Comparative Analysis of Biological Activity of Artificial and Wild Agarwood

3D documentation and classification of incense tree Aquilaria sinensis (Lour.) Spreng. wounds by photogrammetry and its potential conservation applications

In recent years, illegal felling of and damage to the incense tree Aquilaria sinensis (Lour.) Spreng. have been reported in Hong Kong. Their native populations are under increasingly severe threat. Therefore, the development of a standard and efficient method to classify and document wounds on vulnerable trees is urgently needed for conservation purposes. In this study, photogrammetry was used to document wounds in A. sinensis through 3D modeling. A total of 752 wound records from 484 individual A. sinensis trees from Hong Kong were included to establish a new wound classification system. Our major findings include a novel standardized procedure for photogrammetric documentation and a wound classification system. The results of this study will facilitate A. sinensis conservation, by enhancing wound documentation and information transfer to law enforcement and education.

A Study of the Chemical Composition and Biological Activity of Michelia macclurei Dandy Heartwood: New Sources of Natural Antioxidants, Enzyme Inhibitors and Bacterial Inhibitors

The wood of Michelia macclurei Dandy (MD) is an excellent material that is widely used in the furniture, handicraft, and construction industries. However, less research has been conducted on the chemical composition and biological activity of heartwood, which is the main valuable part of the wood. This study aimed to investigate the chemical composition and biological activities of the heartwood of Michelia macclurei Dandy (MDHW) and to confirm the active ingredients. Triple quadrupole gas chromatography-mass spectrometry (GC-MS) was used to characterize the volatile components of MDHW, while ultra-performance liquid chromatography-mass spectrometry was used to analyze the non-volatile components (UPLC-MS). The total reducing power, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging assays, acetylcholinesterase and α-glucosidase inhibition assays, and an antimicrobial test of 4 gram bacteria were used to describe the in vitro bioactivities. The GC-MS analysis showed that the volatile components of MDHW were mainly fatty compounds and terpenoids, with sesquiterpenes and their derivatives dominating the terpene composition. β-elemene was the main terpene component in the steam distillation (11.88%) and ultrasonic extraction (8.2%) methods. A total of 67 compounds, comprising 45 alkaloids, 9 flavonoids, 6 lignans, and others, were found by UPLC-MS analysis. The primary structural kinds of the non-volatile components were 35 isoquinoline alkaloids. Alkaloids were the predominant active constituent in all MDHW extracts, including crude extracts, alkaloid fractions, and non-alkaloid fractions. These extracts all demonstrate some biological effects in terms of antioxidant, enzyme inhibition, and bacterial inhibition. The findings of this study show that MDHW is abundant in chemical structure types, has great bioactivity assessment, and has the potential to be used to create natural antioxidants, products that postpone Alzheimer's disease and lower blood sugar levels and antibacterial agents.

Dimeric 2-(2-phenethyl)chromones from agarwood of Aquilaria filaria

Four new 2-(2-phenethyl)chromone dimers (1-4) were isolated from EtOAc extract of agarwood originating from Aquilaria filaria from Philippines. Their structures were elucidated by spectroscopic analysis (1D and 2D NMR, and HRESIMS) and comparison of the experimental and computed ECD curves. Compounds 1-4 exhibited inhibition of nitric oxide production in lipopolysaccharide-stimulated RAW264.7 cells with IC₅₀ values in the range from 33.94 to 57.53 μM.

Tissue Structure Changes of Aquilaria sinensis Xylem after Fungus Induction

In this study, we analyzed the mechanism and the process of fungal-induced agarwood formation in Aquilaria sinensis and studied the functional changes in the xylem structure after the process. The microscopic structure of the white zone, transition zone, agarwood zone, and decay zone of 12-and 18-months of inoculation A. sinensis xylem was studied. The distribution of nuclei, starch grains, soluble sugars, sesquiterpenes, fungal propagules, and mycelium in xylem tissues was investigated by histochemical analysis. The results show that the process of agarwood formation was accompanied by apoptosis of parenchyma cells such as interxylary phloem, xylem rays, and axial parenchyma. Regular changes in the conversion of starch grains to soluble sugars, the production of sesquiterpenoids, and other characteristic components of agarwood in various types of parenchyma cells were also observed. The material transformation was concentrated in the interxylary phloem, providing a structural and material basis for the formation of agarwood. It is the core part of the production of sesquiterpenoids and other characteristic products of agarwood. Compared with the A. sinensis inoculated for 12 months, the xylem of the A. sinensis inoculated for 18 months was more vigorous. There were no significant differences between the 12 and 18 months of inoculation in terms of sugars and agarwood characteristic products. In production, harvesting after 12 months of inoculation can improve harvesting efficiency.