Effect of Steaming Process on Chemical Content and Biological Activity of Curcuma zedoaria Extract
Keywords:Curcuma zedoaria, Curcuminoids, Steamed rhizome, Anti-microbial activity, Antiinflammatory activity
Introduction: The rhizomes of Curcuma zedoaria Roscoe have been used to treat infection and inflammation in the Thai traditional medicine. The traditional preparation of C.zedoaria is done performed by steaming the rhizome before drying and using. There has been no information about the effect of the steaming on the chemical components and the activity of C.zedoaria. In this report, therefore, we compare the chemical content, anti-inflammatory and antimicrobial activities of steamed, and non-steamed rhizomes of C.zedoaria.
Methods: The steamed and non-steamed rhizomes of C.zedoaria were extracted by maceration with 50% and 95% ethanol to obtain the ethanolic extracts. Then, the extracts were analyzed for curcuminoid content by HPLC technique, antimicrobial activity and anti-inflammatory activity by nitric oxide (NO) production inhibition assay.
Results: The highest curcuminoid content (152.23 ± 1.80 mg/g of dried extract) was found in the 95% ethanolic extract of the steamed rhizome. Both the ethanolic extracts of the steamed and non-steamed rhizomes exhibited anti-microbial activity against S.aureus, MRSA and C.albicans. The 95% ethanolic extract of the steamed rhizomes showed the highest inhibition effect on nitric oxide production with IC50 value of 11.22 ± 1.21 μg/mL.
Conclusion: From these results, it was concluded that the steaming process can increase the curcuminoid content and biological activities of C.zedoaria rhizomes. The best solvent for extraction of this plant part is 95% ethanol which give the highest percent yield of extract and strongest antimicrobial and anti-inflammatory activities.