Table 1. The analogies between Naturally Occurring AMPs and Synthetic AMPs.

	Naturally occurring AMPs	Synthetic AMPs	References
Sources/Origin	-Found in many tissues of many different species -Found in nearly all forms of life, and mostly reported to be isolated from eukaryotes, such as animals, plants and fungi -Found in prokaryotic cells	-Non-natural sources -Often created by mimicking natural sequences	(Jiang et al., 2021; Kumar, Kizhakkedathu & Straus, 2018; Nakatsuji & Gallo, 2012)
Content	-Comprised of l-amino acids recognizable by proteases	-The rational design of sequences comprising analogous d-amino acids substituted for l-amino acids	(Da Cunha et al., 2017; Zhao et al., 2016)
Discovery methods	-Using classic purification and in vitro and in vivo techniques	-Combination of trial-and-error experimentation, screening, or computer-aided design (increasing the peptide post-translational stability without altering biological function).	(Da Cunha et al., 2017; Jiang et al., 2021)
Characteristics	-Frequently susceptible to protease degradation -Low bioavailability (i.e., presence of bioactive molecules at usually low levels). -Low resistance to proteolytic degradation resulting in shorter half-lives	-High bioavailability -Longer half-lives in vivo, while maintaining a similar activity and selectivity. -Designed to improve their potential without side effects -Incorporation of multiple functions in the same peptide sequence	(Azmi, Skwarczynski & Toth, 2016; Da Cunha et al., 2017; Jiang et al., 2021; Lei et al., 2019; Lu et al., 2020; Mahlapuu et al., 2016; Wimley, 2019)
Examples	-Protegerin -Indolicin -Magainin 2 -Moringa oleifera chitin-binding protein (Mo-CBP)	-Iseganan (protegerin as template) -Omiganan (developed from indolicin) -Pexiganan (developed from magainin 2) -Mo-CBP3-PepIII (developed from Mo-CBP)	(Ge et al., 1999; Gottler & Ramamoorthy, 2009; Oliveira et al., 2019; Sader et al., 2004; Trotti et al., 2004)