: 115-38. http://dx.doi.org/10.1016/S0040-4020(01)82208-0 / Venkataramanan MN, Borthakur R, Singh HD. Occurrence of endotrophic myccorhizal fungus in agarwood plant Aquilaria agallocha Roxb. Curr Sci. 1985;54: 928.Table