# He–Ne laser irradiation enhances curcuminoid content in Curcuma longa: a green strategy for functional antioxidants and antimicrobial ingredients

## TL;DR

He–Ne laser treatment increases curcuminoid levels in turmeric, boosting its antioxidant and antimicrobial properties for use in functional foods.

## Contribution

He–Ne laser irradiation is proposed as a green method to enhance curcuminoid content and bioactivity in Curcuma longa.

## Key findings

- Laser treatment increased curcuminoid content in a time-dependent manner, with 15-min exposure yielding the highest bisdemethoxycurcumin enrichment.
- Antioxidant assays showed strong scavenging potential with IC50 values of 0.71 and 0.69 mg mL−1 for 10- and 15-min treatments, respectively.
- Extracts exhibited enhanced antibacterial activity, with 15-min exposure strongest against E. coli and S. aureus.

## Abstract

Curcuma longa rhizomes are rich in curcuminoids with strong antioxidant and antimicrobial activities. Sustainable post-harvest strategies are needed to enhance these bioactive metabolites for functional food applications.

Fresh rhizomes were irradiated with a He–Ne laser for 5, 10, or 15 min. Ethanol extracts were analyzed by High Performance Liquid Chromatography analysis (HPLC) to quantify curcuminoids. Antioxidant activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays, and antibacterial activity tested against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Streptococcus pyogenes (S. pyogenes).

Laser treatment increased curcuminoid content in a time-dependent manner, with 15-min exposure yielding the highest bisdemethoxycurcumin enrichment. Antioxidant assays showed strong scavenging potential, with IC50 values of 0.71 (10-min) and 0.69 mg mL−1 (15-min). Extracts exhibited enhanced antibacterial activity, with 15-min exposure strongest against E. coli and S. aureus, while 10-min treatment yielded higher inhibition of S. pyogenes.

He–Ne laser irradiation is an effective green technique to improve the antioxidant and antimicrobial properties of C. longa extracts, supporting their use as natural functional ingredients.