Phytochemical compositions, antioxidant, anticholinesterase, and antibacterial properties of Clerodendrum thomsoniae Balf.f. leaves: In vitro and in silico analyses

Abstract

Introduction

Clerodendrum thomsoniae Balf.f. (Family: Lamiaceae) is an ornamental plant with a high polyphenol content that has been extensively studied in traditional medicinal systems of several countries for a variety of important pharmacological properties. Present study is aimed to investigate the chemical constituents, and antioxidant, anticholinesterase, and antibacterial properties of methanolic leaf extract of Clerodendrum thomsoniae (MECT) using in vitro and in silico methods.

Methods

The phytochemical characterization of the crude methanolic leaves extract of Clerodendrum thomsoniae (MECT) was investigated using FT-IR and GC-MS studies. The biological evaluation of MECT was conducted using DPPH and β-carotene bleaching assays, acetyl- and butyrylcholinesterase inhibitory properties. The antibacterial effectiveness of the MECT was assessed against E. coli and S. aureus using MIC, MBC, and disc agar diffusion techniques. The bioactive compounds that were identified by GC-MS were subjected to docking studies with several proteins associated with antioxidants, anticholinesterase, and antibacterial properties.

Result

DPPH radical scavenging and β-carotene bleaching assays demonstrated significant antioxidant activities (IC₅₀ values: 162.2±2.8 μg/mL and 179.7±5.1 μg/mL, respectively). The anticholinesterase activity of MECT was demonstrated by its efficient acetylcholinesterase- (132.8±2.3 μg/mL) and butyrylcholinesterase inhibitory (157.6±6.6 μg/mL) activities. MECT is also found to contain significant amounts of phenolics and flavonoids. Results also showed significant antibacterial capacity of MECT against both Gram-negative (E. coli) and Gram-positive (S. aureus) stains. FT-IR and GC-MS analyses revealed the presence of different functional groups with seven phytocompounds which were further used to evaluate the in silico properties of MECT. Molecular docking analysis revealed that 2,4-bis(1,1-dimethylethyl)-phenol has the highest binding affinities with different proteins. ADMET study including toxicity prediction analysis confirmed that most of the phytochemicals were non-toxic.

Conclusion

In conclusion, the findings of the present study suggest that MECT possesses potential antioxidant, anticholinesterase and antibacterial properties and may further be investigated as a therapeutic candidate against microbial infections and oxidative stress mediated neurodegenerative conditions.