A comprehensive review: Biological activity, modification and synthetic methodologies of prenylated flavonoids Author Shi, Shaochun , Jichong Li &, Xuemei Zhao &, Qingbo Liu & **, Shao-Jiang Song & * & Key Laboratory of Computational Chemistry-Based Natural Antitumor Drug Research & Development, Liaoning Province, School of Traditional Chinese Materia Medica, Shenyang Pharmaceutical University, Shenyang, 110016, China Author Li, Jichong Author Zhao, Xuemei Author Liu, Qingbo Author Song, Shao-Jiang text Phytochemistry 2021 112895 2021-11-30 191 1 56 http://dx.doi.org/10.1016/j.phytochem.2021.112895 journal article 10.1016/j.phytochem.2021.112895 1873-3700 8194277

Table 13 The enzymatic activity of compounds against PDE4 (IC 50, μM).

NO.	R1	R2	R3	IC (μM)b 50
a Compounds with inhibition greater than 50% at 10 μM were further determined for corresponding IC values. 50 b Values are represented as means ± SD based on three independent experiments. c Positive control.
537	H	H	α- H	0.0054 ± 0.0003
538	H	H	β- H	0.25 ± 0.01
539	–	–	–	0.02 ± 0.002
441	–	–	–	0.40 ± 0.03
540	–	–	–	0.04 ± 0.003
541	–	–	–	0.87 ± 0.03
542	–	–	–	3.59 ± 0.17
543	–	–	–	0.03 ± 0.002
544	–	–	–	0.63 ± 0.04
545	–	–	–	0.27 ± 0.01
79	–	–	–	0.90 ± 0.04
546	–	–	–	2.33 ± 0.12
294	–	–	–	1.26 ± 0.09
547	–	–	–	2.91 ± 0.13
548	–	–	–	9.90 ± 0.40
33	–	–	–	0.31 ± 0.02
549	–	–	–	0.26 ± 0.02
550	–	–	–	1.88 ± 0.10
551	CH3	CH3	β- H	–
552	H	CH3	β- H	5.18 ± 0.13
553	H	Ac	β- H	4.89 ± 0.20
554	H	tosyl	β- H	–
555	H	p -bromobenzoyl	β- H	–
556	H	naphthalene-2-sulfonyl	β- H	–
557	thiophene-2-carbonyl	thiophene-2-carbonyl	β- H	–
558	CH3	CH3	α- H	–
559	H	disilane	α- H	8.60 ± 0.31
560	–	–	β- H	–
561	–	–	α- H	4.35 ± 0.11
562	–	–	–	7.50 ± 0.34
563	–	–	–	9.21 ± 0.33
Rolipram c	–	–	–	0.62 ± 0.03