The enhancement of bioactive phytochemicals in agarwood leaves by post-harvest application using yeast extract elicitors and evaluation of their bioactivities

ABSTRACT

Agarwood (Aquilaria crassna) leaves are commonly used as an herbal tea for health supplements. The present study aims to develop the post-harvest process of agarwood leaves using yeast extract (YE) as an elicitor and evaluate its anti-inflammatory and anti-diabetic effects. The results showed that 1% of YE elicitation for 120 min significantly increased genkwanin 5-O-β-primevoside (1.8-fold), mangiferin (1.3-fold), and total benzophenones (1.2-fold) contents over the control group. The phenylalanine ammonia-lyase (PAL) activity increased in maximal at 30 min after YE treatment. The agarwood leaf elicitation with 1% YE for 120 min showed a higher anti-inflammation effect by down-regulation of iNOS, IL-6, and COX-2 in LPS-stimulated RAW264.7 cells and an anti-diabetic effect by enhanced AMPK-α1, AMPK-α2, and GLUT4 in L6 cells over the non-treatment. Our results suggest that YE could be a biotic elicitor to enhance the phytochemical contents and increase the benefit of agarwood leaves as a health supplement.

GRAPHICAL ABSTRACT

KEYWORDS:

• Agarwood leaves
• Aquilaria crassna
• post-harvest
• yeast extract
• anti-inflammatory activity
• anti-diabetic activity

Acknowledgements

Author contributions: R.C., J.J., V.W., and K.B. performed the experiments. R.C. participated in data analysis and wrote the manuscript. B.S. provided reference compounds. W.P. conceived and designed the experiment and approved the final draft of the manuscript. All authors reviewed and approved the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This research publication was supported by the Faculty of Pharmaceutical Sciences, Khon Kaen University, Thailand.