Agarwood is fragrant transfused dark resinous heartwood produced by infected or wounded
Aquilaria trees which is grown in Southeast Asia, with Indonesia, Malaysia, Thailand, Vietnam,
Laos and Papua New Guinea, Bhutan, India, Cambodia as the producing countries, and
Singapore being the central trade country (Yagura et al., 2005; Persoon, 2008). Agarwood also
goes by other local names such as oudh, gaharu, eaglewood, aloeswood, sasi, aguru etc. It is also
named “Wood of Gods”. Among 17 species of Agarwood forming Aquilaria, Aquilaria
malacensis Lam. is the best known species for Agarwood (Saikia and Khan 2012) and other
species are A. crassna, A. agalloacha and A. sinensis.
From time immemorial, the essential oil (attar) which has a pleasing deep, earthy, woody and
musky aroma, extracted from Agarwood is used in making perfumes which is eminent in Arab
countries and other Agarwood products are incense sticks, carved beads and boxes, crafted
wooden sculptures from Agarwood which is famous in Korean and Japan. The essential oil is
also used for medicinal purposes in China and Korea. These days, agarwood have found
relevance even in cosmetic industries (Barden et al., 2000). The estimated costs of different
Agarwood products ranges from USD 47-118/kg to USD 1000-1200/kg and it can go higher as
much as USD 9700-32000/kg (Sen et al., 2015) depending on the grade of wood. Now recent
studies also revealed that the secondary metabolites extracted from Agarwood also has
antibacterial activities (Wei et al., 2016). Therefore, it is of no surprise that more and more
traders are attracted in the global business of Agarwood production and cultivation. Due to
extensive harvesting and habitat loss of Aquilaria trees, the populations have reduced to the
extent that the IUCN Red list includes Aquilaria since 1998 (Oldfield et al., 1998). The
Convention on International trade in Endangered Species of Wild Fauna and Flora (CITES 1994)
has listed all Aquilaria species in its Appendix II.
The formation of Agarwood is elicited upon infection by microorganisms as a result, the plant
defense system responds to neutralize the invasion. It is believed that the process of Agarwood
production by wounding of the Aquilaria is due to fungal infection (Pojanagaroon and Kaewrak,
2005), a long term process, even though the involvements of bacteria are not yet uncovered. The
wood may form in the stem, branch or root of the tree. Aquilaria trees are naturally infected by a
variety of fungi including: Aspergillus sp., Botryodyplodia sp., Diplodia sp., Fusarium
bulbiferum, F. laterium, F. oxysporum, F. solani, Penicillium sp., and Pythium sp. (Anon 1998;
Santoso 1996, cited in Soehartono and Mardiastuti 1997; Wiriadinata 1995). The infection
imparted by fungi in natural forest constitutes only 7-10% (Ng et al., 1997).