Electroanalytical determination of catechin flavonoid in ethyl acetate extracts of medicinal plants

Manki S. Maoela, Omotayo A. Arotiba, Priscilla G.L. Baker, Wilfred T. Mabusela, Nazeem Jahed, Everlyne A. Songa, Emmanuel I. Iwuoha

Research output: Contribution to journalArticlepeer-review

47 Citations (Scopus)

Abstract

South African Carpobrotus species have been found to contain hydrolyzable tannins, various flavonoids e.g. rutin and hyperoside, phytosterols and aromatic acids which have a diverse range of pharmacological properties; including antimicrobial and antioxidant activities. In this paper we described the identification and quantification of catechin in C. mellei and C. quadrifidus using cyclic and square wave voltammetry. The oxidation potential of catechin ranges from +171.0 mV to +631.6 mV. The oxidation mechanism proceeds in sequential steps, related to the catechol moiety and 3-hydroxyl group. The oxidation of the catechol electron donating group occurs first at low potential and is a reversible reaction. The 3-hydroxyl group oxidises after and undergoes an irreversible reaction. The limit of detection (LOD) of catechin is 0.84 ppm and limit of quantification (LOQ) is 2.79 ppm with R.S.D. equal to 2.5%. The oxidation potentials of the ethyl acetate extracts of C. mellei and C. quadrifidus correspond with that of catechin. The content of catechin in C. mellei and C. quadrifidus was 5.0 ppm and 4.7 ppm, respectively. Other analytical techniques such as HPLC, UV-VIS, NMR, and FTIR were also used to validate the presence of catechin in the plant extracts.

Original languageEnglish
Pages (from-to)1497-1510
Number of pages14
JournalInternational Journal of Electrochemical Science
Volume4
Issue number11
Publication statusPublished - Nov 2009
Externally publishedYes

Keywords

  • Carpobrotus mellei
  • Carpobrotus quadrifidus
  • Catechin
  • Cyclic voltammetry
  • Flavonoid
  • Square wave voltammetry

ASJC Scopus subject areas

  • Electrochemistry

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