How to get the list of items in a transaction in package arules

I know you can see the content of each transaction using inspect and then extract the items yourself, but is there a convenient way to get a list of all items which belong to a transaction?

a_list <- list( # Create example data
      c("a","b","c"),
      c("a","b"),
      c("a","b","d"),
      c("c","e"),
      c("a","b","d","e")
      )

## set transaction names
names(a_list) <- paste("Tr",c(1:5), sep = "")
a_list

## coerce into transactions
trans1 <- as(a_list, "transactions")

## analyze transactions
summary(trans1)
image(trans1)  

# if you want an actual list structure:
trans1 <- as(a_list, "list")

This is the plot of it from image():

Now with a bigger transactions object:

data("Adult")
adult_list <- as(Adult, "list")