Cinnamon is used by many people who want to grow their orchids without using synthetic pesticides or fungicides. It acts, apparently, as a natural fungicide and can be used for fungus infections on leaves as well.

I think when you say "closing wounds" you mean covering the cut rhizomes of orchid plants that have been divided. It's important to cover that cut before you repot the plant to keep fungus from developing on the exposed area and infecting the plant from the consistently damp root zone.

Here, we just use that black tar stuff commonly sold at garden centers as "pruning sealer." When you have a lot of plants to divide, cinnamon can get pretty expensive, but for the home grower, it's something readily available and stocked in most people's kitchens. I've never tried it personally, so can't tell you how effective it is or if it even works at all....