爵床在傳統中藥中被用為治療發燒及喉嘴痛之處方用藥。由爵床乙醇萃取物中分離純化得neojusticin A（neo A）， neojusticin B（neo B）， justicidin A（jus A）， justicidin B（jus B）及chinensinaphthol methyl ether（CME）五種木質素（lignan）。分析木質對大白鼠肝微粒體單氧酵素催化benzo(a)pyrene 羥化（AHH）活性之影響，結果顯示10 μM木質素對此活性具21%至57%之抑制作用，其中以neo B 具最強之抑制作用，其IC50為6 ± 1 μM。這些木質素（10 μM）對鼠肝微粒體7-ethoxyresorufin O-脫乙基作用活性造成20%至48%之抑制作用。對7-methoxyresorufin O-脫甲基作用活性， neo B 造成較其他木質素強之抑制作用，10 μM neoB使7-methoxyresorufin O-脫甲基作用活性下降70%。對睪酮6β-羥化活性造成19%至74%抑制作用，而neoB之抑制作用最小。酵素動力學分析neo B 抑制AHH活性之作用，結果顯示neo B 為一競爭性（competitive）及非競爭性（noncompetitive）之混合型抑制物，其Ki及KI分別為2 μM及11 μM。分析neo B 對NADPH濃度與AHH活性相關性之結果顯示neo B 非競爭性（uncompetitive）抑制NADPH支持之AHH活性。這些結果顯示木質素可對鼠肝單氧酵素催化活性造成不同程度之抑制影響，其中neo B 對AHH活性具較強抑制作用，neo B可能可降低benzo(a)pyrene之氧化活化作用。

Five lignans, neojusticin A (neo A), neojusticin B (neo B), justicidin A (jus A), justicidin B (jus B), and chinensinaphthol methyl ether
(CME) were isolated from the ethanol extract of Justicia procumbens (J. p.), which has been used as a herbal remedy in traditional Chinese
medicine. The in vitro effects of lignans on rat hepatic cytochrome P450-catalyzed oxidations were studied. Addition of 10 μM lignans
caused 21% to 57% decreases of microsomal benzo(a)pyrene hydroxylation (AHH) activity. Among these lignans, neo B had the strongest
inhibitory effect on AHH activity with an IC50 of 6 ± 1 μM. Lignans at 10 μM decreased 7-ethoxyresorufin O-deethylation activities by
20% to 48%. Neo B at 10 μM caused a 70% decrease of 7-methoxyresorufin O-demethylation activity whereas this oxidation activity was
relatively less affected by other lignans. Lignans (10 μM) also decreased testosterone 6β-hydroxylation activity by 19% to 74% and neo B
had the least inhibitory effect on this activity. Kinetic analysis of AHH activity revealed that neo B was a mixed type inhibitor of competitive
and noncompetitive characteristics with Ki and KI of 2 μM and 11 μM, respectively. With NADPH as the variable cofactor, neo B
showed a uncompetitive type of inhibition of AHH activity. These in vitro results suggested that lignans from J. p. inhibited monooxygenase
activities differentially and neo B might have a role in diminishing the oxidative activation of benzo(a)pyrene.