Phenolic compounds kuwanon

About seventy kinds of new phenolic compounds could be isolated from Japanese cultivated mulberry tree (Morus alba, M. bombycis, and M, Ihou) and Chinese crude drug Sang-Bai-Pi (the root bark of Chinese mulberry tree). Most of them are isoprenylated flavonoids. Among them, kuwanon G (1) was the first isolation of the active substance exhibiting the hypotensive effect from the Japanese Morus alba root bark [9]. Furthermore, kuwanon G (1) and its isoprenylated derivative kuwanon H (2) [10] are considered to be formed through an enzymatic Diels-Alder type reaction of a chalcone and a dehydrokuwanon C or its... 

Formation of some products from [1 — " C] arachidonic acid was studied in rat platelets in the presence of phenolic compounds isolated from the Morus root bark. Morusin (24) was found to inhibit the formation of 12-hydroxy-5,8,10-heptadecatrienoic acid (HHT) and thromboxane B2 (cyclooxygenase products) more strongly than the formation of 12-hydroxy-5,8,10,14-eicosatetraenoic acid (12-HETE) (12-lipoxygenase product). Oxydihydromorusin (34) and kuwanon C (33) were also found to inhibit the formation of thromboxane B2 more... 

On the other hand, in Japan, Sang-Bai-Pi (the root bark of Chinese mulberry tree) imported from China has been used as an herbal medicine, hence a study of the components of this crude drug purchased in the Japanese market was undertaken. Its phenolic components are different from those of Japanese mulberry tree. For example, morusin (3) and kuwanon G (1) are the main phenolic components of Japanese mulberry tree, in the case of Sang-Bai-Pi , these components are minor ones, while sanggenons A (4) [16], C (5) [17], and D (33) [61] are the main components [24]. Sanggenons C (5) and D (33) showed the hypotensive effects as follows Sanggenon C (5) caused transient decrease in arterial blood pressure at the doses of 1 mg/kg in pentobarbital-anesthetized rabbit by 15 mm Hg, while at the doses of 5 mg/kg the compound (5) caused a transient decrease by 100 mm Hg, which continued for more... 

Studies of the phenolic constituents of Morus root bark were originally undertaken to characterize the hypotensive components of the root bark. Kuwanons G (25) (33), H (26) (34), M (160) (136), mulber-rofurans C (130) (111), F (131) (112), and G (27) (112) were shown to be hypotensive components of the root bark of the cultivated mulberry tree. Compounds 25, 26, 130, 131 and 27 were almost equally effective in causing a transient decrease in arterial blood pressure in doses of 0.1-1 mg/Kg (i.v.) in rabbits. Kuwanon M (160) (136) showed hypotensive action in hypertensive rats (2 mg/Kg, i.v,). On the other hand, sanggenons C (164) (140) and D (165) (141) were characterized as the hypotensive compounds of the crude medicine Sang-Bai-Pi . Sanggenon C (164) showed a marked hypotensive effect (1 mg/Kg, i.v.) in rabbits, and 165 showed the same effect (0.5-2.0 mg/Kg, i.v.) in rats. The mechanism of the hypotensive action of 25 and 26 has been discussed (95). 

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