Lawsone as potential antioxidant : Studies on total antioxcidant activity in vitro and molecular docking analysis on superoxide dismutase (SOD) activation in silico

Mohd Noor, Muhammad Noorfaiz (2020) Lawsone as potential antioxidant : Studies on total antioxcidant activity in vitro and molecular docking analysis on superoxide dismutase (SOD) activation in silico. [Project Paper] (Submitted)

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Abstract

Reactive oxygen species (ROS) are produced during normal cellular metabolism and play vital roles in the activation of signalling pathways. However, the imbalance between the ROS production and their elimination through protective mechanisms cause oxidative stress that can lead to chronic inflammation such as eczema and psoriasis on the skin. One of the most important preventive agents for reducing inflammation induced by oxidative stress are natural antioxidants. One of the natural sources with reported high antioxidant properties is Lawsonia inermis or henna, a plant that also scientifically proven for its anti-inflammatory characteristics. Lawsone as the most prominent active compound of henna, is expected to be responsible for the mentioned properties. Superoxide dismutase (SOD) is an anti-oxidative enzyme, where binding of phytochemicals to the domain of SOD receptor will increase its activity and reduce oxidative stress. Objectives: To evaluate the total antioxidant activity of lawsone in vitro and to predict the SOD activation property of lawsone via molecular docking study in silico. Methodology: Cytotoxicity (IC50) of lawsone on human epidermoid carcinoma (A431) and normal mouse fibroblast (3T3) was obtained by performing MTT assay. Next, Ferric Reducing Antioxidant Power (FRAP) assay was carried out in two conditions: (i) in A431 and 3T3 cell lines; (ii) without cell line to assess the total antioxidant activity of lawsone. Next, molecular docking analysis was performed to investigate the activation mechanism of lawsone on SOD via AutoDock Tools (ADT). Prediction of the allosteric site of SOD was made by using AlloSite 2.0 webserver. The interaction between lawsone and SOD was analysed by using Pymol software, ProteinsPlus and PLIP webservers. Results: IC50 of lawsone on A431 cell line was determined at 3650 µM while no IC50 was detected on 3T3 cell line. Meanwhile, lawsone also exhibited the total antioxidant activities in the absence of cells, A431 and 3T3 cell lines at 200µM, with the highest FRAP values of 4.04 ± 0.18µM, 94.41 ± 1.21µM and 93.50 ± 8.48µM respectively. In silico results showed that lawsone binds to two allosteric regions of SOD1; namely Region A and B with binding affinities of -7.3 kcal/mol and -6.6 kcal/mol respectively. Results from PLIP webserver illustrated the hydrophobic interactions between lawsone and protein residues; - i.e. Asn53A, Val7F, Lys9F, Asn53F and Val148F from allosteric region A, and Ile113A, Ile151A and 1le113F from allosteric region B. Four hydrogen bondings with Gly108 (2.09Å & 2.94Å) and Val148 (1.91Å & 2.82Å) of chain A were also detected. Meanwhile, ProteinsPlus showed hydrophobic interaction of lawsone with SOD1 pocket of Ile113A. Conclusion: Lawsone exhibited a low range increment in total antioxidant activity at the low concentration in vitro and have an excellent binding affinity at the allosteric sites of SOD in silico which is predicted to simultaneously trigger the activation of SOD enzyme.

Item Type:	Project Paper
Faculty:	Faculty of Medicine and Health Science
Depositing User:	Ms. Nor Safa'aton Saidin
Date Deposited:	23 Aug 2023 00:47
Last Modified:	23 Aug 2023 00:47
URI:	http://psaspb.upm.edu.my/id/eprint/1280

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