Evaluation of therapeutic effect of Premna herbacea in diabetic rat and isoverbascoside against insulin resistance in L6 muscle cells through bioenergetics and stimulation of JNK and AKT/mTOR signaling cascade

Phenolic enriched fraction of Clerodendrum glandulosum Lindl. leaf extract ameliorates hyperglycemia and oxidative stress in streptozotocin-nicotinamide induced diabetic rats

BACKGROUND

Clerodendrum glandulosum Lindl. is an important ethnomedicinal shrub of Northeast India, used by traditional healers to control various ailments like diabetes, hypertension, arthritis, etc. OBJECTIVES: The present study was conducted to explore the anti-hyperglycemic and antioxidative effects of the polyphenol-rich fraction (PRF) of C. glandulosum leaf extract and identification of its major bioactive compounds. Further, an in-silico molecular docking study was also performed to understand the molecular interactions of the identified major compounds with some target proteins associated with diabetic complications.

MATERIALS AND METHODS

PRF was purified from the hydromethanolic (80% MeOH) extract of leaves and subjected to assessment of in-vitro antioxidant and anti-diabetic properties. It was also subjected to evaluate the ameliorative effect during streptozotocin-nicotinamide-induced hyperglycemia in Wistar albino rats. An in-silico molecular docking study was also performed to complement the in-vitro/in-vivo studies.

RESULTS

Chemical analysis of PRF showed the presence of phenolics like caffeic acid, verbascoside, isoverbascoside, and apigenin, of which verbascoside (598.14 ± 1.24 mg/g) was found to be the principal compound. In-vitro studies showed potent antioxidant (IC50 of DPPH:32.45 ± 2.16 μg/mL; ABTS:39.08 ± 0.53 μg/mL) properties and excellent aldose reductase inhibition potential (IC50 2.18 ± 0.10 μg/mL). Treatment with PRF showed reduced blood glucose levels and increased plasma insulin levels. The results also indicate an improvement of endogenous antioxidants and suppression of inflammatory cytokines (IL-6 and TNF-α) comparable to the standard. Molecular docking studies predicted promising interactions between the identified molecules and the crucial amino acid residues of the enzymes involved in the development of hyperglycemia.

CONCLUSION

This study revealed the antihyperglycemic and antioxidant potential of partially purified fraction PRF of C. glandulosum leaves.

Characterization and active component identification of Premna herbacea roxb. root extract reveals anti-inflammatory effect and amelioration of imiquimod induced psoriasis via modulation of macrophage inflammatory response

BACKGROUND

1-2.88% of human populations are affected by psoriasis, one type of chronic inflammatory skin disease. Skin thickenings, erythema, scaling in skin are the most important symptoms of psoriasis. There are renewed interests amongst scientists in studying anti-inflammatory property of the plant extracts due to lower side effects and cost effectiveness. There are few reports suggesting anti-inflammatory activity of Premna herbacea roxb. but lacks systematic evaluation of these properties.

METHODS

We, initially tested the anti-inflammatory activity of crude root methanolic extract in vitro, where it significantly reduced LPS generated ROS in splenic macrophages. We further tested the TLC and HPLC fraction in order to find active ingredient in Premna herbacea roxb. root extract that ameliorated the chronic inflammation of skin and performed GC-MS and LC-MS studies to identify active component. Upon finding significant anti-inflammatory effect of the crude root extract in vitro, We studied the efficacy of the Premna herbacea roxb. root extract in Imiquimod induced psoriasis like skin inflammation in male BALB/C mice that closely resembles human psoriasis. Immunophenotyping, Cytokine productions were observed by flow cytometry, status of gene expression was done by Real time PCR and nuclear co-localization was studied by confocal microscopy.

RESULTS

We observed progressive increase in signs and symptoms of the disease in imiquimod treated diseased animals but the Premna herbacea roxb. Root Methanolic Extract (PHRME) reduced the thickening of the skin, redness and scaling in these animals. In our study, along with progression of the disease, the production of macrophages increases and with the application of PHRME, the percentage of macrophages have reduced.

CONCLUSION

As per the previous Indigenous traditional knowledge regarding use of Premna herbacea roxb. against inflammatory disorder and lack of detail mechanistic study of the crude root extract prompted us to elucidate the efficacy of the root extract in vitro and in vivo psoriatic mice model. For the first time we have identified three putative bioactive active components (5‑hydroxy-7-methoxyflavanone, 3-Hydroxy-7,8,2',3'-tetramethoxyflavone, 2,4',6'-trimethoxy chalcone) from Premna herbacea root methanolic extract (PHRME) and we suggest PHRME and purified active fractions influence NFκB and COX2 signaling pathway to suppress inflammatory conditions. All of the purified components show strong binding efficiency in our molecular docking analysis. Our study also suggests that Premna herbacea roxb. root extract may be explored as cost effective alternative for established treatment regimen as our study also indicates low side effect of the extract against pre-clinical psoriatic model.

Discovery of New 2-Phenylamino-3-acyl-1,4-naphthoquinones as Inhibitors of Cancer Cells Proliferation: Searching for Intra-Cellular Targets Playing a Role in Cancer Cells Survival

A series of 2-phenylamino-3-acyl-1,4-naphtoquinones were evaluated regarding their in vitro antiproliferative activities using DU-145, MCF-7 and T24 cancer cells. Such activities were discussed in terms of molecular descriptors such as half-wave potentials, hydrophobicity and molar refractivity. Compounds 4 and 11 displayed the highest antiproliferative activity against the three cancer cells and were therefore further investigated. The in silico prediction of drug likeness, using pkCSM and SwissADME explorer online, shows that compound 11 is a suitable lead molecule to be developed. Moreover, the expressions of key genes were studied in DU-145 cancer cells. They include genes involved in apoptosis (Bcl-2), tumor metabolism regulation (mTOR), redox homeostasis (GSR), cell cycle regulation (CDC25A), cell cycle progression (TP53), epigenetic (HDAC4), cell-cell communication (CCN2) and inflammatory pathways (TNF). Compound 11 displays an interesting profile because among these genes, mTOR was significantly less expressed as compared to control conditions. Molecular docking shows that compound 11 has good affinity with mTOR, unraveling a potential inhibitory effect on this protein. Due to the key role of mTOR on tumor metabolism, we suggest that impaired DU-145 cells proliferation by compound 11 is caused by a reduced mTOR expression (less mTOR protein) and inhibitory activity on mTOR protein.

Radical oxygen species: an important breakthrough point for botanical drugs to regulate oxidative stress and treat the disorder of glycolipid metabolism

Background: The incidence of glycolipid metabolic diseases is extremely high worldwide, which greatly hinders people's life expectancy and patients' quality of life. Oxidative stress (OS) aggravates the development of diseases in glycolipid metabolism. Radical oxygen species (ROS) is a key factor in the signal transduction of OS, which can regulate cell apoptosis and contribute to inflammation. Currently, chemotherapies are the main method to treat disorders of glycolipid metabolism, but this can lead to drug resistance and damage to normal organs. Botanical drugs are an important source of new drugs. They are widely found in nature with availability, high practicality, and low cost. There is increasing evidence that herbal medicine has definite therapeutic effects on glycolipid metabolic diseases. Objective: This study aims to provide a valuable method for the treatment of glycolipid metabolic diseases with botanical drugs from the perspective of ROS regulation by botanical drugs and to further promote the development of effective drugs for the clinical treatment of glycolipid metabolic diseases. Methods: Using herb*, plant medicine, Chinese herbal medicine, phytochemicals, natural medicine, phytomedicine, plant extract, botanical drug, ROS, oxygen free radicals, oxygen radical, oxidizing agent, glucose and lipid metabolism, saccharometabolism, glycometabolism, lipid metabolism, blood glucose, lipoprotein, triglyceride, fatty liver, atherosclerosis, obesity, diabetes, dysglycemia, NAFLD, and DM as keywords or subject terms, relevant literature was retrieved from Web of Science and PubMed databases from 2013 to 2022 and was summarized. Results: Botanical drugs can regulate ROS by regulating mitochondrial function, endoplasmic reticulum, phosphatidylinositol 3 kinase (PI3K)/protein kinase B (AKT), erythroid 2-related factor 2 (Nrf-2), nuclear factor κB (NF-κB), and other signaling pathways to improve OS and treat glucolipid metabolic diseases. Conclusion: The regulation of ROS by botanical drugs is multi-mechanism and multifaceted. Both cell studies and animal experiments have demonstrated the effectiveness of botanical drugs in the treatment of glycolipid metabolic diseases by regulating ROS. However, studies on safety need to be further improved, and more studies are needed to support the clinical application of botanical drugs.

Kaempferol 3-O-rutinoside from Antidesma acidum Retz. Stimulates glucose uptake through SIRT1 induction followed by GLUT4 translocation in skeletal muscle L6 cells

ETHNOPHARMACOLOGICAL RELEVANCE

Antidesma acidum Retz, a perennial herb is known for its anti-diabetic potential among the traditional health care providers of the tribal communities of Manipur, India. Scientific validation of the ancient knowledge on traditional use of this plant with the help of modern tools and techniques can promote further research and its use in health care.

AIM OF THE STUDY

Type 2 Diabetes (T2D) is a complex metabolic disorder and linked with hyperglycemia occurring from insufficiency in insulin secretion, action, or both. The aim of this study was to scientifically validate the traditional myth behind the uses of this plant material against diabetes. More specifically, it was aimed to determine the effect of methanolic extract of A. acidum leaves and/or any of its bioactive phytochemical(s), in enhancing insulin sensitization and subsequently stimulating the insulin signaling cascade of glucose metabolism.

MATERIALS AND METHODS

Methanol was used for extraction from the leaf powder of A. acidum followed by bioactivity guided fractionation and isolation of most active component. Biological evaluation was performed to determine the glucose uptake ability against insulin resistance in skeletal muscle (L6) cells. To understand the detailed mechanism of actions of the purified compound, several molecular biology and structural biology experiments such as Western blot, siRNA transfection assay and molecular docking study were performed.

RESULTS AND DISCUSSION

Bioactivity guided isolation of pure compound and spectral data analysis led us to identify the active component as Kaempferol 3-O-rutinoside (KOR) for the first time from the leaf of A. acidum. Over expression of NAD-dependent histone deacetylase, Sirtuin 1 (SIRT1) was observed following KOR treatment. SIRT1 plays an important role in the metabolic pathway and over expression of SIRT implies that it involves in insulin signaling directly or indirectly. Molecular docking and simulation study showed the strong involvement between KOR and SIRT1.Treatment with KOR resulted in significant over expression of SIRT1followed by upregulation of insulin-dependent p-IRS, AKT and AMPK signaling molecules, and stimulation of the GLUT4 translocation, which ultimately enhanced the glucose uptake in sodium palmitate-treated insulin resistant L6 myotubes. Further, the effect of KOR on IRS1, AKT and AMPK phosphorylation, GLUT4 translocation, and glucose uptake was attenuated in SIRT1-knockdown myotubes.

CONCLUSION

Overall, the results of this study suggest that Kaempferol 3-O-rutinoside is the active component presents in the leaf of A. acidum which increases glucose consumption by inducing SIRT1 activation and consequently improves insulin sensitization. These results may find future applications in drug discovery research against T2DM.

A popular fermented soybean food of Northeast India exerted promising antihyperglycemic potential via stimulating PI3K/AKT/AMPK/GLUT4 signaling pathways and regulating muscle glucose metabolism in type 2 diabetes

This study examined the antidiabetic efficacy of popular fermented soybean foods (FSF) of Northeast (NE) India. Results showed that among different FSF, aqueous extract of Hawaijar (AEH), a traditional FSF of Manipur, NE India, significantly augmented glucose utilization in cultured myotubes treated with high glucose (HG, 25 mM). Furthermore, AEH also upregulated glucose uptake, glucose-6-phosphate level, and phopho-PI3K/phospho-AKT/phospho-AMPK/GLUT4 protein expression in HG-treated myotubes. In vivo studies demonstrated that AEH supplementation (50, 100, or 200 mg/kg body weight/day, oral gavaging, 16 weeks) reduced body weight, fasting blood glucose, glycated hemoglobin, insulin resistance, and glucose intolerance in rats fed with high-fat diet (HFD). AEH supplementation stimulated phopho-PI3K/phospho-AKT/phospho-AMPK/GLUT4 signaling cascades involved in glucose metabolism of muscle tissues in diabetic rats. Chemical profiling of AEH (SDS-PAGE, immunoblotting, and HRMS) suggests the possible role of bioactive proteins/peptides and isoflavones underlying the antihyperglycemic potential AEH. Results from this study will be helpful for developing food-based prophylactics/therapeutics in managing hyperglycemia. PRACTICAL APPLICATIONS: Fermented soybean foods are gaining acceptance due to multiple health benefits. This study for the first time reports the antidiabetic potential of Hawaijar, an indigenous fermented soybean food of North-East India. Higher abundance of bioactive compounds (isoflavones and proteins/peptides) in Hawaijar may be responsible for the alleviation of impaired glucose metabolism associated with diabetes. The findings may be helpful for the development of a novel therapeutic to achieve better control of hyperglycemia and improve the lives of the patient population with diabetes.

Chemical composite of indigenous whole grain scented joha rice varietal prevents type 2 diabetes in rats through ameliorating insulin sensitization by the IRS-1/AKT/PI3K signalling cascade

Preventive measures to lower the prevalence of type-2 diabetes development using dietary phytochemicals are most realistic. A phytochemical composite derived from whole grain scented joha rice (PCKJ), which is indigenous to the North-eastern Region, India, was investigated to understand its preventive efficacy in rats in which type 2 diabetes was induced using a high-fat high-fructose (HFHF) diet and a low dose of streptozotocin, and the findings were correlated with those in L6-myotubes. Studies on cultured L6 myotubes revealed that treatment with PCKJ facilitated glucose uptake and GLUT-4 translocation to the plasma membrane, as evidenced by confocal microscopy and/or cell fractionation studies. Furthermore, the FFA-induced L6 myotubes were identified as having elevated levels of PI3K, p-AKT (Ser473) and GLUT-4, which returned to the basal level upon exposure to PCKJ. The administration of PCKJ (100 mg per kg body weight, oral gavage, 24 weeks) to rats significantly reduced their blood glucose levels along with common lipid and liver biomarkers (LDL, triglycerides, cholesterol, ALT, and AST) compared to the control group. Moreover, immunoblotting analysis showed that upon PCKJ treatment, PI3K, p-AKT and GLUT-4 levels are upregulated in the skeletal tissue of HFHF-fed rats, similar to the in vitro model. The alteration in the levels of inflammatory cytokines IL-6, IL-10 and IFN-γ in diabetic rats returned to normal levels upon exposure to PCKJ. Histological analysis of vital tissues further strengthens the findings of the preventive value of PCKJ against the development of insulin resistance. In conclusion, this study showed the prophylactic effect of PCKJ as a potent chemical composite, which can be used to develop functional foods (nutraceuticals) for ameliorating type-2 diabetes by improving insulin sensitization and thereby glucose metabolism.