A saponin-enriched fraction prepared from the MeOH extract of the roots of Clematis chinensis showed cytotoxic activity against HL-60 promyelocytic leukemia cells, from which five new triterpene saponins based on oleanolic acid, along with three known saponins, were isolated. The structures of the new saponins were determined on the basis of spectroscopic analysis, including extensive 1D and 2D NMR data and hydrolysis followed by chromatographic and spectroscopic analysis. Among the isolated saponins, monodesmosidic saponins exhibited cytotoxic activities against cultured tumor cells.

The taste of black tea differs according to the different areas in which the tea is grown, even for the same species of tea. A combination of (1)H NMR spectroscopy and partial least-squares discriminate analysis (PLS-DA) was used to assess the quality differences of tea leaves from four cultivation areas with different elevations, RAN > 1800 m, UDA = 1200 m, MEDA = 600 m, and YATA < 300 m, in Sri Lanka. As a result of a statistical analysis, PLS-DA showed a separation between high- and low-quality black teas derived from the four different tea cultivation areas. RAN from the highest elevation showed characteristic trends in the levels of theaflavin and theaflavin 3,3'-digallate that were found only in RAN, and the levels of theanine and caffeine were higher, and the levels of thearubigins, especially thearubigin 3,3'-digallate, were lower in RAN than in UDA, MEDA, and YATA. The structures of these components were determined by 1D and 2D NMR analyses. These results demonstrate that this method can be used to evaluate black tea quality according to the chemical composition or metabolites, which are characteristic of the tea leaves cultivated in four regions with different elevations in Sri Lanka.

Phytochemical analysis of the leaves of Cestrum nocturnum (Solanaceae) resulted in the isolation of two new flavonol glycosides (1, 2) and seven steroidal saponins (3-9), including four new ones (4, 6, 7, and 9). The structures of the new compounds were determined by spectroscopic analysis, including 2D NMR data, and the results of hydrolytic cleavage. Cytotoxic activities of the isolated compounds against human oral squamous cell carcinoma-(HSC-2) cells and normal human gingival fibroblasts are reported.

Further phytochemical analysis aimed at the triterpene saponin constituents of the roots of Pulsatilla chinensis has resulted in the isolation of four new bisdesmosidic triterpene saponins whose aglycons are based on the lupane skeleton (1-4), together with three known saponins (5-7). The structures of the new compounds were determined by spectroscopic analysis and acid-catalyzed hydrolysis.

No abstract

No abstract

Seven new bisdesmosidic triterpene saponins, with up to eight monosaccharides, which were given the trivial names contortisiliosides A ± G (1 ± 7), were isolated from Enterolobium contortisiliquum. The structures of the new saponins were determined on the basis of extensive spectroscopic and chromatographic analyses of both intact and acid-hydrolyzed compounds. The isolated saponins were evaluated for their cytotoxic activities against BAC1.2F 5 mouse macrophages, EL-4 mouse lymphoma cells, and L-929 mouse fibroblasts. Whereas contortisiliosides A (1) and C (3) were moderately cytotoxic to both BAC1.2F 5 macrophages and EL-4 cells, and contortisiliosides D ± G (4 ± 7) did not show any apparent cytotoxic activities against the three cell lines, contortisilioside B (2) exhibited selective cytotoxic activity against BAC1.2F 5 mouse macrophages, with an IC 50 value of 3.4 mm. The macrophage death caused by 2 was shown to be neither necrotic nor apoptosis-inducing based on the unique morphological change of the killed cells, whose cytosols were transformed into large vacuoles, and according to the TUNEL assay.

1H NMR spectroscopy has been used to demonstrate specific binding of rat 80S ribosomes to the major conformer of an antitumor bicyclic hexapeptidic glucoside, RA-XII, isolated from Rubia cordifolia, in a fast exchange process.