A LC/MS-MS Guided Isolation of Laccaic Acid-A: A Potent Antimicrobial Agent

Abstract:

Background: Lac is traditionally used as a dye because of its coloring properties and it is obtained from Laccifer lacca Kerr. Now a days, it is widely used in food and coloring industry. Purpose: To evaluate the antioxidant, antimicrobial activity of different extracts along with identification of active constituents present in it. Methods: Antioxidant activity was performed by DPPH, reducing power and hydrogen peroxide scavenging activity, whereas antimicrobial activity was performed by well diffusion method to evaluate the antimicrobial potential of chloroform, ethyl acetate, methanol and water extracts. Based on the most potent activity of the extracts were run in LC-MS/MS to identify the active constituent from it. Results: Ethyl acetate and methanol extracts were found to have most potent antioxidant activity with more than 50% inhibition at a concentration of 16 μg/ml where all the three methods when compared with ascorbic acid as standard. Antimicrobial activity was also found to be potent for ethyl acetate and methanol extract having a zone of inhibition of 15 mm and 18 mm for E. coli and S. aureus respectively. Finally, ethyl acetate and methanol extracts were processed for an effective LC-MS/MS run to identify the active constituent as laccaic acid-A in both the extract. Conclusion: Laccaic acid A is identified as the main constituent present in ethyl acetate and methanol fractions responsible for the antioxidant and antimicrobial activity.

Key words: Laccifer lacca Kerr., DPPH, Reducing power, Hydrogen peroxide, Antimicrobial assay, LC-MS/MS, Laccaic acid-A.