Antibacterial and Antibiofilm Effects of Photodynamic Treatment with Curcuma L. and Trans-Cinnamaldehyde against Listeria monocytogenes.

Photodynamic inactivation (PDI) is a highly effective treatment that can eliminate harmful microorganisms in a variety of settings. This study explored the efficacy of a curcumin-rich extract, Curcuma L., (Cur)- and essential oil component, trans-cinnamaldehyde, (Ca)-mediated PDI against Listeria monocytogenes ATCC 15313 (Lm) including planktonic cells and established biofilms on silicone rubber (Si), polytetrafluoroethylene (PTFE), stainless steel 316 (SS), and polyethylene terephthalate (PET). Applying Ca- and Cur-mediated PDI resulted in planktonic cell reductions of 2.7 and 6.4 log CFU/cm2, respectively. Flow cytometric measurements (FCMs) coupled with CFDA/PI and TOTO®-1 staining evidenced that Ca- doubled and Cur-mediated PDI quadrupled the cell damage. Moreover, the enzymatic activity of Lm cells was considerably reduced by Cur-mediated PDI, indicating its superior efficacy. Photosensitization also affected Lm biofilms, but their reduction did not exceed 3.7 log CFU/cm2. Cur-mediated PDI effectively impaired cells on PET and PTFE, while Ca-mediated PDI caused no (TOTO®-1) or only slight (PI) cell damage, sparing the activity of cells. In turn, applying Ca-mediate PDI to Si largely diminished the enzymatic activity in Lm. SS contained 20% dead cells, suggesting that SS itself impacts Lm viability. In addition, the efficacy of Ca-mediated PDI was enhanced on the SS, leading to increased damage to the cells. The weakened viability of Lm on Si and SS could be linked to unfavorable interactions with the surfaces, resulting in a better effect of Ca against Lm. In conclusion, Cur demonstrated excellent photosensitizing properties against Lm in both planktonic and biofilm states. The efficacy of Ca was lower than that of Cur. However, Ca bears potent antibiofilm effects, which vary depending on the surface on which Lm resides. Therefore, this study may help identify more effective plant-based compounds to combat L. monocytogenes in an environmentally sustainable manner.

Correlation between heavy metal elements in Curcuma herbs and their genuineness / 中草药

Objective To study the correlation between the heavy metal elements and the genuineness of Curcum. Methods ICP-MS technique was used to determine the difference of heavy metal elements content in 20 batches of Curcumae Rhizoma, Curcumae Longae Rhizoma, and Curcumae Radix in different original regions and different original plants, and study the effect of water extraction on heavy metal elements content. The relationship between heavy metals content and genuineness in medicinal materials and the distribution change of trace elements in the decoction process from slices into the decoction were studied by systematic cluster analysis. Results The medicinal herbs of the same origin can be grouped together, and the three medicinal herbs which were different medicinal parts of the same original plants could be separated clearly. For the Curcumae Rhizoma from different original plants, C. phaeocaulis and C. kwangsiensis produced from different places have more similar characteristics, and had more similar enrichment of heavy metal elements. The content of heavy metal elements in different producing areas and different original plants tablets were different: Cu > Pb > Cd > As > Hg; Results indicated that heavy metal element of Chinese medicinal materials in the process of decoction had low dissolution rate, and the content of each element changed greatly after decoction. The element content of dissolution was As > Pb > Hg > Cu > Cd, which showed that the content of Cu was greater than other elements in the original slices, but its dissolution rate was low. Conclusion The content of heavy metals in Curcuma from different habitats was obviously different, and it had certain regularity with the varieties of medicinal materials and distribution of producing areas. The origin environment has asignificant effect on the enrichment of heavy metal elements, and the selective enrichment ability of heavy metal elements in different varieties is different. Heavy metal elements distribution changes in the process of decoction from slices into the decoction showed that the content of heavy metals in slices could have no positive correlation with that in patients with oral decoction, and each element had low dissolution rate, which reveals the scientificity and rationality of the clinical application of Chinese materia medica into traditional Chinese medicine decoction, and provides reference for the limited standard content of heavy metals.