A wide variety of solar eruptive phenomena such as flares and CMIs severely shape the interplanetary environment and strongly interact with the Earth magnetic field, posing interesting scientific issues and turning into a possible hazard for space missions and ground facilities. It has been shown in several studies that there is a correlation between changes in the magnetic field configuration of the solar active regions (ARs) and the eruptive events, up to two days prior to the event. In our studies we are investigating a possible correlation between the ARs’ spectral index temporal variation and the eruptive phenomena in the K-band range (18-26 GHz). Our work is conducted in the context of the SunDish project, which aims to map and monitor the Sun at high radio frequencies with the Italian Sardinia and Medicina Radio Telescopes. We are comparing our results with recently updated flare catalogs, based on GOES and AGILE data, in order to correlate our AR data with the flares detection