Looks like the method you've used is descibed in J. Zhishen et al. Food Chemistry 64 (1999) 555-559. Over there they show the calibration line for rutin so you can just apply it for calculating the rutin equivalents.
Actually to analysis the result related to spectrometer, you have to first know about the absorbance of different concentrations of your standard.
Then, it is really hard to estimate that you also got reading in control sample... So please let me know about detail procedure..so that i can help u to analyze ur results
The question is vague. It appears that you intend to estimate total flavonoid in a extract or ployphenol-rich fraction. You have taken OD of using UV/VIS spectrometer at 510nm. It is not clear which estimation protocol you have used, which very important, Also ,you have not mentioned above the standard used for generated calibration graph which I hope, you might done. Based on the values indicated for control and sample, the sample appears to contain significant level of total flavonoid.