Excochinlignan: A new coumarino lignan from Excoecaria cochinchinensis Lour

Excoecaria cochinchinensis Lour. is a well-known medicinal plant in Vietnam, whose parts, particularly leaves, are applied as essential medicine in folk remedies. In this study, the chemical constituents of the plant’s aerial parts, together with their feasibility in enzyme inhibition and antioxidants, were investigated. Seven compounds, including a new coumarino lignan – excochinlignan (1), five known flavonol derivatives (2-6) and one monophenolic (7), were isolated and identified via chromatographic and spectroscopic approaches. In vitro biological evaluation of these compounds revealed the potential of kaempferol (2) and its glycosides (3-6) in all assays. Among them, kaempferol (2) was determined as the most active antioxidant (IC₅₀ 2.86 μM) while its 3-O-xylose derivatives (3) displayed the most significant α-glucosidase (IC₅₀ 65.88 μM) and tyrosinase (IC₅₀ 58.97 μM) inhibition. In silico evaluation via molecular docking simulation suggested the supportive effect of 3-O-xylose, C-4′ hydroxyl and C-4 ketone moieties in the structure of the isolated flavanols (2-6) on their enzyme inhibition and antioxidant properties.