Comparative study of two kalanchoe species: Total flavonoid and phenolic contents and antioxidant properties

Abstract

The research was conducted to determine the antioxidant activity of two Kalanchoespecies in Ghana which are used widely for the treatment of various ailments including stroke and ulcers. The leaves were subjected to methanol and aqueous extractions for each sample. Thin layer chromatography (TLC) was performed to determine the various components in the leaves extract. The concentration of phenol and flavonoid was determined using folin-ciocalteu Zishen et al. (2003) and Lee et al. (2005) method. The extract was also screened to determine the total flavonoid and phenolic content of the methanol and aqueous extracts of the leaves of Kalanchoe pinnata and Kalanchoe integraand also to assess the antioxidant activity. 1,1-Diphenyl-2-picrylhydryzyl [DPPH] radical scavenging activity of both aqueous and methanol extracts of K. integra and K. pinnatawere determined by the Brand-William method (2003) with slight modification. The phytochemical analysis indicated that the leave extracts were rich in total flavonoid and phenolic compounds. However, the aqueous extract of both K. pinnata and K. integrashowed excellent antioxidant activity whereas that of the methanol was less effective compared to the butylated hydroxytoluene (BHT) which was used as control. The reducing power increased with increasing concentration, and the scavenging effect of aqueous extract on the DPPH radical was excellent. In conclusion, n-butanol: chloroform: acetic acid: water (7:3:1:1) is most suitable solvent for TLC analysis of the aqueous and methanol extract of K. pinnata and K. integra. Kalanchoe species possess a strong antioxidant property that reacts with free radicals. Key words: Kalanchoe species, antioxidant, total flavonoids, total phenolic content.