Phytochemical And Biological Activity Studies Of Cosmos Caudatus, Curcuma Mangga And The Online Characterization Of Bioactive Fractions From Melicope Ptelefolia

Author

FARIDAH ABAS

Date

2005

Keyword

Malay traditional vegetables, antioxidant activities, nitric oxide (NO) inhibitory activities, biological activity, phytochemical investigation, cytotoxic activity

Abstract

Twelve species of Malay traditional vegetables were screened for antioxidant and nitric oxide (NO) inhibitory activities. Ferric thiocyanate (FTC), thiobarbituric acid (TBA) and l,l-diphenyl-2-picrylhydrazyl radical (DPPH) methods were used for the antioxidant activity measurements, and the Griess assay on elicited murine peritoneal macrophages was used to assess NO inhibitory activity of the extracts. Melicope ptelefolia, Cosmos caudatus, and Curcuma mangga were selected for further study, based on the results of their biological activity evaluations. Characterization of the NO inhibitory fractions of the Melicope ptelefolia using on-line high performance Uquid chromatography (HPLC)-diode array detector (DAD)-mass spectrometry (MS), identified seven main constituents. The compounds were identified as kokusaginine (1), either kokusagine (2a) or 5-methoxymaculine (2b), 3-prenyl-2,4,6-trihydroxyacetophenone (3), 3-geranyl-2,4,6-trihydroxyacetophenone (4), 3-geranylgeranvl-2,4,6-trihvdroxvaceto-phenone (5), 3-[4-0-(3,7-dimethyl-2,6-octadienyl)phenyl]-2-propenoic acid (6), and 3-farnesylgeranyl-2,4,6-trihydroxyacetophenone (7). Phytochemical investigation of the methanolic extract of Cosmos caud.ah.is led to the isolation of four known compounds namely, quercetin 3-0-ß-arabinofuranoside (17), quercetin 3-0-α-rhamnoside (18), quercetin 3-0-ß-glucoside (19), and quercetin (20). All four compounds isolated from C. caudatus showed strong antioxidant activity. The activity was in the order of 20 > 17 > 18 > 19 > α-tocopherol (standard). From the rhizomes of C. mangga, eleven compounds were isolated, namely a mixture of stigmasterol and ß-sitosterol (141), dememoxycurcurnin (101), bisdemethoxycurcumin (102), l,7-bis(4-hydroxyphenyl)-l,4,6-heptatrien-3-one (113), 7-hydroxy-6-methoxycoumarin (142), curcumin (100), zerumin B (143), curcumanggoside (144), 4-hydroxycinnamic acid (145), labda-8(17),12-diene-15,16-dial (128), and calcaratarin A (146). Curcumanggoside was identified as a new compound, while zerurnin B and calcaratarin A were isolated for the first time from the genus Curcuma. The structures of these compounds were established based on spectral data and comparison with the literature. Four diarylheptanoids, demethoxycurcumin, bisdememoxycurcumin, curcumin, and l,7-bis(4-hydroxyphenyl)-l,4,6-heptatrien-3-one, showed strong antioxidant activity. Zerumin B showed strong and selective cytotoxic activity to four cell lines, including HL-60, HepG2, MCF-7 and DU-145 with IC50 values of 7.21, 25.33, 0.59 and 11.21 uM, respectively.