PT - JOURNAL ARTICLE AU - William Chi Keung Mak TI - Comparisons between the Hydro Distillation and the Steam Distillation in the Extraction of Volatile Compounds from and the Anti-oxidative Activity of <em>Prunella Vulgaris</em> AID - 10.1101/2022.07.07.499219 DP - 2022 Jan 01 TA - bioRxiv PG - 2022.07.07.499219 4099 - http://biorxiv.org/content/early/2022/09/21/2022.07.07.499219.short 4100 - http://biorxiv.org/content/early/2022/09/21/2022.07.07.499219.full AB - Objective In this article, the aim is to verify a suggestion in our earlier study to explain the extraction dynamics of volatile compounds, being extracted from the herb Prunella vulgaris (PV) using the method of steam distillation. Then, the antioxidative property of PV is explored.Methods Because our earlier study suggested that the inefficient extraction using steam distillation was due to the mass of herb in the path of steam flow acting as an obstacle, we used hydro distillation which tried to eliminate this obstacle. We used gas chromatography – mass spectrometry (GC-MS) to characterize the volatile compounds extracted during the distillation process. Then, by treating the cancer cells from the cell line SCC154 with the distillate, the cancer cell cytotoxicity was assessed using the tetrazolium salt-based colorimetric test reagent, the Cell Counting Kit-8. The results provided the bases for comparisons. To assess the anti-oxidative activity of the PV distillate, Folin-Ciocalteu reagent was used.Results We successfully showed that the removal of the obstacle, formed by the mass of herb in the flow path of the uprising steam, enhanced the efficiency of volatile compound extraction and more volatile compounds could be extracted. Also, it was shown that the PV distillate did not exhibit anti-oxidative activity.Conclusions Hydro distillation is a more efficient method than steam distillation to extract volatile compounds from the PV herb. However, mild heating, which did not provide sufficient energy to the convection of the boiling water, did not move the floating herb on top of the boiling water; so, the obstacle still existed and limited the efficiency of extraction. For another issue of the antioxidant effect of the volatile compounds from PV, it was studied using the Folin-Ciocalteu reagent. It showed that the PV volatile compounds did not possess antioxidant property.Competing Interest StatementNo competing interestsPVPrunella vulgarisVOCvolatile organic compoundGC-MSgas chromatography – mass spectrometryROSreactive oxygen speciesNISTNational Institute of Standards and TechnologyANOVAAnalysis of variance