Do Thi Thao

Two new neoclerodane diterpenoids from Scutellaria barbata D. Don growing in Vietnam

Various chromatographic separations of the aerial parts of Scutellaria barbata afforded two new neoclerodane diterpenoids, scutebatas S and T (1 and 2), along with scutebata D (3). Their structures were elucidated by spectroscopic methods including high-resolution electrospray ionization mass spectrometry, 1D and 2D NMR and comparison with the literature values. Compounds 1 and 3 exhibited moderate cytotoxic activities against HL-60 (promyeloblast) human cancer cells. Weak cytotoxic effects toward four tested human cancer cell lines including KB (epidermoid carcinoma), LU-1 (lung adenocarcinoma), MCF7 (breast cancer), and Hep-G2 (hepatoma cancer) were observed for 1 and 3; whereas 2 was inactive on all five tested cell lines.

Synthesis of Chromonylthiazolidines and Their Cytotoxicity to Human Cancer Cell Lines

Nine new chromonylthiazolidine derivatives were successfully semi-synthesized from paeonol. All of the compounds, including starting materials, the intermediate compound and products, were evaluated for their cytotoxic effects toward eight human cancer cell lines. The synthesized chromonylthiazolidines displayed weak cytotoxic effects against the tested cancer cell lines, but selective cytotoxic effects were observed. Compounds 3a and 3b showed the most selective cytotoxic effects against human epidermoid carcinoma (IC50 44.1 ± 3.6 μg/mL) and breast cancer (IC50 32.8 ± 1.4 μg/mL) cell lines, respectively. The results suggest that chromoylthiazolidines are potential low-cost, and selective anticancer agents.

Cytotoxic triterpene saponins from Cercodemas anceps

Seven holostane-type triterpene saponins (1-7), including five new compounds namely cercodemasoides A-E (2-6), were isolated from the sea cucumber Cercodemas anceps. Their structures were elucidated on the basis of spectroscopic evidence including HR ESI MS, ESI MS/MS, 1D and 2D NMR. The cytotoxic effects of isolated compounds were evaluated by SRB method on five human cancer cell lines including Hep-G2 (hepatoma cancer), KB (epidermoid carcinoma), LNCaP (prostate cancer), MCF7 (breast cancer), and SK-Mel2 (melanoma). Compounds 1-7 showed potent cytotoxicity on five tested cancer cell lines with IC50 values ranging from 0.03 ± 0.01 to 7.36 ± 0.46 μM. With respect to the potent cytotoxicity of the isolated saponins, further studies are required to confirm efficacy in vivo and the mechanism of cytotoxic effects.

Cytotoxic triterpene diglycosides from the sea cucumber Stichopus horrens

Using various chromatographic separation techniques, eight triterpene diglycosides (1-8), including four new compounds namely stichorrenosides A-D (1-4), were isolated from a methanol extract of the Vietnamese sea cucumber S. horrens. Their structures were elucidated based on spectroscopic analyses, including HR ESI MS, 1D and 2D NMR. Their in vitro cytotoxic activity against five human cancer cell lines, Hep-G2 (hepatoma cancer), KB (epidermoid carcinoma), LNCaP (prostate cancer), MCF7 (breast cancer), and SK-Mel2 (melanoma), was evaluated using SRB methods. Stichorrenoside D (4), stichoposide A (5), and 3β-O-[β-d-xylopyranosyl-(1→2)-β-d-xylopyranosyl]-23S-acetoxyholost-7-ene (7) showed strong cytotoxicity on all five tested cancer cell lines, whereas significant effect was observed for stichorrenoside C (3) and stichoposide B (6).

Asterosaponins and glycosylated polyhydroxysteroids from the starfish Culcita novaeguineae and their cytotoxic activities

Using combined chromatographic methods, two asterosaponins (compounds 1 and 2), including a new compound novaeguinoside E (compound 1), and six glycosylated polyhydroxysteroids (compounds 3–8) were isolated from a methanol extract of the starfish Culcita novaeguineae. Their structures were determined on the basis of spectroscopic data (1H and 13C NMR, HSQC, HMBC, 1H–1H COSY, ROESY, and HRESI-MS) and by comparison with the literature values. The new compound 1 represents the third example of asterosaponins containing the 5α-cholesta-9(1l)-en-3β,6α,20,22-tetraol aglycone. Among isolated compounds, 4–7 exhibited moderate to weak cytotoxic activities against five human cancer cell lines such as Hep-G2 (hepatoma), KB (epidermoid carcinoma), LNCaP (prostate cancer), MCF7 (breast cancer), and SK-Mel2 (melanoma).

Steroid constituents from the soft coral Sinularia microspiculata

Abstract A methanol extract of the soft coral Sinularia microspiculata revealed five sterols, including two new compounds. Using combined chromatographic and spectroscopic experiments, the new compounds were found to be 7-oxogorgosterol (1) and 16α-hydroxysarcosterol (2). Their structures were determined on the basis of spectroscopic data (1H and 13C NMR, HSQC, HMBC, 1H-1H COSY, NOESY, and FT-ICR-MS) and by comparing obtained results to the values indicated in previous studies. Among the isolated compounds, 3 showed weak cytotoxic effects against HL-60 (IC50  =  89.02  ±  9.93 μM) cell line, whereas 5 was weakly active against HL-60 (IC50  =  82.80  ±  13.65 μM) and SK-Mel2 (IC50  =  72.32  ±  1.30 μM) cell lines.

Toxicity and anticancer effects of an extract from Selaginella tamariscina on a mice model

The toxicity and antitumour effect of the ethanol extract of Selaginella tamariscina (STE), a plant widely used in folk medicine, were examined in a mice model. In the single-dose acute toxicity test, an oral administration of 10,000 mg kg−1 STE did not cause any lethality. The sub-acute toxicity study showed that the treatment by 250, 1000 and 3000 mg kg−1 day−1 for 30 continuous days did neither alter the body weights nor the haematological parameters in BALB/c mice. The anticancer effect of STE was evaluated in BALB/c mice inoculated with Lewis lung carcinoma cells. Oral administration of STE could not prevent the tumour formation but provided strong inhibition of tumour growth.The toxicity and antitumour effect of the ethanol extract of Selaginella tamariscina (STE), a plant widely used in folk medicine, were examined in a mice model. In the single-dose acute toxicity test, an oral administration of 10,000 mg kg(-1) STE did not cause any lethality. The sub-acute toxicity study showed that the treatment by 250, 1000 and 3000 mg kg(-1 )day(-1) for 30 continuous days did neither alter the body weights nor the haematological parameters in BALB/c mice. The anticancer effect of STE was evaluated in BALB/c mice inoculated with Lewis lung carcinoma cells. Oral administration of STE could not prevent the tumour formation but provided strong inhibition of tumour growth.

Selectivity of Pinus sylvestris extract and essential oil to estrogen-insensitive breast cancer cells Pinus sylvestris against cancer cells

Background: So far, the anticancer action of pine tree extracts has mainly been shown for the species distributed widely around the Asian countries. Objective: Therefore, this study was performed to examine the potential cytotoxicity of Scots pine (Pinus sylvestris L.) native also to the European region and growing widely in Estonia. Materials and Methods: The cytotoxic activity of methanol extract and essential oil of Scots pine needles was determined by sulforhodamine B assay in different human cancer cell lines. Results: This needle extract was found to suppress the viability of several human cancer cell lines showing some selectivity to estrogen receptor negative breast cancer cells, MDA-MB-231(half maximal inhibitory concentration [IC50] 35 μg/ml) in comparison with estrogen receptor-positive breast cancer cells, MCF-7 (IC50 86 μg/ml). It is the strongest cytotoxic effect at all measured, thus far for the needles and leaves extracts derived from various pine species, and is also the first study comparing the anticancer effects of pine tree extracts on molecularly different human breast cancer cells. The essential oil showed the stronger cytotoxic effect to both negative and positive breast cancer cell lines (both IC50 29 μg/ml) than pine extract (IC50 42 and 80 μg/ml, respectively). Conclusion: The data from this report indicate that Scots pine needles extract and essential oil exhibits some potential as chemopreventive or chemotherapeutic agent for mammary tumors unresponsive to endocrine treatment.

The hepatoprotective activity of a new derivative kaempferol glycoside from the leaves of Vietnamese Phyllanthus acidus (L.) Skeels

A new derivative kaempferol glycoside, kaempferol-3-O-(2-α-l-rhamnopyranosyl)-β-d-glucuronopyranosyl methyl ester (3), together with six other known kaempferol glycosides, kaempferol-3-O-[α-l-rhamnopyranosyl (1→2)]-β-d-galactopyranoside (1), kaempferol-3-O-(2-α-l-rhamnopyranosyl)-β-d-glucuronopyranoside (2), rutin (4), isoquercitrin (5), quercitrin (6), and myricitrin (7) were isolated from the leaves of Phyllanthus acidus (L.) Skeels (Phyllanthaceae). Here, is the first report described the isolation of compound (1) and (2) from the genus Phyllanthus. Compound (1) presents antioxidant activity in 2,2-diphenyl-1-picryl-hydrazyl-hydrate assay. Compound (2) and (3) performed no antioxidant activity in 2,2-diphenyl-1-picryl-hydrazyl-hydrate and thiobarbituric acid reactive substances assays (IC50 > 100 µM). However, compound (2) showed anti-inflammation activity through inhibiting interleukin 6 and tumor necrosis factor alpha production (P < 0.05). Compound (3) also exhibited cytokine modulating activities such as inhibiting tumor necrosis factor alpha, activating interleukin 10 at concentration of 10 µM (P < 0.05). The interleukin 6 cytokine level was also up or down-regulated by compound (3) at two time points; 24 and 48 h. This activeness of compound (3) might induce hepatoprotection in the acute-phase response by activating the signal transducer and activator of transcription 3(STAT3) through cytokine modulation. Together with other kaempferol glycosides, this new derivative compound may mediate the liver-protective activity of the Vietnamese medicinal plant Phyllanthus acidus.

Cytotoxic Steroids from the Vietnamese Soft Coral Sinularia leptoclados

Fifteen steroids, including two new compounds, leptosteroid (1) and 5,6β-epoxygorgosterol (2), were isolated and structurally elucidated from the Vietnamese soft coral Sinularia leptoclados. Their cytotoxic effect against a panel of eight human cancer cell lines was evaluated using sulforhodamine B (SRB) method. Significant cytotoxicity against hepatoma cancer (HepG2, IC50=21.13±0.70 µM) and colon adenocarcinoma (SW480, IC50=28.65±1.53 µM) cell lines were observed for 1 and against acute leukemia (HL-60, IC50=20.53±2.26 µM) and SW480 (IC50=26.61±1.59 µM) for ergost-5-en-3β,7β-diol (8). In addition, 3β,7β-dihydroxyergosta-5,24(28)-diene (13) showed significant cytotoxic activity on all tested cell lines with IC50 values ranging from 13.45±1.81 to 29.01±3.21 µM.