Clausena lansium Lour. Skeels (Rutaceae) is widely distributed in South China and has historically been used as a traditional medicine in local healthcare systems. Although the characteristic components (carbazole alkaloids and coumarins) of C. lansium have been found to possess a wide variety of biological activities, little attention has been paid toward the other components of this plant. In the current study, phytochemical analysis of isolates from a water-soluble stem and leaf extract of C. lansium led to the identification of 12 compounds, including five aromatic glycosides, four sesquiterpene glycosides, two dihydrofuranocoumarin glycosides, and one adenosine. All compounds were isolated for the first time from the genus Clausena, including a new aromatic glycoside (1), a new dihydrofuranocoumarin glycoside (6), and two new sesquiterpene glycosides (8 and 9). The phytochemical structures of the isolates were elucidated using spectroscopic analyses including NMR and MS. The existence of these compounds demonstrates the taxonomic significance of C. lansium in the genus Clausena and suggests that some glycosides from this plant probably play a role in the anticancer activity of C. lansium to some extent.

Plant fungal diseases pose a serious threat to crop production and safety, and natural products are one of the important directions for the development of new green fungicides. This study found that the extract of Murraya euchristifolia had significant antifungal activity, and a main antifungal coumarin (1) was isolated by bioassay-guided fractionation. The structure of 1 was identified by NMR and MS spectroscopic data as a fused bis-furan coumarin (microminutinin) which was first isolated from the Murraya genus and exhibited strong broad-spectrum antifungal activity against eight plant pathogenic fungi from different families and genera. The EC₅₀ value of 1 (11.33 μg/mL) against Pestalotiopsis theae (the most sensitive to 1) was slightly higher than that (7.03 μg/mL) of the positive drug (80% carbendazim WP), indicating that 1 has the potential to serve as a lead compound for botanical fungicides. The bioassay results against P. theae in vivo indicated that 1 also has the potential for field application. Scanning electron microscopy and optical microscopy revealed that 1 disrupted the morphological structure of mycelium, causing hyphae to twist, shrink, and even crack and severely reducing hyphal branching. Furthermore, propidium iodide staining proved that microminutinin destroyed the integrity of the cell membrane, causing leakage of cellular components. In addition, calcofluor white staining and chitin content changes illustrated that microminutinin disrupted the cell wall structure. This research provides compound sources and a theoretical basis for the development of botanical fungicides.