α-Glucosidase inhibition by Tunisian Scabiosa arenaria Forssk. extracts

Evaluation of acute toxicity of Scabiosa artropurperea var.maritima aqueous extracts in Swiss mice

Scabiosa artropurperea var.maritima is a plant widely distributed in the Mediterranean region and used as a traditional medicine. The present study evaluated the biochemical composition and the potential toxicity of aqueous extract of whole Scabiosa artropurperea var.maritima through acute toxicity oral administration in male mice. Phytochemical analysis of the Scabiosa artropurperea var.maritima revealed high levels of reductor sugars and significant flavonoid and total phenol content. The aqueous extract of Scabiosa artropurperea var.maritima was daily oral administered to mice at doses of 300 (group 1), 2000 (group 2) and 4000 (group 3) mg/kg body weight per day for 14 days. We observed no significant difference in the consumption of food, body weight and relative organ weights except for an increase in the seminal vesicles weight in group 3. Hematological parameters revealed the non-adverse effects of prolonged oral consumption of Scabiosa artropurperea var.maritima except for a slight increase but significant of percentage of hematocrit in group 1 and 3 and a decrease in percentage of granulocytes in group 2. The histopathologic examination did not show any differences in vital organs. We also observed non-adverse effects on the reproductive parameters including testosterone concentration, spermatozoa motility and morphologies. Based on our findings, the aqueous extract of Scabiosa artropurperea var.maritima could be considered safe for oral medication in animals.

Investigation of Phytochemical, Antioxidant and Antidiabetic Potentials of Scabiosa L. (Caprifoliaceae) Species with Chemometric Methods

In this research, the total phenolic and flavonoid amounts, phenolic compositions, in vitro antioxidant, antibacterial and antidiabetic properties of the methanol extracts obtained from Scabiosa L. (Caprifoliaceae) species distributed in the flora of Türkiye were investigated using chemometric methods. For this purpose, principal component (PCA) and agglomerative hierarchical clustering analysis were performed as chemometric methods. Chlorogenic acid, quinic acid and cyranoside were determined in the extracts. According to chemometric analysis, S. columbaria subsp. ochroleuca var. ochroleuca and S. triniifolia species were found to be valuable in terms of methanol extract yields, total phenolic and flavonoid contents, antioxidant and antidiabetic activities while S. columbaria subsp. ochroleuca var. webbiana species were found to be valuable in terms of phenolic composition. The methanol extracts of Scabiosa species showed high antioxidant activity, with high phenolic and flavonoid contents. Among the tested 13 bacteria, Scabiosa extracts showed only low activity against Klebsiella pneumoniae, Streptococcus pneumoniae and Pseudomonas aeruginosa. The extracts showed high α-amylase and α-glucosidase inhibitory activity. The results show that Scabiosa methanol extracts may be a source of alternative antioxidants that may be beneficial in slowing or preventing the progression of various oxidative stress-related diseases.

Total biflavonoids extraction from Selaginella chaetoloma utilizing ultrasound-assisted deep eutectic solvent: Optimization of conditions, extraction mechanism, and biological activity in vitro

In this study, the deep eutectic solvent based ultrasound-assisted extraction (DES-UAE) was investigated for the efficient and environmentally friendly extraction of Selaginella chaetoloma total biflavonoids (SCTB). As an extractant for optimization, tetrapropylaminium bromide-1,4-butanediol (Tpr-But) was employed for the first time. 36 DESs were created, with Tpr-But producing the most effective results. Based on response surface methodology (RSM), the greatest extraction rate of SCTB was determined to be 21.68 ± 0.78 mg/g, the molar ratio of HBD to HBA was 3.70:1, the extraction temperature was 57 °C, and the water content of DES was 22 %. In accordance with Fick's second rule, a kinetic model for the extraction of SCTB by DES-UAE has been derived. With correlation coefficients 0.91, the kinetic model of the extraction process was significantly correlated with the general and exponential equations of kinetics, and some important kinetic parameters such as rate constants, energy of activation and raffinate rate were determined. In addition, molecular dynamics simulations were used to study the extraction mechanisms generated by different solvents. Comparing the effect of several extraction methods on S.chaetoloma using ultrasound-assisted extraction and conventional methods, together with SEM examination, revealed that DES-UAE not only saved time but also enhanced SCTB extraction rate by 1.5-3 folds. SCTB demonstrated superior antioxidant activity in three studies in vitro. Furthermore, the extract could suppress the growth of A549, HCT-116, HepG2, and HT-29 cancer cells. Alpha-Glucosidase (AG) inhibition experiment and molecular docking studies suggested that SCTB exhibited strong inhibitory activity against AG and potential hypoglycemic effects. The results of this study indicated that a Tpr-But-based UAE method was suitable for the efficient and environmentally friendly extraction of SCTB, and also shed light on the mechanisms responsible for the increased extraction efficiency, which could aid in the application of S.chaetoloma and provide insight into the extraction mechanism of DES.

Scabiosa atropurpurea: A rich source of iridoids with α-glucosidase inhibitory activity evaluated by in vitro and in silico studies

Scabiosa atropurpurea L. subsp. maritima (L.) Arc. (Caprifoliaceae) is a plant widely distributed in the Mediterranean region and represented by 32 taxa in the flora of Turkey. In the present study, an in-depth phytochemical investigation of S. atropurpurea methanol extract of the whole plant was carried out using a combination of LC-ESI-FT-MS and NMR analysis. This approach allowed the isolation and structural elucidation of 28 compounds: 17 iridoids, 7 flavonoids, and 4 phenolic acids. Among these compounds, three previously unreported iridoids named secologanin-methyl-hemiacetal, atropurpurin A, and atropurpurin B were identified. The methanol extract of S. atropurpurea was assayed for its antioxidant and antihyperglycemic activity, showing a potent α-glucosidase inhibitory activity (IC₅₀ = 100 μg/mL), higher than that exerted by acarbose (IC₅₀ = 196 μg/mL), used as the positive control. Thus, the most abundant iridoids were selected to be tested for their antihyperglycemic activity, and molecular docking experiments were carried out to assess the possibility for selected compounds to form complexes with α-glucosidase enzyme active site.

Effect of digestion on bound phenolic content, antioxidant activity and hypoglycemic ability of insoluble dietary fibre from four Triticeae crops

To assess the physiological functions of bound phenols in insoluble dietary fiber (IDF) from different Triticeae crops, bound phenols in IDF were extracted from wheat, triticale, barley and quinoa. In addition, model in vitro was established and used in evaluating the release of bound phenols and changes in their physiological functions after simulated digestion. Results showed that bound phenol content in IDF from Triticeae crops before digestion was higher than which during digestion, and its physiological functions were also better (p < .05). Moreover, barley extracted before digestion, its bound phenolic content in IDF was higher than those in other three Triticeae crops, besides,its bound phenol also showed better antioxidant ability. Before digestion, bound phenols in IDF from triticale showed the best hypoglycemic ability (the inhibition rate of α-glucosidase was 95%; the inhibition rate of α-amylase was 97%). In the simulated digestion model, the bound phenols were mainly released during the intestinal digestion stage, they showed better physiological functions than which released at the gastric digestion stage. The bound phenol content in triticale was higher and its physiological functions was better than those in the other crops. PRACTICAL APPLICATIONS: The results of this experiment showed that the release of bound phenols measured by chemical extraction (i.e., before digestion) was higher than that by simulated gastrointestinal digestion. Compared with the chemical extraction method, in vitro gastro-intestinal digestion simulates the pH value and enzyme environment of food in the human body gastrointestinal digestion process more effectively. This study can provide reference for selecting Triticeae crops feeding in the future. To be more precise, bound phenol content in the insoluble dietary fiber of barley was the highest before digestion. The bound phenol in the insoluble dietary fiber of triticale had the best hypoglycemic ability. The bound phenolic compounds are mainly released during intestinal digestion, and their physiological functions are better than that in gastric digestion.

Antioxidant and α-Glucosidase Inhibitory Activities Guided Isolation and Identification of Components from Mango Seed Kernel

In the present study, petroleum ether, dichloromethane, ethyl acetate, and n-butanol fractions of mango seed kernel exhibited different degrees of antioxidant and α-glucosidase inhibitory activity. Thus, quantitative and qualitative analysis of the petroleum ether fraction was conducted by GC-MS. Among identified components, four unsaturated fatty acids had never been reported in natural products before, together with 19 known components. In addition, 17 compounds were isolated and elucidated from other active fractions. Compounds 2, 9, 15, and 17 were isolated for the first time from Mangifera genus. Compounds 1 and 2 exhibited prominent DPPH radical scavenging and α-glucosidase inhibitory effects. In order to further explore their mechanism of α-glucosidase inhibition, their enzyme kinetics and in silico modeling experiments were performed. The results indicated that 1 inhibited α-glucosidase in a noncompetitive manner, whereas 2 acted in a competitive manner. In molecular docking, the stability of binding was enhanced by π-π T-shaped, π-alkyl, π-π stacked, hydrogen bond, and electrostatic interactions. Thus, compounds 1 and 2 were determined to be new potent antioxidant and α-glucosidase inhibitors for preventing food oxidation and enhancing hypoglycemic activity.

Phytochemical investigation of Scabiosa sicula guided by a preliminary HPLC-ESIMSn profiling

The genus Scabiosa (Caprifoliaceae) is represented by 80 species, widely used as medicinal plants for their positive effects on human diseases. On the basis of the interesting biological activity shown by Scabiosa spp., the phytochemical investigation of Scabiosa sicula L., never investigated before, was carried out. An initial LC-MS profile of the MeOH extract of S. sicula whole plant guided the isolation of 34 compounds, of which the structures were unambiguously elucidated by NMR analysis as phenolic compounds and triterpene saponins, among which eight undescribed compounds. Moreover, the total phenolic content of S. sicula methanol extract has been evaluated. On the basis of the pharmacological activities reported for Scabiosa species the antioxidant activity of the methanol extract was tested by TEAC and DPPH assays. Finally, the α-glucosidase inhibitory activity of the methanol extract was assayed, showing an IC₅₀ value (49 μg/mL) comparable to that exerted by acarbose (90 μg/mL), used as positive control.

Phytochemical analysis and biological activities of Hertia cheirifolia L. roots extracts

OBJECTIVE

To test the antioxidant, antimicrobial and α-glucosidase inhibitory activities of the roots extracts from Hertia cheirifolia (H. cheirifolia) L.

METHODS

Total phenolics and total flavonoids content of the different extracts were determined by colorimetric methods and reverse phase high-performance liquid chromatography (RP-HPLC) was performed to identify various chemical components. The different extracts were evaluated for antioxidant activities by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis-3-ethylenebenzothiozoline-6-sulfonic acid (ABTS⁺) and β-carotene bleaching tests and α-glucosidase inhibitory properties. The antimicrobial activity was carried out in vitro by the broth dilution method.

RESULTS

Trans-cinnamic acid, rutin hydrate, naringin and quercetin were the main compounds of the ethyl acetate extract from H. cheirifolia L. This extract has significant scavenging activity to decrease free radicals especially for DPPH and ABTS radicals. As well as, the ethyl acetate extract exhibited an antimicrobial property against bacterial strains. Bacillus licheniformis and Salmonella enterica were the most sensitive strains with minimum inhibitory concentration values of 0.156 mg/mL.

CONCLUSION

The ethyl acetate extract was found to be selectively antioxidant and antimicrobial.

Antioxidant and antidiabetic properties of tartary buckwheat rice flavonoids after in vitro digestion

Oxidative stress and diabetes have a tendency to alter protein, lipid, and DNA moieties. One of the strategic methods used to reduce diabetes-associated oxidative stress is to inhibit the carbohydrate-digesting enzymes, thereby decreasing gastrointestinal glucose production. Plant-derived natural antioxidant molecules are considered a therapeutic tool in the treatment of oxidative stress and diabetes. The objective of this study was to identify tartary buckwheat rice flavonoids and evaluate the effect of in vitro digestion on their antioxidant and antidiabetic properties. High performance liquid chromatography (HPLC) analysis indicated the presence of rutin as a major component and quercitrin as a minor component of both digested and non-digested flavonoids. Both extracts showed a significant antioxidant capacity, but digested flavonoids showed reduced activity compared to non-digested. There were some decreases of the antioxidant activities (2,2'-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt (ABTS), 2,2-diphenyl-1-picrylhydrazy (DPPH) radical, and ferric reducing antioxidant power (FRAP)) of digested tartary buckwheat rice flavonoids compared with non-digested. Flavonoids from both groups significantly inhibited reactive oxygen species (ROS) production and α-glucosidase activity. Both digested and non-digested flavonoids markedly increased glucose consumption and glycogen content in HepG2 cells. Tartary buckwheat rice flavonoids showed appreciable antioxidant and antidiabetic properties, even after digestion. Tartary buckwheat rice appears to be a promising functional food with potent antioxidant and antidiabetic properties.