Having built & finished teak furniture as well as having refinished the interior of Victoria
, I have some experience here. Many planks of a specie vary wildly in color and grain. Graining will also affect final finish color, too.
Assuming that you did not sand through to the substrate and are dealing with only teak and holly, I'll say that unfinished teak is generally light in color. When a finish is applied, it then darkens the degree of which varies according to the type of finish applied. True varnish will darken the most because of the oils. Urethanes (virtually bullet proof) darken less, but add a nice warm glow, IMO.
Wipe a section of teak with plain water. This is the best that you can do without bleaching. IMO, bleaching is not an option (for me) because it casts a really weird silver or white tint to the wood. I'd rather paint it than abuse the poor piece of wood.
A foolproof way of limiting the toning of any wood is to isolate it from the finish. Apply 2 or more coats Zinsser's Shellac Sealer followed by water-based Urethane. NOTE that I do NOT recommend this course of action. It will work, but aesthetically (again, to me), the warm glow imparted by a oil-based finish is comforting. While a water-based urethane will not darken a wood after it dries, it is notoriously difficult to flow-out properly. Most woodworkers stay away from water-based finishes for this reason.
Examples of the variety of teak follow:
Plantation Teak Corner Cabinet: FURNITURE
Interior with light teak floor and darker paneling: VICTORIA (and her mistress)