Significance of Melatonin in the Regulation of Circadian Rhythms and Disease Management.

Melatonin, the 'hormone of darkness' is a neuronal hormone secreted by the pineal gland and other extra pineal sites. Responsible for the circadian rhythm and seasonal behaviour of vertebrates and mammals, melatonin is responsible for regulating various physiological conditions and the maintenance of sleep, body weight and the neuronal activities of the ocular sites. With its unique amphiphilic structure, melatonin can cross the cellular barriers and elucidate its activities in the subcellular components, including mitochondria. Melatonin is a potential scavenger of oxygen and nitrogen-reactive species and can directly obliterate the ROS and RNS by a receptor-independent mechanism. It can also regulate the pro- and anti-inflammatory cytokines in various pathological conditions and exhibit therapeutic activities against neurodegenerative, psychiatric disorders and cancer. Melatonin is also found to show its effects on major organs, particularly the brain, liver and heart, and also imparts a role in the modulation of the immune system. Thus, melatonin is a multifaceted candidate with immense therapeutic potential and is still considered an effective supplement on various therapies. This is primarily due to rectification of aberrant circadian rhythm by improvement of sleep quality associated with risk development of neurodegenerative, cognitive, cardiovascular and other metabolic disorders, thereby enhancing the quality of life.

Pharmacological safety of dimethoxy curcumin-human serum albumin conjugate for potential therapeutic purpose.

Medicinal properties of curcumin are widely published. Previously, researchers used curcuminoid mixture comprising three chemical forms, out of which, the highest quantity is the most active molecule-dimethoxy curcumin (DMC). Reduced bioavailability, poor aqueous solubility, and quick hydrolytic degradation of DMC have projected challenges limiting its therapeutic value. However, selective conjugation of DMC with human serum albumin (HSA) enhances drug stability and solubility by several folds. Studies using animal models demonstrated potential anti-cancer/anti-inflammatory effects of DMCHSA; both studies showed results of local administration in peritoneal cavity and rabbit knee joint. DMC has prospects as intravenous therapeutic agent because carrier is HSA. However, before in vivo testing, important preclinical data required are toxicological safety and bioavailability of soluble forms of DMC. This study evaluated absorption, distribution, metabolism, and excretion of DMCHSA. Imaging technology and molecular analysis proved bio-distribution. The study also assessed the pharmacological safety of DMCHSA in mice in terms of its acute and sub-acute toxicity, complying with regulatory toxicology. Overall, the study demonstrated the safety pharmacology of DMCHSA upon intravenous infusion. This is a novel study establishing the safety of highly soluble and stable formulation of DMCHSA, qualifying it for intravenous administration and further efficacy evaluation in suitable disease models.

Cascade of immune mechanism and consequences of inflammatory disorders.

Inflammatory responses arise as an outcome of tissues or organs exposure towards harmful stimuli like injury, toxic chemicals or pathogenic microorganism. It is a complex cascade of immune mechanism to overcome from tissue injury and to initiate the healing process by recruiting various immune cells, chemical mediators such as the vasoactive peptides and amines, pro-inflammatory cytokines, eicosanoids and acute-phase proteins to prevent tissue damage and ultimately complete restoration of the tissue function. The cytokines exhibits a central function in communication between the cells, inflammatory response initiation, amplification and their regulation. This review covers the importance of inflammatory responses; the significance of cytokines in inflammation and numerous inflammatory disorders/ailments due to the abrupt expression of cytokines and the hyper-inflammatory response or cytokine storm associated with poor prognosis in COVID-19 pandemic. Also highlighting the importance of naturally derived anti-inflammatory metabolites to overcome the side-effects of currently prevailing anti-inflammatory drugs.

In vitro and In vivo toxicity analysis of zinc selenium/zinc sulfide (ZnSe/ZnS) quantum dots.

Despite the versatility of quantum dots (QDs) in optoelectronics and biomedical field, their toxicity risks remain a considerable hindrance for clinical applications. Cytotoxicity of Cadmium containing QDs is well documented and reveals that they are toxic to cells. Reports suggest that the presence of toxic elements at the QD core (e.g., cadmium, selenium) is responsible for its toxicity in in vivo and in vitro levels. Hence, here the toxicity of heavy metal free ZnSe/ZnS QDs on two scenarios were assessed, (i) HEK cells as in vitro system and (ii) Swiss Albino mice as in vivo model. Before toxicity analysis, QDs subjected to various optical and physico-chemical characterization methods such as absorption and emission spectra analysis, observation under U.V light, TEM, DLS, Zeta potential, FTIR, Raman and XPS spectra, ICP-OES, TGA and DTG curve. It is very necessary to characterize the synthesized QDs because their toxicity greatly influenced by the physico-chemical properties. On checking the vulnerability of HEK cells on exposure to ZnSe/ZnS QDs, the obtained results disclose that ZnSe/ZnS QDs showed merest impact on cellular viability at a concentration less than 100 µg/ml. Acute toxicity of 10 mg/kg ZnSe/ZnS QDs was studied in mice and no clinical or behavioural changes were observed. It did not induce any changes in haematological parameters and any loss of body or organ weight. Moderate pathological changes were evident only in the liver, all others organs like kidney, spleen and brain did not show any manifestations of toxicity. Current work lays substantial bedrock for safe biomedical and environmental application of ZnSe/ZnS QDs in near future.

Black phosphorus, a prospective graphene substitute for biomedical applications.

2D materials have gained spectacular status across various scientific and technological disciplines owing to their exceptional unique properties. The very recent member of 2D family, Black Phosphorus monolayers, known as Phosphorene have attracted recent scientific attention since its first exfoliation and appreciable rediscovery in 2014. Compared to other 2D materials and graphene analogs, it has outstanding properties like tunable band gap, good carrier mobility, excellent ON-OFF current ratio, potent in vivo biocompatibility and non-toxic biodegradability. Although the outlook of this material seems to be a promising candidate for future biomedical technology, its practical applications are still highly challenging. Unveiling those challenges by proper characterization and functionalization makes this material a mile stone for future theranostic and biomedicine scenario. This review has given precise attention to familiarize with the unique fundamental properties of black phosphorus, which makes it an excellent platform for future biomedical applications. Also underlines various synthesis procedures applicable for BP nanosheets and quantum dot synthesis. Its various biomedical applications including biosensors, cancer therapy, imaging and photothermal/photo acoustic/photodynamic therapy, drug delivery, neuronal regeneration, 3D printing scaffold etc., are subsequently reviewed. Furthermore this review briefly focused on the toxicity of this emerging material.

Pyrogens, a polypeptide produces fever by metabolic changes in hypothalamus: Mechanisms and detections.

Fever is one of the cardinal symptoms of onset of an infection or inflammation and is the common clinical indicator for medical consultation in mammalian host worldwide. Simply, fever manifested with elevation of body temperature from normal physiological range represents adaptive response of immune system on challenge with an infectious and non-infectious circumstance. Fever usually initiated in the periphery as a result of interaction of immune cells with exogenous or endogenous pyrogens. Peripheral pyrogenic signals gain access to the central nervous system via humoral and neural route. Humoral pathway was initiated with production of pyrogenic cytokines and prostaglandins from immune cells of blood as well as liver, transmitted directly to pre-optic area of hypothalamus through the circumventricular organ of brain. On the other hand an alternative pathway was initiated by the same cytokines indirectly via stimulating the vagal sensory neurons result in pyrogenic fever; so-called neuronal pathway. If the magnitude of pyrogens associated fever is very high, it will lead to severe illness ranging from septic shock to death. So it is necessary to evaluate the presence of pyrogens in implants, medical devices, drugs and biological materials to ensure safety in biomedical applications and therapeutics. Classification, route of administration, mechanism of action and detection of pyrogens and associated products are the major subject of this review.

Amelioration of melatonin on oxidative stress and genotoxic effects induced by cisplatin in vitro.

In this study, we made an effort to evaluate the possible protective actions of melatonin on cisplatin-induced oxidative damage in mice brain homogenate and genotoxic effects in human lymphocytes under in vitro conditions. The tissue homogenate was divided into three parts. The first portion was kept as control treated with dimethyl sulphoxide (DMSO) (group 1) while the second and third portion were treated with 24 µg/g tissue cisplatin alone (group 2) and 24 µg/g tissue cisplatin in combination with 3 mM melatonin (group 3), respectively. We measured the oxidative stress biomarkers such as lipid peroxidation, 8-hydroxy 2' deoxyguanosine (8-OHdG) and antioxidant parameters such as reduced glutathione, superoxide dismutase, glutathione peroxidase, and glutathione reductase in brain homogenate. Likewise peripheral venous blood was collected from healthy donors and human lymphocyte culture was done using karyotyping medium. Cultures were divided into three groups. Group 1 was the control i.e. lymphocytes treated with DMSO 5 µg/mL. In group 2, lymphocytes were treated with 2 µg/mL cisplatin and group 3 with a combination of 2 µg/mL cisplatin and 0.3 mM melatonin. Incubation of tissue homogenates with cisplatin elevated the malondialdehyde and 8-OHdG levels which were then reversed by melatonin. Reduction in antioxidant parameters with respect to corresponding controls were also restored by melatonin treatment. Furthermore, supplementation of melatonin was found to modulate the chromosome damage elicited by cisplatin which was determined using Giemsa (GTG) banding and karyotyping. These findings suggest that melatonin improves the cellular function and helps them to survive in the belligerent environment created by free radicals.

Chemoprotective effect of Sobatum against cyclophosphamide toxicity in mice.

The partially purified component of Solanum trilobatum named as Sobatum was found to be cytotoxic in Dalton's lymphoma ascites (DLA), Ehrlich ascites (EA) and tissue cultured cells. It significantly inhibited the peritoneal and solid tumours induced by DLA and EA tomour cells along with the chemically induced skin carcinogenesis. Sobatum did not produce any chromosomal anomalies in the bone marrow cells of Swiss mice. In the present study, we have evaluated the chemoprotective effect of Sobatum on cyclophosphamide induced toxicity in mice. The results showed that the co-administration of Sobatum increase the total leucocyte count, haemoglobin level, average life span of animals; we concluded that Sobatum has chemoprotective action on cyclophosphamide induced toxicity.

Toxicological evaluation of sobatum.

Sobatum, the partially purified component of the plant Solanum trilobatum was obtained from the petroleum ether/ethyl acetate (75:25) extractable portion. It was identified as beta-sitosterol by comparison with an authentic sample and proved to be an anticancer agent by in vitro and in vivo experiments. The aim of the present study is to evaluate the acute/subacute toxicity of sobatum and its effect on antioxidant enzymes. In the acute toxicity test, there was a single exposure of sobatum in mice in order to evaluate toxicity symptoms. In the subacute toxicity study, the exposure was usually daily so as to evaluate the target organs affected by the compound and the major toxic effects and enzymatic and histopathological changes. The results of the study suggested that sobatum did not induce any toxic symptoms or death immediately after injection or at the end of the experimental period. It was also shown that there was no change in blood parameters or antioxidant enzymes in sobatum-treated animals. Regarding histopathological evaluation, there was no development of gross abnormalities or pathological lesions observed in any of the tissues in sobatum-treated and control groups. Hence, the present study concluded that the anticancer agent, sobatum, did not produce any acute/subacute toxicities or anomalies in the synthesis of antioxidant enzymes.

Effect of Sobatum on radiation-induced toxicity in mice.

Sobatum, the active fraction of the plant Solanum trilobatum was obtained from the petroleum ether/ethyl acetate (75:25) extractable portion. Sobatum was proven to be an anticancer agent by in vitro and in vivo methods. The aim of this study is to evaluate the effect of Sobatum on radiation-induced toxicity in mice. In this assay there are three groups. Group I, the control group, received radiation alone, while groups II and III received Sobatum (100 and 200 mg/kg body weight, respectively) with radiation. Sobatum was administered 24 h before radiation and was continued for 4 alternate days. Body weight, food intake and blood parameters were determined before radiation and every 3 days after radiation for 17 days. The results indicated that there was significantly less body weight gain and food intake in the radiation alone-treated group compared to the Sobatum-treated group. The average leukocyte count and haemoglobin level of the Sobatum-treated group was considerably improved at the end of the experimental period. Hence, it can be concluded that Sobatum reduced the side-effects of radiation-induced toxicity and suggested that it could be used along with radiation therapy.

Effect of Sobatum on tumour development and chemically induced carcinogenesis.

The partially purified component of Solanum trilobatum named Sobatum was obtained from the petroleum ether/ethyl acetate (75:25) extractable portion. It was found to be cytotoxic in Dalton's Lymphoma ascites (DLA), Ehrlich ascites (EA) cell lines and tissue culture cells (L929 and Vero). Sobatum significantly inhibited peritoneal tumours induced by DLA and EA tumour cells. Sobatum was also found to reduce solid tumour growth in mice, when given either simultaneously or prophylactically, and is more active in simultaneous administration (EA). It was found that Sobatum was more active against EA cells-induced solid tumour than DLA-induced solid tumours. On exposure to 7,12-dimethylbenz(a)anthracene (DMBA), about 85.67% animals had induced skin carcinogenesis, which was significantly inhibited to 44.4% by the application of Sobatum. It can be concluded that the Sobatum has the ability to retard the development of solid tumours and DMBA-induced carcinogenesis.

Cytotoxic potential of the preparations from Solanum trilobatum and the effect of sobatum on tumour reduction in mice.

Plant Solanum trilobatum was washed, powdered and used for extraction. The lyophilized aqueous extracted portion was tested for in vitro cytotoxicity by tissue culture technique using L929 and Vero cells. Petroleum ether, chloroform, ethyl acetate and ethanol were used for extraction and the extracted portions were subjected to in vitro tissue culture studies. It was shown that petroleum ether extract induced remarkable cytotoxicity, when compared to all other extracts with an LD50 of 7.0 microg in L929 and 5.8 microg in Vero cells. Further fractionated portions of petroleum ether extract (by adsorption chromatography) underwent tissue culture assay, and results suggest that petroleum ether/ethyl acetate (75:25) extractable portion is the most active fraction, named as sobatum, which induced an LD50 of 7.0 microg in L929 and 7.5 microg in Vero cells. Sobatum significantly inhibit the peritoneal tumours induced by Dalton's lymphoma ascites (DLA) and Ehrlich ascites (EA) tumour cell. The effect was more prominent when sobatum was administered orally as evidenced from the increased percentage of life span. Sobatum, the partially purified portion of Solanum trilobatum, was again fractionated by column chromatography and all the residues were concentrated and crystallized from methanol, giving only one pure crystalline compound, that was identified as Beta-sitosterol by comparing with authentic sample.

Lack of micronucleus induction by 'Sobatum' in bone marrow erythrocytes of Swiss mice.

The plant Solanum trilobatum is mainly used for asthma, chronic febrile affections and difficult parturition. The active principle (Sobatum) obtained from the petroleum ether extract of the plant was proved as an anticancer agent by in vitro and in vivo experiments. Here, an effort was made to evaluate the induction of micronucleus by the Sobatum in the bone marrow of swiss mice. The micronucleus assay was conducted after 24 and 72 h of second administration of the Sobatum. The first set of experiments (24 h after second administration) consisted of 4 groups with 3 male Swiss albino mice each. The first group (as control) received only dimethyl sulfoxide, the second, third and fourth groups received different doses of the Sobatum (100, 200, 400 mg/kg body weight), and the fifth group (as positive control) received cyclophosphamide (100 mg/kg body weight) by i.p. injection. In the second set of experiment (72 h after the second administration) consisting of 5 groups, the first, as control, received dimethyl sulfoxide, the second, third and fourth groups received different concentrations of the Sobatum (100, 200, 400 mg/kg body weight), and the fifth group as positive control received cyclophosphamide (100 mg/kg body weight). All the animals of the first and second sets of experiment were killed 24 and 72 h after the second medication (2 consecutive days), and bone marrow smears were prepared, stained with May-Grunwald and Giemsa stain, and evaluated for the evidence of micronucleus. The study concluded that the Sobatum fails to influence the induction of micronuclei in bone marrow erythrocytes of mice 24 and 72 h after the second administration, thereby proving that Sobatum to has no cytogenetic toxic potential.