Suchandra Chatterjee

Immunomodulatory and radioprotective effects of lignans derived from fresh nutmeg mace (Myristica fragrans) in mammalian splenocytes

Recently, the lignans present in the aqueous extract of fresh nutmeg mace (aril of the fruit of Myristica fragrans) were shown to possess antioxidant properties in cell free systems and protected PUC18 plasmid against radiation-induced DNA damage. The present report describes the immunomodulatory and radiomodifying properties of lignans present in the aqueous extract of fresh nutmeg mace in mammalian splenocytes. These macelignans (ML) inhibited the proliferation of splenocytes in response to polyclonal T cell mitogen concanavalin A (Con A). This inhibition of proliferation was due to cell cycle arrest in G1 phase and augmentation of apoptosis as shown by increase in pre G1 cells. The increase in activation induced cell death by ML was dose dependent. It was found to inhibit the transcription of IL-2 and IL-4 genes in response to Con A. The production of IL-2, IL-4 and IFN-gamma cytokines was significantly inhibited by ML in Con A-stimulated lymphocytes in a dose dependent manner. ML protected splenocytes against radiation-induced intracellular ROS production in a dose dependent manner. ML was not cytotoxic towards lymphocytes. On the contrary, it significantly inhibited the radiation-induced DNA damage in splenocytes as indicated by decrease in DNA fragmentation. To our knowledge, this is the first report showing the antioxidant, radioprotective and immunomodulatory effects of lignans in mammalian cells.

Natural existence of 2-alkylcyclobutanones.

Increased outbreaks of food-borne illnesses, including deaths in recent years, attributed in large part to consumption of food contaminated with Escherichia coli O157:H7, have become a worldwide concern. Food-borne illnesses constitute an unacceptable health risk demanding stringent food safety controls. Despite food irradiation being a known effective method to eliminate pathogens that are difficult to eradicate by conventional methods, consumers and industry at large have been reluctant to adopt it. This is mainly attributed to some apprehensions regarding the safety of irradiated food. One such apprehension relates to 2-alkylcylcyclobutanones, unique radiolytic products thought to be formed in minute quantities in food during radiation processing. We demonstrate here for the first time the natural occurrence of 2-dodecylcyclobutanone and 2-tetradecylcyclobutanone in commercial nonirradiated as well as fresh cashew nut samples and 2-decylcyclobutanone as well as 2-dodecylcyclobutanone in nonirradiated nutmeg samples. The presence of 2-tetradecenylcyclobutanone was also observed in both commercial and irradiated cashew nuts. The present study will provide greater impetus for wider adoption of radiation technology for elimination of food-borne pathogenic bacteria without apprehensions about the technology that can help ensure food safety.

Effect of γ-irradiation on the volatile oil constituents of turmeric (Curcuma longa)

Abstract The volatile essential oils from commercial samples of dry turmeric and samples γ-irradiated at a dose of 10 kGy were isolated using simultaneous distillation extraction technique and analyzed by GLC (Gas Liquid Chromatography) and gas chromatography/mass spectrometry (GC/MS). Some of the major compounds identified by GC/MS were α-phellandrene, p-cymene, 1:8cineol, β-caryophyllene, ar-curcumene, zingeberene, s-sesquiphellandrene, nerolidol, turmerone, ar-turmerone, curlone and dehydrozingerone. No detectable differences were observed between the aroma impact compounds of the irradiated and commercial samples.

Effect of γ-irradiation on the antioxidant activity of turmeric (Curcuma longa L.) extracts

Abstract Effect of γ-irradiation (10KGy) on the antioxidant property of turmeric extracts was investigated. γ-irradiated as well as non-irradiated turmeric samples were subjected to successive solvent extraction using hexane, benzene, and 80% aq. methanol. Benzene extract, containing mainly curcuminoids were subjected to column fractionation in order to isolate the individual curcuminoids. The curcuminoid analogues as well as the above fractions were then tested for their antioxidant activity by measuring thiobarbituric acid value (TBAV) and peroxide value (PV) based on the air oxidation of linoleic acid. γ-irradiation at a dose of 10KGy did not affect the antioxidant activity of turmeric extracts studied.

Evaluation of Antioxidant Activity and Characterization of Phenolic Constituents of Phyllanthus amarus Root

The antioxidant property of the 70% aqueous ethanol extract of Phyllanthus amarus roots and its ether-soluble, ethyl acetate-soluble, and aqueous fractions were investigated by various in vitro assays. The root extracts showed higher DPPH, hydroxyl, superoxide, and nitric oxide radical scavenging and reducing power activity. Among all the samples, the ethyl acetate-soluble fraction demonstrated highest radical scavenging activity and total phenolics content. Twenty-eight different phenolic compounds were identified by LCMS/MS analysis of the ethyl acetate-soluble fraction. The majority of the compounds were found to exist as their glycosides, and many of these were gallic acid derivatives. Free epicatechin and gallic acid were also identified in the ethyl acetate-soluble fraction. The present investigation suggested that P. amarus root is a potent antioxidant and can be used for the prevention of diseases related to oxidative stress.

Stability of lipid constituents in radiation processed fenugreek seeds and turmeric: role of phenolic antioxidants.

Impact of radiation processing on the lipid profile of fenugreek and turmeric was investigated. Oleic and linoleic acid were the dominant fatty acids with an appreciable amount of linolenic acid in both cases. Gamma-irradiation did not bring about any significant changes in the fatty acid profile of these spices despite a high content of unsaturation. The ability of aqueous methanolic extract of both spices with high phenolic content to prevent lipid peroxidation suggests a possible role of phenolic constituents in preventing lipid radiolysis. Among the phenolics identified, kaempferol-3-O-alpha-L-rhamnoside, kaempferol 3,7-O-alpha-L-dirhamnoside, quercetin 3,7-O-alpha-L-dirhamnoside, and 3-O-alpha-L-rhamnosyl quercetin are reported here to occur in fenugreek for the first time. The role of phenolic antioxidants in preventing lipid oxidation in the above spices is discussed.

Effect of post harvest radiation processing and storage on the volatile oil composition and glucosinolate profile of cabbage

Effect of radiation processing (0.5-2 kGy) and storage on the volatile oil constituents and glucosinolate profile of cabbage was investigated. Among the volatile oil constituents, an enhancement in trans-hex-2-enal was noted on irradiation that was attributed to the increased liberation of precursor linolenic acid mainly from monogalactosyl diacyl glycerol (MGDG). Irradiation also enhanced sinigrin, the major glucosinolate of cabbage that accounted for the enhanced allyl isothiocyanate (AITC) in the volatile oils of the irradiated vegetable. During storage the content of trans-hex-2-enal increased immediately after irradiation and then returned to the basal value within 24h while the content of sinigrin and AITC increased post irradiation and thereafter remained constant during storage. Our findings on the enhancement in potentially important health promoting compounds such as sinigrin and AITC demonstrates that besides extending shelf life and safety, radiation processing can have an additional advantage in improving the nutritional quality of cabbage.

Identification of Irradiated Cashew Nut by Electron Paramagnetic Resonance Spectroscopy

Cashew nut samples were irradiated at gamma-radiation doses of 0.25, 0.5, 0.75, and 1 kGy, the permissible dose range for insect disinfestation of food commodities. A weak and short-lived triplet (g = 2.004 and hfcc = 30 G) along with an anisotropic signal (g perpendicular = 2.0069 and g parallel = 2.000) were produced immediately after irradiation. These signals were assigned to that of cellulose and CO 2 (-) radicals. However, the irradiated samples showed a dose-dependent increase of the central line (g = 2.0045 +/- 0.0002). The nature of the free radicals formed during conventional processing such as thermal treatment was investigated and showed an increase in intensity of the central line (g = 2.0045) similar to that of irradiation. Characteristics of the free radicals were studied by their relaxation and thermal behaviors. The present work explores the possibility to identify irradiated cashew nuts from nonirradiated ones by the thermal behaviors of the radicals beyond the period, when the characteristic electron paramagnetic resonance spectral lines of the cellulose free radicals have essentially disappeared. In addition, this study for the first time reports that relaxation behavior of the radicals could be a useful tool to distinguish between roasted and irradiated cashew nuts.

Application of EPR spectroscopy to identify irradiated Indian medicinal plant products.

UNLABELLED A study of gamma-irradiated Indian medicinal plant products was carried out using electron paramagnetic resonance (EPR) spectroscopy. Improved approaches like high-power measurement, microwave saturation, and thermal behavior of the radicals were explored for detection of irradiation. Aswagandha (Withania somnifera), vairi (Salacia reticulata), amla (Emblica officinalis), haldi (Curcumin longa), and guduchi (Tinospora cordifolia) exhibited a weak singlet at g = 2.005 before irradiation. Aswagandha, immediately after radiation treatment, revealed a complex EPR spectrum characterized by EPR spectrum simulation technique as superposition of 3 paramagnetic centers. One group of signal with organic origin was carbohydrate and cellulose radical and the other was isotropic signal of inorganic origin (g⟂ =2.0044 and g|| = 1.9980). However, other products did not exhibit any radiation-specific signal after irradiation. Power saturation and thermal behavior techniques were not suitable for these products. However, amongst all the 3 approaches, high-power measurement of EPR spectra emerged as a suitable technique in identification of the irradiated aswagandha. PRACTICAL APPLICATION Gamma-irradiation confirms hygienic quality and improves shelf life of food and other products. However, there is a lack of international consensus over considering this as a general application and different regulations are being enforced. EPR is one of the most promising techniques to identify irradiated foodstuffs for regulatory requirements but it has many limitations. Improved approaches based on the EPR technique explained in this study may be useful to identify irradiated products and become beneficial to food regulators and food irradiation enterprises to enhance confidence in irradiation technology.

Effect of γ-irradiation on the colour power of turmeric (Curcuma longa) and red chillies (Capsicum annum) during storage

Abstract Colour power of dry turmeric and three varieties of dry red chillies irradiated to doses of 0, 1, 5 and 10 kGy was estimated periodically during storage up to 1 year at ambient conditions, according to the American Spice Trade Association method. γ -irradiation did not cause any significant change in the colour power values of both turmeric and red chilli varieties. However, significant ( p ≤0.05) reduction in colour power values were observed for all the chilli varieties during storage though colour power values for turmeric remained unchanged on storage. ©