Studies On The Chemical Constituents And Antitumor Activity Of Peperomia Dindygulensis Miq

Peperomia dindygulensis Miq belongs to the Peperomia genus of Piperaceae family. It is a one-year epiphyte, which is widely distributed in southern regions of China. P. dindygulensis is traditionally used to treat cough, measles, abscesses and cancerous swelling in folk. It is known that it has good effects on treating stomach, esophageal, liver, mammary and lung cancers in Yunnan province of China. However, few studies on the chemical constituents and activities of this plant have been reported.In order to exploit natural resources, search for its active constituents, extend the clinical effects and develop new drugs from Traditional Chinese Medicine, the article deals with the chemical constituents and antitumor activity of P. dindygulensis.The pieces of P. dindygulensis were extracted successively with 80% ethanol at room temperature. After evaporating ethanol, the residue was suspended in water, then partitioned using petroleum ether, chloroform, ethyl acetate, n-butanol in sequence. Every partition was applied to column chromatography and recrystal to afford thirty-five compounds. Thirty-one compounds were identified on the basis of chemical and spectral analysis (¹H-NMR, ¹³C-NMR, DEPT, HMQC, HMBC, 1D- SEMDY, NOE, FAB-MS, EI-MS, UV).Their structures were identified as:β-Sitosterol (1), Stigmasterol (2), Hexadecanoic acid (3), Octadecanoic acid (4), Peperomin A (5), Peperomin B (6), Peperomin C (7), Peperomin D (8), Peperomin E (9), Lirioresinol B-dimethyl ether (10), 5-hydroxy-7,8,3',4'-tetramethoxy flavone (11), 5-hydroxy-7,8,4'-trimethoxy flavone (12), 5,3'-dihydroxy-7,8,4'-trimethoxy flavone (13), 5,7-dihydroxy-8,4'-dimethoxy flavone (14), Bis-(2-methoxy-4,5-methylenedioxy)-benzophenone (15), Cepharanone B (16), Surinone C (17), Proctorione C (18), Veratric acid (19), Methylparaben (20), Hydroxybenzoic acid (21), Apigenin (22), Luteolin (23), Daucosterol (24), Hypolacetin-7,4'-dimethyl ether-8-O-β-D-glucopyranoside (25), Isoscutellarein-7,4'-dimethyl ether-8-O-α-L-arabinopyranosyl(1→4)-β-D-glucopyran oside(26), Isoscutellarein-4 '-methyl ether-8-O-α-L-arabinopyranosyl( 1→4)-β-D-glucopyranoside (27), Vitexin(28), Apigenin-7-methyl ether-8-C-α-L-arabinopyran osyl(1→2)-β-D-glucopyranoside (29), Apigenin-7-methyl ether-8-C-β-D-galacto pyranosyl(1→2)-β-D-glucopyranoside (30), Potassium chloride(31). Among them, 13, 15, 22, 25, 26, 27, 29 and 30 were new compounds and 3, 4, 14, 16, 19 and 23 were isolated from the Peperomia genus for the first time.According to the MTT assay of seven tumor cell lines, it was concluded that the ethanol extract of P. dindygulensis showed growth inhibitory activity against A549 and Lovo cells. The effective fractions were proved to be chloroform and ethyl acetate partitions. Some compounds isolated from the effective fractions were screened, Compound 5, 6 and 9 exhibited growth inhibitory activity against A549 cells with IC₅₀ value of 10.9μg/ml, 6.5μg/ml and 17.4μg/ml respectively, and Lovo cells with IC₅₀ value of 12.8μg/ml, 8.8μg/ml and 20.2μg/ml, respectively.