Aquilaria sinensis
(Lour.) Gilg. (Thymelaeaceae) is an evergreen tree distributed in Guangdong, Hainan, Guangxi, and Fujian provinces
of China.
The aromatic resinous heartwood derived from the wounded trees of Aquilaria species is called ‘agarwood’.
It is a highly prized product which can be used in fragrances, incense, and traditional medicine
[1].
According to a review, agarwood
possesses aphrodisiac, cardiotonic, and carminative properties.
Previous phytochemical investigations on agarwood revealed sesquiterpenes and
2-(2-phenylethyl)-4H-chromen-4-one
derivatives
to be the major constituents.
These derivatives have been reported to exhibit several biological activities, such as acetylcholinesterase inhibitory, cytotoxic, antibacterial,
and neuroprotective activities
.
In our studies on the anti-inflammatory constituents of Chinese herbal medicines,
many species have been screened for
in vitro
inhibitory activity on neutrophil pro-inflammatory responses.
A. sinensis
was found to be an active species. Phytochemical
investigation of the
resinous wood of A. sinensis
led to the isolation of four new 2-(2-phenylethyl)-4H-chromen-4-one derivatives, 6-hydroxy-5-methoxy-2-[2-(4′-methoxyphenyl)ethyl]chromone (1), 6,7-dimethoxy-2-[2-(2′-hydroxyphenyl)ethyl]chromone (2), 5-hydroxy-6-methoxy-2-[2-(3′-methoxyphenyl)ethyl]chromone (3), and 7-chloro-8-hydroxy-2-[2-(4′-methoxyphenyl)ethyl]chromone (4), and 16 known compounds (5–20) including further congeners and sesquiterpenes. The
structures of the new compounds were established by spectroscopic analyses (1D and 2D NMR, HRESIMS, IR, and UV).
Nine
compounds including 1,
2, and
7-methoxy-2-[2-(4′-methoxyphenyl)ethyl]chromone
(5)
inhibited superoxide anion generation by human neutrophils in response to formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP) with IC50 values ≤ 36.28
μM.
References:
[1] Liu YG, Chen HQ, Yang Y, Zhang Z, Wei JH, Meng H, Chen WP, Feng JD, Gan BG, Chen XY, Gao ZH, Huang JQ, Chen B, Chen HJ. Whole-tree agarwood-inducing technique: an efficient novel technique for producing high-quality agarwood in cultivated Aquilaria sinensis trees. Molecules 2013; 18: 3086 –3106.