It depends on what information you want. The red line appears to interpret the results of the image behind it, so it would likely be best to just use it (although I do not know what it actually plots).
To get the peaks and valleys and their values, use either findpeaks (on the orignal and negated vector) or islocalmax and islocalmin to get the same information. To get the areas, use cumtrapz or trapz depending on the information you want.
See the documentation on the various functions that I link to here for details on using them.
