Xanthine oxidase, a-glucosidase and a-amylase inhibitory activities of the essential oil from Piper lolot: In vitro and in silico studies

Introduction: Piper lolot is a species of herb used as a popular food in Vietnam. Furthermore, the species has been used as a Vietnamese traditional medicine to treat many diseases. Methods: Chemical constituents in the essential oil from leaves of Piper lolot were determined using GC/MS analysis. The anti-gout and anti-diabetic activities of the essential oil were determined through the inhibitory assays against xanthine oxidase, alpha-glucosidase and a-amylase enzymes. In addition, molecular docking simulations were used to elucidate the inhibitory mechanism between the main compounds and the enzymes. Results: The dominant constituents of the Piper lolot essential oils were determined as ss-caryophyllene (20.6%), ss-bisabolene (11.6%), ss-selinene (8.4%), ss-elemene (7.7%), trans-muurola-4 (14),5-diene (7.4%), and (E)-ss-ocimene (6.7%). The essential oil displayed xanthine oxidase, alpha-amylase, and alpha-glucosidase inhibitory activities with IC50 values of 28.4, 130.6, and 59.1 mu g/ mL, respectively. The anti-gout and anti-diabetic activities of the essential oil from the P. lolot species are reported for the first time. Furthermore, molecular docking simulation was consistent to in vitro experiments. Conclusion: The present study provides initial evidence that the essential oil of P. lolot may be a potential natural source to develop new diabetes preparations.