Inhibitory Effects of Compounds from Plumula nelumbinis on Biofilm and Quorum Sensing Against P. aeruginosa.

Quorum sensing (QS), which controls the survival and virulence of Pseudomonas aeruginosa, including the formation of biofilm, is considered to be a new target to overcome pathogens. The aim of this study was to identify new QS inhibitors against P. aeruginosa and provide potential treatments for clinical infections. In this study, 25 compounds were isolated from Plumula nelumbini. Among these compounds, C25 showed the most significant biofilm inhibition activity, reaching 44.63% at 100 µM without inhibiting bacterial growth. Furthermore, C25 showed significant inhibition activity of rhamnolipid, pyocyanin, and elastase. Further mechanistic studies have confirmed that C25 could downregulate key genes in the QS system, including lasI, lasR, lasA, lasB, and pqsR, and Molecular docking studies have shown that C25 can bind to the active sites of the LasR and PqsR receptors. The present study suggests that C25 is a promising QS inhibitor for treating P. aeruginosa infections.

Seco-neferine A-F, three new pairs of benzyltetrahydroisoquinoline alkaloid epimers from Plumula Nelumbinis and their activity.

Three new pairs of benzyltetrahydroisoquinoline (BIQ) alkaloid epimers, Seco-neferine A-F (1-6), were isolated from an EtOH extract of Plumula Nelumbinis. The structures of these compounds were identified by a combination of NMR, HR-ESI-MS, circular dichroism, UV spectroscopic analyses and specific rotations. The structure of compounds 1-6 possesses high similarity with neferine, because these three pairs of epimers have the same skeleton as neferine. Compounds 1,2 and 5,6 are open-loop compounds of position 1' and 1 of neferine respectively. The H connects with position 2' N of compounds 1,2 is replaced by methyl, forming the structure of compounds 3,4. Moreover, six compounds were tested for cytotoxicity against MDA-MB-231 breast cancer cell. Compound 6 displayed moderate inhibitory effects on breast cancer with IC50 of 38.96 µM, while compounds 2,3,4 show certain inhibitory effects.

[Observation on comprehensive control strategy for schistosomiasis with emphasis on infectious source control in Poyang Lake areas from 2009 to 2014].

OBJECTIVE: To evaluate the long-term effect of the comprehensive control strategy for schistosomiasis with emphasis on infectious source control in marshland-type endemic areas of Poyang Lake. METHODS: Three heavy endemic villages with schistosomiasis in the lake areas were selected as pilots for the comprehensive control strategy which included replacing bovine with tractors and forbidding grazing on marshlands. The data of schistosome infections of residents and Oncomelania hupensis snails were collected and analyzed statistically from 2009 to 2014. RESULTS: There were no patients with schistosomiasis through feces examinations in the 3 pilot villages. The average density of live snails in Niuzhou marshland showed a decline trend and the density was stable in Liulingwei marshland. There were no infected snails in the 2 marshlands, and no schistosome adult worms were found in the sentinel rats. CONCLUSION: The implantation of the comprehensive control strategy for schistosomiasis with emphasis on infectious source control can control the prevalence of schistosomiasis during a long period.