To study the antioxidant constituents from the stems of Dendrobium nobile, and to discuss theft structure-activity relationship. Compounds were isolated from a 60% ethanolic extract by various chromatographic techniqu...To study the antioxidant constituents from the stems of Dendrobium nobile, and to discuss theft structure-activity relationship. Compounds were isolated from a 60% ethanolic extract by various chromatographic techniques and were identified by spectral analysis. The antioxidant activities of compounds were evaluated by DPPH free radical scavenging assay. Five phenanthrenes and four lignans were obtained from the active fractions ofD. nobile. Their structures were identified as fimbriatone （1）, confusarin （2）, flavanthrinin （3）, 2,5-dihydroxy-4,9-dimethoxyphenanthrene （4）, 3,7-dihydroxy-2,4-dimethoxyphenanthrene （5）, syringaresinol （6）, pinoresinol （7）, medioresinol （8） and lirioresinol-A （9）, respectively. Compounds 2 and 6 exhibited more potent DPPH scavenging activities than vitamin C. All the above compounds were reported from this plant for the first time, and compounds 3, 4 and 9 were reported for the first time from the genus of Dendrobiurn. For all phenanthrenes and lignans, an electron-donating methoxyl group in the ortho position to the phenolic hydroxyl group exhibits enhanced antioxidant activities.展开更多
Cistanoside compounds were studied as the scavengers of hydroxyl and superoxide anion free radicals with spin trapping ESR method in vitro. Low-temperature ESR technique, experimental technique of immunotoxicology and...Cistanoside compounds were studied as the scavengers of hydroxyl and superoxide anion free radicals with spin trapping ESR method in vitro. Low-temperature ESR technique, experimental technique of immunotoxicology and biochemical method were used to detect the level of reactive oxygen radicals in kidney tissue of rats and SOD level and GSH-Px activity in rat serum. The results indicated that cistanoside compounds could inhibit reactive oxygen free radicals in vitro and prevent and repair the free radical damages for diabetic nephropathy. The experimental data of 揷arbon-particle detection in mouse serum?showed that cistanoside compounds could improve the phagocytotis index of macrophages (Mj) in mice blood and increase the weights of immune organs of mice.展开更多
The green and effective Baeyer-Villiger oxidation reaction of cyclohexanone for preparing e-caprolactone is of particular importance in the synthesis of new polymer materials. We have discussed here several mechanism ...The green and effective Baeyer-Villiger oxidation reaction of cyclohexanone for preparing e-caprolactone is of particular importance in the synthesis of new polymer materials. We have discussed here several mechanism types of Baeyer-Villiger oxidation of cyclohexanone with H2O2 in different reaction systems. Five main types have been addressed, i. e.： （1） the non-catalyzed reaction type, where the C=O of ketones is activated by H＋, which is electrolytically dissociated from H202 and H20, to improve the capability of C=O group for accepting the electron pairs; （2） the thermally activated radical reaction type, where the Criegee intermediate is produced via two steps of radical reaction with -OH attack, with much more hydroxyl radicals being excited in the presence of TS-1 zeolite; （3） the Bronsted acid catalysis reaction type, where both O-O moiety and C=O group could be activated by BriSnsted acid; （4） the solid Lewis acid catalyzed C=O of the substrate activation reaction type through enhancing the donor-acceptor interaction between the antibonding π＊c-o orbital of cyclohexanone and HOMO of Sn-containing zeolites; and （5） the solid Lewis acid catalyzed H202 to form Me-OOH oxidative species by converting the highest occupied molecular orbital （HOMO） of Ti-OOH into a singly occupied molecular orbital （SOMO）, making the O--O group highly electrophilic to attack the C--O of cyclohexanone during the Baeyer-Villiger oxidation process. In the end, we have also compared the different mechanisms and put forward our opinions on the development direction of catalytic materials aiming at eco-friendly Baeyer-Villiger oxidation of cyclohexanone in the years to come.展开更多
Mangosteen peel （Garcinia mangostana L.） is well known as an excellent source of antioxidative compounds. The objective of this study was to determine the most suitable processing condition for ethanolic extraction ...Mangosteen peel （Garcinia mangostana L.） is well known as an excellent source of antioxidative compounds. The objective of this study was to determine the most suitable processing condition for ethanolic extraction of mangosteen peel. The experimental factors included raw material prepared as fresh and dried forms, material-to-solvent ratio varying at 1：3, 1：4, 1：5, 1：6, 1：9 and 1：12, and contacting time at 1, 3, 6, 9, 12 and 16 hours. Antioxidative capacity of all extracts were evaluated and compared according to DPPH radical scarvenging assay, trolox equivalent antioxidant capacity （TEAC assay） and total phenolic compounds. It was found that the extract from dried mangosteen peel had significantly stronger antioxidative capacity than that from fresh mangosteen peel （P 〈 0.05）. The suitable ethanolic extraction was found at the material-to-solvent ratio of 1：6 and 12 hours of contacting time. Mangosteen peel extracts prepared from fresh peel, dried peel, boiled and dried peel were also tested for oxidative rancidity reduction in lard at accelerated temperature of 60 ~C. The antioxidative rancidity was measured by acid value, totox value and thiobarbituric acid test. Commercial rosemary extract and BHT were compared at the equivalent concentration of 1,000 mg/kg. The results showed that the extract from dried mangosteen peel provided antioxidative capacity slightly stronger than fresh mangosteen peel extract, similar to rosemary extract but still poorer than BHT.展开更多
Functional properties of Talbina were used in ancient Arab for nutritional purpose. It was a meal made from barley flour and milk. The high antioxidant Talbina was formulated from whole flour of harley and oat, milk, ...Functional properties of Talbina were used in ancient Arab for nutritional purpose. It was a meal made from barley flour and milk. The high antioxidant Talbina was formulated from whole flour of harley and oat, milk, date palm syrup （debis） and date palm seeds. The chemical composition, organoleptic properties and antioxidant activity of high antioxidant Talbina were determined. Sensory evaluation of traditional and high antioxidant Talbina showed that the developed product Talbina was considered as good for overall acceptability of all panelists. Also, the formulated Talbina contains high values of antioxidants components and natural nutrients. The antioxidant activity of formulated Talbina containing barley or oat may be due to presence of phenolic compounds and proanthocyanidins in the barley and oat. Increasing the antioxidant activity of high antioxidant Talbina containing barley and oat may be due to the adding of dates palm seeds which contain very high values of phenolic compounds and other antioxidants components. Date palm seeds as well as barley and/or oat give high antioxidants components which protect cells from oxidative stress and help to reduce the risk of cancer and heart disease as well as natural anti-depressant. Moreover, increasing the antioxidant activity in the formulated Talbina may play a role for reducing power, radical scavenging activity and the lipid peroxidation inhibition. In conclusion, supplementation of traditional Talbina containing barley and/or oat with date palm syrup （debis） and date palm seeds can produce simple and healthy meal to provide a good source of daily dietary antioxidants and micronutrients.展开更多
Capparis spinosa L. is a traditionally used plant in Algerian folk medicine to treat asthma, rheumatism and other free radicals related disorders such inflammatory. The present study was designated to study the antiox...Capparis spinosa L. is a traditionally used plant in Algerian folk medicine to treat asthma, rheumatism and other free radicals related disorders such inflammatory. The present study was designated to study the antioxidant activity of aerial and root parts of Capparis spinosa L.. Total polyphenol content was determined, after extraction with solvents in five subfractions; methanol （CE）, Hexan （HE） chloroform （CHE）, ethyl acetate （EAE） and aqueous extracts （AE）, employing the ＂Prussian blue assay＂. The results showed that EAE containing the highest concentration of phenolic compounds and Flavonoids followed by those of CHE of aerial and root parts, repectively. The antioxidant protective effects of extracts were determined by measuring the erythrocyte membrane resistance to free radical-induced. The results demonstrated that all the extracts exhibited a protective effect against t-BHP induced oxidative damages in human erythrocytes, the most potents wer CEs and CHEs with 86.55%, 85.81%, 74.59%, and 68.70%, for aerial and root parts, respectively, which were more effective than used standards： Quercetin （65.46%） and rutin （59.62%）. In order to more clarify the previous antioxidants activity of the extracts through other mechanisms, the iron chelating ability assays were realized. The results showed that the iron chelating ability of Aerial and root extracts were very considerable; the CE showed an excellent chelating with ICs0 of 0.197 ± 0.031 μM/quercetin equivalent, higher than that used standard EDTA, with approximately 0.34 folds. These results show that Capparis spinosa L. extracts have strong anti-oxidant effects and may have some clinical benefits.展开更多
Antioxidant efficiency was studied in fresh edible algae： Cladophora, Microspara and Nostochopsis spp. from Nan River, Nan province. The samples were collected from Pua and Tha-Wang-Pha district, studied antioxidant ...Antioxidant efficiency was studied in fresh edible algae： Cladophora, Microspara and Nostochopsis spp. from Nan River, Nan province. The samples were collected from Pua and Tha-Wang-Pha district, studied antioxidant activity and compared the antioxidant efficacy of the extracts from the three fresh edible algae with a standard solution, 3-tert-butyl-4-hydroxyanisole （BHA）. This study found that an extract ofNostochopsis spp. was the highest antioxidant activity to DPPH free radical between 32.1 and 87.5, the highest amount of beta-carotene was 4.71-7.09 mg/g and the highest amount of phenol in fresh edible algae extracts from Microspora was between 9.37 and 37.02 mg/g. The highest vitamin C in Microspora was between 110.41-138.53 mg/100 g.展开更多
文摘To study the antioxidant constituents from the stems of Dendrobium nobile, and to discuss theft structure-activity relationship. Compounds were isolated from a 60% ethanolic extract by various chromatographic techniques and were identified by spectral analysis. The antioxidant activities of compounds were evaluated by DPPH free radical scavenging assay. Five phenanthrenes and four lignans were obtained from the active fractions ofD. nobile. Their structures were identified as fimbriatone （1）, confusarin （2）, flavanthrinin （3）, 2,5-dihydroxy-4,9-dimethoxyphenanthrene （4）, 3,7-dihydroxy-2,4-dimethoxyphenanthrene （5）, syringaresinol （6）, pinoresinol （7）, medioresinol （8） and lirioresinol-A （9）, respectively. Compounds 2 and 6 exhibited more potent DPPH scavenging activities than vitamin C. All the above compounds were reported from this plant for the first time, and compounds 3, 4 and 9 were reported for the first time from the genus of Dendrobiurn. For all phenanthrenes and lignans, an electron-donating methoxyl group in the ortho position to the phenolic hydroxyl group exhibits enhanced antioxidant activities.
文摘Cistanoside compounds were studied as the scavengers of hydroxyl and superoxide anion free radicals with spin trapping ESR method in vitro. Low-temperature ESR technique, experimental technique of immunotoxicology and biochemical method were used to detect the level of reactive oxygen radicals in kidney tissue of rats and SOD level and GSH-Px activity in rat serum. The results indicated that cistanoside compounds could inhibit reactive oxygen free radicals in vitro and prevent and repair the free radical damages for diabetic nephropathy. The experimental data of 揷arbon-particle detection in mouse serum?showed that cistanoside compounds could improve the phagocytotis index of macrophages (Mj) in mice blood and increase the weights of immune organs of mice.
文摘The green and effective Baeyer-Villiger oxidation reaction of cyclohexanone for preparing e-caprolactone is of particular importance in the synthesis of new polymer materials. We have discussed here several mechanism types of Baeyer-Villiger oxidation of cyclohexanone with H2O2 in different reaction systems. Five main types have been addressed, i. e.： （1） the non-catalyzed reaction type, where the C=O of ketones is activated by H＋, which is electrolytically dissociated from H202 and H20, to improve the capability of C=O group for accepting the electron pairs; （2） the thermally activated radical reaction type, where the Criegee intermediate is produced via two steps of radical reaction with -OH attack, with much more hydroxyl radicals being excited in the presence of TS-1 zeolite; （3） the Bronsted acid catalysis reaction type, where both O-O moiety and C=O group could be activated by BriSnsted acid; （4） the solid Lewis acid catalyzed C=O of the substrate activation reaction type through enhancing the donor-acceptor interaction between the antibonding π＊c-o orbital of cyclohexanone and HOMO of Sn-containing zeolites; and （5） the solid Lewis acid catalyzed H202 to form Me-OOH oxidative species by converting the highest occupied molecular orbital （HOMO） of Ti-OOH into a singly occupied molecular orbital （SOMO）, making the O--O group highly electrophilic to attack the C--O of cyclohexanone during the Baeyer-Villiger oxidation process. In the end, we have also compared the different mechanisms and put forward our opinions on the development direction of catalytic materials aiming at eco-friendly Baeyer-Villiger oxidation of cyclohexanone in the years to come.
文摘Mangosteen peel （Garcinia mangostana L.） is well known as an excellent source of antioxidative compounds. The objective of this study was to determine the most suitable processing condition for ethanolic extraction of mangosteen peel. The experimental factors included raw material prepared as fresh and dried forms, material-to-solvent ratio varying at 1：3, 1：4, 1：5, 1：6, 1：9 and 1：12, and contacting time at 1, 3, 6, 9, 12 and 16 hours. Antioxidative capacity of all extracts were evaluated and compared according to DPPH radical scarvenging assay, trolox equivalent antioxidant capacity （TEAC assay） and total phenolic compounds. It was found that the extract from dried mangosteen peel had significantly stronger antioxidative capacity than that from fresh mangosteen peel （P 〈 0.05）. The suitable ethanolic extraction was found at the material-to-solvent ratio of 1：6 and 12 hours of contacting time. Mangosteen peel extracts prepared from fresh peel, dried peel, boiled and dried peel were also tested for oxidative rancidity reduction in lard at accelerated temperature of 60 ~C. The antioxidative rancidity was measured by acid value, totox value and thiobarbituric acid test. Commercial rosemary extract and BHT were compared at the equivalent concentration of 1,000 mg/kg. The results showed that the extract from dried mangosteen peel provided antioxidative capacity slightly stronger than fresh mangosteen peel extract, similar to rosemary extract but still poorer than BHT.
文摘Functional properties of Talbina were used in ancient Arab for nutritional purpose. It was a meal made from barley flour and milk. The high antioxidant Talbina was formulated from whole flour of harley and oat, milk, date palm syrup （debis） and date palm seeds. The chemical composition, organoleptic properties and antioxidant activity of high antioxidant Talbina were determined. Sensory evaluation of traditional and high antioxidant Talbina showed that the developed product Talbina was considered as good for overall acceptability of all panelists. Also, the formulated Talbina contains high values of antioxidants components and natural nutrients. The antioxidant activity of formulated Talbina containing barley or oat may be due to presence of phenolic compounds and proanthocyanidins in the barley and oat. Increasing the antioxidant activity of high antioxidant Talbina containing barley and oat may be due to the adding of dates palm seeds which contain very high values of phenolic compounds and other antioxidants components. Date palm seeds as well as barley and/or oat give high antioxidants components which protect cells from oxidative stress and help to reduce the risk of cancer and heart disease as well as natural anti-depressant. Moreover, increasing the antioxidant activity in the formulated Talbina may play a role for reducing power, radical scavenging activity and the lipid peroxidation inhibition. In conclusion, supplementation of traditional Talbina containing barley and/or oat with date palm syrup （debis） and date palm seeds can produce simple and healthy meal to provide a good source of daily dietary antioxidants and micronutrients.
文摘Capparis spinosa L. is a traditionally used plant in Algerian folk medicine to treat asthma, rheumatism and other free radicals related disorders such inflammatory. The present study was designated to study the antioxidant activity of aerial and root parts of Capparis spinosa L.. Total polyphenol content was determined, after extraction with solvents in five subfractions; methanol （CE）, Hexan （HE） chloroform （CHE）, ethyl acetate （EAE） and aqueous extracts （AE）, employing the ＂Prussian blue assay＂. The results showed that EAE containing the highest concentration of phenolic compounds and Flavonoids followed by those of CHE of aerial and root parts, repectively. The antioxidant protective effects of extracts were determined by measuring the erythrocyte membrane resistance to free radical-induced. The results demonstrated that all the extracts exhibited a protective effect against t-BHP induced oxidative damages in human erythrocytes, the most potents wer CEs and CHEs with 86.55%, 85.81%, 74.59%, and 68.70%, for aerial and root parts, respectively, which were more effective than used standards： Quercetin （65.46%） and rutin （59.62%）. In order to more clarify the previous antioxidants activity of the extracts through other mechanisms, the iron chelating ability assays were realized. The results showed that the iron chelating ability of Aerial and root extracts were very considerable; the CE showed an excellent chelating with ICs0 of 0.197 ± 0.031 μM/quercetin equivalent, higher than that used standard EDTA, with approximately 0.34 folds. These results show that Capparis spinosa L. extracts have strong anti-oxidant effects and may have some clinical benefits.
文摘Antioxidant efficiency was studied in fresh edible algae： Cladophora, Microspara and Nostochopsis spp. from Nan River, Nan province. The samples were collected from Pua and Tha-Wang-Pha district, studied antioxidant activity and compared the antioxidant efficacy of the extracts from the three fresh edible algae with a standard solution, 3-tert-butyl-4-hydroxyanisole （BHA）. This study found that an extract ofNostochopsis spp. was the highest antioxidant activity to DPPH free radical between 32.1 and 87.5, the highest amount of beta-carotene was 4.71-7.09 mg/g and the highest amount of phenol in fresh edible algae extracts from Microspora was between 9.37 and 37.02 mg/g. The highest vitamin C in Microspora was between 110.41-138.53 mg/100 g.
