Differential Impact of Nitric Oxide and Abscisic Acid on the Cellular and Physiological Functioning of sub1A QTL Bearing Rice Genotype under Salt Stress.

Hydroponic culture containing 200 mM NaCl was used to induce oxidative stress in seedlings of cultivars initially primed with 1 mM SNP and 10 µM ABA. Exogenous application of sodium nitroprusside (SNP - a nitric oxide donor) and abscisic acid (ABA) was well sensitized more in cv. Swarna Sub1 than cv. Swarna and also reflected in different cellular responses. The major effects of salinity, irrespective of the cultivar, were lowering the water relation, including relative water content and osmotic potential, and decreasing the compatible solutes like alanine, gamma-aminobutyric acid, and glycine betaine. The accumulated polyamines were reduced more in cv. Swarna with a concomitant decrease in photosynthetic reserves. NADP-malic enzyme activity, sucrose accumulation, ascorbate peroxidase, and glutathione S-transferase activities gradually declined under NaCl stress and the catabolizing enzymes like invertase (both wall and cytosolic forms) also declined. On the contrary, plants suffered from oxidative stress through superoxide, hydrogen peroxide, and their biosynthetic enzymes like NADP(H) oxidase. Moderation of Na+/K+ by both SNP and ABA were correlated with other salt sensitivities in the plants. The maximum effects of SNP and ABA were found in the recovery of antioxidation pathways, osmotic tolerance, and carbohydrate metabolism. Findings predict the efficacy of SNP and ABA either independently or cumulatively in overcoming NaCl toxicity in rice.

Photoactivated TiO2 Nanocomposite Delays the Postharvest Ripening Phenomenon through Ethylene Metabolism and Related Physiological Changes in Capsicum Fruit.

Capsicum is one of the most perishable fruit which undergo rapid loss of commercial value during postharvest storage. In this experiment our aim is to evaluate the effect of photoactivated TiO2 nano-particle complexed with chitosan or TiO2-nanocomposite (TiO2-NC) on extension self-life of Capsicum fruit and its effect on related morphological, physiological and molecular attributes at room temperature (25 °C). Initially, TiO2-NC coated fruits recorded superior maintenance of total soluble solids accumulation along with retention of firmness, cellular integrity, hydration, color etc. On the extended period of storage, fruit recorded a lower bioaccumulation of TiO2 in comparison to metallic silver over the control. On the level of gene expression for ethylene biosynthetic and signaling the TiO2-NC had more regulation, however, discretely to moderate the ripening. Thus, ACC synthase and oxidase recorded a significantly better downregulation as studied from fruit pulp under TiO2-NC than silver. On the signaling path, the transcripts for CaETR1 and CaETR2 were less abundant in fruit under both the treatment when studied against control for 7 d. The reactive oxygen species (ROS) was also correlated to retard the oxidative lysis of polyamine oxidation by diamine and polyamine oxidase activity. The gene expression for hydrolytic activity as non-specific esterase had corroborated the development of essential oil constituents with few of those recorded in significant abundance. Therefore, TiO2-NC would be reliable to induce those metabolites modulating ripening behavior in favor of delayed ripening. From gas chromatography-mass spectrometry (GC-MS) analysis profile of all tested essential oil constituents suggesting positive impact of TiO2-NC on shelf-life extension of Capsicum fruit. Our results indicated the potentiality of TiO2-NC in postharvest storage those may connect ethylene signaling and ROS metabolism in suppression of specific ripening attributes.

Amelioration of sodium and arsenic toxicity in Salvinia natans L. with 2,4-D priming through physiological responses.

Sodium (Na) and arsenic (As) toxicity were monitored by hyperaccumulation of metals in Salvinia natans L. with 2,4-dichlorophenoxyacetic acid (2,4-D) induction. Salvinia was recorded with significant bioaccumulation of those metals with de-folding of cellular attributes in sustenance under toxic environment. 2,4-D priming has revised the growth components like net assimilation rate and relative water content to register initial plants' survival against Na and As. Proline biosynthesis supported in the maintenance of osmotic adjustment and plants sustained better activity through subdued electrolytic leakage. Oxidative stress due to both Na and As exposure is responsible for induction under significant moderation of lipid peroxidation and protein carbonization by 2,4-D application was evident to release the stress from metal and metalloids. Reactive oxygen species (ROS) like superoxide and hydrogen peroxide accumulation were monitored with activity of NADP(H)-oxidase. However, it was downregulated by 2,4-D to check the oxidative damages. Superoxide dismutase and peroxidases were significantly moderated to reduce the oxidative degradation for both metals with 2,4-D induction. Glutathione metabolism and recycling of ascorbate with monodehydroascorbate activity were other features to maintain the redox homeostasis for metal toxicity. At the molecular level, polymorphic variations of concern genes in redox cascades demarked significantly for those two metals and established the biomarker for those metals, respectively. As a whole, the biocompatibility of auxin herbicide in Salvinia may raise the possibility for auxin metabolism and thereby, the bioaccumulation to Na and As vis-à-vis tolerance for ecological safety is established.

An updated overview of the physiological and molecular responses of rice to anoxia.

Waterlogging or flooding in agricultural soil constructs a complex abiotic stress-web in crop plants throughout the lowland agricultural system. In rice, a staple grain crop in the world, submergence creates a long-term and recurrent problem for crops withstanding and their succeeding productivity. Therefore, to restore a satisfactory yield instead of a failure of crop in such submerged areas, the analysis of plants' responses is important. Such analysis will facilitate research about the entity components of plants responses to anoxia or submergence. For example, the development of cellular and molecular cascade in gene expression of ROS signaling and its subsequent responses may lead to either tolerance or susceptibility in plants. Interplay of plant growth regulators [e.g., ethylene (ET), abscisic acid (ABA), gibberellic acid (GA) etc.] is the well-recognized residues in the coordination of signaling, its transmission through cellular network, and finally, modulation of gene expression are the keys to such tolerance. Nucleotide elements that are specifically sensitive to ethylene have been rescued from land-races of aus-type group of rice (Oryza sativa) and those are considered as the prime determinants for tolerance against anoxia. In this comprehensive text, we tried to accommodate and revise the fundamental and pivotal mechanisms of submergence stress at different angles of physiological and cellular responses of plants. These have also been reviewed for modern state of art techniques deciphering the molecular rejoinders like microRNA, protein-protein interaction, feedback regulation of expression, sugar sensing, amplification of elicitor's responses and others. Finally, strategies including physiological selection, metabolic engineering, marker assisted selection, genetical manipulation, interspecific hybridization are involved in developing stress resilience and plants' architecture to support sustainable agriculture under lowland systems.

Clinico-Mycological Profile of Treatment-Naïve, Chronic, Recurrent and Steroid-Modified Dermatophytosis at a Tertiary Care Centre in Eastern India: An Institution-Based Cross-SectionalStudy.

BACKGROUND: Dermatophytosis has recently emerged as a major public health problem in the Indian subcontinent, most cases becoming chronic and recurrent. AIMS: Assessing the clinico-epidemiologic and mycologic profile of treatment naïve, chronic, recurrent and steroid-modified dermatophytosis. MATERIALS AND METHODS: We conducted across-sectional study involving 111 cases of dermatophytosis. Detailed epidemiology, clinical parameters, treatment history and other host factors were assessed along with scraping for potassium hydroxide (KOH) and fungal culture. RESULTS: Among 111 patients,(F: M 1.7:1; mean age 44.4 ± 18.2 years), 51.4% were treatment naïve, while 34.2% and 14.4% presented with chronic and recurrent tinea respectively. Family history and sharing of fomites among infected family members was commoner in the latter groups (P = 0.001). Topical steroid application was reported in 49.5%, however only 7.2% presented with steroid modified tinea. Tinea corporis et cruris (41.4%) was the predominant clinical type followed by tinea corporis (34.2%) and tinea cruris (27.9%). KOH mount and culture were positive in 62.2% and 39.6% cases respectively; commonest isolates being Trichophyton rubrum, and Trichophyton mentagrophytes complex in 15.3% cases each. Trichophyton rubrum was the commonest etiology for treatment naïve and recurrent cases, while Trichophyton mentagrophytes was the commonest isolate from chronic and steroid-modified cases (P = 0.0003). Interestingly, T.mentagrophytes complex and T. rubrum were the commonest causes of tinea corporis and tinea cruris respectively (P = 0.07). CONCLUSION: Trichophyton rubrum was the commonest organism in treatment naïve and recurrent cases, while Trichophyton mentagrophytes complex accounted for most cases of chronic and steroid modified tinea. The difference in predominant species seems to be a major contributory factor for chronicity and recurrence. However, several host factors like topical steroid use and sharing of fomites also play additional roles.

Abscisic acid priming regulates arsenite toxicity in two contrasting rice (Oryza sativa L.) genotypes through differential functioning of sub1A quantitative trait loci.

Arsenite [As(III)] toxicity causes impeded growth, inadequate productivity of plants and toxicity through the food chain. Using various chemical residues for priming is one of the approaches in conferring arsenic tolerance in crops. We investigated the mechanism of abscisic acid (ABA)-induced As(III) tolerance in rice genotypes (cv. Swarna and Swarna Sub1) pretreated with 10 µM of ABA for 24 h and transferred into 0, 25 and 50 µM arsenic for 10 days. Plants showed a dose-dependent bioaccumulation of As(III), oxidative stress indicators like superoxide, hydrogen peroxide, thiobarbituric acid reactive substances and the activity of lipoxygenase. As(III) had disrupted cellular redox that reflecting growth indices like net assimilation rate, relative growth rate, specific leaf weight, leaf mass ratio, relative water content, proline, delta-1-pyrroline-5-carboxylate synthetase and electrolyte leakage. ABA priming was more protective in cv. Swarna Sub1 than Swarna for retrieval of total glutathione pool, non-protein thiols, cysteine, phytochelatin and glutathione reductase. Phosphate metabolisms were significantly curtailed irrespective of genotypes where ABA had moderated phosphate uptake and its metabolizing enzymes like acid phosphatase, alkaline phosphatase and H+/ATPase. Rice seedlings had regulated antioxidative potential with the varied polymorphic expression of those enzymes markedly with antioxidative enzymes. The results have given the possible cellular and physiological traits those may interact with ABA priming in the establishment of plant tolerance with As(III) over accumulation and, thereby, its amelioration for oxidative damages. Finally, cv. Swarna Sub1 was identified as a rice genotype as a candidate for breeding program for sustainability against As(III) stress with cellular and physiological traits serving better for selection pressure.

Chitosan and putrescine modulate reactive oxygen species metabolism and physiological responses during chili fruit ripening.

We investigated the combined effect of chitosan (CHT) and putrescine (PUT) on the postharvest shelf life of Capsicum fruit concerning the metabolism of reactive oxygen species (ROS) through direct and indirect effects on ripening characters cell wall hydrolyzing enzyme and ROS metabolism. The PUT and CHT directly affected quality indices like color, firmness and water loss with a concomitant oxidative bust in the development of O2•- and H2O2 in fruit pulp. This was accompanied by significant suppression of respiratory flux, a decrease of total soluble solids and ascorbic acid content throughout postharvest storage. PUT applied with CHT modified the oxidative metabolism of fruits by a significant reduction in the level of O2•- and H2O2 content. In addition, a significant accumulation of total polyamine under respective treatment was reasonably correlated with both ROS producing enzyme as well as H2O2 and O2•-. Wall hydrolyzing enzymes like pectin methyl esterase and cellulase had marked downregulation both under PUT and CHT + PUT treatment. Moreover, on close observation, the combinational effects of PUT and CHT had better effects in the regulation of those enzymes as compared to individual treatment. Fruits restore higher antioxidative capacities as evident with superoxide dismutase (SOD), guaiacol peroxidases (GPX), ascorbate peroxidase (APX) catalase (CAT), glutathione peroxidase (GPX), NADPH oxidase (NOX) and glutathione reductase (GR), indicating their roles on fruit coat softening. Finally, the treatment of PUT and CHT in combination increased shelf life vis-à-vis the quality of fruit.

2, 4-D removal efficiency of Salvinia natans L. and its tolerance to oxidative stresses through glutathione metabolism under induction of light and darkness.

In a laboratory based study, Salvinia natans L. was pre-treated with reduced glutathione (GSH) following transfer under 2, 4-Dicholro phenoxy acetic acid (2,4-D), peroxide (H2O2), dark and irradiation. Plants recorded 2, 4-D bio-accumulation and tolerance maximally under 500 µM following absorption kinetics modulated with GSH in changes of relative water content (20.98%), growth rate (3.04%) and net assimilation rate (1.3 fold) over control. GSH pre-treatment minimized the oxidative revelation with reactive oxygen species (ROS) by 5.55% decrease under 2, 4-D and 1.3, 1.2, 0.8 fold increase through the other stresses. Apoplastic NADPH-oxidase expression was moderated by GSH with 11.76% less over the control. Also the activity of alcohol dehydrogenase and glutathione-S-transferase had their altered values by 1.5 and 9.0 fold increases respectively and may serve as biomarkers. The oxidized:reduced glutathione was positively correlated with glutathione-peroxidase (r=+0.99) and negatively with glutathione reductase (r=-0.04). The induced activities sustained oxidized:reduced GSH pool by 1.09 fold and had varied polymorphic gene expression under 2, 4-D and allied stresses. This study may be relevant to consider Salvinia as a potent weed species remediating 2, 4-D toxicity in soil with its wider hyper-accumulating efficiency. The cellular responses in tolerance to oxidative stress and thereby, induced physiological attributes may opt for selection pressures in other weed flora for broader aspects of phytoremediation against xenobiotics like 2, 4-D.

Aluminium accumulation in excess and related anti-oxidation responses in C4 weed (Amaranthus viridis L.).

C4 species, Amaranthus viridis L. exhibited a significant bioaccumulation of aluminium (Al) through the duration of 3- and 5-days exposure. As compared to control, Amaranthus appeared as excess-accumulator with maximum 5.85-fold bioaccumulation of Al in root. Cellular responses to Al tolerance initially scored tissue specific distribution of metal through cortical layers revealed by electron microscopy. The affected cells changed an oxidative status as read by histochemical stains, particularly, for hydrogen peroxide. Osmotic stress and its stability were scored by maximum proline and free amino acids accumulation with 1.53 and 1.59-fold increase over control. The accumulation of phenolics and flavonoids were over expressed in the ranges of 2.48-2.50-fold and 2.00-1.5-fold at 3- and 5-days respectively against control. Anti-oxidation to detoxify Al stress was facilitated by variants of peroxidases. For exclusion mechanism of metal, esterase activity significantly over expressed with maximum value of 1.80-fold at 5-days. The polymorphism of esterase exhibited few significant over produced bands, varied in numbers as detected by densitometric scanning. Moreover, plant extract was satisfactorily potential under in vitro anti-oxidation systems through assay of 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS), ferric chelation activity etc. Therefore, weeds like Amaranthus would be a bioprospecting in role likely involved in phytoremediation of metal.

Silver Can Induce Oxidative Stress in Parallel to Other Chemical Elicitors to Modulate the Ripening of Chili Cultivars.

Two chili cultivars, i.e., cv. Bullet and cv. Tejaswini, were evaluated on postharvest related ripening characteristics with varying durations under hydrogen peroxide, putrescine and silver treatments. The reducing sugar was inversely related to the maximum values at 7 days of ripening. Silver and putrescine were the most regulatory in terms of changing of the total carbohydrate content as compared to hydrolysis of the total reducing sugar. Regarding pectin methylesterase activity, both chilies were consistent, regardless of the number of days of incubation. Still, putrescine and silver were significant contributors to variations in cv. Bullet and cv. Tejaswani. For the pigment content, lycopene and chlorophyll increased in a linear manner, although these treatments significantly varied over time. Hydrogen peroxide and putrescine were responsible for the maximum accumulation of lycopene for both the cultivars, whereas, only cv. Tejaswani displayed maximum carotenoid for putrescine. Silver for both chili varieties was the most inhibitory for lycopene and carotenoid content. Superoxide had a good impact on the accumulation of lipid peroxides, irrespective of the chili variety. The maximum accumulation of lipid peroxide was recorded at seven days of treatment. Phenolics and flavonoids were in decreasing order for both the chili varieties, progressing through the days of the study period in a similar manner. Silver was the main contributor to variations in the phenolics and flavonoid contents in cv. Tejaswani. The solubilization of total carbohydrate into reducing sugar was in an inverse relationship, with the maximum values being reached at 7 days of ripening.

Arecoline inhibits pineal-testis function in experimentally induced hypothyroid rats.

Arecoline is known to cause endocrine dysfunction. In the current article role of arecoline on pineal-testis activity was investigated in hypothyroid rats induced by propylthiouracil (PTU). PTU treatment caused thyroid dysfunction ultrastructurally with a fall in T3 and T4 levels followed by a rise of thyroid stimulating hormone (TSH) level. Pineal activity was impaired by PTU treatment, as evident from degenerated synaptic ribbons and mitochondria of the pinealocytes with depletion of pineal and serum N-acetyl serotonin and melatonin levels. Leydig cell function was suppressed, evident from reduced smooth endoplasmic reticulum and depletion of testosterone level. Sex accessories function was impaired by showing scanty rough endoplasmic reticulum with depletion of fructose and sialic acid levels. Arecoline treatment that caused pineal dysfunction and testicular stimulation in control rats, suppressed both pineal and testis functions after PTU treatment. The findings suggest that arecoline inhibits pineal-testis function in experimentally induced hypothyroid rats.

Arecoline plays dual role on adrenal function and glucose-glycogen homeostasis under thermal stress in mice.

Arecoline has biomedical importance, but it has untoward side effects on endocrine functions. The aim is to investigate its role on adrenal activity under thermal stress by ultrastructural and hormonal parameters in mice. Cold (4 °C) or heat (37 °C) stress, or arecoline (10 mg/kg body wt), each for 7 days in cold or heat stress stimulated adrenocortical activity ultrastructurally with an elevation of corticosterone level. Adrenomedullary activity was suppressed in cold stress with depletion of catecholamine levels. In heat stress, adrenomedullary activity was stimulated ultrastructurally with an elevation of catecholamine levels. Arecoline treatment alone, or in cold or heat stress suppressed adrenomedullary activity, judged by ultrastructural and hormonal parameters. Arecoline treatment caused hypoglycemia with an elevation of glycogen level, but cold or heat stress, or arecoline treatment in thermal stress caused hyperglycemia, with a fall in glycogen profile. Thus, arecoline in thermal stress plays a dual role on adrenal function and glucose-glycogen homeostasis in mice.

Abscisic acid induced cellular responses of sub1A QTL to aluminium toxicity in rice (Oryza sativa L.).

Involvement of abscisic acid (ABA) was studied for aluminium (Al) sensitivity through functioning of sub1A quantitative trait loci in rice cultivars. sub1A quantitative trait loci bearing cv. Swarna Sub1 was found almost compatible with non sub1A quantitative trait loci bearing cv. Swarna for abscisic acid accumulation all through the aluminium concentrations. However, abscisic acid was self inductive by over expression of its biosynthetic gene in nine-cis-epoxycarotenoid dioxygenase 3 (NCED3) more in cv. Swarna than other. The effect of abscisic acid pretreatment was variable for specific leaf weight, leaf mass ratio and others for the cultivars. Bio-accumulation of aluminium had revealed the sensitivity of toxicity more in cv. Swarna than other. In connection to oxidative stress generation of reactive oxygen species was detected by both histochemical and in vitro assays through hematoxylin, Evans blue and schiff's reactions. Abscisic acid pretreatment had significantly reversed the effects of aluminium toxicity for reactive oxygen species generation. Regardless of varieties sensitivity of aluminium was more prone in shoot than root as detected by nitro blue tetrazolium and 3,3'-diaminobenzidine mediated signalling. Activity in metal chelation in extra cellular spaces monitored through esterase activity and that also established independence of abscisic acid pretreatment for cv. Swarna Sub1. The specific polymorphism of esterase at protein level strengthened the bio-monitoring of aluminium through the rice varieties as well its modulation with abscisic acid. Abscisic acid has been discussed an important effectors to modulate the tolerance pathway of rice cultivars through intrusion of sub1A quantitative trait loci.

Modulation of physiological responses with TiO2 nano-particle in Azolla pinnata R.Br. under 2,4-D toxicity.

The present work is emphasised with the herbicidal tolerance of Azolla pinnata R.Br. and its modulation with TiO2 nano-particle. Both carbohydrate and nitrogen metabolism were effected with 2,4-D as herbicide and in few cases TiO2-NP had recovered few detrimental effects. From the nutrient status in Azolla it recorded the recovery of nitrogen as well as potassium by TiO2-NP but not in case of phosphorus. However, a conversion of nitrate to ammonium was more induced by TiO2-NP under herbicidal toxicity. Similar results were obtained for inter-conversion of amino acid-nitrate pool, but no changes with glutamine synthase activity with TiO2-NP. Initially, the effects of 2,4-D was monitored with changes of chlorophyll content but had not been recovered with nanoparticle. Photosynthetic reserves expressed as both total and reducing sugar were insensitive to TiO2-NP interference but activity of soluble and wall bound invertase was in reverse trend as compared to control. The 2,4-D mediated changes of redox and its oxidative stress was ameliorated in plants with over expressed ADH activity. As a whole the Azolla bio system with TiO2 supplementation may be useful in sustenance against 2,4-D toxicity through recovery of nitrogen metabolism. Thus, Azolla-TiO2-NP bio system would be realised to monitor the herbicidal toxicity in soil and its possible bioremediation.

Arecoline ameliorates hyperthyroid condition in mice under cold stress.

Betel nut of Areca catechu is chewed by millions of people for increased capacity to work and stress reduction, but it contains arecoline that causes hypothyroidism. The aim is to investigate the role of arecoline on thyroid activity in cold stress in mice. Arecoline treatment (10 mg/kg body wt/day, for 7 d) caused a reduction in thyroid weight and ultrastructural degeneration of thyro-follicular cells with depletion of T3 and T4 levels compared with the control mice. Cold stress (4 °C for 2 h, twice daily, for 7 d) stimulated thyroid activity ultrastructurally with an elevation of T3 and T4 levels. Arecoline treatment in cold stress suppressed thyroid activity by showing reversed changes to those of cold stress. In contrast, TSH concentrations were consistently increased under all experimental conditions. The findings suggest that cold stress causes hyperthyroidism which arecoline can ameliorate in mice.

Arecoline cannot alter testicular dysfunction and pineal activation caused by noise in wistar rat.

Millions of people consume betel nut for increased capacity to work and for stress reduction. The nut contains arecoline, which has multiple side effects on endocrine functions. Objective of the work is to investigate pineal-testicular responses to noise and after arecoline treatment in noise in rats. Noise exposure (100 dB, 6 h daily, 10 days) caused pineal stimulation ultrastructurally and at indoleamines level. Leydig cell dysfunction with fall of testosterone level and suppression of sex accessories were noticed. In contrast, pineal activity was inhibited and reproductive functions were stimulated after arecoline administration, confirmed from reversed changes to those of noise. Arecoline treatment in noise exposure showed same results as in noise both in pineal and in reproductive functions. It is concluded that noise causes testicular dysfunction probably by gonadotropin suppression induced by pineal melatonin in noise. Furthermore, arecoline cannot prevent it in noise in rats.

A protective role of arecoline hydrobromide in experimentally induced male diabetic rats.

OBJECTIVES: Arecoline, the most potent and abundant alkaloid of betel nut, causes elevation of serum testosterone and androgen receptor expression in rat prostate, in addition to increase in serum insulin levels in rats, leading to insulin resistance and type 2 diabetes-like conditions. This study investigated the role of arecoline on the reproductive status of experimentally induced type 1 diabetic rats. METHODS: Changes in the cellular architecture were analyzed by transmission electron microscopy. Blood glucose, serum insulin, testosterone, FSH, and LH were assayed. Fructose content of the coagulating gland and sialic acid content of the seminal vesicles were also analyzed. RESULTS: Arecoline treatment for 10 days at a dose of 10 mg/kg of body weight markedly facilitated ß-cell regeneration and reversed testicular and sex accessory dysfunctions by increasing the levels of serum insulin and gonadotropins in type 1 diabetic rats. Critical genes related to ß-cell regeneration, such as pancreatic and duodenal homeobox 1 (pdx-1) and glucose transporter 2 (GLUT-2), were found to be activated by arecoline at the protein level. CONCLUSION: It can thus be suggested that arecoline is effective in ameliorating the detrimental effects caused by insulin deficiency on gonadal and male sex accessories in rats with type 1 diabetes.

Arecoline augments cellular proliferation in the prostate gland of male Wistar rats.

Areca nut chewing is the fourth most popular habit in the world due to its effects as a mild stimulant, causing a feeling of euphoria and slightly heightened alertness. Areca nuts contain several alkaloids and tannins, of which arecoline is the most abundant and known to have several adverse effects in humans, specially an increased risk of oral cancer. On evaluating the effects of arecoline on the male endocrine physiology in Wistar rats, it was found that arecoline treatment led to an overall enlargement and increase in the wet weight of the prostate gland, and a two-fold increase in serum gonadotropin and testosterone levels. Since the prostate is a major target for testosterone, the consequences of arecoline consumption were studied specifically in the prostate gland. Arecoline treatment led to an increase in the number of rough endoplasmic reticulum and reduction of secretory vesicles, signifying a hyperactive state of the prostate. Increased expression of androgen receptors in response to arecoline allowed for enhanced effect of testosterone in the prostate of treated animals, which augmented cell proliferation, subsequently confirmed by an increase in the expression of Ki-67 protein. Cellular proliferation was also the outcome of concomitant over expression of the G(1)-to-S cell cycle regulatory proteins, cyclin D1 and CDK4, both at the transcriptional and translational levels. Taken together, the findings provide the first evidence that regular use of arecoline may lead to prostatic hyperplasia and hypertrophy, and eventually to disorders associated with prostate enlargement.

Ultrastructural and hormonal changes in the pineal-testicular axis following arecoline administration in rats.

Arecoline is an alkaloid of betel nut of Areca catechu. Betel nut is chewed by millions of people in the world and it causes oral and hepatic cancers in human. It has therapeutic value for the treatment of Alzheimer and schizophrenia. Arecoline has immunosuppressive, mutagenic and genotoxic effects in laboratory animals. It also affects endocrine functions. The objective of this study was to investigate the effects of arecoline on pineal-testicular axis in rats. Since pineal activity is different between day and night, the current study is undertaken in both the photophase and scotophase. The findings were evaluated by ultrastructural and hormonal studies of pineal and testicular Leydig cells, with quantitations of fructose and sialic acid of sex accessories. Arecoline treatment (10 mg/kg body weight daily for 10 days) caused suppression of pineal activity at ultrastructural level by showing dilatation of the cisternae of the rough endoplasmic reticulum (RER), large autophagosome-like bodies with swollen mitochondrial cristae, numerous lysosomes, degenerated synaptic ribbons and reduced number of synaptic-like microvesicles. Moreover, pineal and serum N-acetylserotonin and melatonin levels were decreased with increased serotonin levels in both the gland and serum. In contrast, testicular Leydig cell activity was stimulated with abundance of smooth endoplasmic reticulum (SER), electron-dense core vesicles and vacuolated secretory vesicles, and increased testosterone level in the arecoline recipients. Consequently, the testosterone target, like prostate, was ultrastructurally stimulated with abundance of RER and accumulation of secretory vesicles. Fructose and sialic acid concentrations were also significantly increased respectively in the coagulating gland and seminal vesicle. These results were more significant in the scotophase than the photophase. The findings suggest that arecoline inhibits pineal activity, but stimulates testicular function (testosterone level) and its target organs presumably via muscarinic cholinergic receptor in rats.

Immunosuppression, hepatotoxicity and depression of antioxidant status by arecoline in albino mice.

BACKGROUND: There are about 600 million betel quid chewers in the world. Betal quid chewing is one of the major risk factors of hepatocarcinoma, oropharyngeal and esophagus cancers. Arecoline, the main Areca alkaloid of the betel nut is reported to have cytotoxic, genotoxic and mutagenic effects in various cells. It shows strong correlation to the incidence of oral submucosal fibrosis, leukoplakia and oral cancer, and has also been found to impose toxic manifestations in immune, hepatic and other defense systems of the recipient. AIM: The precise molecular mechanisms underlying the toxic effects of arecoline deserve investigation. To clarify the action of arecoline on defense systems, immune, hepatic and detoxification system were studied in mice. METHOD: Cell count and cell cycle of the splenocytes were studied for evaluating cell immunity. Liver function test (LFT) was followed by assaying different enzyme systems from serum (SGPT, SGOT and ALP) and liver (GST for detoxication enzyme, SOD and catalase for antioxidant enzymes and GSH for non-enzymatic antioxidant) and by ultrastructural studies of hepatocytes. RESULTS: Here we report that arecoline arrested splenic lymphocyte cell cycle at lower concentration with induced apoptosis at higher concentration thereby causing immunosuppression in arecoline recipients. Besides, it resulted in hepatotoxicity in arecoline recipient mice by disrupting the hepatocyte ultrastructure, as judged by liver ultrastructural studies that showed decreased nuclear size, RER with profusely inflated cysternae and abundance of lipid droplets, and by up regulating hepatotoxic marker enzymes (SGOT and SGPT) in serum. Arecoline also caused depression of antioxidants, i.e., superoxide dismutase (SOD), catalase, reduced glutathione (GSH) and glutathione-S-transferase (GST) that are known to neutralize reactive oxygen species. CONCLUSION: All these above-mentioned results led us to conclude that arecoline attacks multiple targets to finally generate systemic toxicity in mice.