Label-free quantitative mass spectrometry analysis of the circadian proteome of Drosophila melanogaster lethal giant larvae mutants reveals potential therapeutic effects of melatonin.

Mutation in the Drosophila melanogaster lethal giant larvae (lgl), a tumor suppressor gene with a well-established role in cellular polarity, is known to results in massive cellular proliferation and neoplastic outgrowths. Although the tumorigenic properties of lgl mutant have been previously studied, however, little is known about its consequences on the proteome. In this study, mass spectrometry-based label-free quantitative proteomics was employed to investigate the changes in the head and intestinal tissues proteins of Drosophila melanogaster, due to lgl mutation and following treatment with melatonin. Additionally, to uncover the time-influenced variations in the proteome during tumorigenesis and melatonin treatment, the rhythmic expression of proteins was also investigated at 6-h intervals within 24-h clock. Together, the present study has identified 434 proteins of altered expressions (p < 0.05 and fold change ±1.5) in the tissues of flies in response to lgl mutation as well as posttreatment with melatonin. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of differentially expressed proteins revealed that lgl mutation had significantly affected the biological functions, including metabolism, and protein synthesis and degradation, in flies' tissues. Besides, melatonin had beneficially mitigated the deleterious effects of lgl mutation by reversing the alterations in protein expression closer to baseline levels. Further, changes in protein expression in the tissues due to lgl mutation and melatonin treatment were found rhythmically orchestrated. Together, these findings provide novel insight into the pathways involved in lgl-induced tumorigenesis as well as demonstrated the efficacy of melatonin as a potential anticancer agent. Data are available via ProteomeXchange with identifier PXD033191.

Molecular mechanisms interlinking biological clock and diabetes mellitus: Effective tools for better management.

BACKGROUND AND AIM: Advances in circadian biology have delineated the link between perturbed biological clock and metabolic diseases. Circadian disturbances are associated with the onset, progression and severity of diabetes mellitus. METHODS: We conducted a literature survey using the key terms - circadian, diabetes, circadian and diabetes, clock genes and diabetes, chronotherapy and peripheral clocks in science direct, PubMed, Google, and Embase till August 23, 2021. RESULTS: Misalignment between peripheral clocks located in pancreas, intestine, liver, adipose tissue and skeletal muscle and with the central oscillator alters the secretion of insulin, incretins, adipokines and soluble factors resulting in the derangement of metabolism leading to chronic hyperglycemia. CONCLUSION: Management of circadian health restores glucose homeostasis confirming that chronotherapy will help in the management of diabetes mellitus. Further, administration of circadian clock modifiers has proved potential therapeutic agents to treat diabetes mellitus. The aim of the review is to highlight the molecular mechanisms linking biological clock and diabetes mellitus and how they are useful for effective management of the disease.

Application of Proteomics in Pancreatic Ductal Adenocarcinoma Biomarker Investigations: A Review.

Pancreatic ductal adenocarcinoma (PDAC), a highly aggressive malignancy with a poor prognosis is usually detected at the advanced stage of the disease. The only US Food and Drug Administration-approved biomarker that is available for PDAC, CA 19-9, is most useful in monitoring treatment response among PDAC patients rather than for early detection. Moreover, when CA 19-9 is solely used for diagnostic purposes, it has only a recorded sensitivity of 79% and specificity of 82% in symptomatic individuals. Therefore, there is an urgent need to identify reliable biomarkers for diagnosis (specifically for the early diagnosis), ascertain prognosis as well as to monitor treatment response and tumour recurrence of PDAC. In recent years, proteomic technologies are growing exponentially at an accelerated rate for a wide range of applications in cancer research. In this review, we discussed the current status of biomarker research for PDAC using various proteomic technologies. This review will explore the potential perspective for understanding and identifying the unique alterations in protein expressions that could prove beneficial in discovering new robust biomarkers to detect PDAC at an early stage, ascertain prognosis of patients with the disease in addition to monitoring treatment response and tumour recurrence of patients.

Melatonin improves cognitive behavior, oxidative stress, and metabolism in tumor-prone lethal giant larvae mutant of Drosophila melanogaster.

Mutant lethal giant larvae (lgl) flies (Drosophila melanogaster) are known to develop epithelial tumors with invasive characteristics. The present study has been conducted to investigate the influence of melatonin (0.025 mM) on behavioral responses of lgl mutant flies as well as on biochemical indices (redox homeostasis, carbohydrate and lipid metabolism, transaminases, and minerals) in hemolymph, and head and intestinal tissues. Behavioral abnormalities were quantitatively observed in lgl flies but were found normalized among melatonin-treated lgl flies. Significantly decreased levels of lipid peroxidation products and antioxidants involved in redox homeostasis were observed in hemolymph and tissues of lgl flies, but had restored close to normalcy in melatonin-treated flies. Carbohydrates including glucose, trehalose, and glycogen were decreased and increased in the hemolymph and tissues of lgl and melatonin-treated lgl flies, respectively. Key enzymes of carbohydrate metabolism showed a significant increment in their levels in lgl mutants but had restored close to wild-type baseline levels in melatonin-treated flies. Variables of lipid metabolism showed significantly inverse levels in hemolymph and tissues of lgl flies, while normalization of most of these variables was observed in melatonin-treated mutants. Lipase, chitinase, transaminases, and alkaline phosphatase showed an increment in their activities and minerals exhibited decrement in lgl flies; reversal of changes was observed under melatonin treatment. The impairment of cognition, disturbance of redox homeostasis and metabolic reprogramming in lgl flies, and restoration of normalcy in all these cellular and behavioral processes indicate that melatonin could act as oncostatic and cytoprotective agents in Drosophila.

Hesperidin modulates the rhythmic proteomic profiling in Drosophila melanogaster under oxidative stress.

The circadian clock regulates vital aspects of physiology including protein synthesis and oxidative stress response. In this investigation, we performed a proteome-wide scrutiny of rhythmic protein accrual in Drosophila melanogaster on exposure to rotenone, rotenone + hesperidin and hesperidin in D. melanogaster. Total protein from fly samples collected at 6 h intervals over the 24 h period was subjected to two-dimensional gel electrophoresis and mass spectrometry. Bioinformatics tool, Protein ANalysis THrough Evolutionary Relationships classification system was used to the determine the biological processes of the proteins of altered abundance. Conspicuous variations in the proteome (151 proteins) of the flies exposed to oxidative stress (by rotenone treatment) and after alleviating oxidative stress (by hesperidin treatment) were observed during the 24 h cycle. Significantly altered levels of abundance of a wide variety of proteins under oxidative stress (rotenone treatment) and under alleviation of oxidative stress (rotenone + hesperidin treatment) and hesperidin (alone) treatment were observed. These proteins are involved in metabolism, muscle activity, heat shock response, redox homeostasis, protein synthesis/folding/degradation, development, ion-channel/cellular transport, and gustatory and olfactory function of the flies. Our data indicates that numerous cellular processes are involved in the temporal regulation of proteins and widespread modulations happen under rotenone treatment and, action of hesperidin could also be seen on these categories of proteins.

Basic chronobiology: what do sleep physicians need to know?

Sleep is an essential physiological process, which profoundly affects a wide range of biological activities. It is now known that sleep supports myriad vital functions in the central nervous system. This includes neural plasticity, learning, memory, cognition and emotional regulation. Additionally, it affects basic processes such as cardiovascular, immunological and metabolic activity. Evidence from multiple lines of research has thus shown that good quality of sleep is essential for both survival and optimal functioning of life. Considerable evidence also supports the conclusion that even minimal dysfunctions in circadian regulation can significantly disrupt sleep and broadly affect body physiology. As a consequence, it is now appreciated that the therapy of sleep disorders is more complex than was once thought. At present, several clinical disciplines have recognized the significance of the biological clock in health and illness, and are incorporating this knowledge into treatment programs. Recent decades have seen the emergence of chronotherapies, i.e., treatment strategies that are aimed at producing adjustments in the circadian clock. The final objective of these approaches is to affect basic cellular and physiological processes, which in turn may be at the root of disorders such as physiological aging, immune functioning, metabolic activity, and psychiatric disturbance. It is suggested that the integration of chronobiological perspectives into many mainstream medical disciplines would be of significant benefit, both for the reduction of the prevalence of diseases and their treatment. This review considers the physiology of sleep and the importance of timekeeping mechanisms in the regulation of overall health.

Chronotherapeutics: Recognizing the Importance of Timing Factors in the Treatment of Disease and Sleep Disorders.

This review describes the characteristics of a number of pathologies, which are considered from the point of view of chronobiology, that is, the way in which biological processes are expressed throughout the 24-hour day. This perspective is a relatively new way of thinking about disease and additionally about how to treat diseases. It has called attention to the importance of not only the quantity of a drug that is administered but also when it is administered. In addition, the review presents an overview of the emerging clinical strategies known as chronotherapeutics, that is, the effects of the daily scheduling of drug administration and the consequences of the activity and efficacy of therapies that are applied in this manner. This article also reviews innovative ways in which physicians are applying time-specified drug treatment (chronopharmacology) for sleep disorders. Here, we present a systematic description of chronopharmacology as well as definitions of key terms that, we believe, will be helpful for newcomers to the field. It is hoped that greater awareness of this new perspective on pharmacology will promote its adoption by researchers and clinicians.

Preventive Efficacy of Vanillic Acid on Regulation of Redox Homeostasis, Matrix Metalloproteinases and Cyclin D1 in Rats Bearing Endometrial Carcinoma.

Endometrial carcinoma is a malignant tumor of the female genital tract. This study has been performed to evaluate the chemopreventive efficacy of vanillic acid (a bio flavonoid) on endometrial carcinoma (EC) by assessing the levels of thiobarbituric acid reactive substances (TBARS), lipid hydroperoxides (LOOH), cytochrome P450, antioxidants-superoxide dismutase (SOD), catalase (CAT), glutathione peroxides (GPx), reduced glutathione (GSH), vitamins C and E, matrix metalloproteinases (MMP-2 and 9) and cell cycle check point protein (cyclin D1) in N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) induced carcinogenic rats. EC provoked by intravaginal detention of MNNG (150 mg/kg b.w. for 90 days), lead to enhancement of the levels of TBARS, LOOH, cytochrome P450, and decrement in the levels of antioxidants (SOD, CAT, GPx, GSH, vitamins C and E) and upregulated expression of MMP-2 and 9 and cyclin D1 (by western blot analysis). The treatment of vanillic acid (100 mg/kg b.w.) to MNNG treated rats (1) normalized the histopathological alterations, (2) reduced the levels of TBARS, LOOH and cytochrome P450 (3) increased the levels of antioxidants (SOD, CAT, GPx, GSH, vitamins C and E) in plasma and uterus and (4) down regulated the expression of MMP-2, 9 and cyclin D1. The effect of vanillic acid is more predominant in pre-treatment group than co-treated rats. Our results designate that vanillic acid inhibits the EC by elevating antioxidants and by regulating the levels of metalloproteinase and cell cycle check point protein.

Influence of Quercetin in the Temporal Regulation of Redox Homeostasis in Drosophila melanogaster.

Numerous biological processes are governed by the biological clock. Studies using Drosophila melanogaster (L.) are valuable that could be of importance for their effective applications on rodent studies. In this study, the beneficial role of quercetin (a flavonoid) on H2O2 induced stress in D. melanogaster was investigated. D. melanogaster flies were divided into four groups (group I - control, group II - H2O2 (acute exposure), group III - quercetin, and group IV - quercetin + H2O2 treated). Negative geotaxis assay, oxidative stress indicators (protein carbonyls, thiobarbituric reactive substances [TBARS]), and antioxidants (superoxide dismutase [SOD], catalase [CAT], glutathione-S-transferase [GST], glutathione peroxidase, and reduced glutathione [GSH]) were measured at 4 h intervals over 24 h and temporal expression of heat shock protein-70 (Hsp70), Upd1 (homolog of IL-6 in Drosophila), and nitric oxide synthase (Nos) was analyzed by Western blotting. Groups II and IV showed altered biochemical rhythms (compared with controls). Decreased mesor values of negative geotaxis, SOD, CAT, GST, and GSH were noticed in H2O2, increased mesor of oxidative stress indicators (TBARS and protein carbonyl content) and a reversibility of the rhythmic characteristics were conspicuous after quercetin treatment. The expression levels of Hsp70, Upd1, and Nos were noticeably maximum at 04:00. Significant elevation of expression by H2O2 was nearly normalized by quercetin treatment. The possible mechanism by which quercetin modulates oxidant-antioxidant imbalance under oxidative stress could be ascribed to the modulation of the rhythmic properties. Our results will be helpful to understand the molecular interlink between circadian rhythm and oxidative stress mechanism.

Influence of the Flavonoid, Quercetin on Antioxidant Status, Lipid Peroxidation and Histopathological Changes in Hyperammonemic Rats.

We have studied the ability of quercetin (a bioflavonoid) in tackling oxidative stress to alleviate the symptoms during ammonium chloride-induced hyperammonemia. Hyperammonemia was induced by the treatment of ammonium chloride (AC) 100 mg/kg b.w for 56 days. Hyperammonemic rats exhibited reduced urea (in plasma) and increased ammonia (in blood), uric acid (in plasma), creatinine (in serum), oxidative stress markers (thiobarbituric acid reactive substances (TBARS) and hydroperoxides (HP) and decreased levels of antioxidants (enzymatic and non-enzymatic) superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH) in plasma and tissues (liver and brain) vitamins E and C (in plasma)). The expression of liver inflammatory markers such as, interleukin 6 (IL-6), inducible nitric oxide synthase (iNOS) and nuclear transcription factor-κB (NF-κB) (by western blotting) were investigated. Histological damages (in liver, brain and kidney) were observed under hyperammonemia and the administration of quercetin (1) normalized the histopathological alterations, (2) reduced the levels of TBARS and HP, (3) elevated the antioxidants (SOD, CAT, GPx, GSH, vitamins E and C), (4) declined the activities of liver marker enzymes (AST, ALT and ALP) and (5) down regulated the expression of IL-6, iNOS and NF-κB. Our results suggest that quercetin might exert defense to AC-induced hyperammonemic rats to tackle (1) oxidative stress and (2) inflammation owing to its antioxidant, anti-inflammatory and cytoprotective effects.

Geraniol Inhibits Endometrial Carcinoma via Downregulating Oncogenes and Upregulating Tumour Suppressor Genes.

Endometrial carcinoma is the fourth most abundant cancer worldwide in women. Female Wistar rats were segregated into five groups: group I-control, group II-MNNG (N-methyl-N'-nitro-N-nitrosoguanidine-150 mg/kg) administered through intravaginal detention of cotton absorbent, group III-geraniol (GOH) only, group IV-GOH-pretreated (7 days before the start of MNNG administration); and group V-Co-administration of geraniol with MNNG. In this study, reverse transcriptase- PCR of K-ras, MAPK, PI3K, Wnt/ß-catenin genes, TGF-ß and expressions of PCNA, PTEN, progesterone receptor and E-cadherin by Western blotting were performed from endometrial cancer tissue and control tissues. The mRNA expressions of K-ras, MAPK, PI3K, Wnt/ß-catenin and TGF-ß were amplified in MNNG induced group. Oral administration of GOH (both pre and co-administration) reversed the mRNA expression towards normal. The reversibility is more predominant in pretreatment groups (p < 0.05). The expression of PCNA was upregulated and downregulation of PTEN, progesterone receptor and E-cadherin was noticed in MNNG induced rats. Pre and co-administration of GOH significantly reversed the expression pattern of proteins. GOH treatment is more effective in pretreatment groups (p < 0.05). These results provide powerful evidences that GOH could influence modulation of MAPK pathways and Wnt signalling pathways in the prevention of endometrial carcinoma in rats.

Role of Bioflavonoid Quercetin on Expression of Urea Cycle Enzymes, Astrocytic and Inflammatory Markers in Hyperammonemic Rats.

This study evaluates the role of quercetin on the expression of urea cycle enzymes, astrocytic, neuronal and inflammatory markers in hyperammonemic rats. Hyperammonemia (provoked by intraperitonial injections of (ammonium chloride-100 mg/kg b.w for 56 days), showed diminished expression of urea cycle enzymes [carbamyl phosphate synthetase-1 (CPS-1), ornithine transcarbamylase (OTC), argininosuccinate synthetase (ASS) and arginase (ARG)] in liver and decreased expression of neuronal and astrocytic markers-glutamine synthase (GS) and phosphate activated glutaminase (PAG) in brain and increased expression of brain inflammatory markers such as interleukin 6 (IL6), inducible nitric oxide synthase (iNOS) and nuclear transcription factor kappa B (NF-κB) (by western blot analysis) and exhibited downregulated expression of soluble guanylate cyclase (sGC), glial fibrillary acidic protein (GFAP) in brain and ASS in liver investigated (by RT-PCR). Oral treatment of quercetin (50 mg/kg b.w) to hyperammonemic rats (1) increased the expression of urea cycle enzymes (CPS-1, OTC, ASS and ARG), neuronal and astrocytic markers (GS and PAG) (2) decreased the expression of IL6, iNOS and NF-κB and (3) upregulated mRNA expression of SGC, GFAP and ASS. Our results specify that quercetin's antihyperammonemic effects could be through its, anti-inflammatory, neuroprotective and hepatoprotective effects.

Temporal regulation of proteome profile in the fruit fly, Drosophila melanogaster.

Background. Diurnal rhythms of protein synthesis controlled by the biological clock underlie the rhythmic physiology in the fruit fly, Drosophila melanogaster. In this study, we conducted a proteome-wide investigation of rhythmic protein accumulation in D. melanogaster. Materials and Methods. Total protein collected from fly samples harvested at 4 h intervals over the 24 h period were subjected to two-dimensional gel electrophoresis, trypsin digestion and MS/MS analysis. Protein spots/clusters were identified with MASCOT search engine and Swiss-Prot database. Expression of proteins was documented as percentage of volume contribution using the Image Master 2D Platinum software. Results. A total of 124 protein spots/clusters were identified using MS/MS analysis. Significant variation in the expression of 88 proteins over the 24-h period was observed. A relatively higher number of proteins was upregulated during the night compared to the daytime. The complexity of temporal regulation of the D. melanogaster proteome was further reflected from functional annotations of the differently expressed proteins, with those that were upregulated at night being restricted to the heat shock proteins and proteins involved in metabolism, muscle activity, protein synthesis/folding/degradation and apoptosis, whilst those that were overexpressed in the daytime were apparently involved in metabolism, muscle activity, ion-channel/cellular transport, protein synthesis/folding/degradation, redox homeostasis, development and transcription. Conclusion. Our data suggests that a wide range of proteins synthesized by the fruit fly, D. melanogaster, is under the regulation of the biological clock.

Chronotherapeutic effect of fisetin on expression of urea cycle enzymes and inflammatory markers in hyperammonaemic rats.

BACKGROUND: Elevated blood ammonia leads to hyperammonaemia that affects vital central nervous system (CNS) functions. Fisetin, a naturally occurring flavonoid, exhibits therapeutic benefits, such as anti-cancer, anti-diabetic, anti-oxidant, anti-angiogenic, neuroprotective and neurotrophic effects. METHODS: In this study, the chronotherapeutic effect of fisetin on ammonium chloride (AC)-induced hyperammonaemic rats was investigated, to ascertain the time point at which the maximum drug effect is achieved. The anti-hyperammonaemic potential of fisetin (50mg/kg b.w. oral) was analysed when administered to AC treated (100mg/kg b.w. i.p.) rats at 06:00, 12:00, 18:00 and 00:00h. Amelioration of pathophysiological conditions by fisetin at different time points was measured by analysing the levels of expression of liver urea cycle enzymes (carbamoyl phosphate synthetase-I (CPS-I), ornithine transcarbamoylase (OTC) and argininosuccinate synthetase (ASS)), nuclear transcription factor kappaB (NF-κB p65), brain glutamine synthetase (GS) and inducible nitric oxide synthase (iNOS) by Western blot analysis. RESULTS: Fisetin increased the expression of CPS-I, OTC, ASS and GS and decreased iNOS and NF-κB p65 in hyperammonaemic rats. Fisetin administration at 00:00h showed more significant effects on the expression of liver and brain markers, compared with other time points. CONCLUSIONS: Fisetin could exhibit anti-hyperammonaemic effect owing to its anti-oxidant and cytoprotective influences. The temporal variation in the effect of fisetin could be due to the (i) chronopharmacological, chronopharmacokinetic properties of fisetin and (ii) modulations in the endogenous circadian rhythms of urea cycle enzymes, brain markers, redox enzymes and renal clearance during hyperammonaemia by fisetin. However, future studies in these lines are necessitated.

Role of Bacopa monnieri in the temporal regulation of oxidative stress in clock mutant (cryb) of Drosophila melanogaster.

Accruing evidences imply that circadian organization of biochemical, endocrinological, cellular and physiological processes contribute to wellness of organisms and in the development of pathologies such as malignancy, sleep and endocrine disorders. Oxidative stress is known to mediate a number of diseases and it is notable to comprehend the orchestration of circadian clock of a model organism of circadian biology, Drosophila melanogaster, under oxidative stress. We investigated the nexus between circadian clock and oxidative stress susceptibility by exposing D. melanogaster to hydrogen peroxide (H2O2) or rotenone; the reversibility of rhythms following exposure to Bacopa monnieri extract (ayurvedic medicine rich in antioxidants) was also investigated. Abolishment of 24h rhythms in physiological response (negative geotaxis), oxidative stress markers (protein carbonyl and thiobarbituric acid reactive substances) and antioxidants (superoxide dismutase, catalase, glutathione-S-transferase and reduced glutathione) were observed under oxidative stress. Furthermore, abolishment of per mRNA rhythm in H2O2 treated wild type flies and augmented susceptibility to oxidative stress in clock mutant (cry(b)) flies connotes the role of circadian clock in reactive oxygen species (ROS) homeostasis. Significant reversibility of rhythms was noted following B. monnieri treatment in wild type flies than cry(b) flies. Our experimental approach revealed a relationship involving oxidative stress and circadian clock in fruit fly and the utility of Drosophila model in screening putative antioxidative phytomedicines prior to their use in mammalian systems.

Effect of melatonin on antioxidant status and circadian activity rhythm during hepatocarcinogenesis in mice.

AIM: Alteration of circadian systems can cause cancer and affects its development and response to therapeutics. The present study investigates whether cancer can disrupt circadian locomotor rhythms and evaluated the influence of melatonin (MLT) and oxaliplatin on the levels of antioxidants and circadian locomotor activity rhythms in N-nitrosodiethylamine (NDEA)-induced liver tumor in Indian field mouse (Mus booduga). MATERIALS AND METHODS: Effects of NDEA, NDEA, and MLT, as well as NDEA and oxaliplatin, on levels of mice liver marker enzymes and antioxidants and their circadian locomotor activity rhythm were assessed. RESULTS: Treatment of mice with NDEA caused significant alteration of their liver marker enzymes [aspartate transaminase and alanine transaminase; P<0.05 Duncan's multiple range test (DMRT) test] antioxidant levels (superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase; P<0.05, DMRT test] and circadian locomotor activity rhythm, which were abrogated when the animals were also given MLT or the anticancer drug, oxaliplatin. CONCLUSION: Our study demonstrated that the circadian clock was disturbed by hepatocarcinogenesis and the effects could be reversed by the chronobiotic, MLT.

Naringenin (citrus flavonone) induces growth inhibition, cell cycle arrest and apoptosis in human hepatocellular carcinoma cells.

Search for new substances with antiproliferative activity and apoptosis inducing potential towards HepG2 cells is important since HCC is notoriously resistant to conventional chemotherapy. Dietary phytochemicals with significant anti-proliferative and apoptosis inducing potential are considered as agents promising for cancer therapy. Naringenin, a common dietary flavonoid abundantly present in fruits and vegetables, is believed to possess strong cytotoxic activity in numerous types of cancer cells. However, the detailed molecular mechanisms of its antiproliferative effects and apoptosis induction are still unclear. In this study, we investigated antiproliferative and apoptosis-inducing effect of naringenin in human hepatocellular carcinoma HepG2 cells. Naringenin was shown to inhibit the proliferation of HepG2 cells resulted partly from an accumulation of cells in the G0/G1 and G2/M phase of the cell cycle. Naringenin induced a rapid accumulation of p53, which might account for the naringenin-induced G0/G1 and G2/M phase arrests in Hep G2 cells. In addition, naringenin have been shown to induce apoptosis as evidenced by nuclei damage and increased proportion of apoptotic cells detected by flow cytometry analysis. Naringenin triggered the mitochondrial-mediated apoptosis pathway as shown by an increased ratio of Bax/Bcl-2, subsequent release of cytochrome C, and sequential activation of caspase-3. Our results showed that naringenin had inhibitory effect on the growth of HepG2 cell line through inhibition of cell proliferation and apoptosis induction. The elucidation of the drug targets of naringenin on inhibition of tumor cells growth should enable further development of naringenin for liver cancer therapy.

Inhibitory effect of naringenin (citrus flavonone) on N-nitrosodiethylamine induced hepatocarcinogenesis in rats.

We evaluated the effects of naringenin on N-nitrosodiethylamine (NDEA)-induced hepatocarcinogenesis in rats. Administration of NDEA induced hepatocellular carcinoma (HCC), as evidenced by changes in histopathological architecture, increased activity of cytochrome P450, decreased activity of glutathione S-transferase (GST) as well as decreased antioxidant status, enhanced lipid peroxidation and increased liver marker enzymes. Pre- and post-treatment with naringenin effectively suppressed NDEA-initiated hepatocarcinoma and the associated preneoplastic lesions by modulating xenobiotic-metabolizing enzymes (XMEs), alleviating lipid peroxidation (through both free radical scavenging and the enhanced antioxidant status), and decreased levels of liver marker enzymes. These results indicate that naringenin prevents lipid peroxidation and hepatic cell damage and also protects the antioxidant system in N-nitrosdithylamine-induced hepatocarcinogenesis.

Attenuation of NDEA-induced hepatocarcinogenesis by naringenin in rats.

Chemoprevention is one of the most promising and realistic approaches in the prevention of cancer. Several bioactive compounds present in fruits and vegetables have revealed their cancer curative potential on hepatocellular carcinoma. Naringenin is one such naturally occurring flavonoid widely found in citrus fruits. In this study, we examined the molecular mechanisms by which naringenin inhibited NDEA-induced hepatocellular carcinoma in rats by analysing the expression patterns of proliferating cell nuclear antigen, Bcl-2, NF-κB, VEGF and MMP-2/9. Enhanced cell proliferation and apoptotic evasion in NDEA-induced hepatocarcinogenesis was associated with imbalance in pro-apoptotic and anti-apoptotic proteins together with upregulation of proliferating cell nuclear antigen (PCNA) and downregulation of caspase-3. Administration of pretreatment and posttreatment of naringenin decreased the expression of PCNA and Bcl-2 and increased the expression of Bax and caspase-3, indicating antiproliferative and apoptotic effects, respectively. Administration of NDEA increased the tumour expression of NF-κB, COX-2, VEGF, MMP-2 and MMP-9 that was correlated with more aggressive lesions and tumour growth. Downregulation of NF-κB, VEGF and MMPs by naringenin seen in the present study were correlated with the inhibition of liver tumour induced by NDEA. Our results suggest that naringenin could act as a legitimate agent by inhibiting cancer processes.

Renal protective effect of hesperidin on gentamicin-induced acute nephrotoxicity in male Wistar albino rats.

OBJECTIVES: The aim of the study was to investigate the renoprotective effect of hesperidin (HDN), a citrus flavanoid with anti-oxidant properties against gentamicin (GEN)-induced nephrotoxicity in male Wistar albino rats. METHODS: Urea, uric acid, creatinine, thiobarbituric acid reactive substances (TBARS), nitric oxide (NO), total cholesterol, free fatty acids, and triglyceride levels were measured in the serum. Further, glutathione (GSH), superoxide dismutase (SOD), and glutathione peroxidase (GPx) activities were determined in the erythrocytes. Morphological changes in renal tissues were examined using light microscopy. RESULTS: Acute renal injury was evidenced by: (1) increased serum urea, uric acid, creatinine, TBARS, and NO, (2) decreased SOD, GPx, and GSH levels, and (3) necrosis in proximal tubules and glomerular atrophy. HDN supplementation to GEN-induced rats significantly decreased serum urea, uric acid, creatinine, TBARS, NO generation, but SOD, GPx activities, and GSH content increased when compared with GEN alone. Moreover, HDN supplementation resulted in complete reversal of GEN-induced tubular necrosis, and an increase in total cholesterol, free fatty acids, and triglycerides to normal levels. DISCUSSION: Our results suggested that HDN acts as a potent scavenger of free radicals in the kidney to prevent the toxic effects of GEN both at the biochemical and histopathological levels.