RESUMO
Dracaena cinnabari, known as the dragon's blood tree, has been used for long time in the Yamani and Arabian folk medicine for many claimed ailments. Chemical analysis of the resin of D. cinnabari resulted in the isolation of the five flavonoiud from the chloroform extract: 4,4'-dihydroxy-2'-methoxychalone, 4,4'-dihydroxy-2-methoxydihydrochalone, 7-hydroxy-3-[3-hydroxy-4-methoxybenzyl] chroman, 7-hydroxy-3-[4-hydroxybenzyl] chroman, and 2',4,4'-trithydroxychalcone; with the latter flavonoid being isolated for the first time from this species. The aqueous extract [AE] of the resin of D. cinnabari, in concentrations ranging from 10[-4] to 0.03 mg/ml, caused concentration-dependent decrease of amplitude of the phasic contractions and relaxed the tone of the longitudinal segments of ileum and uterus, and urinary bladder rings. Bolus injection of AE [10[04] - 0.03 mg] increased the contractility but had no significant effect on the beating rate of the isolated perfused heart of the rat; it also had a hypotensive effect in anesthetized rats when injected in i.v. doses from 0.04 - 12 mg/kg body weight. AE [800 and 1600 mg/kg] increased significantly that rate of urine excertion in conscious rats when administered orally. These observations indicate that resin AE of D. cinnabari has spansmolytic, inotropic, hypotensive and diuretic effects on rats. Furthermore, the observations were discussed in relation to the claimed uses of D. cinnabari resin in folk medicine