Synergistic antibacterial, antifungal and antioxidant efficacy of cinnamon and clove essential oils in combination.

The present investigation aimed to evaluate antibacterial, antifungal and antioxidant efficacy of essential oils of three commonly used spices (black pepper, cinnamon and clove) in combination along with chemical characterization and toxicity evaluation. Among the possible combinations tested, cinnamon/clove oil combination showed synergistic antibacterial activity against foodborne bacteria Staphylococcus aureus, Listeria monocytogenes, Salmonella typhimurium and Pseudomonas aeruginosa and synergistic antifungal activity against Aspergillus niger as well as synergistic antioxidant potential in DPPH radical scavenging model system. GC-HRMS analysis revealed that out of thirteen identified components from clove oil, eugenol was found to be the main constituent of the oil; whereas out of twenty one identified constituents from cinnamon oil, the main component was cinnamaldehyde. Cinnamon/clove oil combination did not show any cytotoxic potential at recommended dosage level (IC50 > 2000 µg/ml). The results provide evidence that cinnamon/clove oil combination might indeed be used as a potential source of safe and effective novel natural antibacterial, antifungal and antioxidant blend in the food and pharmaceutical industries. To the best of our knowledge, this is the first time a combination of essential oils has been tested as natural preservatives to prevent both microbial proliferation and oxidative deterioration at sufficiently low concentrations.

Evaluation of antibiofilm efficacy of essential oil components ß-caryophyllene, cinnamaldehyde and eugenol alone and in combination against biofilm formation and preformed biofilms of Listeria monocytogenes and Salmonella typhimurium.

The aim of this study was to examine whether the process of initial colonization and the formation of mature biofilm structure of foodborne bacterial pathogens Listeria monocytogenes and Salmonella typhimurium can be impeded by active essential oil components ß-caryophyllene, cinnamaldehyde and eugenol at their individual and combined effects. Among the essential oil components tested, cinnamaldehyde and eugenol at their individual effect showed >50% degradation in biofilm biomass against preformed (matured) biofilms of both the studied bacteria, whereas ß-caryophyllene failed to do so. In combination, cinnamaldehyde/eugenol blend showed synergistic antibiofilm efficacy against preformed biofilms of both the studied bacteria L. monocytogenes (FICI: 0·24) and S. typhimurium (FICI: 0·40), whereas other tested combinations showed additive antibiofilm efficacy with FICI ranged from 2·02 to 2·35. Essential oil components alone and in combination also showed much higher inhibition effect on biofilm formation at the initial stage compared to their inhibition effect on preformed biofilms. The results provide evidence that cinnamaldehyde/eugenol combination may help in designing a more potent novel, natural antibiofilm blend at sufficiently low concentrations in the food and pharmaceutical industries. SIGNIFICANCE AND IMPACT OF THE STUDY: In the present work, synergistic antibiofilm efficacy of cinnamaldehyde/eugenol combination against established biofilms of foodborne bacterial pathogens Listeria monocytogenes and Salmonella typhimurium has been reported. These synergistic interactions may help in designing a more potent, safe and effective novel natural antibiofilm agent in food and pharmaceutical industries. Besides, this combination will also be helpful in reducing concentration of individual components, thereby minimizing the undesirable impact on sensory properties of food. To our knowledge, this is the first time, synergistic antibiofilm efficacy of cinnamaldehyde/eugenol blend against established biofilms of foodborne bacterial pathogens has been reported.

Synergistic antibacterial and antibiofilm efficacy of nisin in combination with p-coumaric acid against food-borne bacteria Bacillus cereus and Salmonella typhimurium.

The aim of the study was to evaluate possible antibacterial and antibiofilm efficacy of a bacteriocin, nisin with two essential oil components linalool and p-coumaric acid in combination against food-borne bacteria Bacillus cereus and Salmonella typhimurium. Their inhibition effects on planktonic cells and preformed biofilms were evaluated using microbroth dilution and checkerboard titration methods. Nisin/p-coumaric acid combination showed synergistic effects against planktonic cells of both the studied bacteria, whereas nisin/linalool combination showed synergistic activity against B. cereus and additive effect against S. typhimurium. In preformed biofilms, nisin by itself failed to show >50% antibiofilm efficacy against both the studied bacteria, but in combination with linalool and p-coumaric acid, it exerted >50% antibiofilm efficacy. On the basis of fractional inhibitory concentration indices values, nisin/p-coumaric acid combination exhibited synergistic antibiofilm activity, whereas nisin/linalool combination showed additive effects against preformed biofilms of studied bacteria. The results provide evidence that p-coumaric acid due to its synergistic interactions with nisin against planktonic cells and biofilms of both Gram-positive and Gram-negative food-borne bacteria enhanced the antibacterial spectrum of nisin, which subsequently may facilitate their use in the food industry. SIGNIFICANCE AND IMPACT OF THE STUDY: In the present work, synergistic interactions between a bacteriocin, nisin and essential oil component p-coumaric acid on planktonic cells as well as on biofilms of Gram-positive and Gram-negative food-borne bacteria have been reported. The results of this study provide evidence that nisin/p-coumaric acid combination can be considered as a promising source for development of more potent broad spectrum antimicrobial blend for food preservation, which subsequently may facilitate their use in the food industry. To the best of our knowledge, this is the first report of the antibacterial and antibiofilm efficacy of nisin in combination with essential oil components against food-borne bacteria.

Isolation and identification of a gallotannin 1,2,6-tri-O-galloyl-ß-D-glucopyranose from hydroalcoholic extract of Terminalia chebula fruits effective against multidrug-resistant uropathogens.

AIMS: In this study, an attempt has been made to isolate and identify the bioactive compounds from hydroalcoholic extract of Terminalia chebula fruits effective against multidrug-resistant uropathogens and also to elucidate the influence of metal ions on the growth inhibitory activity of isolated compounds against the studied bacteria, if any. METHODS AND RESULTS: Bioassay-guided fractionation and extensive spectrometric analyses (FT-IR, (1) H NMR, (13) C NMR and ESI-MS) were used to isolate and characterize the bioactive compound. Growth inhibitory activities of isolated compound were studied by agar well diffusion and microbroth dilution assay methods. Checkerboard titration method was used for combination study between antibiotics and isolated compound. Influence of metal ions on growth inhibitory activity of this bioactive compound against the test isolates were also studied by INT [P-iodonitrotetrazolium violet; 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyltetrazolium chloride] colorimetric assay. The isolated bioactive compound 1, 2, 6-tri-O-galloyl-ß-D-glucopyranose was found to be responsible for antibacterial activity against multidrug-resistant uropathogens and showed synergy with trimethoprim and gentamicin. This antibacterial activity of bioactive compound was counteracted by the supplementation of iron in the medium. CONCLUSION: Terminalia chebula fruit extract contains bioactive compound effective against multidrug-resistant uropathogens, and this antibacterial activity may be due to its iron-complexing property. SIGNIFICANCE AND IMPACT OF THE STUDY: To the best of our knowledge, the antibacterial activity exhibited by isolated gallotannin against multidrug-resistant uropathogens is first time reported by us. Besides, these promising findings may lead to the development of antimicrobial agents from T. chebula fruits for the treatment of urinary tract infections caused by these pathogens.

Selection of birefringent spermatozoa under Polscope: effect on intracytoplasmic sperm injection outcome.

The ideal method for sperm selection during Intracytoplasmic sperm injection (ICSI) is still ill-defined. Identification of a viable spermatozoon amongst immotile spermatozoa for ICSI often becomes difficult. Ninety-six ICSI cycles were selected and divided into Group A (azoospermic, n = 58) and Group B (complete asthenozoospermic, n = 38). Oocytes having birefringent meiotic spindle and zona pellucida thickness <20 µm were selected for ICSI. Groups A and B were further divided into A1, A2 and B1, B2, respectively, based on the type of ICSI performed. In Group A1, a motile spermatozoon with normal morphology was injected into a metaphase-II (M-II) oocyte. In Group B1, spermatozoon showing coiling of tail following modified hypo-osmotic swelling test was injected into M-II oocytes. In Groups A2 and B2, ICSI was performed by injecting a spermatozoan with birefringent head. Pronuclear morphology, fertilisation rate, embryo grading and pregnancy rate were assessed. ICSI outcome measures were better in Group A2 than in Group A1 but were statistically insignificant. However, significantly higher percentage of Z1 and Z2 zygotes, Grade I and Grade II embryos and pregnancy rate were observed in Group B2 as compared to Group B1. Selection of birefringent spermatozoa shows promising results in asthenozoospermic men and men undergoing testicular sperm aspiration or extraction before ICSI.

Community based mangrove management: a review on status and sustainability.

Community Based Mangrove Management (CBMM) has been advocated by both academia and governing agencies as a viable alternative for sustainably managing the ecologically important mangrove forests which are disappearing rapidly worldwide. Drawing insights from diverse sustainability issues, capabilities and performances of worldwide CBMM initiatives were examined in this paper. Higher numbers of CBMM initiatives were reported from South Asia and lesser from South America and Africa. Identification of the causes of degradation at a site and use-specific zonal replantations with respect to species associations were identified as major criteria of ecological sustainability. Regarding economic sustainability, transformation of potential uses of mangroves known by local communities into actual ones was found to be necessary. Proper disbursement of accrued benefits among community members irrespective of their socio-cultural status is also a major concern. Restructuring of CBMM institutions by ensuring participation of subsistence based users in decision-making and resource sharing have been identified as a prime determinant of institutional sustainability. However, limited number of studies on socio-political and institutional aspects as well as impacts of globalization induced socio-cultural transformations of communities on CBMM had been actually found. More focused researches on these aspects had been recommended for better community management of these highly stressed forests.

Real time extended range prediction of heat waves over India.

Heat waves over India occur during the months of March-June. This study aims at the real-time monitoring and prediction of heat waves using a multi-model dynamical ensemble prediction system developed at Indian Institute of Tropical Meteorology, India. For this, a criterion has been proposed based on the observed daily gridded maximum temperature (Tmax) datasets, which can be used for real-time prediction as well. A heat wave day is identified when either (1) Tmax (a)≥ its climatological 95th percentile (calculated from daily values during March-June and for 1981-2010), (b) >36 °C, and (c) its departure from normal is >3.5 °C, Or, (2) when the Tmax >44 °C. Three heat wave prone regions, namely, northwest, southeast and northwest-southeast regions are recognized and heat wave spells of minimum consecutive six days are identified objectively for each region during 1981-2018. It is noticed that the prediction system has reasonable skill in predicting the heat waves over heat wave prone regions of India. Forecast verification of heat wave spells during 2003-2018 reveals that the prediction system has great potential in providing overall indication about the onset, duration and demise of the forthcoming heat wave spell with sufficient lead time albeit with some spatio-temporal error.

Atmospheric controls on the precipitation isotopes over the Andaman Islands, Bay of Bengal.

Isotopic analysis of precipitation over the Andaman Island, Bay of Bengal was carried out for the year 2012 and 2013 in order to study the atmospheric controls on rainwater isotopic variations. The oxygen and hydrogen isotopic compositions are typical of the tropical marine sites but show significant variations depending on the ocean-atmosphere conditions; maximum depletion was observed during the tropical cyclones. The isotopic composition of rainwater seems to be controlled by the dynamical nature of the moisture rather than the individual rain events. Precipitation isotopes undergo systematic depletions in response to the organized convection occurring over a large area and are modulated by the integrated effect of convective activities. Precipitation isotopes appear to be linked with the monsoon intraseasonal variability in addition to synoptic scale fluctuations. During the early to mid monsoon the amount effect arose primarily due to rain re-evaporation but in the later phase it was driven by moisture convergence rather than evaporation. Amount effect had distinct characteristics in these two years, which appeared to be modulated by the intraseasonal variability of monsoon. It is shown that the variable nature of amount effect limits our ability to reconstruct the past-monsoon rainfall variability on annual to sub-annual time scale.

Vitamin C prevents cigarette smoke-induced oxidative damage in vivo.

Our recent in vitro results [4] indicate that cigarette smoke induces oxidation of human plasma proteins and extensive oxidative degradation of the guinea pig lung, heart, and liver microsomal proteins, which is almost completely prevented by ascorbic acid. In this paper, we substantiate the in vitro results with in vivo observations. We demonstrate that exposure of subclinical or marginal vitamin C-deficient guinea pigs to cigarette smoke causes oxidation of plasma proteins as well as extensive oxidative degradation of the lung microsomal proteins. Cigarette smoke exposure also results in some discernible damage of the heart microsomal proteins. The oxidative damage has been manifested by SDS-PAGE, accumulation of carbonyl and bityrosine, as well as loss of tryptophan and protein thiols. Cigarette smoke exposure also induces peroxidation of microsomal lipids as evidenced by the formation of conjugated dienes, malondialdehyde, and fluorescent pigment. Cigarette smoke-induced oxidative damage of proteins and peroxidation of lipids are accompanied by marked drop in the tissue ascorbate levels. Protein damage and lipid peroxidation are also observed in cigarette smoke-exposed pair-fed guinea pigs receiving 5 mg vitamin C/animal/day. However, complete protection against protein damage and lipid peroxidation occurs when the guinea pigs are fed 15 mg vitamin C/animal/day. Also, the cigarette smoke-induced oxidative damage of proteins and lipid is reversed after discontinuation of cigarette smoke exposure accompanied by ascorbate therapy. The results, if extrapolated to humans, indicate that comparatively large doses of vitamin C may protect the smokers from cigarette smoke-induced oxidative damage and associated degenerative diseases.

Vitamin C prevents cigarette smoke induced oxidative damage of proteins and increased proteolysis.

Aqueous extract of cigarette smoke (CS) contains some stable oxidants, which oxidize human plasma proteins, bovine serum albumin, amino acid homopolymers, and also cause extensive oxidative degradation of microsomal proteins. Similar observations are made when the aqueous extract of cigarette smoke is replaced by whole phase CS solution or whole phase cigarette smoke. CS-induced microsomal protein degradation is a two step process: (i) oxidation of proteins by the oxidants present in the CS and (ii) rapid proteolytic degradation of the oxidized proteins by proteases present in the microsomes. Using aqueous extract of CS equivalent to that produced from one-twentieth of a cigarette, the observed initial and postcigarette smoke treated values of different parameters of oxidative damage per milligram of microsomal proteins are respectively: 0.24 and 1.74 nmoles for carbonyl formation, 125.4 and 62.8 fluorescence units for tryptophan loss, 10.2 and 33.4 fluorescence units for bityrosine formation, and 58.3 and 12.2 nmoles for loss of protein thiols. When compared with sodium dodecyl sulphate polyacrylamide gel electrophoresis profiles of untreated microsomal proteins, the extent of microsomal protein degradation after treatment with whole phase CS solution or aqueous extract of CS is above 90%. Ascorbate (100 microM) almost completely prevents cigarette smoke-induced protein oxidation and thereby protects the microsomes from subsequent proteolytic degradation. Glutathione is partially effective, but other antioxidants including superoxide dismutase, catalase, vitamin E, probucol, beta-carotene, mannitol, thiourea, and histidine are ineffective. The gas phase cigarette smoke contains unstable reactive oxygen species such as superoxide (O2*-) and hydrogen peroxide (H2O2) that can cause substantial oxidation of pure protein like albumin but is unable to produce significant oxidative damage of microsomal proteins. Gas phase cigarette smoke-induced albumin oxidation is not only inhibited by ascorbate and glutathione but also by superoxide dismutase, catalase and mannitol. The stable oxidants in the cigarette smoke are not present in the tobacco and are apparently produced by the interaction of O2*-/H2O2/OH* of the gas phase with some components of the tar phase during/following the burning of tobacco.

Cigarette smoke-induced protein oxidation and proteolysis is exclusively caused by its tar phase: prevention by vitamin C.

We have reported before that whole phase cigarette smoke (CS) contains stable oxidants that cause oxidative damage and increased proteolysis of proteins [Free Radic. Biol. Med. 27 (1999) 1064]. Here, we demonstrate that these oxidants are exclusively present in the tar phase of the CS and not its gas phase and can almost wholly account for the observed whole phase CS-induced oxidation of human plasma proteins as well as extensive oxidative proteolysis of guinea pig lung and heart microsomal proteins in vitro. The mechanism of the tar phase CS-induced proteolysis of microsomal proteins involves two-steps: (i) initial oxidation of the proteins by oxidants present in the tar extract followed by (ii) rapid proteolytic degradation of the oxidized proteins by proteases present in the microsomes. Like the whole phase CS, the oxidative damage of proteins caused by the tar phase CS, as evidenced by the formation of protein carbonyl and bityrosine as well as loss of tryptophan residues and thiol groups, is also almost completely prevented by ascorbic acid and only partially by glutathione. Other antioxidants, including superoxide dismutase, catalase, vitamin E, beta-carotene and mannitol are ineffective. This again leads us to suggest that adequate intake of vitamin C may help smokers to evade the CS-induced degenerative diseases associated with oxidative damage. The revelation of the acute toxicity of the tar phase with respect to CS-induced oxidative damage also urges the necessity of trapping it more effectively by suitable cigarette filters to reduce the health damage caused to smokers.

A comparative evaluation of some blood sugar lowering agents of plant origin.

A comparison of blood sugar lowering activity of four important medicinal plants (Azadirachta indica, Gymnema sylvestre, Catharanthus roseus and Ocimum sanctum) were carried out against normal and streptozotocin-induced diabetic rat models. The plant extracts decreased the blood sugar level in varying degrees. Blood sugar lowering unit (BLU) of activity of each leaf extract and tolbutamide was calculated by ED50 values. Statistical analysis revealed significant (P < 0.05) variation among the treatments as well as doses with regard to their blood sugar lowering capacity. A. indica leaf extract was found to have the most potent blood sugar-lowering activity followed by C. roseus, G. sylvestre and O. sanctum.

Possible mechanism of antihyperglycemic effect of Azadirachta indica leaf extract: part V.

Effect of Azadirachta indica leaf extract on serotonin inhibition in glucose mediated insulin release in rat pancreas was studied in vitro to elucidate the possible mechanism of antihyperglycemic effect of A. indica leaf extract. A. indica leaf extract blocks significantly (P < 0.05) the inhibitory effect of serotonin on insulin secretion mediated by glucose.

Possible mechanism of hepatoprotective activity of Azadirachta indica leaf extract: part II.

Hepatoprotective activity of Azadirachta indica leaf extract against paracetamol induced hepatic damage in rats has already been reported. In the present investigation effects of Azadirachta indica leaf extract on blood and liver glutathione, Na+K(+)-ATPase activity and thiobarbutiric acid reactive substances against paracetamol induced hepatic damage in rats have been studied with a view to elucidate possible mechanism behind its hepatoprotective action. It was interesting to observe that Azadirachta indica leaf extract has reversal effects on the levels of above mentioned parameters in paracetamol hepatotoxicity. Possible mechanism behind the results are discussed.

Hypoglycemic effect of Ocimum sanctum leaf extract in normal and streptozotocin diabetic rats.

Oral administration of alcoholic extract of leaves of O. sanctum led to marked lowering of blood sugar level in normal, glucose fed hyperglycemic and streptozotocin induced diabetic rats. Further the extract potentiated the action of exogenous insulin in normal rats. The activity of the extract was 91.55 and 70.43% of that of tolbutamide in normal and diabetic rats respectively.

Possible biochemical mode of anti-inflammatory action of Azadirachta indica A. Juss. in rats.

The water soluble part of alcoholic extract of A. indica leaves at a dose of 200 mg/kg, p.o., exerted significant antiinflammatory activity in cotton pellet granuloma assay in rats. The extract also inhibited significantly the biochemical parameters (viz. DNA, RNA, lipid peroxide, acid phosphatase and alkaline phosphatase) studied in cotton pellet exudate.

Effects of chemically-induced stress on blood viscosity of rabbits.

Disease-induced stress in a living system needs its characterization before quantification. We address this problem by studying the flow behaviour of blood of rabbits. The flow behaviour of rabbit blood, both normal and streptozotocin-induced diabetic was observed by plotting viscosity levels against known shear stress. The curves obtained from normal animals showed a curvilinear relationship between eta and tau, whereas the curves obtained from the blood of the induced diabetic animals showed a 'thixotropic' nature i.e. viscosity varies inversely with shear stress. The results obtained were (a) increased viscosity associated with increasing doses, (b) the lower the shear stress, higher was the viscosity and (c) significant variation of viscosity levels between normal and induced-diabetic rabbits observed by increased stress. The possible interpretation of the results in the light of rheological properties of blood is discussed.

Hepatoprotective activity of Azadirachta indica leaves on paracetamol induced hepatic damage in rats.

Effect of A. indica leaf extract on serum enzyme levels (glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, acid phosphatase and alkaline phosphatase) elevated by paracetamol in rats was studied with a view to observe any possible hepatoprotective effect of this plant. It was interesting to observe that serum enzyme levels were much elevated in paracetamol induced animals than in those receiving a combination of paracetamol and lead extract. It is stipulated that the extract treated group was protected from hepatic cell damage caused by paracetamol induction. The findings were further confirmed by histopathological study of liver.

Effects of progesterone on some brain neurotransmitters in intact rats.

Effects of progesterone on four neurotransmitters (viz, noradrenaline, 5-HT, dopamine and histamine) of brain were seen in rats with intact ovaries. It was found that progesterone lowers the noradrenaline concentration in medulla, pons, midbrain, hypothalamus, thalami and pituitary, uniformly, when the rats were killed within 4 hours of progesterone injection. At longer intervals (48 hrs) effects of progesterone were seen when progesterone in heavy dose was administered to rats pretreated with estrogen. It is likely that one of the modes of action of the oral contraceptives may be the reduction of noradrenaline content in selected areas of brain, by progesterone. It is also suggested, therapeutic usage of progesterone carries the risk of development of depression in the user.

Hypoglycemic and antihyperglycemic effect of leaves of Vinca rosea linn.

Oral administration of water fraction of alcoholic extract of leaves of Vinca rosea (fam. apocynaeceae) led to marked lowering of blood glucose level in normal and streptozotocin induced diabetic rats. The hypoglycemic effect of the fraction was comparable with that of tolbutamide.