Medicinal Plant Research 2025, Vol.15, No.6, 264-273 http://hortherbpublisher.com/index.php/mpr 266 2.4 Overview of pharmacological activities of phenylpropanoids Among the phenylpropanoid compounds of A. sinensis, a wide range of pharmaceutical activities has been demonstrated. The majority of them are highly effective antioxidants and anti-inflammatory agents, while phthalides and coumarins were highly inhibitive against nitric oxide production and pro-inflammatory cytokines' release (Wen et al., 2025; Zhang et al., 2025). They further improve blood circulation and inhibit platelet aggregation, producing neuroprotective effects, and hence justify traditional applications in cardiovascular and neurological conditions (Xu et al., 2019; Li et al., 2023; Zou et al., 2024). Furthermore, certain phenylpropanoids possess anti-osteoporotic, antifibrotic, and immunomodulatory activities that extend the therapeutic perspectives for A. sinensis (Chen et al., 2024) (Figure 1). Figure 1 Pharmacological activity of benzo-phenyl compounds from angelica sinensis (Adopted from chen et al., 2024) 3 Biosynthetic Pathways of Phenylpropanoid Compounds inAngelica sinensis 3.1 Overview of the phenylpropanoid pathway mediated by phenylalanine ammonia-lyase (PAL) The phenylpropanoid pathway of Angelica sinensis is initiated by PAL, which catalyzes the deamination of L-phenylalanine to cinnamic acid. This is an important entry point in the biosynthesis of a great array of diverse secondary metabolites, including coumarins, flavonoids, and lignins. PAL has been considered the rate-limiting enzyme, and it is highly expressed in the root tails, which is coincident with the ferulic acid content and other phenylpropanoid derivatives (Xu et al., 2019; Yang et al., 2020). It proceeds down the pathway through a series of enzymatic steps: hydroxylation and activation to CoA esters, forming precursors for downstream products, as described by Roy et al. (2016). 3.2 Roles and regulation of key enzymes Key enzymes of the pathway include PAL, cinnamate 4-hydroxylase (C4H), 4-coumarate-CoA ligase (4CL), coumarate 3-hydroxylase (C3H), caffeic acid O-methyltransferase (COMT), and caffeoyl-CoA O-methyltransferase (CCoAOMT). These enzymes are expressed differentially in root parts: the highest expression levels for transcripts PAL, C3H, and CQT in the tails reflect higher biosynthetic activity for ferulic acid and its derivatives (Xu et al., 2019; Yang et al., 2020). The control is at the level of transcription and epigenetic modifications, whereby DNA methylation, most of which is CHH-type, affects the expression of key genes such as AsCOMT1, implicated in the biosynthesis of both lignin and ferulic acid (Li et al., 2023). 3.3 Enzymes involved in coumarin backbone formation Coumarin biosynthesis relies on p-coumaroyl-CoA 2'-hydroxylase (C2'H) for the synthesis of umbelliferone; UbiA PTs for prenylation; and cytochrome P450 cyclases, belonging to the CYP736 subfamily for formation of the core skeleton. These β-glucosidases participate in the conversion process of glycosylated coumarins to their
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