Enhancement of chemical constituents in hydrosol and residual water of Aquilaria malaccensis tetraploid

Aquilaria malaccensis is an agarwood-producing species in the family Thymeleaeceae. Agarwood is a fragrant resin used in the manufacture of incense sticks, and in pharmaceutical, perfumery and cosmetic industries. In addition to the resin, hydrosol and residual water by-products from agarwood woodchip distillation are also utilized. Hydrosol contains water-soluble fragrant chemicals used as a tonic drink, in cooking and cosmetics while the residual water is used in spas and aromatic bath treatments. The present study was conducted to identify and compare compounds present in hydrosol and residual water by-products of diploid and polyploid A. malaccensis. Four different four-month-old A. malaccensis plants were compared: soil-grown diploid seedlings (DS), in vitro-grown seedlings (DV), tissue culture-derived plantlets (DC) and artificially induced tetraploid plantlets (TC). Hydrosol water from TC leaf and root samples were found to contain higher amounts of compounds compared with other samples. The TC leaf samples were qualitatively better as key compounds of agarwood such as α- and γ-eudesmol were detected. TC stem samples also contained higher amounts of key compounds compared with other samples, while the overall amount of compounds was highest in DS stem samples. The residual water of TC stem and root samples contained key compounds not detected in other samples, while DS residual water samples contained the highest total amount of compounds. Aquilaria malaccensis tetraploids performed better than their diploid counterparts in production of compounds, and thus may be a better planting material choice for commercial plantations.