Antiplatelet and Anticoagulant Activities of Angelica shikokiana Extract and Its Isolated Compounds.

Angelica shikokiana is a Japanese medicinal plant that is used traditionally in several ailments of cardiovascular diseases. However, there is no report regarding its anticoagulant or antiplatelet activities. So this study was designed to screen for such activities (anticoagulant by prothrombin time [PT], activated partial thromboplastin time, and thrombin time assays and antiplatelet activities against adenosine 5'-diphosphate [ADP] and arachidonic acid-induced platelet aggregations) for the methanol extract of the aerial part (Angelica methanol extract [AME]), its isolated coumarins, flavonoids, and flavonoid metabolites. The AME had potent anticoagulant and antiplatelet activities, and the flavonoid compounds were evidenced to be responsible for such activities. Among coumarins compounds, hyuganin C showed significant prolongation of only PT, while other coumarins were inactive. Similarly, hyuganin C and bergapten were the only active coumarins against ADP-induced platelet aggregation. Compared to the parent compounds, colonic metabolites of the flavonoids had similar anticoagulant and antiplatelet activities, while glucuronides showed sharp decreases in all studied activities. This is the first report showing that the medicinal plant A shikokiana has potent antiplatelet and anticoagulant activities.

Improved Biological Activities of Isoepoxypteryxin by Biotransformation.

Isoepoxypteryxin is the major coumarin of a Japanese medicinal plant Angelica shikokiana. This research was designed to study the effect of structural changes through fungal biotransformation on the reported biological activities of isoepoxypteryxin. Among the tested microorganisms, only Cordyceps sinensis had enzymes that could catalyze the ester hydrolysis and the reductive cleavage of the epoxide ring of isoepoxypteryxin, separately, to give two more polar metabolites (+)-cis-khellactone (P1) and a new coumarin derivative (+)-cis-3'-[(2-methyl-3-hydroxybutanoyl)oxy]-4'-acetoxy-3',4'-dihydroseselin (P2), respectively. The polar metabolite P2 showed stronger cytotoxicity and higher selectivity than isoepoxypteryxin. On the molecular level, P2 showed more in vitro inhibition of both tubulin polymerization and histone deacetylase 8 (HDAC8). Similarly, P2 showed more neuroprotection against amyloid beta fragment 1 - 42 (Aß1 - 42 )-induced neurotoxicity in human neuroblastoma cells (SH-SY5Y) and exhibited more inhibition of the in vitro aggregation of Aß1 - 42 . Both metabolites showed stronger antiplatelet aggregation by increased inhibition of thromboxane-A2 synthase (TXS) activity and thromboxane-A2 (TXA2) production. This study is the first to describe the improved cytotoxic, neuroprotective, and antiplatelet aggregation activities of isoepoxypteryxin through its biotransformation by C. sinensis.