DNA dye: Are there any natural dye for DNA (instead of artificial ones)? In order to make easy and low-cost experiments, we are searching for natural dyes (or easy to make) that can color DNA, instead of for instance Ethidium Bromide that is hard to find and is expensive.

We are new to this field, but we learned that DNA dyes need to intercalate in between DNA bases. To do so, the molecule must be preferably poly-cyclic, aromatic and planar.

So the question is, is there any chemical that can be readily used for this purpose or if not, any lead about a molecule that can be easy to find by anyone.
Though not a naturally occurring dye, methylene blue has been used as a DNA stain. It is inexpensive and readily available. It is also comparatively nontoxic, and is used as a medication in pisciculture, so it can be found in pet stores.
If you choose to use methylene blue, save some for the blue bottle demonstration, a sensitive test for oxygen. Vitamin C or other reducing agents can be used instead of glucose.