Essential oils were extracted from the culm and leaf of Cymbopogon citratus collected from different regions of Vietnam and analyzed using GC/MS. The results showed that citral is the major component accounting for 61.20%–76.46% of the essential oils. The citral content was higher in the essential oil obtained from the leaf than in that from the culm of lemongrass in all regions. In particular, camphene, valerianol, and epi-α-muurolol can be used to differentiate essential oils originating from leaves versus culms. The cytotoxic effects of the essential oils on various lung cancer cell lines were evaluated in the present study. All essential oils exhibited cytotoxicity in the tested cells. The Ha Loc leaf essential oil (HLL) exhibited the most potent effects on A549 and H1975 cells, with IC50 values of 1.73 ± 0.37 and 4.01 ± 0.30 μg/mL, respectively. The Hy Cuong leaf essential oil (HCL) showed the strongest effect on H1299 cells, with an IC50 value of 2.45 ± 0.21 μg/mL. The Kim Duc culm (KDC) essential oil exerted the strongest cytotoxic effects against H1650 cells, with an IC50 value of 4.86 ± 0.29 μg/mL. The HLL induced apoptosis and cycle arrest in A549 cells according to flow cytometric analysis and fluorescent nuclear staining assays. The western blot analysis indicated that HLL induced the apoptotic effect by altering the regulating proteins of the apoptosis process such as caspase-3, Bcl-2, and Bax. The data strongly suggested that the intrinsic pathway may play an important role in the apoptotic effects of HLL.

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Using various chromatographic methods, four new steroids, astropectenols A-D (1-4), along with three known compounds (5-7) were isolated from a methanol extract of the starfish Astropecten polyacanthus. The structure elucidation was confirmed by spectroscopic methods, including one dimensional (1D)-, 2D-NMR and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). The CH 2 Cl 2 fraction and compound 7 exhibit potent cytotoxic effects against HL-60 human leukemia cells with the IC 50 of 8.29 µg/mL and 2.70 µM, respectively, comparing to the positive control, mitoxantrone (IC 50 6.80 µM). When HL-60 cells were treated with the CH 2 Cl 2 fraction or compound 7, several apoptosis events like chromatin condensation and the increase of the population of sub-G1 hypodiploid cells were observed. Investigations for the possible mechanism underlying the induction of apoptosis showed that CH 2 Cl 2 fraction or compound 7 induced apoptosis through down-regulation of Bcl-2, up-regulation of Bax, cleavage of caspase-9, cleavage of caspase-3 and cleavage of poly(ADP-ribose) polymerase (PARP) in HL-60 cells. Furthermore, the apoptosis induction of HL-60 cell by CH 2 Cl 2 fraction or compound 7 was attended by the decreasing of phospho-extracellular signal-regulated kinase (ERK) 1/2 and C-myc. These results indicated that the CH 2 Cl 2 fraction and compound 7 could induce the apoptosis of HL-60 cells via the inactivation of ERK 1/2 and the decrease of C-myc. Our finding suggested the potential using of the CH 2 Cl 2 fraction and compound 7 for leukemia treatment. Key words Astropecten polyacanthus; starfish; oxygenated steroid; cytotoxic; apoptosisEchinoderms represent an outstanding source of polar steroids of a great structural diversity, showing various biological activities. Among five living classes of the phylum Echinodermata, two classes Asteroidea (starfish) and Ophiuroidea (brittle stars) are especially rich in polar steroids.1) The research on starfish has expanded rapidly over the past few years, which has been prompted by the discovery of a variety of unique structures and the interest in their pharmacological properties. Starfish have attracted organic chemists, biochemists, and pharmacologists as a fascinating source of bioactive marine natural products, especially steroids and steroidal glycosides. 2)Some polyhydroxylated steroids from starfish exhibited antibacterial and cytotoxic activities. 1)In our screening research for anti-cancer agents from Vietnamese echinoderms, we found the starfish Astropecten polyacanthus to possess significant cytotoxic effects. As part of our continuing investigations on this starfish, we report herein the isolation, structural elucidation, and evaluation of anticancer activity of extracts and seven steroids, including four new compounds 1-4, from the starfish A. polyacanthus.

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Degalactotigonin (1) and three other steroidal compounds solasodine (2), O-acetyl solasodine (3), and soladulcoside A (4) were isolated from the methanolic extract of Solanum nigrum, and their chemical structures were elucidated by spectroscopic analyses. The isolated compounds were evaluated for cytotoxic activity against human pancreatic cancer cell lines (PANC1 and MIA-PaCa2) and lung cancer cell lines (A549, NCI-H1975, and NCI-H1299). Only degalactotigonin (1) showed potent cytotoxicity against these cancer cell lines. Compound 1 induced apoptosis in PANC1 and A549 cells. Further study on its mechanism of action in PANC1 cells demonstrated that 1 significantly inhibited EGF-induced proliferation and migration in a concentration-dependent manner. Treatment of PANC1 cells with degalactotigonin induced cell cycle arrest at G0/G1 phase. Compound 1 induced downregulation of cyclin D1 and upregulation of p21 in a time- and concentration-dependent manner and inhibited EGF-induced phosphorylation of EGFR, as well as activation of EGFR downstream signaling molecules such as Akt and ERK.