Chemical composition, enzyme inhibitory activities, and molecular docking studies of essential oil of <i>Knema globularia</i> leaves from Vietnam

Abstract

In the present work, chemical composition, enzyme inhibitory activities, and molecular docking studies of essential oil (EO) of <i>Knema globularia</i> leaves collected from Vinh Phuc Province, Vietnam, were investigated. The EO from the leaves of <i>K. globularia</i> was obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS) analysis. The leaf EO yield was 0.14 ± 0.01% (w/w), comprising 39 identified components, constituting 96.77% of the EO content. Notable constituents included β-caryophyllene (54.11%), α-humulene (12.67%), and (<i>E</i>)-β-ocimene (8.82%). Enzyme inhibitions were assessed via the α-amylase inhibitory assay (IC₅₀ = 282.71 ± 10.06 μg/mL) and tyrosinase inhibitory assay (IC₅₀ = 993.92 ± 37.40 μg/mL). The molecular docking method has been employed to observe valuable binding interactions and binding energy with the main compounds on the target enzymes α-amylase and tyrosinase. Caryophyllene oxide exhibits the strongest affinity with α-amylase among the other major compounds. Meanwhile, viridiflorene shows the best binding energy with the tyrosinase enzyme. This is the first study providing valuable scientific data on the <i>in vitro</i> inhibitory activities of α-amylase and tyrosinase enzymes of the leaf EO of <i>K. globularia</i> and evaluating its main compounds through a molecular docking approach on these enzyme targets.