Aquilaria leaves (Thymelaeaceae): A comprehensive review of ethnobotany, traditional applications, phytochemistry, pharmacological activities, toxicity and quality evaluation.

Abstract

Ethnopharmacological relevance: Aquilaria species are well known for agarwood, while their leaves are also used in regional folk medicine and consumed as herbal teas in southern China and Southeast Asia, mainly for inflammatory conditions, infections, and stress-related symptoms.

Aims of the review: This review summarizes the ethnobotany, taxonomy, traditional applications, phytochemistry, pharmacology, toxicity and quality evaluation of Aquilaria leaves, and identifies gaps that warrant further investigation.

Materials and methods: Relevant literature was collected from Web of Science, ScienceDirect, Google Scholar, PubMed, CNKI, and Wan Fang Data, including journal articles, books, and dissertations. Flora of China and Plants of the World Online were consulted to verify species distribution and accepted botanical names. Chemical structures were drawn using ChemDraw 22.0.0.

Results: A total of 185 compounds have been recorded from Aquilaria leaves. Phytochemical and pharmacological studies mainly involve three species, A. sinensis, A. crassna, and A. malaccensis. The major compound classes include flavonoids, terpenoids, benzophenones, organic acids, xanthones, and 2-(2-phenylethyl)chromones, with flavonoids (39) and terpenoids (43) predominating. Pharmacological studies have largely focused on crude extracts, with relatively few investigations of isolated compounds, and have demonstrated anti-inflammatory, antioxidant, antibacterial, antidiabetic, laxative, and neuroprotective activities. Available toxicological studies generally indicate low acute toxicity within the tested dose ranges, although evidence on long-term safety remains limited. Quality evaluation has mainly relied on chromatographic profiling and multi-component determination, while standardized quality criteria remain to be established.

Conclusions: This review highlights Aquilaria leaves as a renewable and underexplored medicinal resource by integrating evidence from traditional applications, phytochemistry, pharmacology, toxicity, and quality evaluation. However, current evidence is still limited by crude-extract-based studies, insufficient active-constituent characterization, and limited long-term safety and clinical data. Further research is needed to identify the active constituents, elucidate their underlying mechanisms, and establish standardized quality control and safety evaluation systems for the safe and effective use of Aquilaria leaves.