If there is only one ...
as in the example then match everything up to and everything from
forward and replace them both with the empty string:
x <- "the text I need to extract
giving:
[1] "the text I need to extract"
If there could be multiple occurrences in the same string then try:
library(gsubfn)
strapplyc(x, "(.*?)", simplify = c)
giving the same in this example.