Effect of Daily Chewing Soft Buds and Leaves of Catha edulis (Khat) on the Antioxidant Defense System and Oxidative Stress Markers in Blood

Khalid Mohammed Naji,Maher Ali Al-Maqtari,R. Nagesh Babu,Qais Yusuf M. Abdullah,Adnan Ali Al-Asbahi,Varadahally Rangaiah Devaraj

doi:10.1007/s13369-014-1492-x

Khalid Mohammed Naji, Maher Ali Al-Maqtari + Show 4 more

Open Access

https://doi.org/10.1007/s13369-014-1492-x

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Abstract

Catha edulis (Khat) is one of the major economic, social and health problems in Yemen. This paper aimed to study the effect of Khat on the oxidative status of Khat chewers by measuring the levels of enzymatic and non-enzymatic antioxidant as well as lipid peroxidation. The results exhibited significant reduction in erythrocytes superoxide dismutase (SOD, EC: 1.15.1.1), and catalase (CAT, EC: 1.11.1.6) in Khat chewers, in addition to elevation of serum glutathione-S-transferase (GST, EC: 2.5.1.18). Furthermore, non-enzymatic antioxidants glutathione (GSH) and vitamin C were significantly reduced (p < 0.001; p < 0.015), whereas malondialdehyde (MDA) was significantly elevated (p < 0.001). The depletion of GSH and vitamin C along with MDA elevation in Khat chewers compared with control reflects the obvious oxidative status, a result of enormous reactive oxygen species (ROS) formation, leading to membrane damage. ROS possibly induced by active components of Khat or by pesticides added to the Khat tree. In addition, the reduction of SOD and CAT is indicative to cellular proteins damage which occurred by ROS. As well, the elevation of GST may due to a leakage of cellular GST to blood stream; this implies that GST active site was not affected. This study concludes that daily chewing Khat for long period certainly induce ROS production, leading to oxidative toxicity. Both enzymatic and non-enzymatic antioxidants are involved in the protection against this toxicity. People who habitually chew Khat for long term will be susceptible to the oxidative toxicity; therefore, they recommended giving up of Khat chewing.

Highlights

The interruption of balance between oxidants and reductants within the body due to the excess production of peroxides and free radicals causes damage to cellular components and tissues leading to oxidative stress [1]
We investigate the effect of chewing Khat in daily manner on the oxidative stress status by monitoring the activities of antioxidants enzymes (SOD, CAT and GST) and measuring the levels of non-enzymatic antioxidants, as well as malondialdehyde (MDA) the final product of lipid peroxidation
0.2 ml of whole blood was added to 1.8 ml distilled water and was incubated for 10 min at 37 ◦C for complete hemolysis

Summary

Introduction

The interruption of balance between oxidants and reductants within the body due to the excess production of peroxides and free radicals causes damage to cellular components and tissues leading to oxidative stress [1]. Oxidative stress occurs either due to the increasing level of the reactive oxygen species (ROS), or a decrease in the antioxidant defense. The capacity of antioxidant defense systems to catch ROS is very crucial for protecting the tissues from oxidative damage. Cellular antioxidant defense systems including enzymatic [such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathioneS-transferase (GST) and glutathione reductase (GR)] and. Pesticides can induce oxidative stress, either by overproduction of free radicals or by alteration in antioxidant defense mechanisms, including detoxification and scavenging enzymes [6]

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