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Antioxidant power of phytochemicals from Psidium guajava leaf.
J Zhejiang Univ Sci. 2004 Jun; 5(6):676-83.JZ

Abstract

Dried ground leaves of Psidium guajava L. (guava) were extracted by water and aqueous ethyl alcohol 50% (1:10) ratio, and the total phenolic content in the extracts was determined spectrophotometrically according to Folin- Ciocalteu's phenol method and calculated as gallic acid equivalent (GAE). Remarkably high total phenolic content 575.3 +/-15.5 and 511.6+/-6.2 mg of GAE/g of dried weight material (for ethanol guava leaf extracts and water guava leaf extracts, respectively) were obtained. The antioxidant activity of lyophilized extracts was determined at ambient temperature by means of a 2,2-diphenyl-1-picrylhydryzyl (DPPH*) colorimetry with detection scheme at 515 nm. The activity was evaluated by the decrease in absorbance as the result of DPPH* color change from purple to yellow. The higher the sample concentration used, the stronger was the free radical-scavenging effect. The results obtained showed that ascorbic acid was a substantially more powerful antioxidant than the extracts from guava leaf. On the other hand, the commercial guava leaf extracts and ethanol guava leaf extracts showed almost the same antioxidant power whereas water guava leaf extracts showed lower antioxidant activity. The parameter EC(50) and the time needed to reach the steady state to EC(50) concentration (T(EC(50))) affected the antiradical capacity of the sample. The antioxidant efficiency (AE) has been shown to be a more adequate parameter for selecting antioxidants than the widely used EC(50). This study revealed that guava leaf extracts comprise effective potential source of natural antioxidants.

Authors+Show Affiliations

Department of Food Science and Technology, Functional Foods Research Center of Ministry of Education, Southern Yangtze University, Wuxi 214036, China. qiandahe@vip.sina.comNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

15101101

Citation

Qian, He, and Venant Nihorimbere. "Antioxidant Power of Phytochemicals From Psidium Guajava Leaf." Journal of Zhejiang University. Science, vol. 5, no. 6, 2004, pp. 676-83.
Qian H, Nihorimbere V. Antioxidant power of phytochemicals from Psidium guajava leaf. J Zhejiang Univ Sci. 2004;5(6):676-83.
Qian, H., & Nihorimbere, V. (2004). Antioxidant power of phytochemicals from Psidium guajava leaf. Journal of Zhejiang University. Science, 5(6), 676-83.
Qian H, Nihorimbere V. Antioxidant Power of Phytochemicals From Psidium Guajava Leaf. J Zhejiang Univ Sci. 2004;5(6):676-83. PubMed PMID: 15101101.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Antioxidant power of phytochemicals from Psidium guajava leaf. AU - Qian,He, AU - Nihorimbere,Venant, PY - 2004/4/22/pubmed PY - 2005/2/4/medline PY - 2004/4/22/entrez SP - 676 EP - 83 JF - Journal of Zhejiang University. Science JO - J Zhejiang Univ Sci VL - 5 IS - 6 N2 - Dried ground leaves of Psidium guajava L. (guava) were extracted by water and aqueous ethyl alcohol 50% (1:10) ratio, and the total phenolic content in the extracts was determined spectrophotometrically according to Folin- Ciocalteu's phenol method and calculated as gallic acid equivalent (GAE). Remarkably high total phenolic content 575.3 +/-15.5 and 511.6+/-6.2 mg of GAE/g of dried weight material (for ethanol guava leaf extracts and water guava leaf extracts, respectively) were obtained. The antioxidant activity of lyophilized extracts was determined at ambient temperature by means of a 2,2-diphenyl-1-picrylhydryzyl (DPPH*) colorimetry with detection scheme at 515 nm. The activity was evaluated by the decrease in absorbance as the result of DPPH* color change from purple to yellow. The higher the sample concentration used, the stronger was the free radical-scavenging effect. The results obtained showed that ascorbic acid was a substantially more powerful antioxidant than the extracts from guava leaf. On the other hand, the commercial guava leaf extracts and ethanol guava leaf extracts showed almost the same antioxidant power whereas water guava leaf extracts showed lower antioxidant activity. The parameter EC(50) and the time needed to reach the steady state to EC(50) concentration (T(EC(50))) affected the antiradical capacity of the sample. The antioxidant efficiency (AE) has been shown to be a more adequate parameter for selecting antioxidants than the widely used EC(50). This study revealed that guava leaf extracts comprise effective potential source of natural antioxidants. SN - 1009-3095 UR - https://www.unboundmedicine.com/medline/citation/15101101/Antioxidant_power_of_phytochemicals_from_Psidium_guajava_leaf_ DB - PRIME DP - Unbound Medicine ER -