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Nikitina, V. S.; Shendel, G. V.; Gerchikov, A. Ya.; Efimenko, N. B.

doi:10.1023/a:1010344221983

Cited by 7 publications

(2 citation statements)

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“…In this group, the antioxidant activity is characterized in terms of a decrease in the oxidation rate (Table 2), which is analogous to the approach used in [21]. Among inhibitors of the second type appearing as SC extracts of a dark-green color (where the active compounds most likely represent phenols, catechols, azulenes, chlorophylls), the maximum activity was observed for the SCV extracts of aloe, green tea, and parsley.…”

Section: Resultsmentioning

confidence: 99%

Content of antioxidants in plant extracts obtained by supercritical extraction

Sizova

Popova²

2006

Pharm Chem J

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The content of natural antioxidants in extracts of medicinal plants, fruits, and seeds obtained by supercritical fluid extraction was determined by a microcalorimetric technique using the model reaction of induced cumene oxidation. All tested extracts can be divided into two groups according to their antioxidant activity. The first group includes extracts containing strong antioxidants with high inhibition rate constants; the second group includes preparations containing week antioxidants capable of reducing the oxidation rate. Among the preparations studied, the maximum concentrations of antioxidants were found in the extracts of sage (10.0´10 -2 mole/kg), rosemary (5.3´10 -2 mole/kg), cranberry (1.4´10 -2 mole/kg), and carrot (1.2´10 -2 mole/kg). The rate constants of reactions between antioxidants and peroxide radicals were calculated (k 7 = (0.4 -9.0)´10 4 liter/(mole sec)). With respect to this value, several types of natural antioxidants can be distinguished in each extract. The most active antioxidants are those contained in the rosemary extract, their reaction rate constants being about 2.3´10 5 liter/(mole sec). It is suggested that the most active components are tocopherols, polyphenols, and quinones.

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Section: Resultsmentioning

confidence: 99%

Content of antioxidants in plant extracts obtained by supercritical extraction

Sizova

Popova²

2006

Pharm Chem J

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“…Materials were studied using methods described at the Institute of Chemical Physics, Russian Academy of Sciences [1,2,11,17,20] based on the model initiated free-radical cumene oxidation reaction at 60°C; the initiator was azo-bis-isobutyronitrile (AIBN) and the rate of initiation w i was 6.8´10 8 liter/mol · sec. Figure 1 shows heat production curves for the model initiated free-radical cumene oxidation reaction with addition of fatty oils.…”

Section: Methodsmentioning

confidence: 99%

Estimation of vitamin E in plant oils by microcalorimetry

Sizova

Andreeva

2007

Pharm Chem J

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Microcalorimetric studies were performed to estimate the content of vitamin E (tocopherols) in natural plant oils. The approach used was a kinetic method of estimating vitamin E and was based on the ability of tocopherols to inhibit a liquid-phase free-radical oxidation reaction. A model reaction consisting of the initiation of cumene (isopropylbenzene) oxidation showed that fatty oils inhibit the free-radical reaction with an induction period proportional to the content of tocopherols in oils. Tocopherol contents measured here were in good agreement with values reported in the literature. Experimental curves were used to calculate oxidation inhibition rate constants; all the oils tested (cameline seed, wintercress, rapeseed, and cedar) had essentially identical values, at k 7 = (1.4 -6.8)´10 4 mol/liter · sec.

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