Chemical Composition, Anti-Quorum Sensing, Enzyme Inhibitory, and Antioxidant Properties of Phenolic Extracts of Clinopodium nepeta L. Kuntze.

Hatem Beddiar,Chawki Bensouici,Selcuk Kucukaydin,Merzoug Benahmed,Abdelhakim Elomri,Alfred Ngenge Tamfu,Hocine Laouer,Louiza Boudiba,Özgür Ceylan,Sameh Boudiba,Karima Hanini,Salah Akkal,Rodica Mihaela Dinica

doi:10.3390/plants10091955

Abstract

Phenolic extracts of Clinopodium nepeta were prepared and their preliminary phenolic profiles determined using HPLC-DAD with 26 phenolic standards. Apigenin (21.75 ± 0.41 µg/g), myricetin (72.58 ± 0.57 µg/g), and rosmarinic acid (88.51 ± 0.55 µg/g) were the most abundant compounds in DCM (dichloromethane), AcOEt (ethyl acetate), and BuOH (butanol) extracts, respectively. The DCM and AcOEt extracts inhibited quorum-sensing mediated violacein production by C. violaceum CV12472. Anti-quorum-sensing zones on C. violaceum CV026 at MIC (minimal inhibitory concentration) were 10.3 ± 0.8 mm for DCM extract and 12.0 ± 0.5 mm for AcOEt extract. Extracts showed concentration-dependent inhibition of swarming motility on flagellated P. aeruginosa PA01 and at the highest test concentration of 100 μg/mL, AcOEt (35.42 ± 1.00%) extract displayed the best activity. FRAP assay indicated that the BuOH extract (A0.50 = 17.42 ± 0.25 µg/mL) was more active than standard α-tocopherol (A0.50 = 34.93 ± 2.38 µg/mL). BuOH extract was more active than other extracts except in the ABTS●+, where the DCM extract was most active. This antioxidant activity could be attributed to the phenolic compounds detected. C. nepeta extracts showed moderate inhibition on acetylcholinesterase (AChE), butyrylcholinesterase (BChE), tyrosinase, and α-amylase. The results indicate that C. nepeta is a potent source of natural antioxidants that could be used in managing microbial resistance and Alzheimer′s disease.

Highlights

Throughout the ages, human beings have depended on plants for their basic needs such as source of food [1], medicine [2,3], carpentry [4], fertilizer [5,6], and aromatics [7], amongst others
The results of preliminary phenolic chemical composition reported here indicate that DCM, AcOEt, and BuOH extracts of C. nepeta contain various selected phenolic compounds
The results reported as A0.50 values are compared with antioxidant positive controls (BHA and BHT)

Summary

Introduction

Throughout the ages, human beings have depended on plants for their basic needs such as source of food [1], medicine [2,3], carpentry [4], fertilizer [5,6], and aromatics [7], amongst others The use of this rich source of natural compounds and their derivatives is increasing day by day and continuous progress is being made in the development of proper extractive methods. There is much progress and advancements in the methods of characterization and identification of valuable phytoconstituents contained in the various plant extracts as well as their versatile eco-friendly applications, in particular the discovery of new and safer therapeutic agents with minor side effects [8,9] Because of their richness in a large variety of secondary plant metabolites, such as flavonoids, alkaloids, terpenoids, tannins, etc. Phenolic compounds (flavonoids, phenolic acids, etc.), as an inexhaustible source of scientific research represent a good example, due to their widespread groups of metabolites, known for benefits to human health and they have been a bottomless source of scientific research [26]

Objectives

Results

Discussion

Conclusion