Effect of Xylocarpus granatum Bark Extract on Amelioration of Hyperglycaemia and Oxidative Stress Associated Complications in STZ-Induced Diabetic Mice

Ackee (Blighia sapida K.D. Koenig) Leaves and Arils Methanolic Extracts Ameliorate CdCl2-Induced Oxidative Stress Biomarkers in Drosophila melanogaster

Different ethnomedical benefits have been documented on different parts of Ackee (Blighia sapida); however, their roles in ameliorating oxidative damages are not well established. CdCl2 inhibitory effects on some oxidative-stress biomarkers and ameliorative potentials of Ackee leaves (AL) and arils (AS) methanolic extracts were studied using Drosophila melanogaster as a model. One to 3-day-old D. melanogaster flies were orally exposed to different concentrations of CdCl2 in their diet for 7 days. The fly’s survival profile and negative geotaxis assays were subsequently analysed. Methanolic extracts of AL and AS treatments showed negative geotaxis behaviour, and extracts were able to ameliorate the effect of Cd2+ on catalase and GST activities and increase total thiol and GSH levels, while it reduced the H2O2 generation ( $p\le 0.05$ ) when compared to the control. Furthermore, Cd2+ exhibited noncompetitive and uncompetitive enzyme inhibition on catalase and GST activities, respectively, which may have resulted in the formation of Enzyme-substrate-Cd2+ transition complexes, thus inhibiting the conversion of substrate to product. This study, thus, suggests that the Cd2+ mechanism of toxicity was associated with oxidative damage, as evidenced by the alteration in the oxidative stress-antioxidant imbalance, and that the AL and AS extracts possess essential phytochemicals that could alleviate possibly deleterious oxidative damage effects of environmental pollutants such as CdCl2. Thus, Ackee plant parts possess essential phytonutrients which could serve as valuable resources in heavy metal toxicity management.

3,4‑Dihydroxyacetophenone attenuates oxidative stress‑induced damage to HUVECs via regulation of the Nrf2/HO‑1 pathway

It has been reported that oxidative stress plays a prominent role in diabetic macrovascular diseases. 3,4-Dihydroxyacetophenone (3,4-DHAP) has been found to have a variety of biological activities. However, few studies have assessed the antioxidant capacity of 3,4-DHAP and the underlying mechanisms. Thus, the aim of the present study was to explore the effects of 3,4-DHAP on oxidative stress in human umbilical vein endothelial cells (HUVECs). HUVECs were pre-treated with 3,4-DHAP and then exposed to high glucose conditions. Cell viability and cytotoxicity were measured using an MTT assay. Reactive oxygen species (ROS) levels were measured using an inverted fluorescence microscope and a fluorescent enzyme labeling instrument. Protein expression levels of nuclear factor E2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), microtubule-associated protein 1A/1B-light chain 3 (LC3) and poly ADP-ribose polymerase-1 (PARP-1) were measured using western blotting, and mRNA expression of Nrf2 and HO-1 were measured through reverse transcription-quantitative PCR (RT-qPCR). Nrf2 nuclear translocation was evaluated using immunofluorescence analysis and autophagosomes were observed using transmission electron microscope (TEM). The results of the present study demonstrated that compared with the control group, cell viability of the high glucose group was reduced and cell cytotoxicity of the high glucose group was increased. ROS production in the high glucose group was clearly enhanced. In addition, high glucose upregulated Nrf2 and HO-1 protein and mRNA expression levels. Nuclear translocation of Nrf2 in the high glucose group was also increased. The formation of autophagosomes in the high glucose group was also higher than that in the control group. Furthermore, LC3-II/LC3-I and PARP-1 protein expression levels were increased after treatment with high glucose. However, compared to the high glucose group, 3,4-DHAP (10 µmol/l) significantly enhanced cell viability. 3,4-DHAP markedly decreased the production of ROS, increased Nrf2 and HO-1 protein and mRNA expression levels, and promoted nuclear translocation of Nrf2 in HUVECs. In addition, 3,4-DHAP promoted the formation of autophagosomes, and notably increased the protein expression levels of LC3-II/LC3-I and PARP-1. Moreover, it was determined that compared to the 3,4-DHAP group, treatment with 3,4-DHAP and ML385 enhanced cell viability, and decreased ROS production, Nrf2 and HO-1 protein and mRNA expression levels, nuclear translocation of Nrf2, and LC3-II/LC3-I and PARP-1 protein expression levels. Collectively, the results of the present study showed that 3,4-DHAP protected HUVECs against oxidative stress via regulation of the Nrf2/HO-1 pathway, by increasing autophagy and promoting DNA damage repair.

Ethnomedicinal Use, Phytochemistry, and Pharmacology of Xylocarpus granatum J. Koenig

The mangrove plants are the potential sources of foods and remedies for people living in the forests and nearby communities. Xylocarpus granatum J. Koenig is traditionally used to treat various diseases including diarrhea, cholera, dysentery, fever, malaria, and viral infections, among others. To summarize critically the taxonomy, ethnomedicinal, phytochemistry, and pharmacological activities of X. granatum, information was collected from different databases. An up-to-date search (till June 2020) was carried out with the help of various scientific web resources from databases such as PubMed, Science Direct, Google Scholar, and various patent offices (e.g., WIPO, CIPO, and USPTO) using the keywords “Xylocarpus granatum” and then paired with ethnomedicinal use and phytochemical, phytochemistry, and pharmacological activity (in vitro, ex vivo, and in vivo studies). Findings revealed that seeds, fruits, stem bark, leaf, and twigs of X. granatum exhibited a wide range of key phytochemicals including limonoids, phragmalin, limonoid-based alkaloids, mexicanolides, protolimonoids, flavonols, and lactones. The plant possessed potent antioxidant, anticancer, antidiabetic, antimicrobial, antimalarial, antifeedant, and neuroprotective activities. No clinical studies have been reported in the databases. Ethnomedicinal assessment indicated the application of X. granatum in various fields of medical science specially to treat various human ailments, and this was attributed to the presence of enormous alkaloids as confirmed by pharmacological studies. However, to understand the mechanism of action in-depth studies are required. In view of these findings, more research is necessary to explore and characterize the chemical compounds and toxicological aspects of this medicinal mangrove plant. Overall, it can be stated that X. granatum may be one of the hopeful medicinal herbs for the treatment of various diseases in human beings.

GC-MS analysis and molecular docking of bioactive compounds of Camellia sinensis and Camellia assamica

The methanol extract of Camellia sinensis (MES) and acetone extract of Camellia assamica (AEA) were subjected to the thin layer chromatography to separate the bioactive compounds. The antimicrobial activity of all the fractions was carried out against pathogenic microorganisms by the agar-well diffusion method. The most effective bioactive fraction of each plant species was analysed by GC-MS. Fraction L of methanol extract of C. sinensis (MES) and fraction 5 of acetone extract of C. assamica (AEA) were found very effective against selected pathogenic strains. GC-MS analysis of this fraction showed the presence of n-heptadecanol-1 (68.63%) in MES and 2',6'dihydroxyacetophenone, bis(trimethylsilyl) (17.58%) in AEA with the highest area. The compounds n-heptadecanol-1 and 2',6'dihydroxyacetophenone, bis(trimethylsilyl) ether were used for docking to analyse its therapeutic potential. The ligand compound n-heptadecanol-1 (HEP) from MES of C. sinensis and 2',6'dihydroxyacetophenone, bis(trimethylsilyl) ether from AEA of C. assamica were docked with the target protein dihydropteoate synthase (DHPS) active sites of Escherichia coli and Staphylococcus aureus active sites via Auto Dock Vina, thereby forecasting the finest binding position of ligands. AutoDock Vina docked results revealed the involvement of binding energy for the establishment of the protein-ligand structure complex, besides generating an interpretation of all apparent molecular interactions accountable for its activity. Further, the protein-ligand complex of MES, EcDHPS + HEP and SaDHPS + HEP exhibiting the best binding affinity were - 4.8 kcal/mol and - 3.6 kcal/mol. The protein-ligand complex of AEA, i.e., EcDHPS + DHA and SaDHPS + DHA exhibited the best binding affinity of - 4.8 kcal/mol and - 4.8 kcal/mol.

Strawberry Leaf Extract Treatment Alleviates Cognitive Impairment by Activating Nrf2/HO-1 Signaling in Rats With Streptozotocin-Induced Diabetes

Diabetes-associated cognitive impairment (DACI) is a common complication of diabetes mellitus (DM) that affects the central nervous system. Cognitive impairment, such as learning and memory impairment, and even dementia, is the main clinical manifestation of DACI. Unfortunately, there is no effective means by which to delay the cognitive symptoms of DM. Evidence has shown that strawberry leaf extract could alleviate cognitive decline, suppress oxidative stress, and reduce inflammatory responses in rats. In the present study, we evaluated the effect of strawberry leaf extract on cognitive function in a rat model of streptozotocin (STZ)-induced diabetes. After the continuous administration of strawberry leaf extract for 4 weeks, the Morris Water Maze (MWM) test results showed that the cognitive impairment of the rats was alleviated. Moreover, strawberry leaf extract significantly reduced the level of reactive oxygen species (ROS), decreased the level of malondialdehyde (MDA), improved the activity of superoxide dismutase (SOD) and catalase (CAT), decreased the mRNA expression of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) and decreased the protein expression of caspase-3 and caspase-9 in the hippocampus of DM rats. Also, transcription factor nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2)/hemeoxygenase-1(HO-1) signaling was activated by the administration of strawberry leaf extract. Our findings indicate that strawberry leaf extract may be a potential drug candidate for the treatment of DACI and may be used as a basis for further research on the development of drugs for cognitive impairment in diabetes.

Antioxidant and antiglycation activities of traditional plants and identification of bioactive compounds from extracts of Hordeum vulgare by LC-MS and GC-MS

Glycation has been involved in Schiff base reaction lead to hyperglycemia at cellular level. The current study aimed to identify the bioactive compounds from selected folkloric plants for their antiglycation and antioxidant potential. Methanol extracts demonstrated the highest activities, therefore, it was further fractionated using n-hexane, dichloromethane, ethyl acetate, and methanol solvents to isolate the nonpolar compounds from the Hordeum vulgare. Moreover, n-hexane and dichloromethane fractions of H. vulgare demonstrated the best antioxidant (61.58% and 62.89%) and antiglycation activities (72.52% and 61.52%) at 2 mg/ml, respectively. Analytical techniques of LC-MS and GC-MS were employed for identification of bioactive compounds; Biochanin A in dichloromethane (DCM) and Vitamin E in n-hexane fractions. There was a strong correlation between antioxidant and antiglycation activities (r = 0.97 and r = 0.96) of DCM & n-hexane fractions of H. vulgare. Findings of this study established the role of Biochanin A and Vit E from H. vulgare as potent antiglycation agents. PRACTICAL APPLICATIONS: The results of this study confirmed the potential role of Black Barley has involved in the inhibition of protein glycation, which can be the potential treatment to reduce the complications of Diabetic Patients. The Black Barley has a rich source of identified compounds Biochanin A and Vitamin E. We can use this plant as a staple food in curing the severity of diabetes. The other practical approach is to use this plant as an ingredient of different food products. The extraction of identified bioactive compounds from the plant will be a good and cheap source of the treatment.

α-Glucosidase Inhibitory Isomeric Corniculatolides from the Stems of the Indian Mangrove Plant, Xylocarpus granatum

Three new isomeric corniculatolides (1, 2, and 3) with an unusual caffrane and isocorniculane framework, and five known metabolites were isolated from the chloroform extract of the stems of Xylocarpus granatum. The structures of the new metabolites were deduced as corniculatolide B (1), isocorniculatolide B (2), and corniculatolide C (3) by spectroscopic data analysis and a combination of chemical transformations and supported by single-crystal X-ray crystallographic data of 1 and 3. The isolated compounds were evaluated for their in vitro cytotoxicity and α-glucosidase (Saccharomyces cerevisiae) inhibitory potential. Compound 3 possessed α-glucosidase inhibitory activity with an IC₅₀ value of 24.8 μM, whereas these rare macrolides showed no effect on the mammalian cancer cell lines MIAPaCa-2, DU145, MCF-7, and HTC-116.