Quorum sensing (QS) plays an important role in virulence of Pseudomonas aeruginosa, blocking of QS ability are viewed as viable antimicrobial chemotherapy and which may prove to be a safe anti-virulent drug. Bioactive components from Piper betle have been reported to possess antimicrobial ability. This study envisages on the anti-QS properties of ethanolic extract of P. betle leaf (PbLE) using P. aeruginosa PAO1 as a model organism. A marked reduction in swarming, swimming, and twitching ability of the bacteria is demonstrated in presence of PbLE. The biofilm and pyocyanin production also shows a marked reduction in presence of PbLE, though it does not affect the bacterial growth. Thus, the studies hint on the possible effect of the bioactive components of PbLE on reducing the virulent ability of the bacteria; identification of bioactive compounds should be investigated further.Electronic supplementary materialThe online version of this article (doi:10.1007/s13205-015-0348-8) contains supplementary material, which is available to authorized users.

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Background: The purpose of this study is to evaluate the effect of green synthesized silver nanoparticles on postharvest physiology of cut flower in relation to improvement of its vase life as well as keeping quality of the flowers taking gladiolus cut spikes as a model. Results: The synthesized Piper betle mediated silver nanoparticles (PbSNPs) were characterized by using UVvisible spectroscopy and transmission electron microscopy studies. It was revealed that PbSNPs ranges from 30 to 50 nm in diameter and spherical in shape. The experiments were conducted to study the effect of PbSNPs on post-harvest physiology, vascular blockage, prolonging vase life, and keeping the quality of cut spike of gladiolus. The treatment consisted of six vase solutions, viz. distilled water (control), 4% sucrose (T 1 ), 4% sucrose + 100 ppm 5-SSA (T 2 ), 4% sucrose + 2 ppm PbSNPs (T 3 ), 4% sucrose + 4 ppm PbSNPs (T 4 ), and 4% sucrose + 6 ppm PbSNPs (T 5 ). Experimental outcomes depicted that T 4 vase solution gives the best results in all the aspects statistically compared to its positive control (T 2 ). The results also show PbSNPs in vase solution might have played a significant role for scavenging the reactive oxygen species by inducing antioxidant enzyme system at the time of senescence, leading to a decrease in lipid peroxidation and increase in the membrane stability.Conclusions: This study revealed that application of T 4 vase solution helps to maintain spikes fresh and dry weight, reduce the vascular blockage, improve the antioxidative defense, and stabilize the membrane integrity that leads to delay senescence.

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SummaryThe effective potentiality of anticancerous drugs, namely, cisplatin, etoposide and vinblastine, as well as the ethanolic extract of Piper betle L. leaves, is evaluated (concentrations used: 0.001, 0.01, 0.1, 1.0 and 10.0 µM for vinblastine; 25, 50, 75, 100, 125 and 150 µM for other test materials) on germinating grass pea (Lathyrus sativus L.) seedlings in relation to radicle length and mitotic index. Furthermore, inhibition in the frequency of dividing polyploid cells induced due to prior treatments of colchicine (0.5%, 8 h) and in vitro callus growth are also assessed following treatments with different concentrations of the test materials. The objective of the present study is to determine the effectivity of the test materials on a plant species with the view to develop a plant system (convenient to use and cost effective) as a model for preliminary screening of novel anticancerous drugs as well as plant extract(s) possessing such potentiality for further exploration.