Covering: 2012 to 2014. Previous review: Nat. Prod. Rep., 2012, 29, 1382 The present
review discusses the isolation, structure determination, synthesis, biosynthesis and
biological activities of secondary metabolites bearing a guanidine group. Topics include non-
ribosomal peptides, alkaloids, guanidine-bearing terpenes, polyketides and shikimic acid
derivatives from natural sources. A critical analysis of some yet underdeveloped aspects of
guanidine metabolites is also presented.

Covering: 2015 and 2016 The chemistry and biology of natural guanidines isolated from
microbial culture media, from marine invertebrates, as well as from terrestrial plants and
animals, are reviewed. Emphasis is directed to the biosynthesis, total synthesis, ecological
roles as well as on the evolution of guanidines isolated from natural sources.