Characterization of Maltase and Sucrase Inhibitory Constituents from Rhodiola crenulata

Antidiabetic Potential of Bananas (Musa spp.): A Systematic Review of Bioactive Compounds and Antihyperglycemic Activities

PURPOSE OF REVIEW

Bananas (Musa spp.), a staple fruit crop in Southeast Asia, are widely recognised for their nutritional value and potential medicinal properties, including the management of diabetes. To address the diabetes pandemic, various studies have explored the efficacy of many natural foods in reducing blood glucose, preventing complications that arise from the chronic illness. However, a comprehensive overview of bioactive compounds and their antidiabetic effects across different banana species in recent years is lacking. This review provides a comprehensive overview of bioactive compounds in various parts of the bananas that have demonstrated antihyperglycemic activities. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we conducted a thorough literature search using ScienceDirect, Scopus, and PubMed databases, resulting in the inclusion of 27 relevant articles.

RECENT FINDINGS

Emerging evidence suggests that different parts of the banana plant contain various bioactive compounds with antihyperglycemic activities, offering promising benefits for diabetes management. The findings reveal that the antihyperglycemic effects of bananas can be attributed to specific bioactive compounds, such as phenols, saponins, alkaloids, sterols, and flavonoids, through mechanisms like inhibition of α-glucosidase, β-glucosidase, α-amylase and sucrase enzymes, glucose uptake assay, and inhibition of formation of advanced glycation end-products. Liver glycogen content and fasting blood glucose in rat models, along with HbA1c measurements in human subjects, were also assessed to evaluate invivo antidiabetic activity, which has yielded positive outcomes. The results support the potential medicinal and pharmaceutical benefits of bananas in clinical diabetes management and suggest that incorporating banana-derived compounds could enhance the cost-effectiveness of antidiabetic treatments.

Antioxidant and Hypoglycemic Potential of Phytogenic Selenium Nanoparticle- and Light Regime-Mediated In Vitro Caralluma tuberculata Callus Culture Extract

In vitro plant cultures have emerged as a viable source, holding auspicious reservoirs for medicinal applications. This study aims to delineate the antioxidant and hypoglycemic potential of phytosynthesized selenium nanoparticle (SeNP)- and light stress-mediated in vitro callus cultures of Caralluma tuberculata extract. The morphophysicochemical characteristics of biogenic SeNPs were assessed through a combination of analytical techniques, including UV-visible spectrophotometry, scanning electron microscopy, energy-dispersive X-rays, Fourier transform infrared spectrometry, and zeta potential spectroscopy. The antioxidative potential of the callus extract 200 and 800 μg/mL concentrations was assessed through various tests and exhibited pronounced scavenging potential in reducing power (26.29%), ABTS + scavenging (42.51%), hydrogen peroxide inhibition (37.26%), hydroxyl radical scavenging (40.23%), and phosphomolybdate (71.66%), respectively. To inspect the hypoglycemic capacity of the callus extract, various assays consistently demonstrated a dosage-dependent relationship, with higher concentrations of the callus extract exerting a potent inhibitory impact on the catalytic sites of the alpha-amylase (78.24%), alpha-glucosidase (71.55%), antisucrase (59.24%), and antilipase (74.26%) enzyme activities, glucose uptake by yeast cells at 5, 10, and 25 mmol/L glucose solution (72.18, 60.58 and 69.33%), and glucose adsorption capacity at 5, 10, and 25 mmol/L glucose solution (74.37, 83.55, and 86.49%), respectively. The findings of this study propose selenium NPs and light-stress-mediated in vitro callus cultures of C. tuberculata potentially operating as competitive inhibitors. The outcomes of the study were exceptional and hold promising implications for future medicinal applications.

Possible Side Effects of Polyphenols and Their Interactions with Medicines

Polyphenols are an important component of plant-derived food with a wide spectrum of beneficial effects on human health. For many years, they have aroused great interest, especially due to their antioxidant properties, which are used in the prevention and treatment of many diseases. Unfortunately, as with any chemical substance, depending on the conditions, dose, and interactions with the environment, it is possible for polyphenols to also exert harmful effects. This review presents a comprehensive current state of the knowledge on the negative impact of polyphenols on human health, describing the possible side effects of polyphenol intake, especially in the form of supplements. The review begins with a brief overview of the physiological role of polyphenols and their potential use in disease prevention, followed by the harmful effects of polyphenols which are exerted in particular situations. The individual chapters discuss the consequences of polyphenols’ ability to block iron uptake, which in some subpopulations can be harmful, as well as the possible inhibition of digestive enzymes, inhibition of intestinal microbiota, interactions of polyphenolic compounds with drugs, and impact on hormonal balance. Finally, the prooxidative activity of polyphenols as well as their mutagenic, carcinogenic, and genotoxic effects are presented. According to the authors, there is a need to raise public awareness about the possible side effects of polyphenols supplementation, especially in the case of vulnerable subpopulations.

In Vitro Digestibility and Bioaccessibility of Nutrients and Non-Nutrients Composing Extruded Brewers' Spent Grain

This study aimed to evaluate the effect of the extrusion process on the bioaccessibility of brewers’ spent grain (BSG) nutrients (carbohydrates and proteins) and non-nutrients (bioactive compounds). BSG and extruded BSG (EBSG) were digested in vitro simulating human oral-gastro-intestinal digestion and colonic fermentation. The duodenal bioaccessibility of glucose, amino acids and phenolic compounds was analyzed. The fermentability of the dietary fiber was assessed by analysis of short-chain fatty acids. Additionally, assessment of the bioaccessibility of phenolic compounds after colonic fermentation was undertaken. The antioxidant, anti-inflammatory and antidiabetic properties of the bioaccessible compounds were studied. Extrusion caused no change in the digestibility of gluten and glucose bioaccessibility (p > 0.05). Moreover, the bioaccessibility of amino acids and phenolic compounds significantly increased (p < 0.05) due to extrusion. However, higher short-chain fatty acid content was formed in colonic fermentation of BSG (p < 0.05) compared to EBSG. The latter inhibited intracellular ROS formation in IEC-6 cells and showed anti-inflammatory properties in RAW264.7 cells. With respect to antidiabetic properties, glucose absorption was lower, and the inhibition of carbohydrases higher (p < 0.05), in the presence of EBSG compared to BSG. The effects of EBSG and BSG digests on glucose transporters were not significantly different (p > 0.05). In conclusion, extrusion positively affected the nutritional value and health-promoting properties of BSG.

Hypoglycemic effects of Rhodiola crenulata (HK. f. et. Thoms) H. Ohba in vitro and in vivo and its ingredient identification by UPLC-triple-TOF/MS

Rhodiola crenulata (HK. f. et. Thoms) H. Ohba (RC), mainly distributed in the highly cold region of China, has long been used as a medicine/healthy food for eliminating fatigue and increasing blood circulation. This study aimed to evaluate the inhibitory effects of the RCRS extract on α-amylase and α-glucosidase (sucrase and maltase) in vitro and in vivo, and tentatively analyze and identify its chemical ingredients using UPLC-Triple-TOF/MS. The Rhodiola crenulata RCRS extract had strong inhibitory activities against α-amylase, sucrase and maltase with an IC₅₀ of 0.031 mg mL^-1, 0.142 mg mL^-1 and 0.214 mg mL^-1, respectively. Furthermore, the RCRS extract could significantly decrease the postprandial blood glucose (PBG) level of normal mice in a starch tolerance test, and reduce the PBG levels of diabetic mice in a starch/maltose/sucrose tolerance test. UHPLC-Triple-TOF-MS/MS analysis indicated that hydroxybenzoic acids, hydroxycinnamic acids, alcohol glycosides, flavonols and their derivatives were the main active ingredients in the RCRS extract. The results demonstrate that the RCRS extract of Rhodiola crenulata could be employed as a healthy food or medicine for controlling postprandial blood glucose levels.

Quality Evaluation of Randomized Controlled Trials of Rhodiola Species: A Systematic Review

Background

Rhodiola is a worldwide used medicinal plant for its various medicinal functions, and the number of randomized controlled trials (RCTs) of Rhodiola is increasing in recent years. This study aims to evaluate the reporting quality and risk of bias of the current RCT reports of different Rhodiola species.

Methods

Six databases including Embase, PubMed, Web of Science, the Cochrane Library, ClinicalTrial.gov, and China National Knowledge Infrastructure were searched to identify RCTs that used Rhodiola as a single intervention and were published in English or Chinese from inception to December 2020. The Consolidated Standards of Reporting Trials (CONSORT) 2010 statement was used as the checklist for assessment, and a scoring system was applied to the evaluation of RCTs. Score 0 represents no reporting or inadequate reporting, and score 1 represents adequate reporting. The risk of bias of the included studies was also assessed using the Cochrane Risk of Bias tool.

Results

A total of 39 RCTs were included in this study, including 23 RCTs of Rhodiola rosea (R. rosea), 8 RCTs of Rhodiola crenulata (R. crenulata), and 8 RCTs of Rhodiola wallichiana (R. wallichiana). None of the included studies met all the CONSORT statement criteria, and the reporting quality of RCTs of the three Rhodiola species was all generally poor. Based on the risk of bias assessment, the majority of included studies were judged to have an unclear risk of bias in most domains due to inadequate reporting.

Conclusions

There is inadequate reporting among the included RCTs of different Rhodiola species, and RCTs of Rhodiola with higher reporting quality and better methodological quality are needed.

Comparison of edible brown algae extracts for the inhibition of intestinal carbohydrate digestive enzymes involved in glucose release from the diet

Type II diabetes is considered the most common metabolic disorder in the developed world and currently affects about one in ten globally. A therapeutic target for the management of type II diabetes is the inhibition of α- glucosidase, an essential enzyme located at the brush border of the small intestinal epithelium. The inhibition of α-glucosidase results in reduced digestion of carbohydrates and a decrease in postprandial blood glucose. Although pharmaceutical synthetic inhibitors are available, these are usually associated with significant gastrointestinal side effects. In the present study, the impact of inhibitors derived from edible brown algae is being investigated and compared for their effect on glycaemic control. Carbohydrate- and polyphenolic-enriched extracts derived from Ascophyllum nodosum, Fucus vesiculosus and Undaria pinnatifida were characterised and screened for their inhibitory effects on maltase and sucrase enzymes. Furthermore, enzyme kinetics and the mechanism of inhibition of maltase and sucrase were determined using linear and nonlinear regression methods. All tested extracts showed a dose-dependent inhibitory effect of α-glucosidase with IC50 values ranging from 0⋅26 to 0⋅47 mg/ml for maltase; however, the only extract that was able to inhibit sucrase activity was A. nodosum, with an IC50 value of 0⋅83 mg/ml. The present study demonstrates the mechanisms in which different brown seaweed extracts with varying composition and molecular weight distribution differentially inhibit α-glucosidase activities. The data highlight that all brown seaweed extracts are not equal in the inhibition of carbohydrate digestive enzymes involved in postprandial glycaemia.

Synthesis of 2-(4-hydroxyphenyl)ethyl 3,4,5-Trihydroxybenzoate and Its Inhibitory Effect on Sucrase and Maltase

We report on the synthesis of an active component, 2-(4-hydroxyphenyl)ethyl 3,4,5-trihydroxybenzoate (HETB), from Rhodiola crenulata. Subsequent analysis revealed that HETB exhibits α-glucosidase inhibitory activities on maltase and sucrase, with potency exceeding that of the known α-glucosidase inhibitors (voglibose and acarbose). An inhibition kinetics study revealed that HETB, acarbose, and voglibose bind to maltase and sucrase, and HETB was shown to be a strong competitive inhibitor of maltase and sucrase. In a molecular docking study based on the crystal structure of α-glucosidase from Saccharomyces cerevisiae, we revealed the HETB binding in the active site of maltase via hydrogen-bond interactions with five amino acid residues: Ser 240, Asp 242, Glu 277, Arg 315, and Asn 350. For HETB docked to the sucrase active site, seven hydrogen bonds (with Asn 114, Glu 148, Gln 201, Asn 228, Gln 381, Ile 383, and Ser 412) were shown.

Acylated Aminooligosaccharides from the Yellow Sea Streptomyces sp. HO1518 as Both α-Glucosidase and Lipase Inhibitors

Three new acylated aminooligosaccharide (1-3), along with five known congeners (4-8), were isolated from the marine-derived Streptomyces sp. HO1518. Their structures were fully elucidated by extensive spectroscopic analysis, mainly based on 1D-selective and 2D TOCSY, HSQC-TOCSY, and HRESIMS spectrometry measurements, and by chemical transformations. All of the compounds were evaluated for their α-glucosidase and pancreatic lipase inhibitory activities. Among the isolates, D6-O-isobutyryl-acarviostatin II03 (3) and D6-O-acetyl-acarviostatin II03 (8), sharing acarviostatin II03-type structure, showed the most potent α-glucosidase and lipase inhibitory effects, far stronger than the antidiabetic acarbose towards α-glucosidase and almost equal to the anti-obesity orlistat towards lipase in vitro. This is the first report on inhibitory activities against the two major digestive enzymes for acylated aminooligosaccharides. The results from our investigation highlight the potential of acylated aminooligosaccharides for the future development of multi-target anti-diabetic drug.

Phytochemical, Antibacterial and Antioxidant Activity Evaluation of Rhodiola crenulata

The chemical components, as well as the antibacterial and antioxidant activities of the essential oil (EO) and crude extracts prepared from Rhodiola crenulata were investigated. The essential oil was separated by hydrodistillation, and gas chromatography-mass spectrometry (GC-MS) was used to identify its constituents. A total of twenty-seven compounds was identified from the EO, and its major components were 1-octanol (42.217%), geraniol (19.914%), and 6-methyl-5-hepten-2-ol (13.151%). Solvent extraction and fractionation were applied for preparing the ethanol extract (crude extract, CE), petroleum ether extract (PE), ethyl acetate extract (EE), n-butanol extract (BE), and water extract (WE). The CE, EE and BE were abundant in phenols and flavonoids, and EE had the highest total phenol and total flavonoid contents. Gallic acid, ethyl gallate, rosavin and herbacetin were identified in the EE. The antibacterial activity results showed that the EO exhibited moderate inhibitory activity to the typical clinic bacteria, and EE exhibited the strongest antibacterial activity among the five extracts. For the compounds, ethyl gallate showed the strongest inhibitory activity to the test bacteria, and its minimum inhibitory concentration (MIC) value and minimum bactericidal concentration (MBC) value for all the tested bacteria was 0.24 mg/mL and 0.48 mg/mL, respectively. The results of antioxidant activity showed that both CE and EE exhibited strong antioxidant activities in the DPPH radical scavenging and Fe2+ reducing power tests, however, EO showed relatively weaker antioxidant ability. Ethyl gallate and rosavin exhibited excellent activity in the DPPH radical scavenging assay, and their IC50 value was 5.3 µg/mL and 5.9 µg/mL, respectively. Rosavin showed better reduction power activity than the other three compounds. These results could provide more evidence for the traditional use of R. crenulata, and would be helpful for improving its application further.