Two New Aristolochic Acid Derivatives from the Roots of Aristolochia fangchi and Their Cytotoxicities
Chemical and pharmaceutical bulletin
Note Guang Fang Ji, the root of Aristolochia fangchi Y. C. WU ex L. D. CHOU et S. M. HWANG (Aristolochiaceae), is distributed in many places of southeastern of China. For thousands of years it has been used in traditional Chinese medicine to treat arthritis, rheumatism, and edema of the lower extremities. 1) However, in the last 20 years it has been found that Aristolochia plants (which contain aristolochic acids compounds) can cause serious kidney damage, and the products of aristolochia
... aristolochia species have also been linked to certain types of cancer, most often occurring in the urinary tract. 2-6) Therefore many countries including China have banned the use of plants that contain aristolochic acid. 7) Much attention has been paid to the chemical constituents, the nephrotoxic and carcinogenic effects of aristolochic acid derivatives, and the corresponding plants for years. Several aristolochic acids and aristolactams have been isolated from this plant.    In the course of our systemic investigation of the chemical constitutes and their toxicities, two new and three known compounds from the roots of Aristolochia fangchi were isolated. This paper deals with the structure determination of the new compounds and cytotoxicities of the compounds obtained. Results and Discussion The air-dried and powdered roots of Guang Fang Ji were extracted with 90% ethanol, and the extracts were separated as described in the experimental section to yield compounds 1-5. The three known compounds were identified as aristolochic acid A (1), aristolochic acid B (2), and aristolochic acid C (3) by comparison of their spectral data with data reported in the literature      (Fig. 1) . Compound 4 was obtained as a yellow amorphous powder. The high resolution MS analysis of quasimolecular ion peaks in the positive-ion FAB-MS of 4 showed a molecular ion peak at m/z 328.2459, indicating a molecular formula of C 16 H 9 NO 7 . The UV absorption of 4 at 218, 256, 295, 351, and 371 nm showed it was a phenanthro type derivative. 11,15) Its IR spectrum showed absorption bands due to hydroxyl, nitro, and carboxyl functions at 3438, 1337, 1520, and 1715 cm Ϫ1 , indicating that 4 was an aristolochic acid derivative. This was also confirmed by fragment ion peaks at m/z 328 [MϩH] ϩ , m/z 282 [MϩHϪNO 2 ] ϩ , m/z 265 [MϩHϪNO 2 Ϫ OH] ϩ , and m/z 237 [MϩHϪNO 2 ϪCOOH] ϩ , separately. Phytochemical investigation of 90% ethanol extracts of the roots of Aristolochia fangchi yielded two new aristolochic acid derivatives named Aristolochic Acid F and Aristolochic Acid G, together with three known compounds. Their structures were elucidated by spectral analysis. The cytotoxicity of the isolated compounds was also determined.