Author
Jia Zhongjian
Bio: Jia Zhongjian is an academic researcher from Lanzhou University. The author has contributed to research in topics: Iridoid & Verbascoside. The author has an hindex of 13, co-authored 24 publications receiving 952 citations.
Papers
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TL;DR: The superoxide anions scavenging activity and antioxidation of seven flavonoids (quercetin, rutin, morin, acacetin, hispidulin, hesperidin, and naringin) were studied in this paper.
535 citations
TL;DR: A new phenylpropanoid glycoside, pedicularioside A, and five known glycosides, acteoside, isoacteosides, decaffeoylacteside, echinacoside and 8-acetylharpagide, were isolated from whole plants of Pedicularis striata as discussed by the authors.
65 citations
TL;DR: In this paper, tortosides A-F were isolated from whole plants of Pedicularis torta, along with 11 known compounds, including 6 new lignan glucosides, including cistanosides C and D, verbascoside, 8-epiloganin, gardoside methyl ester and loganic acid.
65 citations
TL;DR: Five phenylpropanoid glycosides from Pedicularis are studied, as phenolic compounds can protect against oxidative hemolysis, and a chemically synthesised compound, permethylacteoside, as an inhibitory activity is related to the number of phenolic hydroxy groups.
Abstract: Five phenylpropanoid glycosides from Pedicularis, isoacteoside (1), acteoside (2), echinacoside (3), pedicularioside A (4), cistanoside D (5), and a chemically synthesised compound, permethylacteoside (6), as phenolic compounds can protect against oxidative hemolysis. The inhibitory activity is related to the number of phenolic hydroxy groups. Compounds 1, 2, 3, and 4, possessing four phenolic hydroxy groups, have stronger inhibitory activities than 5 possessing only two phenolic hydroxy groups, and compound 6 with no phenolic hydroxy group inhibited oxidative hemolysis weakly.
46 citations
TL;DR: In this paper, seven guaianolides were isolated from Saussurea involucrata, four of them new, and their structures were elucidated by spectroscopic methods, some chemical transformations and X-ray diffraction.
39 citations
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TL;DR: The factors underlying the influence of the different classes of polyphenols in enhancing their resistance to oxidation are discussed and support the contention that the partition coefficients of the flavonoids as well as their rates of reaction with the relevant radicals define the antioxidant activities in the lipophilic phase.
8,513 citations
TL;DR: An overview of the nutritional effects of the main groups of polyphenolic compounds, including their metabolism, effects on nutrient bioavailability, and antioxidant activity, is offered, as well as a brief description of the chemistry ofpolyphenols and their occurrence in plant foods.
Abstract: Polyphenols constitute one of the most numerous and ubiquitous groups of plant metabolites and are an integral part of both human and animal diets. Ranging from simple phenolic molecules to highly polymerized compounds with molecular weights of greater than 30,000 Da, the occurrence of this complex group of substances in plant foods is extremely variable. Polyphenols traditionally have been considered antinutrients by animal nutritionists, because of the adverse effect of tannins, one type of polyphenol, on protein digestibility. However, recent interest in food phenolics has increased greatly, owing to their antioxidant capacity (free radical scavenging and metal chelating activities) and their possible beneficial implications in human health, such as in the treatment and prevention of cancer, cardiovascular disease, and other pathologies. Much of the literature refers to a single group of plant phenolics, the flavonoids. This review offers an overview of the nutritional effects of the main groups of polyphenolic compounds, including their metabolism, effects on nutrient bioavailability, and antioxidant activity, as well as a brief description of the chemistry of polyphenols and their occurrence in plant foods.
3,821 citations
TL;DR: Flavonoids are plant pigments that are synthesised from phenylalanine, generally display marvelous colors known from flower petals, mostly emit brilliant fluorescence when they are excited by UV light, and are ubiquitous to green plant cells.
2,424 citations
TL;DR: The structural requirements for the antioxidant and free radical scavenging functions of flavonoids include a hydroxyl group in carbon position three, a double bond between carbon positions two and three, carbonyl groups in carbon positions four, and polyhydroxylation of the A and B aromatic rings.
Abstract: Flavonoids are a group of polyphenolic compounds, diverse in chemical structure and characteristics, found ubiquitously in plants. Therefore, flavonoids are part of the human diet. Over 4,000 different flavonoids have been identified within the major flavonoid classes which include flavonols, flavones, flavanones, catechins, anthocyanidins, isoflavones, dihydroflavonols, and chalcones. Flavonoids are absorbed from the gastrointestinal tracts of humans and animals and are excreted either unchanged or as flavonoid metabolites in the urine and feces. Flavonoids are potent antioxidants, free radical scavengers, and metal chelators and inhibit lipid peroxidation. The structural requirements for the antioxidant and free radical scavenging functions of flavonoids include a hydroxyl group in carbon position three, a double bond between carbon positions two and three, a carbonyl group in carbon position four, and polyhydroxylation of the A and B aromatic rings. Epidemiological studies show an inverse correlation between dietary flavonoid intake and mortality from coronary heart disease (CHD) which is explained in part by the inhibition of low density lipoprotein oxidation and reduced platelet aggregability. Dietary intake of flavonoids range between 23 mg/day estimated in The Netherlands and 170 mg/day estimated in the USA. Major dietary sources of flavonoids determined from studies and analyses conducted in The Netherlands include tea, onions, apples, and red wine. More research is needed for further elucidation of the mechanisms of flavonoid absorption, metabolism, biochemical action, and association with CHD.
2,201 citations
TL;DR: The relative antioxidant activities, against radicals generated in the aqueous phase, of a range of plant-derived polyphenolic flavonoids, constituents of fruit, vegetables, tea and wine, have been assessed and compounds such as quercetin and cyanidin have antioxidant potentials four times that of Trolox, the vitamin E analogue.
Abstract: The relative antioxidant activities, against radicals generated in the aqueous phase, of a range of plant-derived polyphenolic flavonoids, constituents of fruit, vegetables, tea and wine, have been assessed. The results show that compounds such as quercetin and cyanidin, with 3′,4′ dihydroxy substituents in the B ring and conjugation between the A and B rings, have antioxidant potentials four times that of Trolox, the vitamin E analogue. Removing the ortho-dihydroxy substitution, as in kaempferol, or the potential for electron deloculisation by reducing the 2.3 double bond in the C ring, as in catechin and epicatechin, decreases the antioxidant activity by more than 50%. but these structures are still more effective than α-tocopherol or ascorbate. The relative significance of the positions and extents of hydroxylation of the A and B rings to the total antioxidant activity of these plant polyphenols is demonstrated.
2,101 citations