Rocaglamides, glycosides, and putrescine bisamides from Aglaia dasyclada.

A phytochemical analysis of the leaves of Aglaia dasyclada collected in Yunnan Province (People's Republic of China) yielded five cyclopentabenzofurans (1-5) of the rocaglamide family that are common secondary metabolites of Aglaia species as well as four biogenetically related compounds of the aglain (7), aglaforbesin (8) and forbaglin (9, 10) types. In addition, the cinnamic acid amide dasyclamide (6), which is a putative biogenetic precursor of these compounds (7-10), was isolated. The structures of the new compounds (6-10) were assigned unambiguously from the combined use of 1D and 2D NMR spectroscopy and mass spectrometry.

A new calyculin derivative from the sponge Theonella swinhoei is a novel and potent inhibitor of tumor cell proliferation.

A novel calyculin derivative was isolated from the marine sponge Theonella swinhoei. Using human and animal tumor cell lines and freshly explanted peripheral blood cells, we investigated several biological effects of this natural product (i.e. cell growth, cytotoxicity, induction of differentiation and apoptosis). The new calyculin exhibited a dose-dependent cytotoxicity against various cell lines from different species and tissues. The ID50 values ranged between 20 and 90 ng/ml. Viability of a multidrug resistant HELA subclone was not affected. Apoptosis of the Hodgkin's lymphoma cell line HDLM-2 induced by antiserum was not prevented by the substance. A reduced drug sensitivity of the monocytic cell line MONOMAC-6 could be observed after induction of differentiation of these cells by phorbol ester and lipopolysaccharide. Even so, non-dividing peripheral blood cells were also resistant to the action of the calyculin derivative, suggesting that the cytotoxin may act preferentially on proliferating cells rather than on quiescent cells. Our data introduce a new calyculin as a marine natural product with interesting features stimulating further studies as a chemotherapeutic or investigational drug.

Bioactive alkaloids from the tropical marine sponge Axinella carteri.

Analysis of the tropical marine sponge Axinella carteri afforded six unusual alkaloids, including the new brominated guanidine derivative 3-bromo-hymenialdisine. The structure elucidation of the new alkaloid is described. The alkaloid patterns of sponges collected in Indonesia or in the Philippines were shown to be qualitatively identical suggesting de novo synthesis by the sponge or by endosymbiontic microorganisms rather than uptake by filter feeding. All alkaloids were screened for insecticidal activity as well as for cytotoxicity. The guanidine alkaloids hymenialdisine and debromohymenialdisine exhibited insecticidal activity towards neonate larvae of the polyphagous pest insect Spodoptera littoralis (LD50s of 88 and 125 ppm, respectively), when incorporated into artificial diet and offered to the larvae in a chronic feeding bioassay. The remaining alkaloids, including the new compound were inactive in this bioassay. Cytotoxicity was studied in vitro using L5178y mouse lymphoma cells. Debromohymenialdisine was again the most active compound (ED50 1.8 micrograms/ml) followed by hymenialdisine and 3-bromohymenialdisine, which were essentially equitoxic and exhibited ED50s of 3.9 micrograms/ml in both cases. The remaining alkaloids were inactive against this cell line.

Qualitative and Quantitative Analysis of the Phenolic Constituents from Orthosiphon aristatus.

ORTHOSIPHON ARISTATUS (Orthosiphonis folium DAB 9) was studied with regard to its phenolic constituents. Twenty compounds were isolated and identified on the basis of their spectral characteristics. The compounds included nine lipophilic flavones, two flavonol glycosides, and nine caffeic acid derivatives. The presence of the recently reported methylripariochromene A could not be confirmed. All compounds identified were quantified by HPLC. The caffeic acid derivatives including the major compounds rosmarinic acid and 2,3-dicaffeoyltartaric acid (67% of total identified phenolics) predominated over the flavones (33%) in an aqueous MeOH extract. The predominance of the caffeic acid derivatives was even more pronounced in a hot water extract (94.5% of total identified phenolics) that was comparable to a herbal tea.