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Catechin isolated from cashew nut shell exhibits antibacterial activity against clinical isolates of MRSA through
Simran Sinsinwar1, Vellingiri Vadivel2
1Chemical Biology Lab (ASK-II-409), School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur, Tamil Nadu, India.
Abstract:
Staphylococcus aureus causes severe infections and among all methicillin-resistant S. aureus (MRSA) remains a great challenge in spite of decade research of antibacterial compounds. Even though some synthetic antibiotics have been developed, they are not effective against MRSA, and hence, there is a search for natural, alternative and plant-based antibacterial compound. In this connection, catechin isolated from cashew nut shell was investigated for its antibacterial potential against MRSA. Catechin exhibited zone of inhibition (ZOI) and minimum inhibitory concentration (MIC) in a range of 15.1-19.5 mm and 78.1-156.2 μg/ml, respectively, against ATCC and clinical isolates of MRSA. Among all clinical isolates, clinical isolate-3 exhibited highest sensitivity to catechin. Catechin has arrested the growth of MRSA strains and also caused toxicity by membrane disruption which was illustrated by AO/EB fluorescence staining. Increased nucleic acid leakage (1.58-28.6-fold) and protein leakage (1.40-23.50-fold) was noticed in MRSA due to catechin treatment when compared to methicillin. Bacteria treated with catechin at its MIC showed 1.52-, 1.87- and 1.74-fold increase of ROS production in methicillin susceptible S. aureus (MSSA), MRSA and clinical isolate-3 strains, respectively, as compared to control. Superoxide dismutase (5.31-9.63 U/mg protein) and catalase (1573-3930 U/mg protein) were significantly decreased as compared to control in catechin-treated S. aureus. Thus, catechin exhibited antibacterial activity through oxidative stress by increased production of ROS and decreased antioxidant enzymes. Altogether results suggest that catechin is a promising lead compound with antibacterial potential against MRSA. KEY POINTS: • Catechin was isolated and identified as active compound in cashew nut shell. • Catechin exhibited antimicrobial activity against clinical isolates of MRSA. • Bacterial cell wall damage was caused by catechin in MRSA strains. • Catechin increased the oxidative stress in MRSA by intracellular ROS production.
Insights
Catechin from cashew nut shells shows antibacterial potential against methicillin-resistant Staphylococcus aureus (MRSA). This natural compound disrupts MRSA cell membranes and increases oxidative stress, offering a promising alternative to synthetic antibiotics.
Area of Science:
- Microbiology
- Natural Product Chemistry
- Pharmacology
Background:
- Methicillin-resistant Staphylococcus aureus (MRSA) poses a significant challenge due to its resistance to conventional antibiotics.
- There is an ongoing need for novel antibacterial agents, particularly those derived from natural sources.
- Plant-based compounds are being explored as potential alternatives for combating resistant bacterial strains.
Purpose of the Study:
- To investigate the antibacterial activity of catechin, a compound isolated from cashew nut shells, against MRSA.
- To elucidate the mechanism of action of catechin in inhibiting MRSA growth.
- To assess the potential of catechin as a natural antibacterial agent.
Main Methods:
- Isolation and identification of catechin from cashew nut shell.
- Determination of antibacterial activity using zone of inhibition (ZOI) and minimum inhibitory concentration (MIC) assays against MRSA strains.
- Assessment of membrane integrity and cell death using AO/EB fluorescence staining.
- Measurement of nucleic acid and protein leakage.
- Evaluation of reactive oxygen species (ROS) production and antioxidant enzyme activity (superoxide dismutase and catalase).
Main Results:
- Catechin demonstrated significant antibacterial activity against both ATCC and clinical isolates of MRSA, with ZOI ranging from 15.1-19.5 mm and MICs from 78.1-156.2 μg/ml.
- Catechin induced membrane disruption and cell death in MRSA, evidenced by increased nucleic acid and protein leakage.
- Treatment with catechin led to a significant increase in intracellular ROS production and a decrease in the activity of antioxidant enzymes (superoxide dismutase and catalase) in MRSA.
- Clinical isolate-3 showed the highest sensitivity to catechin among the tested isolates.
Conclusions:
- Catechin exhibits potent antibacterial activity against MRSA, acting through mechanisms including membrane disruption and oxidative stress induction.
- The increased production of ROS and decreased antioxidant enzyme activity contribute to catechin's antibacterial effects.
- Catechin is a promising natural compound with significant potential as a lead for developing new anti-MRSA therapies.
