ABSTRACT
Objective: To investigate the chemical constituents from the ethyl acetate extracts in the roots of Rumex nepalensis. Methods: The compounds were isolated by using various chromatographic techniques, such as silica gel column, Sephadex LH-20 column, and semi-preparative HPLC. The structures of these compounds were determined by spectral data analyses. Results: Sixteen compounds were obtained and identified as ferulic acid (1), 7-hydroxy-5-methoxyphthalide (2), methyl 2-acetyl-3,5-dihydroxyphenylacetate (3), methylorsellinate (4), methyl p-hydroxycinnamate (5), 1-(2-Hydroxy-5-Methyl-phenyl)-ethanon (6), methyl syringate (7), 1-(2,4-dihydroxy-6-methylphenyl)-ethanon (8), 4-hydroxy-benzeneethanol (9), isovanillin (10), fallacinol (11), 7-hydroxy-2-methyl-5-methylchromone (12), 3-acetyl-2-methyl-1,5-dihydroxy-2,3-epoxynaphthoquinol (13), emodin (14), chrysophanol (15), and physcion (16). Conclusion: Compounds 12 and 13 are isolated from this plant for the first time, and compounds 1-11 are firstly isolated from the plants of Rumex L..
ABSTRACT
Objective: To study the anti-complementary anthraquinones from Polygonum cuspidatum and their action targets. Methods: The anti-complementary activity-directed isolation was carried out with the hemolysis test as guide. All isolates were evaluated for their in vitro anti-complementary activities. The action targets of the main bioactive constituents were also examined using complement-depleted sera. Results: Ten anthraquinones and three other compounds were isolated from the EtOAc fraction of P. cuspidatum extract, including physcion (1), chrysophanol (2), questin (3), emodin-8-O-β-D-glucoside (4), emodin (5), rhein (6), fallacinol (7), citreorosein (8), xanthorin (9), isorhodoptilometrin (10), 2, 5-dimethyl-7-hydroxychromone (11), 7-hydroxy-4-methoxy-5-methylcoumarin (12), and 5, 7-dihydroxy-1-isobenzofuranone (13). Compounds 9 and 10 were isolated from the the plants of Polygonaceae for the first time, and compound 9 was the alizarin-type anthraquinone first obtained from P. cuspidatum. Compounds 3-9 showed the anti-complementary activity in different degrees, and compound 7 exhibited the most significant activity against the classical and alternative pathway [CH50 = (6 ± 2) μg/mL, AP50 = (50 ± 5) μg/mL]. The study on the preliminary mechanism revealed that compound 4 interacted with C1q, C2, and C9 in complement activation cascade, while compound 7 acted on C1q, C2, C4, and C9. Conclusion: The anthraquinones are main anti-complementary constituents in P. cuspidatum; and fallacinol (7) is a potential complement inhibitor with strong activity and definite targets, which should be further studied in future.