Antioxidant dehydrotocopherols as a new chemical character of Stemona species

Brem, Brigitte; Seger, Christoph; Pacher, Thomas; Hartl, Markus; Hadaček, Franz; Hofer, Otmar; Vajrodaya, Srunya; Greger, Harald

doi:10.1016/j.phytochem.2004.08.023

Cited by 69 publications

(65 citation statements)

References 26 publications

(34 reference statements)

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“…An increase in tocopherol content around the second day under both stresses not correlated with the chlorophyll degradation may indicate that in the leaves of tomato plants this compound was synthesized de novo at an early phase of salinity stress, and tocopherol probably acted as a typical antioxidant reducing susceptibility of thylakoid membranes to peroxidation. The observations of Brem et al (2004) indicating that during in vitro study tocopherol achieved a plateau in its antioxidant activity after 90 min seem to prove the above suggestion. All the above data allow to suppose that the constitutive level of tocopherol in tomato plants was utilized between the first and third h after NaCl treatment and later its regeneration was not sufficient, therefore its biosynthesis started.…”

Section: Discussionsupporting

confidence: 58%

Tocopherol content and enzymatic antioxidant activities in chloroplasts from NaCl-stressed tomato plants

et al. 2008

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Changes in tocopherol, chlorophyll and TBARS levels and the activities of antioxidant enzymes i.e., GSH-Px, GST, and SOD in chloroplasts of tomato plants subjected to moderate (50 mM) and severe (150 mM) NaCl stress were determined. Increase in tocopherol content around the second day under both stresses did not correlate with the chlorophyll degradation while such correlation was observed from the fifth day of severe stress. The activities of GSH-Px and GST as well as TBARS content showed NaCl-induced enhancement which was dose-and time-dependent. However, chloroplastic SOD was rather not involved in the response of tomato plants to NaCl stress. The obtained results suggest that under the moderate stress similarly as in the early phase of severe stress tocopherol functions as a typical antioxidant, while in the late phase of the latter it may be involved in senescence signaling pathway and enables the recovery and recycling of the compounds significant for a plant organism.

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Section: Discussionsupporting

confidence: 58%

Tocopherol content and enzymatic antioxidant activities in chloroplasts from NaCl-stressed tomato plants

et al. 2008

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“…The mixtures were then mixed with a vortex mixer and incubated in the dark at room temperature for 30 min. The absorbance was measured spectrophotometrically at 520 nm with a microplate reader (DTX 880 multimode detector) (Brem et al, 2004). The percentage of inhibition was calculated by the equation:…”

Section: Dpph Radical Scavenging Assaymentioning

confidence: 99%

Evaluation of antioxidant and anti-tyrosinase activities as well as stability of green and roasted coffee bean extracts from Coffea arabica and Coffea canephora grown in Thailand

Kiattisin¹,

Nantarat²,

Leelapornpisid³

2016

J. Pharmacognosy Phytother.

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Coffea arabica (Arabica) and Coffea canephora (Robusta) are the economic plants in Thailand that are widely cultivated in Northern and Southern Thailand. This study aims to evaluate the antioxidant, antityrosinase activities, toxicity, stability and identify chemical components of the coffee bean extracts. The best extract that showed good biological activities will be further used to develop cosmeceutical products. Green and roasted coffee beans from two species were extracted with hexane following ethanol by maceration. Their antioxidant activities were detected by 2,2-diphenyl-1-picryl hydrazyl (DPPH), 2,2'-Azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) and lipid peroxidation inhibition assays. In addition, anti-tyrosinase activity was also evaluated. The results revealed that the ethanolic coffee bean extracts showed a higher level of antioxidant activity than in the hexane extracts. All extracts also possessed a considerable anti-tyrosinase activity, but less potent than kojic acid and arbutin. Chemical compounds of these extracts were determined using caffeine and chlorogenic acid as standards of reference by the thin layer chromatography and the high performance liquid chromatography. The green coffee bean extracts consisted of caffeine and chlorogenic acid while the roasted coffee bean extracts presented only caffeine due to a few chlorogenic acid content after the roasting process. The ethanolic coffee bean extracts that showed good activities were selected to be evaluated on toxicity and stability. The selected extracts were kept at various storage conditions to evaluate their stability using DPPH assay and anti-tyrosinase activity assay. The result showed that the extracts were not toxic to cells. Therefore, the extracts were safe to be components in skin care products. After the stability test, the extracts indicated a good stability and activities. These results led to the conclusions that the coffee bean extracts possess a good biological activities and are assumed to be promising natural active ingredients with a good stability profile for further development of cosmeceutical or anti-aging products.

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“…Stemona is the largest genus with about 25 species occurring as subshrubs or twining herbs, mostly with perennial tuberous roots (Brem et al 2002(Brem et al , 2004.…”

Section: Alkaloids From Stemonaceaementioning

confidence: 99%

Plant Natural Products as a Source for Developing Environmentally Acceptable Insecticides

Isman

Akhtar

2007

Insecticides Design Using Advanced Technologies

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Antioxidant dehydrotocopherols as a new chemical character of Stemona species

Cited by 69 publications

References 26 publications

Tocopherol content and enzymatic antioxidant activities in chloroplasts from NaCl-stressed tomato plants

Tocopherol content and enzymatic antioxidant activities in chloroplasts from NaCl-stressed tomato plants

Evaluation of antioxidant and anti-tyrosinase activities as well as stability of green and roasted coffee bean extracts from Coffea arabica and Coffea canephora grown in Thailand

Plant Natural Products as a Source for Developing Environmentally Acceptable Insecticides

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