Chemical constituents of Cochlospermum regium (Schrank) Pilg. root and its antioxidant, antidiabetic, antiglycation, and anticholinesterase effects in Wistar rats

Evaluation of Carbonic Anhydrase, Acetylcholinesterase, Butyrylcholinesterase, and α-Glycosidase Inhibition Effects and Antioxidant Activity of Baicalin Hydrate

Baicalin is the foremost prevalent flavonoid found in Scutellaria baicalensis. It also frequently occurs in many multi-herbal preparations utilized in Eastern countries. The current research has assessed and compared the antioxidant, antidiabetic, anticholinergic, and antiglaucoma properties of baicalin hydrate. Baicalin hydrate was tested for its antioxidant capacity using a variety of techniques, including N,N-dimethyl-p-phenylenediamine dihydrochloride radical (DMPD•+) scavenging activity, 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulphonate) radical (ABTS•+) scavenging activity, 1,1-diphenyl-2-picrylhydrazyl radical (DPPH•) scavenging activity, potassium ferric cyanide reduction ability, and cupric ions (Cu2+) reducing activities. Also, for comparative purposes, reference antioxidants, such as butylated hydroxyanisole (BHA), Trolox, α-Tocopherol, and butylated hydroxytoluene (BHT) were employed. Baicalin hydrate had an IC50 value of 13.40 μg/mL (r2: 0.9940) for DPPH radical scavenging, whereas BHA, BHT, Trolox, and α-Tocopherol had IC50 values of 10.10, 25.95, 7.059, and 11.31 μg/mL for DPPH• scavenging, respectively. These findings showed that baicalin hydrate had comparably close and similar DPPH• scavenging capability to BHA, α-tocopherol, and Trolox, but it performed better than BHT. Additionally, apart from these studies, baicalin hydrate was tested for its ability to inhibit a number of metabolic enzymes, including acetylcholinesterase (AChE), butyrylcholinesterase (BChE), carbonic anhydrase II (CA II), and α-glycosidase, which have been linked to several serious illnesses, such as Alzheimer's disease (AD), glaucoma, and diabetes, where the Ki values of baicalin hydrate toward the aforementioned enzymes were 10.01 ± 2.86, 3.50 ± 0.68, 19.25 ± 1.79, and 26.98 ± 9.91 nM, respectively.

Pressurized Liquid Extraction for the Production of Extracts with Antioxidant Activity from Borututu (Cochlospermum angolense Welw.)

Borututu (Cochlospermum angolense Welw.) roots have been described as a rich source of phenolic compounds. Despite the potential of this plant for the production of bioactive extracts, studies reported until now have been scarce, and they have been based on the use of inefficient conventional extraction techniques. In this study, pressurized liquid extraction (PLE) was investigated for the production of borututu root extracts. Different temperatures (50–200 °C) and solvents (water, ethanol, and 50% ethanol:water) were applied. The total phenolic compound (TPC) content, the main phenolic compounds and the in vitro antioxidant activity of the extracts were evaluated. The results were compared with those obtained by conventional decoction with water. The highest concentrations of TPC and antioxidant activity were obtained with 50% ethanol:water, followed by water. The extract obtained with 50% ethanol:water at 150 °C had a TPC concentration of 343.80 mg/g and presented the largest antioxidant activity (1488 and 4979 µmol Trolox/g extract, determined by DDPH and ABTS assay, respectively). These values were considerably higher than those obtained by conventional decoction. Ellagic acid, and ellagic and methyl ellagic acid glycosides were the main phenolic compounds found in the extracts. Therefore, was PLE demonstrated to be a selective and efficient technique to obtain extracts with high concentrations of phenolic compounds and high antioxidant activity form borututu roots.

Anti-hyperglycemic potential and chemical constituents of Aristolochia triangularis Cham. leaves - A medicinal species native to Brazilian forests

ETHNOPHARMACOLOGICAL RELEVANCE

Aristolochia triangularis Cham. has been used in Brazilian traditional medicine for various therapeutic purposes, including as a leaf-based infusion for diabetes management.

AIM OF THE STUDY

This study was designed to chemically characterize an infusion of in natura A. triangularis leaves and evaluate the in vivo anti-hyperglycemic properties of this infusion.

MATERIALS AND METHODS

Chemical composition was examined using liquid-liquid extraction procedure, chromatographic methods, NMR, and LC-MS/MS. The in vivo anti-hyperglycemic activity of the freeze-dried infusion of A. triangularis leaves (Inf-L-At) was assessed using oral glucose tolerance test (OGTT). Initially, normoglycemic male rats were pre-treated with orally administered Inf-L-At at doses of 62.5, 125, and 250 mg/kg for two consecutive days. On the day of the OGTT, fasting animals received a glucose load (4 g/kg) 30 min after treatment with Inf-L-At, and the blood glucose levels were verified at 15, 30, 60, and 180 min. Intestinal maltase, lactase, and sucrase activities and muscle and liver glycogen contents were also assessed after the OGTT.

RESULTS

Inf-L-At extract led to glycemic reduction with no dose-response at 15, 30, and 60 min comparable to that of the antidiabetic drug glibenclamide and was accompanied by an increase in hepatic and muscle glycogen contents. Additionally, there was a significant statistically decrease in the in vitro activity of disaccharidases. Maltase and sucrase activities were inhibited at all doses, whereas lactase activity was inhibited only at 62.5 and 250 mg/kg. In total, 75 compounds were found in the infusion, including seven new ones, (7S*,8S*,7ꞌS*,8ꞌR*)-4,4ꞌ-dihydroxy-3,3ꞌ-dimethoxy-7,9ꞌ-epoxylignan-7ꞌ-ol; 4ꞌ-hydroxy-3ꞌ-methoxy-3,4-methylenedioxy-7,9ꞌ-epoxylignan-9,7ꞌ-diol; triangularisines A, B, and C; N-ethyl-N-methyl-affineine; and N-methyl pachyconfine, and one previously not described as a natural product, epi-secoisolariciresinol monomethyl ether.

CONCLUSION

The results demonstrated the anti-hyperglycemic activity of the infusion from A. triangularis leaves and showed that it is a rich source of lignoids, alkaloids, and glycosylated flavonoids, which are known to exhibit antidiabetic effects and other biological properties that can be beneficial for patients with chronic hyperglycemia, thus certifying the popular use of this herbal drink.

Phenolic compounds and bioactive extract produced by endophytic fungus Coriolopsis rigida

Coriolopsis rigida was isolated as an endophytic fungus from the medicinal plant Cochlospermum regium, and their production of secondary metabolites has not yet been investigated. Thus, the endophyte was cultivated on rice solid media to evaluate its ability to produce bioactive compounds and then the chloroform extract was obtained. Two phenolic compounds, tyrosol (1) and a new natural product p-hydroxyphenylacetamide (2), were isolated from the extract. The structures of the compounds were elucidated mainly by NMR. The extract showed potent antioxidant activity with an efficient concentration (EC₅₀) value of 0.33 mg mL^-1. Additionally, demonstrated allelopathic activity inhibited the seedling growth of Lactuca sativa L. and Raphanus sativus L. by 63% and 55%, respectively.

Plasticity of the spinal glymphatic system in male SD rats with painful diabetic neuropathy induced by type 2 diabetes mellitus

The glymphatic system is a recently discovered glial‐dependent macroscopic interstitial waste clearance system that promotes the efficient elimination of soluble proteins and metabolites from the central nervous system. Its anatomic foundation is the astrocytes and aquaporin‐4 (AQP4) water channels on the endfeet of astrocytes. The aim of this study is to evaluate the plasticity of the spinal glymphatic system in male SD rats with painful diabetic neuropathy (PDN) induced by type 2 diabetes mellitus. PDN rats were modeled under a high‐fat and high‐glucose diet with a low dose of streptozotocin. MRI was applied to observe the infiltration and clearance of contrast to indicate the functional variability of the glymphatic system at the spinal cord level. The paw withdrawal threshold was used to represent mechanical allodynia. The numerical change of glial fibrillary acidic protein (GFAP) positive astrocytes was assessed and the polarity reversal of AQP4 protein was measured by immunofluorescence. As a result, deceased contrast infiltration and clearance, enhanced mechanical allodynia, increased number of GFAP positive astrocytes, and reversed polarity of AQP4 protein were found in the PDN rats. The above molecular level changes may contribute to the impairment of the spinal glymphatic system in PDN rats. This study revealed the molecular and functional variations of the spinal glymphatic system in PDN rats and for the first time indicated that there might be a correlation between the impaired spinal glymphatic system and PDN rats.

Flavonoid constituents of Amomum tsao-ko Crevost et Lemarie and their antioxidant and antidiabetic effects in diabetic rats - in vitro and in vivo studies

Amomum tsao-ko Crevost et Lemarie (A. tsao-ko) is a well-known dietary spice and traditional Chinese medicine. This study aimed to identify the flavonoids in A. tsao-ko and evaluate their antioxidant and antidiabetic activities in in vitro and in vivo studies. A. tsao-ko methanol extracts possessed a high flavonoid content (1.21 mg QE per g DW) and a total of 29 flavonoids were identified by employing UPLC-MS/MS. In vitro, A. tsao-ko demonstrated antioxidant activity (ORAC value of 34276.57 μM TE/100 g DW, IC₅₀ of ABTS of 3.49 mg mL^-1 and FRAP value of 207.42 μM Fe²⁺ per g DW) and α-amylase and α-glucosidase inhibitory ability with IC₅₀ values of 14.23 and 1.76 mg mL^-1, respectively. In vivo, type 2 diabetes mellitus (T2DM) models were induced by a combined high-fat diet (HFD) and streptozotocin (STZ) injection in rats. Treatment with the A. tsao-ko extract (100 mg freeze-dried powder per kg bw) for 6 weeks could significantly improve impaired glucose tolerance, decrease the levels of fasting blood glucose (FBG), insulin, and malondialdehyde (MDA), and increase the superoxide dismutase (SOD) level. Histopathology revealed that the A. tsao-ko extract preserved the architecture and function of the pancreas. In conclusion, the flavonoid composition of A. tsao-ko exhibits excellent antioxidant and antidiabetic activity in vitro and in vivo. A. tsao-ko could be a novel natural material and developed as a related functional food and medicine in T2DM management.

Gallic Acid and Diabetes Mellitus: Its Association with Oxidative Stress

Diabetes mellitus (DM) is a severe chronic metabolic disease with increased mortality and morbidity. The pathological progression of DM is intimately connected with the formation and activation of oxidative stress (OS). Especially, the involvement of OS with hyperglycemia, insulin resistance, and inflammation has shown a vital role in the pathophysiological development of DM and related complications. Interestingly, accumulating studies have focused on the exploration of natural antioxidants for their improvement on DM. Of specific interest is gallic acid (GA), which is rich in many edible and herbal plants and has progressively demonstrated robust antioxidative and anti-inflammatory effects on metabolic disorders. To provide a better understanding of its potential therapeutic impacts and enhancement of human health care, the available research evidence supporting the effective antidiabetic properties of GA and relevant derivatives are needed to be summarized and discussed, with emphasis on its regulation on OS and inflammation against DM. This review aims to highlight the latest viewpoints and current research information on the role of OS in diabetes and to provide scientific support for GA as a potential antihypoglycemic agent for DM and its complications.

Therapeutic Potential of Polyphenols in the Management of Diabetic Neuropathy

Diabetic neuropathy (DN) is a common and serious diabetes-associated complication that primarily takes place because of neuronal dysfunction in patients with diabetes. Use of current therapeutic agents in DN treatment is quite challenging because of their severe adverse effects. Therefore, there is an increased need of identifying new safe and effective therapeutic agents. DN complications are associated with poor glycemic control and metabolic imbalances, primarily oxidative stress (OS) and inflammation. Various mediators and signaling pathways such as glutamate pathway, activation of channels, trophic factors, inflammation, OS, advanced glycation end products, and polyol pathway have a significant contribution to the progression and pathogenesis of DN. It has been indicated that polyphenols have the potential to affect DN pathogenesis and could be used as potential alternative therapy. Several polyphenols including kolaviron, resveratrol, naringenin, quercetin, kaempferol, and curcumin have been administered in patients with DN. Furthermore, chlorogenic acid can provide protection against glutamate neurotoxicity via its hydrolysate, caffeoyl acid group, and caffeic acid through regulating the entry of calcium into neurons. Epigallocatechin-3-gallate treatment can protect motor neurons by regulating the glutamate level. It has been demonstrated that these polyphenols can be promising in combating DN-associated damaging pathways. In this article, we have summarized DN-associated metabolic pathways and clinical manifestations. Finally, we have also focused on the roles of polyphenols in the treatment of DN.

Antidiabetic potential of dietary polyphenols: A mechanistic review

Diabetes is a metabolic disorder that has caused enormous harm to the public health worldwide. In this study, we evaluated the potential of phenolic compounds on diabetes management, addressing their mechanisms of action, in addition to discussing the digestion, absorption, metabolism, bioavailability, and toxic effects of these compounds. The intake of phenolic compounds can play a fundamental role on diabetes management, since they can reduce blood glucose levels, oxidative stress, protein glycation, inhibit the activity of dipeptidyl peptidase - IV and other key enzymes related to carbohydrate metabolism, activate various biochemical pathways to improve pancreatic β-cell functions, increase insulin secretion, and improve insulin resistance. In this way, they can be considered a potential strategy in the development of pharmaceutical approaches that aim to reduce complications resulting from the progression of this metabolic pathology.

Phytochemical components and bioactivities of novel medicinal food - Peony roots

Peony as an important medicinal material is widely cultivated in China, which is one of the natural distribution centers of wild peony species. So far, however, there has not been a systematic study of the roots from China's wild peonies. In this study, the total phenolic (TPC), total flavonoid (TFC), other secondary metabolites, and microelement content, as well as the antioxidant, antibacterial, anticholinesterase, and antitumor activities of peony roots from 15 species and 2 subspecies were measured. Thirteen secondary metabolites were detected, with Paeoniflorin and Paeonol being the highest content bio-activities compounds. Additionally, the peony roots had a significant antioxidant activities and bacteriostatic effect against Gram-positive bacteria, with MIC varying from 0.063 to 1 mg/mL. P. anomala subsp. veitchii and P. lactiflora showed outstanding anticholinesterase capacities and cytotoxic activities. Taken together, the data presented here provide new insights into both the medicinal and edible potential of roots from wild peony species.

Antidiabetic effect of two different Ganoderma species tested in alloxan diabetic rats

This study was designed to define total protein, phenol and flavonoid content as well as LC-MS/MS phenolic profile related to antioxidant and antidiabetic activity of ethanolic (EtOH) and water extracts of G. pfeifferi and G. resinaceum. G. resinaceum water extract possessed the highest ability to scavenge DPPH˙ and O₂˙⁻, while the EtOH extract of the same species showed better activity on NO˙ related to other extracts. The highest level of bioactive compounds was determined generally in EtOH extracts. Antidiabetic action was evaluated by the oral glucose tolerance test (OGTT) and histological examination of pancreas and liver in normoglycemic and alloxan-induced diabetic animals. Histological examination of pancreatic tissue demonstrated that G. pfeifferi extracts have protective effects. To conclude, analysed extracts could be considered as a promising candidate for further research with the aim to promote antidiabetic activity, which is for the first time reported for G. pfeifferi.

Antidiabetic potentials of G. pfeifferi and G. resinaceum were obtained in this study and found to be of even higher bioactivity than the previously reported and well known G. lucidum.