Aristolic acid

Aristolic acid, CigHuO N, crystallises in orange-red needles, m.p. 260-270°, and, like the two foregoing alkaloids, gives a green solution with concentrated sulphuric acid. 

Reduction of aristolochic acid I with NaBH4 was investigated by Ito et al. They found that aristolochic acid I was reduced to 9,10-dihydroaristolochic acid I (69) at room temperature (85% yield), and they also isolated a nitrogen-free product, aristolic acid (70) (Scheme 8) (5% yield). When this reaction takes place at 90-100°C for 3 hr, however, the main product obtained was aristolic acid. Decarboxylation of 9,10-dihydroaristolochic acid I with copper powder in... 

In addition, intraamniotic injection of aristolochic acid I in mid-term pregnant dogs and rats led to termination of pregnancy (106). Later, Che et al. reported that four Aristolochia alkaloids, aristolochic acid I and its methyl ester, aristolic acid, and (125)-7,12-secoish-waran-12-ol were ineffective in antifertility tests, when administered to mice, hamsters, or rats (707). 

H OCHj H och3 6-Methoxy aristolic acid (56) A. kwangsiensis A. versicolor 247 222... 

This acid induced impairment of development and reconciled with decreases found in uterine weight and its total protein contents. It prevented specific uterine alkaline phosphatase activity. On the otherhand, specific uterine acid phosphatase activity remained low on days 4 and 5 and increased significantly thereafter. It indicated that aristolic acid interferes with steroidal conditioning of the uterus and renders it hostile to ovum implantation. 

Methyl ester of aristolic acid (55) isolated from A. indica exerted 100%, 25% and 20 % abortifacient activity in mice when administered at the dose level of 60 mg/kg body weight on days 6 or 7, 10 and 12 post coitum, respectively [88]. 

Lajide et al. examined the antifeedeant activity of the metabolites of A. albida root extracts, aristolic acid (51), aristolochic acid (5), 6-hydroxy-... 

When aristolochic acid-I is reduced under usual conditions (for example LiAlH4/THF, reflux for 2 h), aristololactam-I is formed. However, if this alkaloid is dissolved in 1% aq. ammonia and NaBH4 is added, aristolochic acid-I loses its nitro moiety, and aristolic acid is obtained in more than 90% yield [4]. 

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