Table 1. Major classes of natural preservatives of plant origin

Class	Subclass	Examples	References
Phenolics	Simple phenols	Catechol	Hintz et al., 2015
		Epicatechin	Mason and Wasserman, 1987
	Phenolic acids	Cinnamic acid	Cowan, 1999
			Hintz et al., 2015
	Quinones	Hypericin	Cowan, 1999
			Hintz et al., 2015
	Flavonoids	Chrysin	Dua et al., 2013
		Quercetin	Lee et al., 2011
	Flavones	Abyssinone	Cowan, 1999
	Flavonols	Totarol	Cowan, 1999
	Tannins	Ellagitannin	Dua et al., 2013
			Lee et al., 2016
	Coumarins	Coumarin	Cowan, 1999
		Warfarin	Hintz et al., 2015
		7-Hydroxycoumarin
Terpenoids, essential oils		Capsaicin	Bajpai et al., 2008
		Eugenol	Gutierrez et al., 2008
		Thymol	Helander et al., 1998
		Carvacrol	Tiwari et al., 1998
Alkaloids		Berberine	Cowan, 1999
		Harmane	Garba and Okeniyi, 2012
		Piperine
Lectins and polypeptides		Mannose-specific agglutinin	Cowan, 1999
		Fabatin	Cowan, 1999
Polyacetylenes		8S-Heptadeca-2(Z),9(Z)-diene-4,6-diyne-1,8-diol	Cowan, 1999
Antimicrobial peptide (pAMP)		Potato defensin, hevein, thionines,	Hintz et al., 2015
		snakins, lipid transfer protein etc.	Jessen et al., 2006