Sucrase Inhibitory Activity Research Articles

Comparative analysis of metabolites and in vitro hypoglycemic activity of Taiwanofungus camphoratus cultured using various methods

Taiwanofungus camphoratus has attracted much attention because it can abundantly produce various active substances that exhibit blood-sugar lowering, immunity improving, and antioxidant properties. Currently, T. camphoratus is cultured using four main methods: cutting wood culture, solid-state fermentation, submerged fermentation, and dish culture. T. camphoratus produces different metabolites under different culture methods. In this study, nontargeted metabolomics was used to compare the metabolites of T. camphoratus produced under these four culture methods. Principal component analysis and supervised partial least squares-discriminant analysis were used to analyze the differences in the metabolites. Moreover, in vitro hypoglycemic activity of T. camphoratus extracts produced under four culture methods was compared by assessing their ability to inhibit the activity of α-glucosidase, α-amylase, and sucrase. A total of 186 metabolites were identified. In total, 127 metabolites were common under the four culture methods. Under solid-state fermentation, submerged fermentation, and cutting wood culture, 12, 1, and 4 metabolites were unique, respectively. The differential metabolites produced by T. camphoratus under four culture methods were mainly triterpenoids, phenolic compounds, and fatty acid compounds. α-glucosidase, α-amylase, and sucrase activity inhibition was the best using T. camphoratus extract obtained under cutting wood culture; the inhibition rates were 55.97%, 51.96%, and 78.02%, respectively, which were comparable to those exhibited by 0.001, 3, and 12 mg/mL acarbose (positive control). The metabolites produced by T. camphoratus and α-glucosidase, α-amylase, and sucrase inhibitory activities were different under the four culture methods. Cutting wood culture exhibited the best enzyme inhibitory activity. This study provided a theoretical basis for further use and development of various culture methods for the rational production of active metabolites of T. camphoratus.

Characterization of alkaloids and phenolics in Nitraria roborowskii Kom. fruit by UHPLC-triple-TOF-MS/MS and its sucrase and maltase inhibitory effects

Nitraria roborowskii Kom (NRK), with high economic and ecological value, is mainly distributed in the Qaidam Basin, China. However, research on its chemical components and bioactivities is still rare. In this study, its chemical constituents (52) including 10 β-carboline alkaloids, nine cyclic peptides, three indole alkaloids, five pyrrole alkaloids, eight phenolic acids and 17 flavonoids were identified tentatively using UPLC-triple-TOF-MS/MS. Notablely, one new β-carboline alkaloid and five new cyclic peptides were confirmed using MS/MS fragmentation pathways. In addition, experiments in vitro indicated that NRK-C had strong maltase and sucrase inhibitory activities (IC50 of 0.202 and 0.103 mg/mL, respectively). Polysaccharide tolerance experiments confirmed NRK-C (400 mg/kg) was associated with decreased postprandial blood glucose (PBG) in diabetic mice. These results suggested that NRK fruit might be used as a functional ingredient in food products.

Sucrase Inhibitory Activities of Ethanol Extract of Unripe Peels of Musa Paradisiaca Linn and its Chemical Constituents

a peer-reviewed, open access online international journal which publishes original research papers. The journal welcomes submission from scholars and experts for possible publication from all over the world. The scope of the journal includes: Pharmaceutical research, chemistry and biochemistry of naturally occurring compounds, biological evaluation of crude extracts, ethnomedicine, traditional and complementary medicine, ethnopharmacology, biomedical research, Biotechnology, Evaluation of natural substances of land and sea and of plants, microbes and animals, pharmacognosy, bioavailability, clinical, pharmacological, toxicological studies and pharmacokinetics of phytochemicals, Isolation and characterization of compounds, structure elucidation, synthesis and experimental biosynthesis of natural Product as well as developments of methods in these areas are welcomed in the journal.

In Vitro and in Vivo Anti-Hyperglycemic Activities of Taxifolin and Its Derivatives Isolated from Pigmented Rice (Oryzae sativa L. cv. Superhongmi).

Superhongmi is a new rice variety, which was developed for the enrichment of bioactive compounds through cross-breeding three varieties of rice breeds in Korea. The high-performance liquid chromatography coupled with a photodiode array detector quadrupole and tandem time-of-flight mass spectrometry (HPLC/PDA/QTOF-MS) analysis has revealed that superhongmi bran extract contained four taxifolin derivatives as well as cyanidin 3-glucoside. The high-performance countercurrent chromatography (CCC) and reversed-phase HPLC led to the isolation of aforementioned five compounds, and spectroscopic analysis identified cyanidin 3-glucoside (1), along with (2R,3R)-taxifolin 3-O-β-d-glucopyranoside (2), (2R,3R)-4'-O-methyltaxifolin 3-O-β-d-glucopyranoside (a novel compound) (3), (2R,3R)-taxifolin (4), and (2R,3R)-4'-O-methyltaxifolin (5). Compound 2 had the highest rat small intestinal sucrase inhibitory activity (0.54 mM) relevant for potentially managing postprandial hyperglycemia, followed by compound 1 (0.97 mM) and compound 4 (1.74 mM, IC50). The anti-hyperglycemic effect of compound 4 (taxifolin), a main peak in HPLC analysis was investigated using a Sprague-Dawley (SD) rat model. Compared to a control, taxifolin treatment (p < 0.001) reduced significantly after sucrose loading the observed postprandial blood glucose and the maximum blood glucose (Cmax) by 15% (203.60 ± 15.86 to 172.30 ± 12.74). These results indicate that taxifolin derivatives that inhibit the activity of carbohydrate-hydrolyzing enzymes resulting in reduced dietary carbohydrate absorption can potentially be used as a strategy to manage diabetes.

Maltase and sucrase inhibitory activities and hypoglycemic effects of carbon dots derived from charred Fructus crataegi

Although carbon dots (CDs) have been widely applied in nanobiotechnology and biomedicine, few studies have evaluated the intrinsic self-bioactivities and no reports have described the disaccharidase inhibitory activities of CDs. In this study, charred Fructus crataegi-derived CDs (CFC-CDs) having an average diameter of 1.3–5.6 nm are developed, without further modifications. Owing to an abundance of surface groups, CFC-CDs show distinct solubility, biocompatibility, and bioactivity. Moreover, CFC-CDs inhibit the catalytic activities of sucrase and maltase in vitro and reduce postprandial blood glucose levels in vivo, possibly by acting as a disaccharidase inhibitor. This discovery provides guidance for further research on the bioactivities of CDs and supports their potential applications in the biomedical and healthcare fields.

In Vitro and In Vivo Anti‐Hyperglycemic and Antioxidant Effects of Phenolic Compounds isolated from Oryza sativa L.(Keun‐nun‐Jami) Variety

Type 2 diabetes, one of the chronic diseases, is a problem in both developed and developing countries. In particular, excessive ingestion of grain, such as rice, can result in hyperglycemia and type 2 diabetes. Therefore, a Oryza sativa L. variety, Keun‐nun‐Jami (KNJM) extracts were investigated for their anti‐hyperglycemic effect using in vitro and animal models. In vitro study inhibitory activities of both ethyl alcohol extracts of bran and germ against rat intestinal sucrase and maltase were evaluated. Oxygen radical absorbance capacity (ORAC) was also investigated. Ethyl alcohol extract of KNJM bran (EKB) had the highest sucrase inhibitory activity followed by ethyl alcohol extract of KNJM germ (EKG). Taxifolin, a flavonol, was isolated from the extract of KNJM along with three unknown compounds using HPLC and semi‐prep HPLC systems. Their structures were elucidated by extensive spectroscopic analysis, including 1D and 2D NMR, and FTICR‐MS. Furthermore, post‐prandial blood anti‐hyperglycemic effect of the extacts and taxifolin were measured using SD (Sprague Dawley) rat model. Postprandial blood glucose levels were tested for 3 hr after sucrose and starch administration with or without 500 mg of EKB, EKG, and taxifolin, respectively. Similar to result in vitro study, EKB which has higher content of taxifolin than that of EKG had stronger anti‐hyperglycemic effect than that of EKG. These results indicate that taxifolin from KNJM serves to reduce post‐prandial blood glucose rise and slower absorption of glucose in the small intestine, via carbohydrate hydrolyzing enzymes inhibition. These findings suggest that EKB has better potential for this bioactivity and this observation possibly correlates with the taxifolin contents observed in both extracts. Selected variety of colored rice, KNJM may provide the potential to contribute as a dietary strategy for controlling postprandial hyperglycemia.Support or Funding InformationThis work was supported by a grant from the Next‐Generation BioGreen 21 Program (No.PJ01314003), Rural Development Administration, Republic of KoreaThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Phytochemical characteristics of callus suspension culture of Helicteres angustifolia L. and its in vitro antioxidant, antidiabetic and immunomodulatory activities

Helicteres angustifolia L. (H.angustifolia) is an important medicinal plant. This study investigated the phytochemical characteristics of callus suspension cultures of H.angustifolia and its bioactive functions, such as antioxidant, antidiabetic and immunomodulatory activities. Results demonstrated that the cultures were rich in phenolic compounds, flavonoids, terpenoids, saponins and triterpenoids. Compared to the equivalent wild roots, the cultures yielded larger amounts of total phenolics (17.75 mg GAE g−1), flavonoids (56.15 mg RE g−1), saponins (29.21 mg OAE g−1) and polysaccharides (13.69 mg g−1), about 1.62-, 1.90-, 1.14- and 3.41-fold higher than those from the equivalent wild roots, respectively. Furthermore, as the valuable target product from in vitro culture, phenolic compounds were subjected to HPLC analysis, reflecting that some representative phenolic compounds fluctuated significantly under the cultivation conditions. Additionally, bioactive assays showed that the extract of callus suspension cultures (CE) possessed strong antioxidant activities, and rat maltase (IC50 = 13.29 mg mL−1) and sucrase (IC50 = 13.76 mg mL−1) inhibitory activities. As for the immunomodulatory activity, CE could stimulate the proliferation of macrophages (121.93 ± 1.76%) and the production of nitric oxide (200% of the control) and phagocytic activity (178% of the control) at 6.25 μg mL−1. Moreover, CE could mitigate DOX-induced macrophages damage to some extent. In conclusion, the callus suspension culture of H.angustifolia is a potential source for bioactive phytochemical compounds and functional foods.

Combination of pH-controlled fermentation in mild acidic conditions and enzymatic hydrolysis by Savinase to improve metabolic health-promoting properties of lentil

This work evaluated the feasibility of pH-controlled fermentation by Lactobacillus plantarum CECT 748 combined with Savinase-hydrolysis (LPHS) for producing multifunctional lentil ingredients targeted for metabolic syndrome (MetS) relieving. LPHS process was compared with L. plantarum-fermentation (LP) and Savinase-hydrolysis (HS), applied separately. LPHS soluble fraction exhibited higher peptides, p-hydroxybenzoic acid, flavonols, antioxidant (400.74 mM TE/g), angiotensin I-converting enzyme (ACE) (95.43%) and α-glucosidase-inhibitory activities (40.55 and 25.03% for maltase and sacarase activities, respectively) than LP and HS. L. plantarum was responsible for the phenolic profile changes and sucrase inhibitory activity of LPHS while Savinase contributed to peptides release and ACE and maltase inhibitory and antioxidant activities. The most active LPHS fraction contained 3 peptides with potential biological activity and flavonoids and phenolic acids. LPHS simulated gastrointestinal digestion enhanced its peptides, phenolics, ACE-inhibitory and antioxidant activities. This study opens new opportunities regarding the production of lentil-multifunctional ingredients for MetS management.

Calorie Restriction Effect of Heat-Processed Onion Extract (ONI) Using In Vitro and In Vivo Animal Models.

Onion (Allium cepa L.) is widely consumed as food or medicinal plant due to its well-defined health benefits. The antioxidant and antihyperlipidemic effects of onion and its extracts have been reported well. However, very limited information on anti-hyperglycemic effect is available in processed onion extracts. In our previous study, we reported that Amadori rearrangement compounds (ARCs) produced by heat-processing in Korean ginseng can reduce carbohydrate absorption by inhibiting intestinal carbohydrate hydrolyzing enzymes in both in vitro and in vivo animal models. To prove the enhancement of anti-hyperglycemic effect and ARCs content by heat-processing in onion extract, a correlation between the anti-hyperglycemic activity and the total content of ARCs of heat-processed onion extract (ONI) was investigated. ONI has a high content of ARCs and had high rat small intestinal sucrase inhibitory activity (0.34 ± 0.03 mg/mL, IC50) relevant for the potential management of postprandial hyperglycemia. The effect of ONI on the postprandial blood glucose increase was investigated in Sprague Dawley (SD) rats fed on sucrose or starch meals. The maximum blood glucose levels (Cmax) of heat-processed onion extract were significantly decreased by about 8.7% (from 188.60 ± 5.37 to 172.27 ± 3.96, p < 0.001) and 14.2% (from 204.04 ± 8.73 to 175.13 ± 14.09, p < 0.01) in sucrose and starch loading tests, respectively. These results indicate that ARCs in onion extract produced by heat-processing have anti-diabetic effect by suppressing carbohydrate absorption via inhibition of intestinal sucrase, thereby reducing the postprandial increase of blood glucose. Therefore, enhancement of ARCs in onion by heat-processing might be a good strategy for the development of the new product on the management of hyperglycemia.

Rat intestinal sucrase inhibited by minor constituents from the leaves and twigs of Archidendron clypearia (Jack.) Nielsen

In the search for plants, containing compounds with α-glucosidase inhibitory activity, we found that a methanolic extract from the leaves and twigs of Archidendron clypearia (Jack.) Nielsen significantly inhibited rat intestinal sucrase in vitro. A phytochemical investigation of the aqueous layer of an A. clypearia extract led to the isolation of 14 compounds (1–14). Their structures were established through extensive 1D and 2D NMR, CD data, and MS analysis. The methanolic extract, as well as the water layer at a concentration of 3.0mg/mL, showed potent sucrase inhibitory activity, with 67.78±2.53% and 95.33±2.15% inhibition, respectively. In addition, compounds 6, 7, and 10 (1.0mM) showed potent sucrase inhibition (88.36±1.15%, 81.57±1.07%, and 66.32±4.73% inhibition, respectively), which was comparable to that of the positive control, acarbose, which exhibited 89.54±0.91% inhibition. Other compounds showed moderate or weak inhibitory activity at the same concentration. The sucrase inhibitory activity of the extracts and purified compounds may provide a novel opportunity to develop a new class of antidiabetic agents.

In vivo maltase and sucrase inhibitory activities of five underutilized Nigerian edible fruits

BACKGROUND: Inhibition of intestinal maltase and sucrase prevents postprandial blood glucose excursions which is beneficial in ameliorating diabetes-associated complications. OBJECTIVE: In this study, the inhibitory effects of fruit extracts of Parinari macrophylla, Detarium microcarpum, Ziziphus spina-christi, Z. mairei and Parkia biglobosa were investigated against intestinal maltase and sucrase. METHODS: Rats were given co-administration of the fruit extracts with maltose or sucrose and blood glucose levels were measured at 0, 30, 90 and 120 min. RESULTS: The glucose-time curves indicated that all the fruits had the most potent inhibitory effects on both maltase and sucrase within the first 30 min. The computed Area Under the Curves (AUC0–120) for all the fruits indicated more potent inhibitory effects against intestinal maltase than sucrase. The ED50 range for the fruits extract against maltase and sucrase were 647.15–1118.35 and 942.44–1851.94 mg/kg bw respectively. CONCLUSION: The data suggests that the fruits could prevent postprandial hyperglycemia via inhibition of intestinal maltase and sucrase.

Blueberry extract inhibits carbohydrate-hydrolyzing enzymes and these inhibitory activities are not proanthocyanidin dependent

This study investigates the carbohydrate-hydrolyzing inhibitory potential of blueberry extract on carbohydrate-hydrolyzing enzymes and evaluates if the inhibitory activity is proanthocyanidin (PAC) or lower molecular weight phenolic dependent. Freeze-dried blueberry powder was extracted using acetone and subjected to C18 extraction (BAE). Low-molecular weight phenolics (BAE-LMW) and PACs (BAE-PAC) were separated from BAE with gel filtration chromatography using LH-20 column. Total phenolic content, PAC content, and phenolic profiles using HPLC, as well as rat α-glucosidase, sucrase, and maltase inhibitory activities, were determined for all samples. The rat alpha-glucosidase inhibitory activity of BAE (IC50 0.390 mg/mL TP basis) was enhanced in BAE-LMW (IC50 0.242 mg/mL TP basis) and reduced in BAE-PAC (IC50 0.915 mg/mL TP basis). Similar trends were observed with maltase and sucrase inhibitory activities. Our findings suggest that blueberry acetone extract has inhibitory activity on carbohydrate-hydrolyzing enzymes and this effect is dependent on LMWs rather than PAC.

Triterpenoid saponins from the roots of Rosa rugosa Thunb. as rat intestinal sucrase inhibitors.

Medicinal plants constitute an important source of potential therapeutic agents for diabetes. The purpose of present study is to investigate the effect of root extract of Rosa rugosa Thunb. on inhibition of sucrase related to diabetes mellitus (DM). Bioassay-guided fractionation of the methanol extract led to the identification of 13 triterpenoid saponins (1-13). Their structures were elucidated on the basis of extensive spectroscopic analysis, including 1D, 2D NMR, and MS. The n-butanol fraction showed potent rat intestinal sucrase inhibitory activity with value of 87.62±5.84% inhibition compared to the positive control acarbose (50.96±2.97% inhibition at 0.02mM). Subsequently, compounds 11-13 (1.0mM) exhibited significant sucrase inhibitory activity, with inhibition percentage values of 41.17±3.52, 46.80±4.00, and 39.39±4.19%, respectively. Whereas, compounds 2-6, 8, and 10 showed moderate sucrase inhibitory activity (ranging from 13.26±7.00 to 32.08±6.04% inhibition) at a same concentration. The data provide a starting point for creating new sucrase inhibitors, which may be useful for the development of effective therapies for the treatment of DM.

Evaluation of the In vitro Anti-hyperglycemic Effect of Cinnamomum cassia Derived Phenolic Phytochemicals, via Carbohydrate Hydrolyzing Enzyme Inhibition

Cinnamomum cassia (cinnamon) proanthocyanidins (PACs) are believed to have anti-hyperglycemic potential via stimulation of insulin sensitivity. The present study investigates the carbohydrate hydrolyzing enzyme inhibition of cinnamon PACs. Five grams of cinnamon bark powder were extracted in 100 mL acetone solution (CAE) (acetone: water: hydrochloric acid, 70:29.9:0.01) for 2 h at room temperature and in 100 mL deionized water for 30 min at 90 °C (CWE). PACs were purified from CAE using LH-20 (CAE-PAC) to be further evaluated. PAC contents were evaluated by 4-Dimethylaminocinnamaldehyde (DMAC) assay and yielded 795, 177 and 123 mg/g, for CAE-PAC, CAE and CWE respectively. The total phenolic contents of CAE and CWE were determined to be 152 and 134 mg/g respectively. All extracts were adjusted to the same PAC content (180, 90, 45 and 20 μg) and the inhibitory activity against rat α-glucosidase was determined. The CAE-PAC fraction had very low rat α-glucosidase inhibitory activity, CAE had the highest (IC50 0.474 mg/mL total phenolic (TP) basis) followed by CWE (IC50 0.697 mg/mL TP basis). The specific maltase and sucrase inhibitory activities were determined and CAE (IC50 0.38 and 0.10 mg/mL TP basis) had higher inhibition than CWE (IC50 0.74 and 0.37 mg/mL TP basis). Results suggest that the observed bioactivity is not PAC dependent and that CAE has a higher anti-hyperglycemic potential than CWE via inhibition of carbohydrate hydrolyzing enzymes.

Anti‐hyperglycemic effect of selected sugar alcohols (829.32)

In this study, we estimated the anti‐hyperglycemic effect of the most widely used seven sugar alcohols including xylitol, erythritol, maltitol, isomalt, mannitol, sorbitol, and inositol. Sugar alcohols, also known as polyols, are considered as sugar substitutes because they are contain low calories and some sugar alcohols do not raise blood glucose. However, there are few studies on the anti‐hyperglycemic activity of sugar alcohols. Therefore, we investigated inhibitory activity of sugar alcohols against rat intestinal α‐glucosidase, porcine pancreatic α‐amylase, and sucrase using in‐vitro. We also examined phenolic‐linked antioxidant activity, oxygen radical absorbance capacity (ORAC) to evaluate antioxidant activity of sugar alcohols. Among seven sugar alcohols xylitol had the highest α‐glucosidase inhibitory activity and maltitol had the highest sucrase inhibitory activity. These result indicated that some sugar alcohols exhibit considerable anti‐hyperglycemic activity with inhibitory activity about carbohydrate absorption‐linked enzymes such as α‐glucosidase and sucrase.

In vitro determination of bioactive fraction of blueberry for type 2 diabetes prevention (647.17)

The present study investigates the carbohydrate hydrolysis enzyme inhibitory activity of blueberries and if this activity is proanthocaynidin (PAC) or low molecular weight phenolic (LMP) dependent. Freeze‐dried blueberry powder was extracted using 70% acetone solution (BAE) and in deionized water (BWE). Sugars were removed from both extracts using C18 cartridges. BAE resulted to higher PAC and total phenolic content (TPC), so BAE was used for the remaining experiment. LMP and PAC were separated from BAE using a LH‐20 column by washing using 30%methanol solution (LMP recovery) and eluting using 70% acetone solution (PAC recovery). PAC contents were determined as 0.86 mg/mL, 0.56 mg/g, 0.11 mg/g and 0.61 mg/mL for BAE, BWE, LMP and PAC, respectively. The TPC of BAE, BWE, LMP and PAC were determined to be 3.88 mg/mL, 2.64 mg/mL, 1.90 mg/mL and 1.85 mg/mL, respectively. Evaluation of rat α‐glucosidase inhibitory activity, revealed that LMP (IC50 0.24 mg/mL TPC basis) had the highest inhibitory activity followed by BAE (IC50 0.39 mg/mL TPC basis), PAC (IC50 0.92 mg/mL TPC basis). Evaluation of specific maltase and sucrase inhibitory activities confirmed same trend as with observed rat α‐glucosidase inhibitory activities (LMP&gt;BAE&gt;PAC). Our findings suggest that blueberry extract has α‐glucosidase inhibitory activity, which is low molecular weight phenolic dependent.Grant Funding Source: Supported by US Army Natick Soldier Research Engineering Center

Rat intestinal sucrase inhibition of constituents from the roots of Rosa rugosa Thunb.

A new octanordammarane triterpene, 3β,15α-dihydroxymansumbinol (1) and a novel A-ring contracted oleanane triterpenoid, 2-formyl-(A)1–19α-hydroxy-1-norolean-2,12-dien-28-oic acid (2) were isolated from the roots extract of Rosa rugosa along with fifteen known compounds (3–17). Their structures were elucidated by extensive spectroscopic analysis, including 1D and 2D NMR, and FTICRMS. The MeOH extract, as well as CH2Cl2 and EtOAc fractions at a concentration of 0.5mg/mL showed potent sucrase inhibitory activity, with inhibition percentage values of 84.67±5.37%, 87.50±2.78%, and 81.91±2.90%, respectively. In addition, compounds 7–13 (1.0mM) showed potent sucrase inhibitory activity (61.88±3.19% to 84.70±3.07% inhibition), which was comparable to that of the positive control, acarbose, with an inhibition percentage value of 50.96±2.97%. Compounds 1, 2, 4, and 14–17 showed moderate and/or weak inhibitory activities at the same concentration. The α-glucosidase inhibitory activities of the extracts and purified compounds may provide a novel opportunity to develop a new class of antidiabetic agents.

Enhanced antioxidant and antidiabetic activities of barley and wheat after soaking with tea catechin

Barley and wheat were investigated as natural α-glucosidase inhibitors having potent inhibitory activities against the antidiabetic enzymes α-glucosidase, maltase, and sucrase. After soaking with tea catechin as an elicitor, extracts of barley and wheat were prepared using thermal treatment in an autoclave at 121°C for 15 min, then the in vitro antioxidant and antidiabetic activities were determined. The total soluble phenolics contents of barley and wheat during soaking were increased by addition of tea catechin, which also contributed to the peroxyl radical-scavenging activity and the reducing capacity. The rat α-glucosidase, maltase, and sucrase inhibitory activities of barley were increased with an increase in the added tea catechin concentration from 0.1% to 0.5%. Tea catechin may have a role as an elicitor for production of phenolics that exhibit antioxidant activities and rat-intestinal maltase and sucrase inhibitory activities during the soaking process of barley and wheat.

Evaluation of in vitro anti‐hyperglycemic effect of Cinnamon cassia derived phenolic phytochemicals

Cinnamon cassia (Cinnamon) proanthocyanidins (PACs) are shown to have anti‐hyperglycemia potential. The present study investigates the carbohydrate hydrolysis enzyme inhibition of cinnamon PACs. Five grams of cinnamon bark powder were extracted in 100 mL acetone solution (CAE) (acetone: water: hydrochloric acid, 70:29.9:0.01) for 2 hours at room temperature and in 100 mL deionized water for 30 min at 90 □ (CWE). PACs were purified from CAE using LH‐20 (CAE‐PAC) to be further evaluated. PAC contents were evaluated by 4‐ Dimethylaminocinnamaldehyde (DMAC) assay and yielded 795, 177 and 123 mg/g, for CAE‐PAC, CAE and CWE respectively. The total phenolic contents of CAE and CWE were determined to be 152 and 134 mg/g respectively. All extracts were adjusted to the same PAC content (180, 90, 45 and 20 μg) and the inhibitory activity against rat α‐glucosidase was determined. The CAE‐PAC fraction had very low rat α‐glucosidase inhibitory activity, CAE had the highest (IC50 3.13 mg/mL DW) followed by CWE (IC50 5.21 mg/mL DW). The specific maltase and sucrase inhibitory activities were determined and CAE (IC50 2.47 and 0.63 mg/mL DW) had higher inhibition than CWE (IC50 5.56 and 2.79 mg/mL DW). Results suggest that the observed bioactivity is not PAC dependent and that CAE has higher anti‐hyperglycemic potential than CWE via inhibition of carbohydrate hydrolysis enzymes.This research was supported by US Army Natick Soldier Research Engineering Center

Chemical Constituents of the Aerial Parts of Scutellaria lateriflora and their α-Glucosidase Inhibitory Activities

MeOH extracts of 37 herbs were tested in screening experiments for rat intestinal alpha-glucosidase. The MeOH extract of the aerial parts of Scutellaria lateriflora L. (Lamiaceae) significantly inhibited sucrase and maltase activities, using sucrose and maltase as the substrates. Enzyme inhibition guided-fractionation of the MeOH extract of S. lateriflora resulted in the isolation of a new diterpene glucoside, deacetylajugarin-IV 18-O-beta-D-glucopyranoside (1), along with 20 known phenolics (2-21). The structures of 1-21 were elucidated on the basis of MS and NMR data analyses. Baicalein (4) and baicalin (10), a glycoside of 4, showed moderate sucrase inhibitory activities at IC50 values of 14.9 and 36.3 microM, respectively, whereas luteolin (3), acteoside (16), leucosceptoside A (18), and isoacteoside (20) showed weak inhibitory activities at IC50 values of 811, 522, 727, and 443 microM, respectively. This is the first report on mammalian alpha-glucosidase inhibitory activities of S. lateriflora extract and identification of the constituents responsible for the activities. Apigenin (2), luteolin (3), 6-methoxyluteolin 4'-methyl ether (6), isoscutellarin 8-O-beta-D-glucuronide (7), luteolin 7-O-beta-D-glucuronide (9), wogonin 7-O-beta-D-glucuronide methyl ester (12), eriodictyol (13), naringenin (14), naringenin 7-O-beta-D-glucuronide (15), jionoside D (17), leucosceptoside A (18), and (+)-syringaresinol 4'-O-beta-D-glucopyranoside (21) were isolated from this plant for the first time. The inhibitory properties of S. lateriflora extract against alpha-glucosidase provide a prospect for its antidiabetic usage.