Nimbin analogs stimulate glucose uptake and glycogen storage in the insulin signalling cascade by enhancing the IRTK, PI3K and Glut-4 mechanism in myotubes.

BACKGROUND: Diabetes Mellitus is a metabolic disorder characterized by insulin dysfunction or failure of the pancreatic ß-cells to produce insulin resulting in hyperglycemia. Adverse effects of hyperglycemic conditions continue to be common, reducing treatment adherence. Intensified therapies are required for the constant loss of endogenous islet reserve. AIM: This study aimed to evaluate the effect of Nimbin semi-natural analogs (N2, N5, N7, and N8) from A. indica on high glucose-induced ROS and apoptosis with insulin resistance in L6 myotubes evaluated along with Wortmannin and Genistein inhibitors and the expression of key genes in the insulin signalling pathway. MATERIALS AND METHODS: The analogs were screened for anti-oxidant and anti-diabetic activity using cell-free assays; The ability of analogs to suppress ROS and prevent apoptosis induced by High glucose and uptake glucose and glycogen storage in L6 myotubes was evaluated using DCFH-DA, AO-PI and 2NBDG staining. Further, the glucose uptake was performed in the presence of Insulin Receptor Tyrosine Kinase (IRTK) inhibitors, and the expression of key genes PI3K, Glut-4, GS and IRTK in the insulin signalling pathway were evaluated. KEY FINDINGS: The Nimbin analogs were not toxic to the L6 cells, and the analogs could scavenge ROS and suppress cellular damage induced due to high glucose. Enhanced glucose uptake was observed in N2, N5 and N7 compared to N8. The maximum activity of optimum concentration was found to be 100 µM. The N2, N5 and N7 showed an increase in IRTK, which is equivalent to insulin at a concentration of 100 µM. The IRTK inhibitor with Genistein (50 µM) confirmed the presence of IRTK-dependent glucose transport activation; it also supports the expression of key genes PI3K, Glut-4, GS and IRTK. As a result of PI3K activation, N2, N5, and N7 exhibited the insulin-mimetic effect by enhancing glucose uptake and glycogen conversion regulating glucose metabolism. SIGNIFICANCE: N2, N5 and N7 could therapeutically benefit against insulin resistance by glucose metabolism modulation, insulin secretion, ß-cell stimulation, inhibition of gluconeogenic enzymes and ROS protection.

Nimbin analog N2 alleviates high testosterone induced oxidative stress in CHO cells and alters the expression of Tox3 and Dennd1a signal transduction pathway involved in the PCOS zebrafish.

Polycystic ovarian syndrome (PCOS) is a hormonal disorder that causes enlargement of ovaries and follicular maturation arrest, which lacks efficient treatment. N2, a semi-natural triterpenoid from the neem family, was already reported to have antioxidant and antiinflammatory properties in our previous report. This study investigated the anti-androgenic property of N2 on testosterone-induced oxidative stress in Chinese Hamster Ovarian cells (CHO) and PCOS zebrafish model. The testosterone exposure disrupted the antioxidant enzymes and ROS level and enhanced the apoptosis in both CHO cells and PCOS zebrafish. However, N2 significantly protected the CHO cells from ROS and apoptosis. N2 improved the Gonado somatic index (GSI) and upregulated the expression of the SOD enzyme in zebrafish ovaries. Moreover, the testosterone-induced follicular maturation arrest was normalized by N2 treatment in histopathology studies. In addition, the gene expression studies of Tox3 and Denndla in zebrafish demonstrated that N2 could impair PCOS condition. Furthermore, to confirm the N2 activity, the in-silico studies were performed against PCOS susceptible genes Tox3 and Dennd1a using molecular docking and molecular dynamic simulations. The results suggested that N2 alleviated the oxidative stress and apoptosis in-vitro and in-vivo and altered the expression of PCOS key genes.

Nimbin analogs N5 and N7 regulate the expression of lipid metabolic genes and inhibit lipid accumulation in high-fat diet-induced zebrafish larvae: An antihyperlipidemic study.

BACKGROUND: Excess accumulation of lipids leads to obesity. Triterpenoids are a group of plant compounds which poses various biological activities. The biological activities of Nimbin analogs N5 and N7 were addressed in this study on inhibiting lipid aggregation and underlying the derivatives molecular mechanisms for a therapeutical approach. AIM: This study aims to evaluate the anti-adipogenic activity of semi-natural Nimbin analogs, N5 and N7, on zebrafish larvae induced with oxidative stress due to a high-fat diet (HFD) and adipogenesis using specific fluorescent stains. MATERIALS AND METHODS: Zebrafish at 4 days post fertilized (dpf) larvae were divided into groups for the HFD diet along with exposure to various concentrations of N5 and N7. HFD induced accumulation of neutral lipids and triglycerides (Oil Red O and Nile red staining, respectively) with weight gain, which generated intracellular ROS (DCFH-DA staining) and superoxide anion production (DHE staining) with depleted glutathione levels (NDA staining) were assayed. HFD exposure promoted the accumulation of inflammatory macrophages (Neutral red staining) and impaired glucose metabolism (2NBDG staining). The ability of N5 and N7 to reduce total regulating lipogenic specific genes C/EBP-α, SREBP-1 and FAS were evaluated using relative gene expression. KEY FINDINGS: The Nimbin analogues N5 and N7 suppressed adipogenesis, forming intracellular ROS and superoxide anion while simultaneously restoring glutathione levels. The analogues significantly lowered total TC and TG levels, prevented inflammatory macrophage build-up and boosted glucose absorption. Also, N5 and N7 down-regulate the lipogenic-specific genes. SIGNIFICANCE: Nimbin analogs N5 and N7 enhance lipolysis and inhibit adipogenesis in in-vivo zebrafish larvae model.

Deacetyl epoxyazadiradione protects aminoglycoside antibiotic-induced renal cell apoptosis, in vitro.

Aminoglycoside antibiotics such as gentamicin are used frequently to treat bacterial infections in humans. Excessive consumption of these antibiotics lead to renal dysfunction. One of the factors contributing to renal dysfunction is oxidative damage, which causes apoptosis. Hence, this study investigates the effect of the antioxidant compound deacetyl epoxyazadiradione (DEA) in reducing cell death induced by gentamicin treatment in kidney cells (Madin-Darby canine kidney cells). The antioxidant experiments showed that reactive oxygen species level is decreased up to 27.06 ± 0.18% in 150 µM of DEA treatment. At this concentration, the activity of antioxidant enzymes such as superoxide dismutase increased from 0.4 ± 0.04 to 1.46 ± 0.05 µmol/min/L and catalase increased from 7.48 ± 0.39 to 17.6 ± 0.74 U/mg. The relative folds of gene expression of mitochondrial enzymes such as GST, GPx and GR restored from 0.596 ± 0.019, 0.521 ± 0.013 and 0.775 ± 0.014 to 0.866 ± 0.013, 0.669 ± 0.015 and 0.8615 ± 0.028, respectively. Consequently, the percentage of cell viability increases upto 91.8 ± 2.01 from 61.93 ± 1.63 with much less fragmentation in genomic DNA. Additionally, molecular docking results showed that DEA could bind to Bax, Bcl- 2, Caspase- 3 and Caspase- 9 proteins. These results indicate that DEA could reduce cell apoptosis by reducing oxidative stress due to antibiotics and interrupting the apoptotic signal pathway in kidney cells.

Withaferin A targets the membrane of Pseudomonas aeruginosa and mitigates the inflammation in zebrafish larvae; an in vitro and in vivo approach.

Infections due to multidrug-resistant Pseudomonas aeruginosa are prevalent among patients with cystic fibrosis. The emergence of antibiotic-resistant pathogens necessitated the development of novel low-risk natural antibacterial compounds. Herbal medicines are used from dates of the origin of mankind and still serve their purpose as therapeutic agents. We demonstrated the antibacterial activity of Withaferin A extracted from the traditional herb, ashwagandha or winter cherry (Withania somnifera). Withaferin A exhibits strong antibacterial activity against P. aeruginosa with a minimum inhibitory concentration of 60 µM and minimum bactericidal concentration of 80 µM. Results obtained from membrane stabilization assay and electron microscopic analysis showed that Withaferin A acts by damaging the cell membrane of P. aeruginosa. Additionally, we investigated oxidative stress and inflammatory response after Withaferin A treatment in P. aeruginosa infected zebrafish larvae model. The results indicate that the level of ROS, and its related lipid peroxidation and apoptosis were significantly reduced after treated with Withaferin A. Consequently, an increment in antioxidant enzymes level such as superoxide dismutase (SOD) and catalase (CAT) was observed. Macrophage localization experiment showed a smaller number of localized macrophages in zebrafish, which indicates the reduction in inflammatory response. In conclusion, Withaferin A could serve as an alternative natural product in the treatment of infections caused by P. aeruginosa.

Deacetylated nimbin analog N2 fortifies alloxan-induced pancreatic ß-cell damage in insulin-resistant zebrafish larvae by upregulating phosphoenolpyruvate carboxykinase (PEPCK) and insulin levels.

This study aims to evaluate the protective behaviour of N2, a semi-natural analog of nimbin, for its anti-diabetic efficacy against alloxan-induced oxidative damage and ß-cell dysfunction in in-vivo zebrafish larvae. A 500 µM of alloxan was exposed to zebrafish larvae for 24 h to induce oxidative stress in the pancreatic ß-cells and co-exposed with N2 to study the protection of N2 by inhibiting ROS by DCFH-DA, DHE and NDA staining along with Cellular damage, apoptosis and lipid peroxidation. The zebrafish was further exposed to 500 µM alloxan for 72 h to induce ß-cell destruction along with depleted glucose uptake and co-exposed to N2 to study the protective mechanism. Glucose levels were estimated, and PCR was used to verify the mRNA expression of phosphoenolpyruvate carboxykinase (PEPCK) and insulin. Alloxan induced (24 h) oxidative stress in the pancreatic ß-cells in which N2's co-exposure inhibited ROS by eliminating O-2 radicals and restoring the glutathione levels, thus preventing cellular damage and lipid peroxidation. The zebrafish exposed to 500 µM alloxan for 72 h was observed with ß-cell destruction along with depleted glucose uptake when stained with 2NBDG, wherein N2 was able to protect the pancreatic ß-cells from oxidative damage, promoted high glucose uptake and reduced glucose levels. N2 stimulated insulin production and downregulated PEPCK by inhibiting gluconeogenesis, attenuating post-prandial hyperglycemia. N2 may contribute to anti-oxidant protection against alloxan-induced ß-cell damage and anti-hyperglycemic activity, restoring insulin function and suppressing PEPCK expression.

Deacetylepoxyazadiradione Derived from Epoxyazadiradione of Neem (Azadirachta indica A. Juss) Fruits Mitigates LPS-Induced Oxidative Stress and Inflammation in Zebrafish Larvae.

Reactive oxygen species (ROS) produced by cell metabolism have a duplex role in oxidation and inflammation reactions which involve cell damage or repair responses. Excess ROS production has detrimental effects on the survival of cells. We examined the protective effect of a semi-natural compound NF2 (deacetylepoxyazadiradione), for its protective activity against free radical-mediated stress and inflammatory response to lipopolysaccharide (LPS) using zebrafish larvae. Preliminary antioxidant assays indicated an increase in scavenging of free radicals from NF2 than NF1 (Epoxyazadiradione) in a concentration-dependent manner. Cell cytotoxicity was determined using rat myoblast cell lines (L6), and more than 95 % of cell viability was obtained. Zebrafish developmental toxicity test indicated that NF2 is not toxic even at 150 µM. The percentage of ROS, lipid peroxidation, nitric oxide and apoptosis were reduced significantly in NF2 treated LPS-stressed zebrafish larvae. The reduced number of employed macrophages on NF2 treatment was observed in neutral red dye-marked macrophage localization images. Relative expression of antioxidant genes in zebrafish larvae after treatment with NF2 is significantly increased. The RT-PCR quantification of antioxidant and anti-inflammatory gene expression indicated decreased relative folds of pro-inflammatory cytokines, iNOS and increased relative folds of mitochondrial antioxidant genes (GR, GST and GPx) in LPS stressed zebrafish larvae after treatment with NF2. From the overall obtained results, it can be concluded that NF2 reduced the oxidative stress and inflammatory response by scavenging free radicals caused by LPS.

Anti-inflammatory role demonstrated both in vitro and in vivo models using nonsteroidal tetranortriterpenoid, Nimbin (N1) and its analogs (N2 and N3) that alleviate the domestication of alternative medicine.

Human health may benefit from the study of natural compounds and phytoconstituents that can protect from inflammation. We investigated Nimbin (N1), a member of the ring C Seco-tetranortriterpenoids family, and its semi-natural analog deacetyl Nimbin namely N2 and N3 for their anti-inflammatory properties. As key findings, N1, N2, and N3 were able to improve wound healing by cell proliferation in a period of 24 h and were able to reduce the reactive oxygen species (ROS) production in Madin-Darby Canine Kidney cells which were screened using dichloro-dihydro fluorescein diacetate (DCF-DA) staining. When the zebrafish larvae were subjected to DCF-DA assay N1, N2, and N3 were able to substantially reduce the ROS levels in a dose-dependent manner. In zebrafish larvae, the cell death indicates the fluorescent intensity due to acridine orange staining that was found to be dramatically decreasing upon the treatment of N1, N2, and N3. The cell membrane lipid peroxidation levels were also reduced in a dose-dependent manner upon the treatment of Nimbin and its analogs indicating lesser blue fluorescent levels. Among the Nimbin and its analogs, N2 was subjected to have better activity. To confirm the activity of N1, N2, and N3, in silico characterization was performed using Density functional theory and molecular docking. As a result, N2 exhibited the lowest electronegative value and highest binding energy when docked with anti-inflammatory and antioxidant proteins CAT, COX, GP, IL-1, and MPO. Furthermore, the therapeutic potential of N2 must be explored at the molecular level as well as in clinical studies for the treatment of inflammation-associated diseases.