N-Benzoyl-L-phenylalaninol

Bioassay-directed fractionation led to the isolation of seven compounds from a sample of the dried leaves, twigs, and branches of Diospyros quaesita Thw. (Ebenaceae). One of the isolates, betulinic acid 3-caffeate (1), showed in vitro antimalarial activity against Plasmodium falciparum clones D(6) (chloroquine-sensitive) and W(2) (chloroquine-resistant) with IC(50) values of 1.40 and 0.98 microM, respectively. Evaluation of compound 1 in the human oral epidermoid (KB) cancer cell line revealed cytotoxicity at ED(50) of 4.0 microM. In an attempt to reduce the cytotoxicity of 1, the acetylated derivative 1a and betulinic acid (1b) were prepared. Of the seven isolates, diospyrosin (2) was determined to be a new neolignan. In addition to 1, other known compounds isolated in this study were pinoresinol, lariciresinol, N-benzoyl-L-phenylalaninol, scopoletin, and poriferast-5-en-3beta,7alpha-diol. The structure of 2 was elucidated based on spectroscopic data analysis including 1D- and 2D-NMR, and HR-ESI-MS.

Objective: To study the chemical constituents in the introduced Coleus forskohlii. Method: The chemical constituents were isolated by column chromato-graphy. The structures were elucidated on the basis of IR, MS, 1H-NMR and 13C-NMR experiments. Result: Eight compounds were obtained, the structures of which were identified as cytochalasin B (1), N-benzoyl-L-phenylalaninol (2), 3,6-dibenzyl-2,5-dioxopiperazine (3), 2-furoic acid (4), vanillic acid (5), loliolide (6) and forskolin D (7). Conclusion: Compounds 1-6 were isolated from the genus Coleus for the first time.

Fifteen alkaloids were isolated from the 95% ethanol extract of the whole plants of Viola yedoensis by various column chromatographic techniques such as silica gel and Sephadex LH-20. Their structures were identified as neoechinulin A(1),N-benzoyl-L-p-hydroxy-phenylalaninol(2),aurantiamide acetate(3),aurantiamide(4),anabellamide(5),trichosanatine(6),indole-3-carboxylic acid methyl ester(7),3-carboxyindole(8),N-trans-feruloyl-tyramine(9),paprazine(10),7'-(3', 4'-dihydroxyphenyl)-N-[(4-methoxyphenyl)ethyl]propenamide(11),cannabisin F(12),N-(4-hydroxyphenethyl)octacosanamide(13),N-(4-hydroxyphenethyl)hexacosanamide(14)and N-benzoyl-L-phenylalaninol(15). All the compounds except 3 and 4 were isolated from this plant for the first time. These alkaloids exhibited anti-complement activity against the classical pathway(CP)and the alternative pathway(AP)with the CH50 and AP50 values ranging from 0.12 to 0.33 g·L⁻¹ and 0.22 to 0.50 g·L⁻¹, respectively. Preliminary mechanism study using complement-depleted sera showed that these alkaloids acted on different complement components in the complement activation cascade.