[Chemical Constituents from the Roots of Rhodomyrtus tomentosa].

Objective: To investigate the chemical constituents of the roots of Rhodomyrtus tomentosa and their antitumor activities. Methods: Various column chromatographic techniques were used to isolate the compounds. The structures were elucidated by their physicochemical properties and spectra data. Moreover, MTT assay was used to evaluate the antitumor activity against melanoma SK-MEI-110 cells. Results: Thirteen compounds were obtained from the roots of Rhodomyrtus tomentosa, and their structures were determined as 2α, 3ß, 23-trihydroxyoleana-11,13( 18)-dien-28-oic acid( 1),3ß,23-dihydroxyolean-18-en-28-oic acid( 2), lupeol( 3), betulin( 4), betulinic acid( 5), friedelin( 6), ß-sitosterol( 7), thero-2, 3-bis-( 4-hydroxy-3-methoxypheyl)-3-methoxy-propanol( 8), evafolin B( 9), ß-hydroxypropiovanillone ( 10), 8, 8'-bis-( dihydroconiferyl)-diferuloylate( 11), gallate acid( 12) and methyl gallate( 13). Conclusion: Compounds 1,2,8 ~ 10 and 13 are isolated from this plant for the first time. Compounds 1 ~ 6 exhibite inhibitory effects on melanoma SK-MEL-110 cells.

Eudesmane-type sesquiterpene derivatives from Laggera alata.

Ten eudesmane-type sesquiterpene derivatives (1-10), including six cuauhtemone derivatives (1-6), one di-norsesquiterpene (3-oxo-di-nor-eudesma-4-en-11-oic acid, 7), and three eudesmane glycosides (alatoside F-H, 8-10) were isolated from the whole plants of Laggera alata together with 12 known compounds. Their structures were elucidated on the basis of extensive spectroscopic analysis, acid hydrolysis, and compounds 1 and 7 were studied by single-crystal X-ray diffraction analysis. The absolute configuration of 1 was determined by the application of the modified Mosher's method. All of the isolated eudesmane-type sesquiterpenes were evaluated for their cytotoxic activities on six human cancer cell lines, but all of the compounds were inactive on the tested cell lines in the concentration of 100 µg/mL.

5-Hy-droxy-3,4',6,7-tetra-meth-oxy-flavone.

The title compound, C(19)H(18)O(7) [systematic name 5-hy-droxy-3,6,7-tri-meth--oxy-2-(4-meth-oxy-phen-yl)-4H-1-benzopyran-4-one], is a flavonoid which was isolated from the traditional Chinese medicine Laggera alata. The benzene ring of the benzopyran-one unit forms dihedral angles of 1.72 (3) and 37.39 (5)° with the pyran ring and the substituent benzene ring, respectively. The mol-ecular conformation is stabilized by an intra-molecular phenol O-H⋯O(ketone) hydrogen bond.

(1)H and (13)C NMR assignments for two new steroids from the coral Chromonephthea sp.

Two new steroids isolated from EtOH extracts of the South China Sea soft coral Chromonephthea sp. were identified. One-dimensional (1D) and two-dimensional (2D) NMR experiments including COSY, HSQC, HMBC and NOESY were used for the determination of their structure.