A Preliminary Research On Regulation Of The Spoilage Of Scophthalmus Maximus By Seaweed Polyphenols Quorum Sensing Inhibitor(QSI)

In this paper, the anti-QS activity of the seaweed polyphenols on spoilage bacteriawas determined by using Chromobacterium violaceum CV026biosensor detectingsystem. The structure characteristics and chemical composition of Seaweedpolyphenols QSI were investigated by UV-vis scanning, FTIR spectra and HPLCanalysis. The inhibitory effect of seaweed polyphenols QSI on spoilage ofScophthalmus maximus was also studied. This results are as follows:1. Screening of seaweed polyphenols with anti-QS activityThe seaweed polyphenols were extracted by water and alcohol, respectively. Thenthe quorum-sensing inhibitory activity of the extracts was screened byChromobacterium violaceum CV026biosensor detecting system. The inhibitoryeffect of alcohol extract of seaweed polyphenols was stronger than that of waterextract. Twelve seaweed polyphenols having quorum sensing inhibitory activity werefound from25species of seaweed. Three types of economic marine algae, includingUlva lactucal, Sargassum vachellianum and Undaria pinnatifida, possessed strongerQuorum sensing inhibitory activity. The three kinds of seaweed polyphenolsdecreased the amount of violacein in a concentration-dependent manner within therange0.1~0.5mg/mL.2. The structure characteristics of seaweed polyphenols QSIUlva lactucal, Sargassum vachellianum and Undaria pinnatifida were analyzed byUV spectrophotometry and Infrared Spectroscopy (gallic acid, catechol were used asstandard compound). The chemical composition and contents of the three Seaweedpolyphenols QSI were further determined by HPLC. The results showed that:Ultraviolet absorption spectra of Ulva lactucal, Sargassum vachellianum and Undariapinnatifida were similar to that of gallic acid and catechol. FT-IR spectras of Ulva lactucal, Sargassum vachellianum, Undaria pinnatifida, gallic acid, catechol andphloroglucinol had obvious streching vibration of phenol hydroxyl, aromatic rings.Thus we deduced that seaweed polyphenols QSI compound might share similarstructure with gallic acid, catechol or phloroglucinol. The chemical compositions ofthe three kinds of seaweed polyphenols exhibited significant difference, however, allof them contain epicatchin and catechol, of which catechol occupied large proportion.3. Regulation of Scophthalmus maximus spoilage and quorum-sensing byseaweed polyphenols QSIScophthalmus maximus were disposed using three kinds of seaweed polyphenolsQSI individually at concentration of0.5mg/mL and stored at4℃. Sensory evaluation,total bacterial colonies, TVB-N, pH and other spoilage index were assayedperiodically, sterile distilled water was used as controls. Quorum-sensingphenomenon of bacteria in Scophthalmus maximus under different storage phaseswere determined by Chromobacterium violaceum CV026detection system throughflatsmearing method. The results showed that total bacterial counts, pH value, volatilebasic nitrogen(TVB-N) content increased as the storage time prolonged, which wasaccordance with the sensory evaluation result. Increasing rate of bacterial coloniesamount was dramatically lower in the group disposed by Seaweed polyphenols thanthe control ones (P<0.05), the group treated by Ulva lactucal polyphenols was lowest.the group disposed by Undaria pinnatifida showed the worst regulatory effect, yet isstill better than the control one. The control group showed certain purple phenomenonin the spoilage stage, the other groups showed no purple phenomenon, same resultwas show in the bacteria of fresh Scophthalmus maximus. It was speculated thatamount of bacteria in Scophthalmus maximus having quorum-sensing phenomenonwas increasing and seaweed polyphenols had regulatory effect on quorum-sensingthem at4℃.