Statistical analysis
All the data are presented as standard error of the mean ± (SEM) from triplicate experiments and were analysed using Statistically Package for Social Sciences (SPSS) software version 17.0. A one-way analysis of variance (ANOVA) was used for multiple comparison. The concentration of the compounds required to inhibit 50 % oxidation (IC50) for active extract was determined using probit programme. The correlation between TPC and TFC in the extracts and antioxidant properties was described by the Pearson product-movement correlation coefficient (r). P < 0.05 was considered to be
statistically significant.