Darren Grice

Cytotoxic Effects of Bangladeshi Medicinal Plant Extracts

To investigate the cytotoxic effect of some Bangladeshi medicinal plant extracts, 16 Bangladeshi medicinal plants were successively extracted with n-hexane, dichloromethane, methanol and water. The methanolic and aqueous extracts were screened for cytotoxic activity against healthy mouse fibroblasts (NIH3T3) and three human cancer-cell lines (gastric: AGS; colon: HT-29; and breast: MDA-MB-435S) using the MTT assay. Two methanolic extracts (Hygrophila auriculata and Hibiscus tiliaceous) and one aqueous extract (Limnophila indica) showed no toxicity against healthy mouse fibroblasts, but selective cytotoxicity against breast cancer cells (IC50 1.1–1.6 mg mL−1). Seven methanolic extracts from L. indica, Clerodendron inerme, Cynometra ramiflora, Xylocarpus moluccensis, Argemone mexicana, Ammannia baccifera and Acrostichum aureum and four aqueous extracts from Hygrophila auriculata, Bruguiera gymnorrhiza, X. moluccensis and Aegiceras corniculatum showed low toxicity (IC50 > 2.5 mg mL−1) against mouse fibroblasts but selective cytotoxicity (IC50 0.2–2.3 mg mL−1) against different cancer cell lines. The methanolic extract of Blumea lacera showed the highest cytotoxicity (IC50 0.01–0.08 mg mL−1) against all tested cell lines among all extracts tested in this study. For some of the plants their traditional use as anticancer treatments correlates with the cytotoxic results, whereas for others so far unknown cytotoxic activities were identified.

Galectin inhibitory disaccharides promote tumour immunity in a breast cancer model

High level galectin-1 expression results in cancer cell evasion of the immune response, increased tumour survival and aggressive metastases. Using a galectin-1 polyclonal antibody, high levels of galectin-1 protein were shown to be expressed by breast cancer cells established from FVB/N MMTV-c-neu mice as well as by the B16F10 melanoma cell line. In mixed lymphocyte cultures using tumour cells as antigenic stimulators, addition of recombinant galectin-1 dose-dependently inhibited lymphocyte production. Disaccharides were identified that inhibited galectin-1 function and increased growth and activation of CD8(+) CTLs killing cancer cells. X-ray crystallographic structures of human galectin-1 in complex with inhibitory disaccharides revealed their mode of binding. Combining galectin-blocking carbohydrates as adjuvants with vaccine immunotherapy in vivo to promote immune responses significantly decreased tumour progression and improved the outcomes for tumour challenged mice. This is the first report showing that suitably selected galectin-1 blocking disaccharides will act as adjuvants promoting vaccine stimulated immune responses against tumours in vivo.

Antibacterial metabolites from Australian macrofungi from the genus Cortinarius

In this study, ethyl acetate and aqueous fractions from 117 collections of Australian macrofungi belonging to the mushroom genus Cortinarius were screened for antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa. Overall, the lipophilic fractions were more active than the aqueous fractions. The ethyl acetate fractions of most or all collections of 13 species, namely Cortinarius ardesiacus, C. archeri, C. austrosaginus, C. austrovenetus, C. austroviolaceus, C. coelopus, C. [Dermocybe canaria](2), C. clelandii, C. [D. kula], C. memoria-annae, C. persplendidus, C. sinapicolor, C. vinosipes and forty seven collections of un-described Cortinarius species exhibited IC(50) values of 0.09 mg/mL against S. aureus. In contrast, most or all collections of only four species, namely C. abnormis, C. austroalbidus, C. [D. kula], C. persplendidus, and eleven un-described Cortinarius collections exhibited similar effects against P. aeruginosa (IC(50) <or= 0.09 mg/mL). Anthraquinonoid pigments isolated from C. basirubescens together with emodin physcion and erythrogluacin were assessed for their antimicrobial activity. The fungal octaketides austrocortilutein, austrocortirubin, torosachrysone, physcion and emodin were found to strongly inhibit the growth of S. aureus (IC(50) 0.7-12 microg/mL) whereas only physcion and emodin exhibited potency against P. aeruginosa (IC(50) 1.5 and 2.0 microg/mL, respectively).

(2S,3S)-sulfated pterosin C, a cytotoxic sesquiterpene from the Bangladeshi mangrove fern Acrostichum aureum.

Two new sesquiterpenes, (2R,3S)-sulfated pterosin C (1) and (2S,3S)-sulfated pterosin C (2), along with two known derivatives, (2S,3S)-pterosin C and (2R)-pterosin P, were isolated from a methanolic extract of the aerial parts of Acrostichum aureum. The structures of 1 and 2 were determined by the interpretation of their spectroscopic data. The isolated pterosins were evaluated for their cytotoxic activity against the AGS, HT-29, MDA-MB-231, and MCF-7 human cancer cell lines and the NIH3T3 normal mouse fibroblast cell line, using the MTT assay. Compound 2 showed IC50 values in the range 23.9-68.8 μM. The lowest IC50 value (23.9 μM) was recorded against AGS gastric adenocarcinoma cells. Compound 2 was found to exert an apoptotic effect on AGS cells within 24 h of treatment, which increased with time and was greater than the positive control, cycloheximide. The cytotoxicity of 2 seems to be due in part to the sulfate group on C-14 and the configuration at C-2.

Evaluation of cytotoxic activity of patriscabratine, tetracosane and various flavonoids isolated from the Bangladeshi medicinal plant Acrostichum aureum.

Context: Acrostichum aureumL. (Pteridaceae), a mangrove fern, has been used as a Bangladeshi traditional medicine for a variety of diseases including peptic ulcer. Objective: Isolation and structural elucidation of cytotoxic secondary metabolites from the methanol extract of the aerial parts of A. aureum. Materials and methods: Compounds were isolated using HPLC. The compound structures were elucidated by 1D and 2D NMR, MS and other spectroscopic methods using published data. The compounds were tested for their cytotoxic activity against healthy and cancer cells using the MTT assay. Active compounds were further evaluated for apoptosis–and necrosis-inducing potential against gastric cancer cells (AGS) using the FITC Annexin V apoptosis assay. Results and discussion:Seven known compounds, patriscabratine, tetracosane and 5 flavonoids (quercetin-3-O-β-d-glucoside, quercetin-3-O-β-d-glucosyl-(6→1)-α-l-rhamnoside, quercetin-3-O-α-l-rhamnoside, quercetin-3-O-α-l-rhamnosyl-7-O-β-d-glucoside and kaempferol) were isolated. Patriscabratine was found moderately cytotoxic against AGS, MDA-MB-231 and MCF-7 cells with IC50 values ranging from 69.8 to 197.3 μM. Tetracosane showed some cytotoxic activity against AGS, MDA-MB-231, HT-29 and NIH 3T3 cells with IC50 values ranging from 128.7 to >250 μM. Patriscabratine and tetracosane displayed an apoptotic effect (10%) on AGS cells within 24 h which was increased (20%) after 48 h, and was comparable to, if not greater, than the positive control, cycloheximide. Conclusion:Except for quercetin-3-O-β-d-glucoside and kaempferol; compounds were isolated for the first time from this plant and evaluated for their cytotoxic activity. The results highlight the potential of this plant as a source of bioactive compounds and provide a rationale for its traditional use in peptic ulcer treatment.

Ethanolic and aqueous extracts derived from Australian fungi inhibit cancer cell growth in vitro

Fifteen Australian macrofungi were investigated for cytotoxic activity. Ethanol, cold and hot water extracts of each species were screened for cytotoxic activity against normal mouse fibroblast cells (NIH/3T3), healthy human epithelial kidney cells (HEK-293), four cancer cell lines, gastric adenocarcinoma cells (AGS), two mammary gland adenocarcinoma cells (MDA-MB-231, MCF7) and colorectal adenocarcinoma cells (HT-29) with a validated MTT assay. Most extracts derived from Omphalotus nidiformis, Cordyceps cranstounii and Cordyceps gunnii demonstrated significant cytotoxic activity toward a variety of cancer cell lines. In contrast only some extracts from Coprinus comatus, Cordyceps hawkesii, Hypholoma fasciculare, Lepista nuda, Leratiomyces ceres and Ophiocordyceps robertsii displayed significant cytotoxic activity, which was usually selective for only one or two cancer cell lines tested. The least cytotoxic species evaluated in this study were Agaricus bitorquis, Coprinopsis atrametaria, Psathyrella asperospora, Russula clelandii, Tricholoma sp. AU2 and Xerula mundroola.

Isotopic profiling of seized benzylpiperazine and trifluoromethylphenylpiperazine tablets using δ13C and δ15N stable isotopes

This paper demonstrates the use of isotopic analysis of 23 benzylpiperazine (BZP) and trifluoromethylphenylpiperazine (TFMPP) containing tablets seized on two independent occasions by the Northern Territory (NT) Police, Australia. Isolation (High Performance Liquid Chromatography (HPLC)) of BZP and TFMPP followed by Isotope Ratio Mass Spectrometry (IRMS) (carbon and nitrogen stable isotopes) analysis was performed. Results are presented for δ13C and δ15N values of the respective piperazine analogues. The isotopic data and statistical analysis suggest a common source of manufacture for the BZP samples but suggest different sources for the TFMPP isolated from the corresponding BZP containing tablets investigated. The use of IRMS in this case study demonstrated the ability to obtain information regarding the BZP/TFMPP sources unattainable via conventional chemical analysis.