Steroidal glycosides from the bulbs of Bessera elegans and their cytotoxic activities

A role of uroleuconaphins, polyketide red pigments in aphid, as a chemopreventor in the host defense system against infection with entomopathogenic fungi

Four red polyketide pigments, uroleuconaphins A₁ (1) and B₁ (2) and their glucosides 3 and 4, were isolated from the red goldenrod aphid Uroleucon nigrotuberculatum. Although these red pigments exist only as glucosides 3 and 4 in the intact insect body, 3 and 4 convert instantly to aglycones 1 and 2 at death. Pigments 1 and 2 inhibited the growth of Lecanicillium sp. (Ascomycota: Cordycipitaceae) and 1, 2, and 3 were active against Conidiobolus obscurus (Entomophthoromycota; Entomophthorales); these fungal species are pathogenic. We therefore regard aphid pigments 1-4 as chemopreventive agents that aid in the resistance of infection by entomopathogenic fungi at the level of the individual aphid and/or at the species level.

Steroidal Glycosides from Convallaria majalis Whole Plants and Their Cytotoxic Activity

Phytochemical examination of Convallaria majalis (Liliaceae) whole plants yielded 15 steroidal glycosides (1–15), including nine new compounds (4–6, 10–15) with a lycotetrose unit. The structures of the new compounds were determined using two-dimensional Nuclear magnetic resonance (NMR) analyses and chemical methods. The isolated compounds were evaluated for cytotoxicity against HL-60 human promyelocytic leukemia cells, A549 human lung adenocarcinoma cells, and HSC-4 and HSC-2 human oral squamous cell carcinoma cell lines. Of these, (25S)-spirost-5-en-3β-yl O-β-d-glucopyranosyl-(1→2)-O-[β-d-xylopyranosyl-(1→3)]-O-β-d-glucopyranosyl-(1→4)-β-d-galactopyranoside (1) exhibited cytotoxic activity against HL-60, A549, HSC-4, and HSC-2 cells with IC₅₀ values ranging from 0.96 to 3.15 μM. The corresponding furostanol glycoside of 1, (25S)-26-[(β-d-glucopyranosyl)oxy]-22α-hydroxyfurost-5-en-3β-yl O-β-d-glucopyranosyl-(1→2)-O-[β-d-xylopyranosyl-(1→3)]-O-β-d-glucopyranosyl-(1→4)-β-d-galactopyranoside (8), was cytotoxic to the adherent cell lines of A549, HSC-4, and HSC-2 cells with IC₅₀ values of 2.97, 11.04, and 8.25 μM, respectively. The spirostanol lycotetroside (1) caused necrotic cell death in A549 cells in a dose-dependent manner. Alternatively, the furostanol lycotetroside (8) induced apoptotic cell death in A549 cells in a time-dependent manner, as was evident by morphological observations and flow cytometry analyses.

Rapid Characterization of Constituents in Tribulus terrestris from Different Habitats by UHPLC/Q-TOF MS

A strategy for rapid identification of the chemical constituents from crude extracts of Tribulus terrestris was proposed using an informatics platform for the UHPLC/Q-TOF MS^E data analyses. This strategy mainly utilizes neutral losses, characteristic fragments, and in-house library to rapidly identify the structure of the compounds. With this strategy, rapid characterization of the chemical components of T. terrestris from Beijing, China was successfully achieved. A total of 82 steroidal saponins and nine flavonoids were identified or tentatively identified from T. terrestris. Among them, 15 new components were deduced based on retention times and characteristic MS fragmentation patterns. Furthermore, the chemical components of T. terrestris, including the other two samples from Xinjiang Uygur Autonomous region, China, and Rome, Italy, were also identified with this strategy. Altogether, 141 chemical components were identified from these three samples, of which 39 components were identified or tentatively identified as new compounds, including 35 groups of isomers. It demonstrated that this strategy provided an efficient protocol for the rapid identification of chemical constituents in complex samples such as traditional Chinese medicines (TCMs) by UHPLC/Q-TOF MS^E with informatics platform. Graphical Abstract ᅟ.

Vetiverianines A, B, and C: Sesquiterpenoids from Vetiveria zizanioides Roots

Three new sesquiterpenoids-vetiverianines A (1), B (2), and C (3)-and a known eudesmane sesquiterpenoid (4) were isolated from the roots of Vetiveria zizanioides. Vetiverianine A (1) has a unique carbon framework comprising a rigid tricyclic ring system. Vetiverianines B (2) and C (3) are new eremophilane sesquiterpenoids. The structures of sesquiterpenoids 1-3, including the absolute configurations, were determined by NMR spectroscopic, X-ray crystallography, and vibrational circular dichroism data analysis. Vetiverianine C (3) exhibited weak cytotoxic activity against HL-60 cells.

Cardiac glycosides from the seeds of Thevetia peruviana and their pro-apoptotic activity toward cancer cells

Phytochemical investigation of the seeds of Thevetia peruviana resulted in the isolation of seven cardiac glycosides (1-7), including two new compounds (1 and 2). Cytotoxicity of them toward cancer cell lines P15 (human lung cancer cell), MGC-803 (human gastric cancer cells), SW1990 (human pancreatic cancer cells), and normal hepatocyte cell LO2 suggested that compound 1 could selectively inhibit the proliferation of cancer cell lines with IC50 from 0.05 to 0.15 μM. Pro-apoptotic activity revealed that it induced the apoptosis of MGC-803 cancer cells in a dose-dependent manner. Meanwhile, treatment of MGC-803 cancer cells with 1 resulted in diminution of pro-caspases 3 and 9 and activation of caspases 3 and 9, while it increased the Bax/Bcl-2 ratio in a dose-dependent manner. These meant that 1 induced the apoptosis of cancer cells by involving the intrinsic apoptotic pathway. In addition, the cell cycle distribution of MGC-803 cancer cells treated by 1 revealed that it could lead to cell cycle arrest at the G2/M phase. Altogether, this study suggested that compound 1 may exhibit anticancer activity by its capability of induction of intrinsic apoptosis and cell cycle arrest at G2/M phase.

Steroidal Saponins from the Rhizomes of Anemarrhena asphodeloides

Four new steroid saponins 1-4 were isolated from the rhizomes of Anemarrhena asphodeloides (Asparagaceae), as well as four known saponins: anemarsaponin B (5) timosaponin D (6), timosaponin E1 (7) anemarsaponin B II (8). Their structures were established through UV and NMR as well as MS data. All the compounds were evaluated for cytotoxicity against HepG2 and SGC7901 human cancer lines. Compounds 3 and 7 displayed medium antiproliferative activities on HepG2 and SGC7901 cells, with IC50 values of 43.90 and 57.90 μM, respectively.

A New Neolignan Glycoside from Vetiveria zizanioides Roots

A new neolignan glycoside (1) and four known aromatic compounds (2-5) were isolated from the roots of Vetiveria zizanioides. The structure of compound 1 was determined based on spectroscopic analysis and hydrolysis. The structure of known flavonoid glycoside 3 was confirmed by X-ray crystallography. Compound 5 showed weak cytotoxic activity against HL-60 cells with an IC50 value of 13.1 ± 0.04 μM.

Two New Homoisoflavonoids from the Bulbs of Bessera elegans

A further chemical investigation of the bulbs of Bessera elegans (Liliaceae) led to the isolation of a new homoisoflavonoid (1), a new scillascillin-type homoisoflavonoid (2), three known flavonoids (3–5), and two known norlignans (6 and 7). The structures of the new homoisoflavonoids (1 and 2) were determined based on the results of extensive spectroscopic analysis, including two-dimensional NMR data. The isolated compounds (1–7) were evaluated for cytotoxicity against HL-60 human promyelocytic leukemia cells and TIG-3 normal human diploid fibroblasts. Compound 1 exhibited potent tumor-selective cytotoxic activity against HL-60 cells.