Α-glucosidase Inhibitory Activities Of Extracts Research Articles

Anti-Inflammatory, Antidiabetic, and Antioxidant Properties of Extracts Prepared from Pinot Noir Grape Marc, Free and Incorporated in Porous Silica-Based Supports.

This study presents properties of hydroethanolic extracts prepared from Pinot Noir (PN) grape pomace through conventional, ultrasound-assisted or solvothermal extraction. The components of the extracts were identified by HPLC. The total content of polyphenols, flavonoids, anthocyanins, and condensed tannins, as well as antioxidant activity and α-glucosidase inhibitory activity of extracts were evaluated using UV-vis spectroscopy. All extracts were rich in phenolic compounds, proving a good radical scavenging activity. The extract obtained by conventional extraction at 80 °C showed the best α-glucosidase inhibitory activity close to that of (-)-epigallocatechin gallate. To improve the chemical stability of polyphenols, the chosen extract was incorporated in porous silica-based supports: amine functionalized silica (MCM-NH2), fucoidan-coated amine functionalized silica (MCM-NH2-Fuc), MCM-41, and diatomite. The PN extract exhibited moderate activity against Gram-positive S. aureus (MIC = 156.25 μg/mL) better than against Gram-negative E. coli (MIC = 312.5 μg/mL). The biocompatibility of PN extract, free and incorporated in MCM-NH2 and MCM-NH2-Fuc, was assessed on RAW 264.7 mouse macrophage cells, and the samples showcased a good cytocompatibility at 10 µg/mL concentration. At this concentration, PN and PN@MCM-NH2-Fuc reduced the inflammation by inhibiting NO production. The anti-inflammatory potential against COX and LOX enzymes of selected samples was evaluated and compared with that of Indomethacin and Zileuton, respectively. The best anti-inflammatory activity was observed when PN extract was loaded on MCM-NH2-Fuc support.

Phenolic Composition, Antioxidant, and α-Glucosidase Inhibitory Activities of Extracts from Polygonatum sibiricum

As a traditional Chinese medicine and functional food, Polygonatum sibiricum contains many bioactive compounds with multiple biological activities. Presently, we obtained three extracts from Polygonatum sibiricum by different solvents and comparably analyzed their total phenols, flavonoids, and chemical compositions. Meanwhile, the antioxidant activity and the attenuation of palmitic acid (PA)-induced hepatic oxidative stress of these extracts were further investigated. The results showed that the active substances in Polygonatum sibiricum were inclined to dissolve in ethanol (EE), and twenty compounds were identified. EE exhibited the best antioxidant activity to scavenging DPPH and ABTS free radicals, as well as reducing power. Meanwhile, extracts from Polygonatum sibiricum, especially EE, could significantly increase the activity of SOD and HO-1 and ameliorate PA-induced oxidative stress in HepG2 cells through Nrf2-related pathways. Furthermore, EE could significantly inhibit the activity of α-glucosidase and effectively reduce the rapid rise of blood glucose induced by sucrose loading.

In vitro α-glucosidase inhibitory activity of medicinal plants used traditionally for treating diabetes in Vhembe District, South Africa

Introduction: α-Glucosidase is the major enzyme implicated in intestinal glucose absorption, and its inhibition is a target for the management of diabetes mellitus. This study investigated the in vitro α-glucosidase inhibitory activity of extracts from different parts of 20 selected medicinal plants and the potential for plant-part substitution and plant species combinations used by traditional healers to treat diabetes. Methods: Acetone and petroleum ether extracts from different parts of 20 plant species traditionally used to treat diabetes were individually evaluated in vitro using an α-glucosidase assay. The potential for plant-part substitution was investigated by including leaf extracts where non-renewable parts are used traditionally. The extracts of plant species were combined and investigated as used traditionally. Results: Anthocleista grandiflora stem bark acetone, Artabotrys brachypetalus leaf petroleum ether, and Dichrostachys cinerea root petroleum ether extracts exhibited remarkable α-glucosidase inhibitory activities with IC50 values of 9, 14, and 12 μg/mL, respectively. The α-glucosidase inhibitory activities of A. grandiflora, A. brachypetalus, Asparagus virgatus, Brackenridgea zanguebarica, Maerua edulis, Pterocarpus angolensis, and Tabernaemontana elegans were documented for the first time, suggesting their antidiabetic potential. The leaf acetone extracts of Brackenridgea zanguebarica and Terminalia sericea had similar α-glucosidase inhibitory activities when compared to their stem bark and root, respectively. The combination of Dichrostachys cinerea leaf with Elephantorrhiza elephantina root, extracted with petroleum ether, resulted in a synergistic inhibitory effect. Conclusion: The valorization of these newly documented species holds potential for the discovery of more effective and perhaps novel antidiabetic remedies or drug principles.

α-glucosidase Inhibitory Activity of Extracts and Compounds from the Leaves of Ruellia tuberosa L.

Background: In recent years, the study of the structure and biological activity of medicinal plants has been particularly important to search for diabetes medicine. Ruellia tuberosa is used to treat various diseases such as diabetes by inhibiting the activity of α-glucosidase. Objective: In this study, an experiment was designed to isolatedisolate and identifiedidentifyα-glucosidase inhibitory extracts and compounds from Ruellia tuberosa L. through bio-assay guided isolation. Method: Dry powder of Ruellia tuberosa L. was extracted with 70% ethanol, followed by liquidliquid partition with n-hexane, ethyl acetate and butanol, respectively. The extracts were evaluated withα-glucosidase inhibition. The potential extracts were isolated to identifynew compounds. The effects of these compounds on the α-glucosidase inhibitory were evaluated. Results: The a-glucosidase inhibitory activities showed that the n-hexane, ethyl acetate and the butanol extract had the α-glucosidase inhibition with an IC50 of 46.2 ± 0.9, 6.6 ± 2.9 and 8.9 ± 0.9 μg/mL, respectively. From the n-hexane and ethyl acetate extracts, the structures of four compounds were elucidated by NMR spectroscopic method, including lupeol (1), syringaresinol (2), apigenin (3), verbascoside (4). The a-glucosidase inhibitory activities showed that all isolated compounds were more active than the positive control - acarbose with an IC50 of 37.5 ± 0.4; 19.5 ± 0.2; 20.1 ± 0.3; 69.3 ± 0.2 μg/mL, respectively. Conclusion: The ethyl acetate extract showed strong activity about 19 times more than the positive control - acarbose. The compound syringaresinol (2) was the most powerful α-glucosidase inhibitor. Therefore, Ruellia tuberosa L. contains many compounds that can inhibit α-glucosidase activity.

Alpha amylase and alpha glucosidase inhibitory activities of extracts of Dialium guineense stem bark

Background: Dialium guineense belongs to the Leguminosae family, and grows in dense forests in Africa along the southern edge of the Sahel. The bark, leaves and fruits of the plant have medicinal properties and are used to treat diseases such as stomatitis, toothache, fever, diarrhoea, palpitations, and microbial infections. Aim: The present study investigated the α-amylase and α-glucosidase inhibitory activities of extracts of Dialium guineense stem bark. Methods:Aqueous and ethanol extracts of D. guineense stem bark were prepared using standard method. Alpha amylase and alpha glucosidase inhibitory activities of the extracts were determined in vitro. Acarbose was used as the reference drug. Results: The results showed that both extracts of Dialium guineense possess α-amylase and α-glucosidase inhibitory activities. The aqueous extract (IC50 = 76.55 ± 3.01 µg/mL) showed a better α-amylase inhibitory activity when compared with the ethanol extract (IC50 = 137.78 ± 5.18 µg/mL) (p < 0.05), but there was no significant difference in the corresponding α-glucosidase inhibitory activity between the two extracts (p > 0.05). The α-amylase and α-glucosidase inhibitory activities of the extracts were concentration-dependent, and comparable to those of acarbose. Conclusion: The results of this study indicate that Dialium guineense shows great potential in the treatment of Diabetes mellitus.

The Influence of Solvent, Host, and Phenological Stage on the Yield, Chemical Composition, and Antidiabetic and Antioxidant Properties of Phragmanthera capitata (Sprengel) S. Balle.

Phragmanthera capitata was reported to possess many biological properties making it a good candidate for the formulation of a phytomedicine with multiple effects. In this work, we studied some factors likely to modify these therapeutic properties with the aim to contribute to its standardization as an improved traditional medicine. P. capitata parasitizing Persea americana, Psidium guajava, and Podocarpus mannii were harvested at three phenological stages (vegetative, flowering, and fruiting stages). The extracts were prepared by maceration in n-hexane, ethyl acetate, ethanol, methanol, and distilled water. The total phenolic, flavonoid, flavonol, and tannin contents were measured using appropriate methods. The antioxidant potential of extracts was investigated using TAC, DPPH scavenging, and FRAP methods. The α-amylase and α-glucosidase inhibitory activities of extracts were determined using enzymatic methods. The ethyl acetate extracts with the best phenolic content were subjected to HPLC analysis. The extraction yields were higher with methanol. The ethyl acetate extract of P. capitata harvested from P. guajava showed a stable HPLC profile during the development of the plant, while extracts from the plant collected from P. americana and P. mannii showed both qualitative and quantitative variations according to phonological stages of the plant. The inhibition of α-amylase was more pronounced for P. capitata harvested from P. guajava, decreasing during flowering and fruiting, while inhibition of α-glucosidase was not influenced by the phenological stage and the host of the plant. The α-amylase inhibitors were better extracted by ethyl acetate and those of α-glucosidase by ethanol or methanol. The phenolic contents and antioxidant properties of the extracts were influenced by the phenological stage of P. capitata and its hosts. These results suggest that it is preferable to harvest P. capitata during flowering or during fruiting stages on any host. None of the used solvents permitted an optimal extraction of active principles form P. capitata, suggesting that the mixture of solvents must be considered in further studies.

In vitro α-Amylase and α-Glucosidase inhibitory activity of extracts of Feronia elephantum fruit and Paspalum scrobiculatum Grains.

In vitro α-Amylase and α-Glucosidase inhibitory activity of extracts of Feronia elephantum fruit and Paspalum scrobiculatum Grains.

Cytotoxic activities against MCF-7 and MDA-MB-231, antioxidant and α-glucosidase inhibitory activities of Trachelospermum jasminoides extracts in vitro

The present study investigated the cytotoxic activities against MCF-7 and MDA-MB-231 cells, and the potential antioxidant and α-glucosidase inhibitory activities of the extracts of the aerial parts of Trachelospermum jasminoides, a traditional medicinal plant used for the treatment of rheumatic arthralgia in China. In MTT assay and microscopic analysis, the ethyl acetate extract (EAE) of T. jasminoides showed moderate cytotoxic effect against MCF-7 and MDA-MB-231 with IC50 values of 109.54 ± 2.39 μg/mL and 162.68 ± 9.52 μg/mL, respectively, but the water extract (WE) was inactive against both of them. With gallic acid and rutine as equivalents for determination, the total phenolic and total flavonoid contents in the EAE (54.93 ± 0.32 mg GAE/g and 186.75 ± 4.55 mg RE/g, respectively) were higher than those of the WE. The antioxidant activities of the EAE and WE, which were evaluated by reducing power assay, DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay and hydroxyl radical scavenging assay, may be directly associated with the high contents of phenols and flavonoids in T. jasminoides. The EAE showed higher inhibitory effect in the α-glucosidase inhibition tests with an IC50 value of 776.81 ± 107.80 μg/mL as compared to the WE with 2607.48 ± 364.31 μg/mL. Furthermore, the antioxidant activity and the inhibitory effects of the fractions against α-glucosidase were concentration-dependent.

Alpha-Glucosidase Inhibitory Activity in Different Pepper Cultivars (Capsicum annuum L.)

The number of cases of type II diabetes has increased dramatically worldwide. Plant-based foods offer some options for treating this disease. Effective diabetes prevention is achieved by controlling postprandial hyperglycemia by α-glucosidase inhibition. This study investigated the α-glucosidase inhibitory activity of extracts of 14 cultivars of pepper fruits (Capsicum annuum L.), which are widely consumed in Korea. Pepper fruit extracts were prepared with 70% ethanol and water, and diluted to 50% and 25% strengths before performing an α-glucosidase inhibition assay. No significant differences in α-glucosidase inhibitory activity were found between the two different aqueous extracts. Mee-In and Dda-Go-Ddo-Dda-Go cultivars had the highest and most sustained inhibitory activity (almost 100%) against α-glucosidase. In contrast, while extracts from Soon- Han-Gil-Sang, Gil-Sang, Sweety, Hyul-Jo K, Shin-Hong, and Ai-Mat inhibited α-glucosidase activity, the level of inhibition sharply decreased with decreasing extract concentrations between 100% and 50%. The results of this study suggest the possible existence of unknown inhibitors that are present at different concentrations in different pepper cultivars. Further studies are required to identify the unknown enzymes that are key to α-glucosidase inhibition in pepper fruits.

α-Glucosidase inhibitory activity of extracts from Cordia morelosana

α-Glucosidase inhibitory activity of extracts from Cordia morelosana

In vitro α-amylase and α-glucosidase inhibitory activity of extracts and compounds from cultivated Artemisia dracunculus

In vitro α-amylase and α-glucosidase inhibitory activity of extracts and compounds from cultivated Artemisia dracunculus

Invitro Antidiabetic Activities of Agar, Agarosa, and Agaropectin from Gracilaria gigas Seaweed

&lt;p&gt;Some types of seaweed are reported to have antidiabet activity in vivo or in vitro,&lt;br /&gt;but the activity antidiabet fractions of polysaccharides from seaweed has not been widely&lt;br /&gt;reported. Gracilaria gigas is one type of red seaweed that can produce agar and it has two&lt;br /&gt;factions, namely agarose and agaropectin. The aim of this study was to obtain an agar&lt;br /&gt;extract, agarose fraction, agaropektin fraction of Gracilaria gigas and to determine the&lt;br /&gt;α-glucosidase inhibitory activity of extracts and the fractions. Extraction of agar that used&lt;br /&gt;an ethanol solution, and to fractionate agarose and agaropektin used dimetilsulfoxide&lt;br /&gt;solution. The results showed that the fraction of the agarose having lower sulfate content&lt;br /&gt;(0.28%) compared with agar (5.91%) and agaropektin (6.07%). Types of samples (agar,&lt;br /&gt;agarose, and agaropektin) and sample doses significantly in inhibiting α-glucosidase&lt;br /&gt;enzyme activity. Agarose fraction has IC50 value against α-glucosidase lowest (96.86 ± 4.61&lt;br /&gt;ppm), followed by the extract agar (116.63 ± 5.61 ppm), then the fraction agaropektin&lt;br /&gt;(158.34 ± 1.77 ppm).&lt;br /&gt;Keywords: α-glucosidase, extract, fraction, Gracilaria gigas, IC50&lt;/p&gt;

AKTIVITAS ANTIDIABET SECARA INVITRO AGAR-AGAR, AGAROSA, DAN AGAROPEKTIN DARI RUMPUT LAUT Gracilaria gigas

Some types of seaweed are reported to have antidiabet activity in vivo or in vitro, but the activity antidiabet fractions of polysaccharides from seaweed has not been widely reported. Gracilaria gigas is one type of red seaweed that can produce agar and it has two factions, namely agarose and agaropectin. The aim of this study was to obtain an agar extract, agarose fraction, agaropektin fraction of Gracilaria gigas and to determine the α-glucosidase inhibitory activity of extracts and the fractions. Extraction of agar that used an ethanol solution, and to fractionate agarose and agaropektin used dimetilsulfoxide solution. The results showed that the fraction of the agarose having lower sulfate content (0.28%) compared with agar (5.91%) and agaropektin (6.07%). Types of samples (agar, agarose, and agaropektin) and sample doses significantly in inhibiting α-glucosidase enzyme activity. Agarose fraction has IC50 value against α-glucosidase lowest (96.86 ± 4.61 ppm), followed by the extract agar (116.63 ± 5.61 ppm), then the fraction agaropektin (158.34 ± 1.77 ppm). Keywords: α-glucosidase, extract, fraction, Gracilaria gigas, IC50

Antioxidant, antiproliferative, and α-glucosidase inhibitory activities of extracts from Impatiens textori Miq

Impatiens textori Miq is an annual plant used in traditional Chinese medicine to treat superficial infections and fingernail inflammation. In the present study, methanol extract and fractions of I. textori Miq were investigated for their antioxidant properties, α-glucosidase inhibitory activities, and antiproliferative activities against human gastric (AGS), human cervical (HeLa), human non-small lung (A549), and human colon adenocarcinoma (HT-29) cancer cell lines. Results showed that the ethyl-acetate fraction had high total phenolic and total flavonoid contents of 141.39 ± 1.54 mg GAE/g and 125.93 ± 7.60 mg QE/g, respectively, high 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity with an IC50 of 9.80 ± 0.08 μg/ml, and significant reducing power among all the extracts and fractions, suggesting that I. textori Miq is an exceptional source of natural antioxidants. In addition, the ethyl-acetate fraction possessed significant α-glucosidase inhibitory activity. The antiproliferative activity of the ethyl-acetate fraction was higher than that of the methanol extract and others fractions. These findings suggest the potential use of this plant as an antitumor agent. Key words: Impatiens textori Miq, antioxidant, 1,1-diphenyl-2-picrylhydrazyl (DPPH), reducing power, antitumor, α-glucosidase.

Quantitative analysis of neosalacinol and neokotalanol, another two potent α-glucosidase inhibitors from Salacia species, by LC-MS with ion pair chromatography

A quantitative analytical method for the highly polar sulfonium pseudo-sugar constituents neosalacinol (3) and neokotalanol (4), another two potent α-glucosidase inhibitors isolated from Ayurvedic traditional medicine Salacia species, was developed by employing an ion pair reagent upon chromatographic separation. The optimum conditions for separation and detection of these two constituents were achieved on an ODS column (3-µm particle size, 2.1-mm i.d.×100mm) with 5mM undecafluorohexanoic acid-MeOH (99:1, v/v) as the mobile phase and using MS equipped with an electrospray ionization source. More than ten samples of Salacia from different origins were analyzed, and the results indicated that the assay was reproducible and precise and could be readily utilized for evaluation of α-glucosidase inhibitory activity of Salacia species. By combining this assay with the quantitative analytical method previously developed for salacinol (1) and kotalanol (2), a more precise and strict evaluation of α-glucosidase inhibitory activities of extracts from Salacia species (R=0.959 for maltase and 0.795 for sucrase) was achieved.

Antioxidant activity and α-glucosidase inhibitory potential of onion (Allium cepa L.) extracts

In the current study, we evaluated total phenolics, phenolic profile, and oxygen radical absorbance capacity (ORAC) of onion (Allium cepa L.). The inhibitory activity of onion extracts against porcine pancreatic α-amylase and rat intestinal α-glucosidase was also investigated. Ethyl alcohol extract of onion skin had the highest α-glucosidase inhibitory activity, ORAC value and total phenolic content, followed by water extract of skin, ethyl alcohol extract of pulp, and water extract of pulp. The α-glucosidase inhibitory activity of the extracts was compared to selected specific phenolics detected in the extracts using high performance liquid chromatography (HPLC). Quercetin, a major phenolic compound in onion extract had high α-glucosidase inhibitiory activity. The α-glucosidase inhibitory activity of the onion extracts correlated to the phenolic content and antioxidant activity of the extracts. These results suggest that onion which has high quercetin content has the potential to contribute as a dietary supplement for controlling hyperglycemia and oxidative stress-linked diabetes complications.

구기자 추출물의 항비만 및 혈당강하 효과

구기자는 식용가능하고 제2형 당뇨병 합병증인 지방간분해, 고혈압 및 고혈당에 효능이 있다고 알려져 있다. 하지만 당 대사 및 지질 대사에 작용하는 정확한 기작에 대한 연구는 아직 미비하기에 탄수화물 소화효소인 α-amylase와 α-glucosidase의 저해활성 및 정상생쥐를 이용한 혈당강하 효과와 3T3-L1 adipocyte를 통하여 비만축적 억제효과를 보았다. 구기자 추출은 80% MeOH, 70% EtOH 및 열수추출하였으며 이들 중 α-amylase 50% 저해 활성(IC50)은 saliva α-amylase에서 acarbose, 80% MeOH, 70% EtOH, aqueous(7.04, 3.19, 3.20, 3.66 ㎎/mL), pacreas α-amylase acarbose, 80% MeOH, 70% EtOH, aqueous(10.97, 4.16, 3.07, 3.55 ㎎/mL)로 saliva α-amylase에선 acarbose보다 80% MeOH, 70% EtOH 추출물이 가장 낮은 농도에서 IC50값을 나타냈고 pacreas α-amylase에서는 70% EtOH 추출물이 가장 낮은 농도에서 IC??값을 나타냈다. 또한 10 ㎍/mL 농도에서 yeast α-glucosidase 활성저해 IC50값은 80% MeOH, 70% EtOH, aqueous(5.01, 4.98, 4.80 ㎍/mL)로 구기자 추출물 모두 acarbose(5.05)보다 우수한 IC50값을 나타냈다. 정상 생쥐에게 탄수화물 소화효소의 저해활성이 높은 70% EtOH추출물을 전분과 함께 경구투여 한 후 내당능을 측정한 결과, 전분과 함께 100, 200 ㎎/㎏ body weight를 경구투여한 경우, 대조군에 비해 투여 후 30, 60, 90, 120분에 혈당 증가가 낮았다. 또한 추출물을 100 ㎎보다 200 ㎎ 투여하였을 경우 대조군에 비해 각각 19% 및 40%씩 저하되었으며, 120분에는 대조군 수준이 되었다. 그리고 3T3-L1 adipocyte에서 비만축적 억제효과를 측정한 결과 70% EtOH 추출물 농도가 증가함에 따라 leptin, 중성지방 농도가 감소하였고 유리지방산 농도는 증가하였다. 이상의 연구 결과 구기자 추출물 중 70% EtOH는 acarbose보다 높은 α-glucosidase, α-amylase 저해활성을 나타냈으며, 정상생쥐를 통해 식후 혈당증가를 저하시키는 효과를 확인하였고 GLUT4 발현 역시 증가함을 확인했다. 이를 통해 구기자 추출물이 지방축적 억제와 인슐린 저항성 억제 및 혈당강하 기전을 확인하여 제2형 당뇨병 개선에 효과적인 것으로 판단, 추후 더 연구하여 보다 더 정확한 성분을 조사할 필요성이 있다고 사료된다.