Planta Med 2014; 80 - P2P31
DOI: 10.1055/s-0034-1394866

In vitro antioxidant activities of Bauhinia strychnifolia extracts: Comparison with green tea extracts

A Itharat 1, 2, S Sayompark 1, P Hansakul 3, B Dechayont 1
  • 1Department of Applied Thai Traditional Medicine Faculty of Medicine, Thammasat University, Klongluang, Pathumthani 12120, Thailand
  • 2Center of Excellence in Applied Thai Traditional Medicine Research (CEATMR), Faculty of Medicine, Thammasat University, Klongluang, Pathumtani, 12120, Thailand
  • 3Department of Preclinical Science, Faculty of Medicine, Thammasat University, Klongluang, Pathumthani 12120, Thailand

Dried stems and leaves of Bauhinia strychnifolia Craib. have long been used in Thailand to make tea for promoting health and for detoxification of the body. The objectives of this study were to investigate antioxidant activities of B. strychnifolia dried stem and leaf extracts obtained by different extraction methods. The antioxidant power of B. strychnifolia extracts and water extracts of green tea leaves (Camellia sinensis) were evaluated using four different methods: DPPH radical scavenging assay [1], Ferric reducing antioxidant power (FRAP) assay[2], and Superoxide radical scavenging by NBT dye reduction assay[3], and measurement of total phenolic contents by the Folin-Ciocalteu colorimetric method [4]. The 95% ethanolic extract of B. strychnifolia stems exhibited the strongest DPPH radical scavenging activity, with an EC50 value of 4.21 ± 0.77 µg/ml. This was in agreement with results from the Ferric reducing antioxidant power assay, which showed that this extract had the highest FRAP value and TEAC (Trolox equivalent antioxidant capacity) values of 1481.21 ± 0.76 mg Fe(II)/g and 421.44 ± 1.87 mg Trolox/g, respectively. The 50% ethanolic extracts of B. strychnifolia stems showed the highest superoxide radical scavenging activities with an EC50 value of 85.69 ± 0.37 µg/ml. The total phenolic contents of all extracts ranged from 143.65 to 390.10 mg GAE/g. The 95% ethanolic extract of B. strychnifolia stems had the highest total phenolic contents (390.10 ± 1.25 mg GAE/g). Green tea water extracts showed less antioxidant activity than 95% ethanol Bauhinia stem extracts, by all assays, except by the DPPH assay. The results from this study indicate that ethanolic extracts of B. strychnifolia stems are rich in phenolic content and demonstrate as good, or better antioxidant activities compared to green tea.

Keywords: Bauhinia strychnifolia Craib, green tea extracts, antioxidant activity, total phenolic content

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