K. Murugesan

Antibacterial and cytotoxic effect of biologically synthesized silver nanoparticles using aqueous root extract of Erythrina indica lam.

Simple, yet an effective and rapid approach for the green synthesis of silver nanoparticles (Ag NPs) using root extract of Erythrina indica and its in vitro antibacterial activity was tried against human pathogenic bacteria and its cytotoxic effect in breast and lung cancer cell lines has been demonstrated in this study. Various instrumental techniques were adopted to characterize the synthesized Ag NPs viz. UV-Vis (Ultra violet), FTIR (Fourier Transform Infrared), XRD (X-ray diffraction), DLS (Dynamic light scattering), HR TEM (High-resolution transmission electron microscopy), EDX (Energy-dispersive X-ray spectroscopy). Surface plasmon spectra for Ag NPs are centered nearly at 438 nm with dark brown color. FTIR analysis revealed the presence of terpenes, phenol, flavonols and tannin act as effective reducing and capping agents for converting silver nitrate to Ag NPs. The synthesized Ag NPs were found to be spherical in shape with size in the range of 20-118 nm. Moreover, the synthesized Ag NPs showed potent antibacterial activity against Gram positive and Gram negative bacteria and these biologically synthesized nanoparticles were also proved to exhibit excellent cytotoxic effect on breast and lung cancer cell lines.

In Vitro Antioxidant and Anticancer potential of Bark of Costus pictus D.DON

Abstract Objective To evaluate the antioxidant and anticancer potential of different fractions of bark of Costus pictus using various in vitro antioxidant assay systems. Methods In this study, assay like DPPH radical, superoxide anion radical scavenging activity, nitric oxide scavenging activity, hydrogen peroxide scavenging activity, metal chelating activity and reducing power were used. The concentrations of total phenolic and flavonoids were also calculated for the extracts. Result The present study elucidated for the first time the antioxidant property of bark of C. pictus . This study suggested that, among the three fractions, the chloroform fraction possesses high antioxidant activity which might be helpful in preventing or slowing the progress of various oxidative stress related disorders. Moreover, all fractions possess potent anticancer properties against colon cancer cells of HT29 and lung carcinoma cells of A549. Conclusions It can be concluded that the extract of the bark of C. pictus has potential natural antioxidant and this can be used in food industries. There are few reports on the antioxidant capacity of bark of C. pictus and the mechanism of different fractions of bark of C. pictus as antioxidative agents is still not fully understood. Hence further research is underway to analyse and isolate the active compounds responsible for the antioxidant and anticancer activity of different fractions of the bark of C. pictus .

Phytochemical screening and “in–vitro” anti–oxidant activity of methanolic root extract of Erythrina indica

Objective Erythrina indica belongs to the family Leguminoseae and it is a medium-sized, spiny, deciduous tree normally growing up to 6–9 m tall. It is also known as “Indian coral tree” or “Tigers clow” or “variegated coral tree” or “Kalyana murungai” or “Mulmurukku” (in Tamil). It is a native of costal forest communities from East Africa, through southeast to Australia. In India, it is distributed in coast forests from Bombay to Malabar. The objective of this study is to explore the phytochemistry and the antioxidant potential of methanolic root extract of Erythrina indica which is considered traditionally as an important medicinal plant.

Evaluation of larvicidal activity of the aerial extracts of a medicinal plant, Ammannia baccifera (Linn) against two important species of mosquitoes, Aedes aegypti and Culex quinquefasciatus

Abstract Objective To analyze the larvicidal effect of the aerial extracts of Ammannia baccifera on two important mosquito species, Aedes aegypti and Culex quinquefasciatus. Methods The larval mortality of fourth instar larvae of A. aegypti and C. quinquefasciatus after 24h and 48h of treatment were observed separately in control 50, 100, 150, 200, 250, 300, 350, 400, 450 and 500 mg/L concentrations of the aerial extracts (methanol, ethyl acetate, chloroform) of A. baccifera. Results Based on the probit analysis, the 24h and 48h aerial methanol extract of A. baccifera LC50value of C. quinquefasciatus was found to be in 164.00 mg/L and 107.00 mg/L and LC90values for C. quinquefasciatus was found be in 310.00 and 261.00 mg/L. The 24h and 48h aerial part of methanol extract of A. baccifera LC50value of A. aegypti was found be in 226.00 mg/L and 186.00 mg/L and LC90values was found be in 476.00 and 309.00 mg/L. Conclusions The results indicate that the A. baccifera could be effectively used for the control of mosquito larvae and the possibility of exploiting for the development of commercial larvicides a plant widely occurring in India.

Application of ozone on induction of resistance in Vigna unguiculata cv. Co 6, against Fusarium wilt

Abstract The efficacy of ozone in controlling Fusarium oxysporum, the casual agent of wilt disease, was evaluated in Vigna unguiculata (cowpea). Different concentrations of ozone (T1, T2, T3, T4 and T5) were passed to the Vigna unguiculata seedlings among which T3 treatment reduced Fusarium wilt more effectively than other treatments by enhancing growth promotion along with the activation of the defense-related enzymes than other treatments. T3 treatment provokes enhanced biomass production along with increased activity of chitinase, β-1,3-glucanase, peroxidase and phenylalanine ammonia-lyase than other treatments relative to control seedlings. Moreover, this is the first report of ozone protecting seedlings against Fusarium wilt of Vigna unguiculata plants.

Enhancing salt tolerance in eggplant by introduction of foreign halotolerance gene, HAL1 isolated from yeast

Agrobacterium-mediated gene transfer method for production of transgenic eggplants (Solanum melongena L. var. PKM1) has been optimized. Polymerase chain reaction of transgenic plants confirmed the presence of the expected HAL1 fragment. Different tests were carried out to evaluate the level of salt tolerance for the transgenic and control plants with culture media in vitro (0, 50, 100, 150, or 200 mM NaCl) and with soil in greenhouse (0, 25, 50, 75, or 100 mM NaCl). Differences in callus growth between transgenic and control lines were observed. At 150 mM NaCl, the weight of calli from the transgenic population did not differ significantly from that in non salt condition, while the growth of wild-type control calli was strongly inhibited. A preliminary evaluation in vivo under controlled greenhouse conditions showed that at moderate salt concentrations (25 mM NaCl), a similar response to salinity in the original line and in the transgenic progeny was found. However, at higher salt concentration (50 mM NaCl), total dry weight (relative growth) was not significantly decreased by salinity in the transgenic population, while a growth reduction was observed in the wild-type control. Our results indicated that a higher level of salt tolerance was found in the transgenic lines than in the wild-type control. Thus, in this present study we have demonstrated the possibility of increasing salt tolerance in eggplant by introducing the foreign gene, HAL1 derived from yeast.

Induction of systemic resistance in Lycopersicon esculentum cv. PKM1 (tomato) against Cucumber mosaic virus by UV-B irradiation on calli

Studies were done to evaluate the effect of UV-B irradiation on calli to induce resistance in the regenerated Lycopersicon esculentum cv. PKM1 (tomato) plantlets against Cucumber mosaic virus (CMV)-induced diseases. Plantlets regenerated from the UV-B (TL, TM, TH) treated calli are referred to as TL, TM and TH plantlets respectively, and they hold remarkably increased soluble phenolics, salicylic acid and peroxidase content compared to control plantlets without any treatment. All the plantlets challenge-inoculated with CMV showed disease severity ranging from TM = 32%, TH = 56%, TL = 78% and C = 92%. But in contrast, ELISA results show that CMV accumulation in young uninoculated leaves were significantly less in the TH plantlets than TM plantlets, which reveals that TH treatment affects virus accumulation and also affected the plantlets physiological properties and chlorophyll content due to high UV-B dosage. However, in TM plantlets, physiological properties were not affected and these plantlets were effectively elicited against CMV attack. Exposure of UV-B (TM) on calli certainly activates an effective defense response and empowers the tomato plantlets survival against viral attack.