Potential inhibition of glycation and free radical scavenging activities of purple sweet potato extracts / Potencial inibição da glicação e sequestro de radicais livres de extratos de batata doce roxa

Purple sweet potato (PSP) contains antioxidant compounds and it can be used to prevent oxidative damage to cellular components of human body. The research purpose is to find out the potential of PSP extract on inhibiting glycation process and free radicals scavenging activities. Purple sweet potato was extracted using ethanol 25, 50, and 75% (PSP25, PSP50, PSP75) and then it was analyzed for free radical scavenging activities and antiglycation in forming advanced glycation end products (AGEs) using spectrophotometric method. Then all the collected data were examined with one-way ANOVA (p<0.05). The results showed that PSP extract has antioxidant activities and antiglycation properties.Based on IC50 values, PSP75 extract has a lower IC50 value compared to PSP25 and PSP50 (P <0.05) and has better activity in scavenging DPPH, hydroxyl, and superoxide radicals. This potentiality was shown by the IC50 value of each PSP extract. The value of IC50 of scavenging DPPH radical acitivity for PSP25, PSP50, PSP75 extracts was respectively 281.08, 254.94, and 241.30 µg/mL. The value of IC50 scavenging hydroxyl radicals was respectively 1.03, 088, and 0,79 mg/mL, and the IC50 value of scavenging radicals of superoxide anion was respectively 1.10, 0.97, and 0.82 mg/mL. The absorbance value of PSP75 in the BNT test and Fluorescence intensity are lower than PSP25 and PSP50, so that PSP75 extract is better at inhibiting glycation reaction.It can be concluded that the PSP extract has the potential in the inhibition of the glycation reaction and in the activity of elimination of free radicals (DPPH, hydroxyl, and superoxide radicals).

Batata-doce roxa (PSP) contém compostos antioxidantes e pode ser usada para prevenir o dano oxidativo aos componentes celulares do corpo humano. O objetivo da pesquisa é descobrir o potencial do extrato de PSP na inibição do processo de glicação e atividades de eliminação de radicais livres. A batata-doce roxa foi extraída usando etanol 25, 50 e 75% (PSP25, PSP50, PSP75) e, em seguida, foi analisada quanto a atividades de eliminação de radicais livres e antiglicação na formação de produtos finais de glicação avançada (AGEs) usando método espectrofotométrico. Em seguida, todos os dados coletados foram examinados com uma análise de variância simples (one-way ANOVA) (p <0,05). Os resultados mostraram que o extrato de PSP possui atividade antioxidante e propriedades antiglicantes. O extrato de PSP75 apresentou a maior atividade de eliminação dos radicais DPPH, hidroxila e superóxido significativamente maiores (P <0,05) que os extratos PSP25 e PSP50. Esta potencialidade foi demonstrada pelo valor de IC50 de cada extrato de PSP. O valor de IC50 da atividade de eliminação do radical DPPH para os extractos PSP25, PSP50, PSP75 foi respectivamente de 281,08, 254,94 e 241,30 g/mL. O valor IC50 dos sequestrantes dos radicais hidroxila foi, respectivamente, de 1,03, 088 e 0,79 mg/mL, e o valor de IC50 dos radicais sequestrantes do superóxido foi, respectivamente, 1,10, 0,97 e 0,82 mg/mL. Como antiglicante, o extrato de PSP75 tem uma capacidade melhor do que PSP25 e PSP50 em inibir produtos de AGEs. Pode-se concluir que o extrato etanólico PSP75 possui alta atividade antioxidante e potencial como antiglicante.

Antioxidant and antiglycation properties of two mango (Mangifera indica L.) cultivars from Senegal

Objective: To evaluate the total phenolic contents, antioxidant and antiglycation activities of leaves, barks, roots and kernels from two cultivars of Mangifera indica (Anacardiaceae). Methods: Total phenolic contents were determined by using Folin-Ciocalteu's method. The antioxidant activities were assessed by three different protocols including DPPH, oxygen radical absorbance capacity and iron (II) chelation assays. In addition, in vitro bovine serum albumin/D-ribose assay was chosen to evaluate the antiglycation properties of the extracts. Results: All the investigated extracts were found to contain high level of total phenols as well as potent antioxidant activities. Kernel extracts showed the highest total phenol contents and DPPH radical scavenging activities whereas higher oxygen radical absorbance capacity values were observed for leave, root and bark extracts. Besides, extracts from leaves, roots and barks from both cultivars exhibited potent inhibitory effects against the formation of advanced glycation end products, with IC

Antioxidant and antiglycation properties of two mango (Mangifera indica L.) cultivars from Senegal

Objective:To evaluate the total phenolic contents,antioxidant and antigiycation activities of leaves,barks,roots and kernels from two cultiivars of Mangifera indica (Anacardiiaceae).Method:Total phenolic contents were determined by using Folin-Ciocalteu's method.The antioxidant activities were assessed by three different protocols including DPPH,oxygen radical absorbance capacity and iron (Ⅱ) chelation assays.In addition,in vitro bovine serum albumin/D-ribose assay was chosen to evaluate the antiglycation properties of the extracts.Results:All the investigated extracts were found to contain high level of total phenols as well as potent antioxidant activities.Kernel extracts showed the highest total phenol contents and DPPH radical scavenging activities whereas higher oxygen radical absorbance capacity values were observed for leave,root and bark extracts.Besides,extracts from leaves,roots and barks from both cultivars exhibited potent inhibitory effects against the formation of advanced glycation end products,with IC50 values lower than the standard positive control aminoguanidine.Conclusions:The potent antigiycation and antioxidative activities of these two Mangifera indica cultivars suggest a possible role in targeting aging,diabetic complications and oxidative stress related diseases.

Evaluation of in vitro antioxidant, antiglycation and antimicrobial potential of indigenous Myanmar medicinal plants / 中西医结合学报

<p><b>OBJECTIVE</b>Myanmar has a long history of using medicinal plants for treatment of various diseases. To the best of our knowledge there are no previous reports on antiglycation activities of medicinal plants from Myanmar. Therefore, this study was aimed to evaluate the antioxidant, antiglycation and antimicrobial properties of 20 ethanolic extracts from 17 medicinal plants indigenous to Myanmar.</p><p><b>METHODS</b>In vitro scavenging assays of 2,2-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide (NO), superoxide (SO) radicals were used to determine the antioxidant activities. Folin-Ciocalteu's method was performed to determine the total phenolic content. Antiglycation and antimicrobial activities were detected by bovine serum albumin-fluorescent assay and agar well diffusion method.</p><p><b>RESULTS</b>Terminalia chebula Retz. (Fruit), containing the highest total phenolic content, showed high antioxidant activities with inhibition of 77.98% ± 0.92%, 88.95% ± 2.42%, 88.56% ± 1.87% and 70.74%± 2.57% for DPPH, NO, SO assays and antiglycation activity respectively. It also showed the antimicrobial activities against Staphylococcus aureus, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans with inhibition zone of 19, 18, 17, 25 and 15 mm, respectively. Garcinia mangostana Linn. showed the strongest activities for SO and antiglycation assays with inhibition of 93.68% ± 2.63% and 82.37% ± 1.78%. Bark of Melia sp. was the best NO radical scavenger with inhibition rate of 89.39%± 0.60%.</p><p><b>CONCLUSION</b>The results suggest that these plants are potential sources of antioxidants with free radical-scavenging and antiglycation activities and could be useful for decreasing the oxidative stress and glycation end-product formation in glycation-related diseases.</p>

Antioxidant activity and protective role on protein glycation of synthetic aminocoumarins

Background: Synthesized aminocoumarins are heterocyclic compounds possessing potential for the treatment of insulin-dependent diabetes mellitus with unexplored anti-glycative action. Results: In this study 4-aminocoumarin derivatives (4-ACDs) were evaluated in vitro for antiglycation (AG) activities by using the human serum albumin (HSA)/glucose system, for 8 weeks of incubation. The glycation and conformational alteration of HSA in the presence of the tested compounds were evaluated by Congo red assay, fluorescence and circular dichroism spectroscopy. The antioxidant (AO) capacity were also tested by four different assays including: DPPH (2,2'-diphenyl-1-picrylhydrazyl radical), ABTS (2,2-azinobis (3-ethylbenzothiazoline-6-sulphonate) diammonium salt), FRAP (ferric reducing antioxidant power) and β-carotene-linoleic acid assay. The tested compounds showed AG and AO effects. The intensity of the accomplished AO potential is related to the type of the used assay. Significant alterations in the secondary (monitored by CD spectropolarimetry) and tertiary structure (assessed by spectrofluorimetry) of HSA upon glycation were mitigated by the 4-ACDs, suggesting their suppressive role in the late stage (post-Amadori) of the HSA glycation. Conclusions: By the analogues, in vitro ascertained AO and AG properties of 4-ACD may be recognized as rationale for their protective role against oxidative changes of proteins, thereby precluding diabetic complications in humans.

Antioxidant and antiglycation properties of different solvent extracts from Chinese olive (Canarium album L.) fruit

Objective: To evaluate the antioxidant activity, antiglycation property, and bioactive components content of different solvent extracts from Chinese olive (Canarium album L.) fruit. Methods: The dry powder of Chinese olive fruit was extracted with different solvents, i.e., water, water/ethanol (1/1, v/v), ethanol, methanol, acetone and ethyl acetate. The total phenolic, total flavonoids and total triterpenoids contents of various extracts were determined by spectrophotometric methods. Phenolic compounds were identified by high performance liquid chromatography. The assayed antioxidant activity was determined in vitro models such as antioxidant capacity by radical scavenging activity using 2,2'-Azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), 1,1-diphenyl-2-picryl- hydrazyl (DPPH) and nitrite oxide methods, chelating activity on metal ions, lipid and protein peroxidation methods. In vitro glucose-bovine serum albumin assay was used to evaluate the antiglycation of various extracts. Results: The water/ethanol extracts of Chinese olive fruit exerted significant scavenging effects on free radicals and strong inhibitory effects on advanced glycation end products formation. The Chinese olive fruit extracts were rich in phenolic compounds and triterpenoids. Gallic acid, ferulic acid and rutin were identified from the water/ethanol extracts. Correlation analysis indicated that there was a linear relationship between the antioxidant potency, free radical scavenging ability and phenolic compounds content of the Chinese olive fruit extracts. Conclusions: Chinese olive fruit could be a natural candidate for studies of dietary complement to diabetes treatment since it combines antioxidant and antiglycation activities.

Antioxidant and antiglycation properties of different solvent extracts from Chinese olive (Canarium album L.) fruit

OBJECTIVE@#To evaluate the antioxidant activity, antiglycation property, and bioactive components content of different solvent extracts from Chinese olive (Canarium album L.) fruit.@*METHODS@#The dry powder of Chinese olive fruit was extracted with different solvents, i.e., water, water/ethanol (1/1, v/v), ethanol, methanol, acetone and ethyl acetate. The total phenolic, total flavonoids and total triterpenoids contents of various extracts were determined by spectrophotometric methods. Phenolic compounds were identified by high performance liquid chromatography. The assayed antioxidant activity was determined in vitro models such as antioxidant capacity by radical scavenging activity using 2,2'-Azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), 1,1-diphenyl-2-picryl- hydrazyl (DPPH) and nitrite oxide methods, chelating activity on metal ions, lipid and protein peroxidation methods. In vitro glucose-bovine serum albumin assay was used to evaluate the antiglycation of various extracts.@*RESULTS@#The water/ethanol extracts of Chinese olive fruit exerted significant scavenging effects on free radicals and strong inhibitory effects on advanced glycation end products formation. The Chinese olive fruit extracts were rich in phenolic compounds and triterpenoids. Gallic acid, ferulic acid and rutin were identified from the water/ethanol extracts. Correlation analysis indicated that there was a linear relationship between the antioxidant potency, free radical scavenging ability and phenolic compounds content of the Chinese olive fruit extracts.@*CONCLUSIONS@#Chinese olive fruit could be a natural candidate for studies of dietary complement to diabetes treatment since it combines antioxidant and antiglycation activities.

(1H-Pyrrolo [2,3-B] Pyridine) 7-Azaindole as Cholinesterase/ Glycation Inhibitors.

As a part of our program to discover novel analoges of (1H-pyrrolo [2,3-b] pyridine) 7- azaindole having useful biological activities, a variety of 7-azaindole analogs 1-9 with variable substituents on phenyl ring of phenacyl moiety were synthesized and evaluated for their AChE, BChE and antiglycation Inhibitory potential. Compounds 2-5 were found to be AChE inhibitors with IC50 1.34 μM, 11.60 μM, 0.96 μM and 0.97 μM respectively, while compounds 2-5 were also found to be BChE inhibitors with IC50 1.25 μM, 3.93 μM, IC50 9.18μM and 10.20μM respectively. Compounds 2 (IC50 = 1.25±0.019uM) and 3 (IC50 = 3.93±0.36uM), showed potent BChE inhibitory potential than standard Galantamine (IC50 = 8.51±0.02uM). Besides this, compounds 2-9 were evaluated for glycation inhibition activity. Compound 5 (IC50 values 120.6+0.2uM) showed potent antiglycation potential than standard rutin (IC50=294.50+1.5uM). The size of the substituent, electron donating or withdrawing effect of substituents as well as the position of substituent on phenyl effects the activity.

Antiglycation, Antioxidant and Antidiabetic Activity of Mature Strawberry (Fragaria × Ananassa) Fruits.

A comprehensive in vitro study involving antiglycation, antioxidant and anti-diabetic assays was carried out in mature fruits of strawberry. The effect of aqueous extract of mature strawberry fruits on glycation of guanosine with glucose and fructose with or without oxidizing entities like reactive oxygen species was analyzed. Spectral studies showed that glycation and/or fructation of guanosine was significantly inhibited by aqueous extract of strawberry. The UV absorbance of the glycation reactions was found to be maximum at 24 hrs. and decreased consecutively for 48, 72 and 96 hours. Inhibition of oxidative damage due to reactive oxygen species was also observed in presence of the plant extract. To our knowledge, antiglycation activity of strawberry fruit with reference to guanosine is being demonstrated for the first time. To determine the antioxidant activity of the plant extract, in vitro antioxidant enzymes assays (catalase, peroxidase, polyphenol oxidase and ascorbic acid oxidase) and antioxidant assays (DPPH, superoxide anion scavenging activity and xanthine oxidase) were performed. Maximum inhibition activity of 79.36%, 65.62% and 62.78% was observed for DPPH, superoxide anion scavenging and xanthine oxidase, respectively. In antidiabetic assays, IC50 value for alpha – amylase and alpha – glucosidase activity of fruit extract of strawberry was found to be 86.47 ± 1.12μg/ml and 76.83 ± 0.93 μg/ml, respectively. Thus, the aqueous extract of strawberry showed antiglycation, antioxidant and antidiabetic properties indicating that strawberry fruits, as a dietary supplement, may be utilized towards management of diabetes.

Inhibition of advanced glycation end products formation by stilbene and phenanthrene derivatives from Prosthechea michuacana in vitro and in vivo / Inhibición de la formación de subproductos en la glicosilación avanzada por derivados de estilbeno y fenantreno de Prosthechea michuacana, in vitro e in vivo

In our previous study, we isolated from chloroform extract of the bulbs of orchid P. michuacana, three antioxidant compounds: two stilbene alpha-alpha´-dihydro, 3´,5´,2-trimethoxy-3-hydroxy-4-acetyl-4´-isopentenyl stilbene, 5-[2-(3-hydroxy-5-methoxyphenyl)ethyl]-2-methoxyphenol (gigantol) and one phenanthrene 4,6,7-trihydroxy-2-methoxy-8-(methylbut-2-enylphenanthren-1-1´-4´,6´,7´-trihydroxy-2´-methoxy-8´-(methylbut-2´-enyl)-phenanthrene. Following the study, we investigated the ability of isolated compounds to inhibit advanced glycation in vitro. Bovine serum albumin was glycated in the presence of glucose or methylglyoxal. Amadori-rich protein was prepared by dialyzing lysozyme that had been glycated by ribose. We also evaluated renal function by checking formation of advanced glycation and tail tendon collagen quality in streptozotocin-induced diabetic mice. Also determined the effect on LDL and hemoglobin. Compounds can efficiently inhibit the formation of AGEs by trapping reactive methylglyoxal and showed potent anti-Amadorin activity. Also exhibited a significant inhibitory activity on the glycated hemoglobin (GHb and HbA1c). Compounds showed a protective renal effect and reduction in mice tail tendon collagen. Also the tested compounds are potent agents for protecting LDL against oxidation and glycation. We concluded that compounds from P. michuacana are potent antiglycation agents, which can be of great value in the prevention of diabetic glycation-associated-pathogenesis.

En un estudio anterior, aislamos del extracto clorofórmico de los bulbos de la orquídea Prosthechea michuacana, tres compuestos antioxidantes: los estilbenos alfa-alfa´-dihidro, 3´,5´,2-trimethoxi-3-hidroxi-4-acetil-4´-isopentenil-stilbeno, 5-[2-(3-hydroxy-5-methoxyphenyl)ethyl]-2-methoxyphenol (gigantol) y el fenantreno 4,6,7-trihidroxi -2-methoxi-8-(metilbut-2-enilfenantren-1-1´-4´,6´,7´-trihidroxi-2´-metoxi-8´-(metilbut-2´-enil)-fenantreno. Continuando con el estudio, investigamos la capacidad de estos compuestos para inhibir la glicación avanzada in vitro. La seroalbúmina bovina se glicosiló en presencia de glucosa o metilglioxal. La reacción de Amadori se determinó con lisozima glicosilada previamente tratada con ribosa. También se evaluó la función renal mediante la formación de la glicación avanzada y la inhibición de AGEs en el ensayo sobre el colágeno del tendón de la cola en ratones con diabetes inducida con estreptozotocina. También determinamos el efecto de los compuestos aislados sobre LDL y hemoglobin. Los compuestos pueden inhibir eficazmente la formación de AGE atrapando el metilglioxal reactivo y muestran potente actividad anti Amadorin. También mostraron una actividad inhibitoria significativa en la formación de la hemoglobina glucosilada, GHB y HbA1c. Mostraron un efecto protector renal y una reducción en el colágeno glicosiladó del tendón de la cola. También estos compuestos son potentes agentes para la protección de LDL frente la oxidación y la glicación. En base a los resultados obtenidos se concluye que los compuestos aislados son potentes agentes antiglicación, que pueden ser de gran valor en la prevención de la patogénesis de la diabetes asociada a la glicación.

Antioxidant activities of Juniperus foetidissima essential oils against several oxidative systems

The present study aimed to evaluate the antioxidant activity of essential oils obtained from branchlets of male and female trees as well as fruits of Juniperus foetidissima Willd., Cupressaceae, from Iran. For this purpose, essential oils of J. foetidissima were phytochemically analyzed and different concentrations of them were tested in five oxidative systems: 1) low-density lipoprotein oxidation; 2) linoleic acid peroxidation; 3) red blood cell hemolysis; 4) hemoglobin glycation; and 5) insulin glycation assays. In all employed systems, antioxidant effects were observed from the three tested oils though in varying degrees. The most promising activities of the oils were observed against hemoglobin and insulin glycation. Antioxidant activities of the oils did not appear to be dose-dependent. In addition, no consistent superiority in antioxidant effects was observed from a single oil in different assays. In view of the current results, J. foetidissima branchlet and fruit oils could be regarded as effective natural products with anti-glycation activity.

Anti-diabetic activity of an hexane extract of Prosthechea michuacana in streptozotocin-induced diabetic rats / Actividad antidiabética de un extracto de hexane de Prosthechea michuacana en ratas diabéticas inducidas por estreptozotocina

In this study we investigated the antihyperglycaemic, antihyperlipidaemic and antiglycation effects of some extracts of Prosthechea michuacana bulbs in normoglycemic and diabetic rats induced by streptozocin (STZ). Hexane, chloroform and methanol extracts of P. michuacana were screened for hypoglycemic activity, and biochemical parameters as serum triglycerides, total cholesterol, lipid peroxidation, liver glycogen, skeletal muscle glycogen levels, superoxide dismutase, catalase, glutathione reductase and glutathione peroxidase activity in diabetic rats. Additionally we determined Glucose 6 Phosphatase and glucokinase activities in liver, inhibition of insulin and protein glycation. Glucose levels in blood plasma were determined by using GOD-POD method. Administration of chloroform and methanol extracts showed no effect on STZ induced diabetic rats (SD). On the other hand, treatment with hexane extract at 200 and 400 mg/kg doses, resulted in a reversal of diabetes and its complications. Both doses significantly brought down blood glucose concentration (35.75 and 47.78 percent in diabetic rats, 50.64 and 57.10 percent in nondiabetic rats), increased glycogenesis and decreased glyconeogenesis bringing the glucose metabolism toward normalcy. These doses also reversed the hyperlipidemia by reducing cholesterol (41.56 percent, 46.08 percent) and triglycerides (37.5 percent, 46.27 percent) and improved hepatic antioxidant enzyme activities. Its effect was compared with that of glibenclamide and tolbutamide, as reference antidiabetic drugs. The hexane extract decreased the hyperinsulinemia by 24 percent in SD and showed a significant change on AGEs formation in vitro with IC50 values of 48.3 ug/ml comparable to inhibitory effect of aminoguanidine with IC50 values of 27.2 ug/ml. It reduced HbA1C levels by 6.4 percent in chronic STZ-diabetic rats. It is concluded that hexane extract of Prosthechea michuacana bulbs possesses anti-hyperglycemic and antihyperlipemic...

En este estudio se determinaron los efectos antidiabéticos, antihiperlipidemico y glicación (AGEs) de algunos extractos de Prosthechea michuacana (PM) en ratas normoglucémicas y con diabetes inducida por estreptozotocina (STZ). Se probó el efecto de los extractos de hexano, cloroformo, metanol de PM sobre la actividad hipoglucemiante, la carga de glucosa, los parámetros bioquímicos tales como triglicéridos, niveles de colesterol total, peroxidación lipídica, glucógeno del hígado, los niveles de glucógeno muscular, niveles de superoxide dismutase, catalasa, glutation reductasa and glutation peroxidasa en ratas normales y diabéticas. También se determinó la glucosa 6 Phosphatasa y las actividades de GK en el hígado, la inhibición de la insulina y la glicosilación de las proteínas. Los niveles de glucosa sanguínea se determinaron por el método de GOD-POD. La administración de los extractos de cloroformo y metanol no presentaron ningún efecto sobre la SD, en cambio el tratamiento con el extracto de hexano (PM) a dosis de 200 y 400 mg/kg, inhibió la diabetes y sus complicaciones. Ambas dosis redujeron significativamente los niveles de glucosa sanguínea (35.75 y 47.78 por ciento en las ratas diabéticas, 50.64 y 57.10 por ciento en las ratas diabéticas), el aumento de la glucogénesis y la disminución de la gluconeogénesis conduce el metabolismo de la glucosa hacia la normalidad. Estas dosis disminuyeron la hiperlipidemia reduciendo el colesterol (41.56 por ciento, 46.08 por ciento) y los triglicéridos (37.5 por ciento, 46.27 por ciento) así como también mejoran las actividades antioxidantes de las enzimas hepáticas. Su efecto se comparó con la glibenclamida y tolbutamida, fármacos usados como antidiabeticos. El extracto de hexano disminuyo la hiperinsulinemia en un 24 por ciento en SD. PM mostró un cambio significativo in vitro sobre la formación de los AGEs con valores de IC50 de 48.3 mg/ml comparable al efecto inhibidor de la aminoguanidina con valores de IC50 de...