**2.4 Phenolics**

Phenolic compounds are considered highly abundant group of plant metabolites. These metabolites are classified into three major groups: flavonoids (polyphenolic compounds, which exist as aglycones, methylated derivatives, and glucosides in plants), phenolic acids (e.g., hydroxybenzoic and hydroxycinnamic acids), and polyphenols [55, 56]. Additionally, these APD-APIs are characterized by a hydroxyl group bonded to an aromatic hydrocarbon group, with the most basic being a phenol (C6H5OH). Phenolics include lignins and tannins (polyphenolic compounds with high molecular weight) such as hydrolyzable and condensed tannins. Classification of phenolics is normally based on three methods: (1) number of hydroxylic groups, (2) chemical composition, and (3) number of aromatic rings as well as number of carbon atoms in the side chain [56]. Generally, phenolic compounds are rarely in a free form in plants, and therefore, they exist as glycosylates and polyphenols [55–57]. Phenolic compounds such as ellagic acid have shown significant degree of activity against malaria parasites, for example, [58] reported antimalarial activity of ellagic acid against *Plasmodium vinckei*. The presence of the phenolics in plants used traditionally against malaria has been noted in several of experimental reports [59–61]. The *Artocarpus styracifolius* (Moraceae) ethyl acetate extract (10 μg/ml) containing flavonoids (polyphenol) inactivated FcB1 *P. falciparum* significantly [62, 63]. According to [62], prenylated flavonoids including artoheterophyllin displayed high activity against *P. falciparum* strain FcB1 (IC50 = 4.797 μM) (**Figure 4**).

**Figure 4.** *Structural summary of some of the antimalarial phenolics.*
