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Antioxidant capacity and phenolic contents of three Quercus species

100%

Thi Tuyen P., Tan Khang D., Thu Ha P. T., Ngoc Hai T., Elzaawely A. A., Dang Xuan T.

International Letters of Natural Sciences

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2016

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tom 54

The antioxidant capability and phenolic contents of ethanol extracts (free phenolics) and ethyl acetate extracts (bound phenolics) of three Quercus species were estimated in this work. The antioxidant activities were examined by 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) free radical, reducing power and β-carotene bleaching methods. HPLC was employed to detect major phenolic acids. The leaf extract of Q. salicina contained maximum total phenolics while the highest total flavonoid content was found in the leaf extract of Q. serrata. The antioxidant activities varied among three species. Bark extract of Q. salicina was the most potential and it was closed to levels of the standard antioxidative dibutyl hydroxytoluene (BHT). The bark extract of Q. serrata also showed promising antioxidant activities despite their eminence was negligibly lower than Q. salicina. Stronger antioxidant activities of free phenolics than those of the bound phenolics may be attributed to higher quantities of free phenolics in the barks of Quercus species, however total flavonoids may not contribute a critical role. By HPLC analysis, thirteen phenolic acids were detected in the leaf and bark extracts. Of them, Q. salicina showed maximum in number (ten compounds) and quantities of detected phenolic acids. Ellagic, chlorogenic and benzoic acids were dominant in Quercus species. Findings of this study revealed that leaves and barks of three Quercus species are rich source of antioxidants, and Q. salicina is the most promising and should be elaborated to exploit its pharmaceutical properties.

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Development of new drought tolerant breeding lines for Vietnam using marker-assisted backcrossing

84%

Thu Ha P. T., Khang D. T., Tuyen P. T., Toan T. B., Huong N. N., Lang N. T., Buu B. C., Xuan T. D.

International Letters of Natural Sciences

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2016

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tom 59

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Correlation among agro-morphological variation and genetic diversity of rice (Oryza sativa L.) under drought stress

84%

Thu Ha P. T., Khang D. T., Tuyen P. T., Minh L. T., Minh T. N., Thi Lang N., Buu B. C., Xuan T. D.

International Letters of Natural Sciences

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2016

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tom 58

In this study, the correlation coefficients among agro-morphological variation, genetic diversity, and drought tolerance in 44 rice cultivars were analyzed. The drought tolerance at seeding stage (DTS) was significantly proportional to drought tolerance at vegetative stage (DTV) (r = 0.60). In addition, DTS and DTV had strong significant positive correlation to leaf roll (r = 0.87 and 0.54, respectively). Means of unfilled grains and tilling per panicle were proportionally correlated to DTS (r = 0.22 and 0.25, respectively), and DTV (r = 0.20 and 0.36, respectively). However, weight of 1000 grains and filled grains were recorded no correlation to DTS and DTV. At a homologous coefficient of 16.85 integrated from cluster analysis of agro-morphological, quantitative characteristics and drought tolerant scores, the rice cultivars were divided into five groups. Maximum polymorphic information content (PIC) values were detected in three markers including RM11125, RM21, and RM5629, which were from 0.78 to 0.79. Cluster analysis of microsatellite markers revealed that by a genetic distance of 0.63, the rice varieties were separated into three clusters. The results provide valuable information for rice breeders to select donors in breeding rice integrated with drought tolerance and good agronomic characteristics.

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Allelopathic activity of dehulled rice and its allelochemicals on weed germination

68%

Khang D. T., Anh L. H., Thu Ha P. T., Tuyen P. T., Quan N. V., Minh L. T., Quan N. T., Minh T. N., Xuan T. D., Khanh T. D., Trung K. H.

International Letters of Natural Sciences

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2016

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tom 58

In this study, the allelopathic potential of dehulled rice, rice, and hulls of rice on germination of weeds was evaluated in laboratory. Phenolic acids in growth media of these plants were also identified and quantified using HPLC. Identified allelochemicals were reversely tested for phytotoxic effects on germination and seedling growth of barnyardgrass, lettuce, radish and rice. The results showed that the inhibitory effects of dehulled rice were stronger than those of hulls and rice. Dehulled rice caused 66.7% and 50.6% reduction in radish root length and lettuce shoot height, respectively. Dehulled rice showed strong inhibitory effects on root length of lettuce and shoot height of radish while hulls and rice exhibited stimulation. Regarding phenolic identification, vanillin and vanillic acid were detected as allelochemicals in root exudates of rice and tested plants. The results revealed that most of the vanillin and vanillic acid treatments showed high inhibitory effects on germination rates and seedling growth of lettuce and radish, high stimulatory activity on root elongation of rice. Vanillic acid (100 ppm and 200 ppm), vanillin (100 ppm) and their mixture (200 ppm) completely inhibited survival of lettuce. The findings indicate the allelopathic potential of dehulled rice which can be used for identification of more phytotoxins to produce bioherbicides in agricultural practices.

Ograniczanie wyników

4 International Letters of Natural Sciences

4 Thu Ha P. T.

3 Khang D. T.

3 Tuyen P. T.

3 Xuan T. D.

2 Buu B. C.

2 Minh L. T.

2 Minh T. N.

1 Anh L. H.

1 Dang Xuan T.

1 Elzaawely A. A.

1 Huong N. N.

1 Khanh T. D.

1 Lang N. T.

1 Ngoc Hai T.

1 Quan N. T.

1 Quan N. V.

1 Tan Khang D.

1 Thi Lang N.

1 Thi Tuyen P.

1 Toan T. B.

1 Trung K. H.

4 2016

Antioxidant capacity and phenolic contents of three Quercus species

Development of new drought tolerant breeding lines for Vietnam using marker-assisted backcrossing

Correlation among agro-morphological variation and genetic diversity of rice (Oryza sativa L.) under drought stress

Allelopathic activity of dehulled rice and its allelochemicals on weed germination