Kuwanon hypotensive action

Kuwanon M (160) 136), mp 252-254 °C, [a]o -2.0°, C50H48O12, was found to have a hypotensive action in hypertensive rats (2 mg/Kg, i.v.). Its structure was derived on the basis of spectral evidence. Kuwanon M (160) is optically active and is presumably formed by an enzymatically-controlled Diels-Alder type reaction between kuwanon C (33) and a coexisting dehydro derivative and subsequent cyclodehydrogenation. Takasugi et al. have isolated a similar compound, dimora-cin (101) 84), mp 238-240 °C, [a]o — 5°, as a phytoalexin from diseased... 

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). 

---