Sharmeen_2021_Chem.Biodivers__

The chemical and pharmacological profiles of essential oils (EOs) hydrodistilled in yields of 0.03-0.77 % (w/w) from three exotic (Cinnamomum camphora, Petroselinum crispum, and Syzygium samarangense) and two endemic (Pittosporum senacia subsp. senacia and Syzygium coriaceum) medicinal plants were studied. GC-MS/GC-FID analysis of the EOs identified the most dominant components to be myristicin (40.3 %), myrcene (62.2 %), 1,8-cineole (54.0 %), beta-pinene (21.3 %) and (E)-beta-ocimene (24.4 %) in P. crispum, P. senacia and C. camphora, S. samarangense and S. coriaceum EOs, respectively. All EOs were found to possess anti-amylase (0.70-1.50mM ACAE/g EO) and anti-tyrosinase (109.35-158.23mg KAE/g) properties, whereas no glucosidase inhibition was displayed. Only Syzygium EOs acted as dual inhibitors of both acetyl- and butyryl-cholinesterases, while P. senacia and C. camphora EOs inhibited acetylcholinesterase selectively and P. crispum EO was inactive (AChE: 4.64-4.96mg GALAE/g; BChE: 5.96 and 7.10mg GALAE/g). Molecular docking revealed 1,8-cineole to present the best binding affinities with butyrylcholinesterase, amylase and tyrosinase, while both myristicin and beta-pinene with acetylcholinesterase and finally beta-pinene with glucosidase. In vitro antioxidant potency was also demonstrated in different assays (DPPH: 13.52-53.91mg TE/g, ABTS: 5.49-75.62mg TE/g; CUPRAC: 45.38-243.21mg TE/g, FRAP: 42.49-110.64mg TE/g; and phosphomolybdenum assay: 82.61-160.93mM TE/g). Principal component analysis revealed the EOs to differ greatly in their bioactivities due to their chemodiversity. This study has unveiled some interesting preliminary pharmacological profiles of the EOs that could be explored for their potential applications as phytotherapeutics.