Evaluation of In Vitro Cytotoxic Property Against Cholangiocarcinoma Cell Line and GC/MS Analysis from Leaf of Erythrophleum succirubrum Gagnep.

OBJECTIVE: Plants are valuable sources of new pharmaceuticals. Secondary metabolites of the genus Erythrophleum exhibit cytotoxicity and may have therapeutic value. The cytotoxic activity of ethanolic leaf extract of Erythrophleum succirubrum Gagnep. against a human cholangiocarcinoma cell line was assessed. METHODS: Crude extract of E. succirubrum was prepared by ethanol extraction. The ethanolic leaf extract of E. succirubrum was evaluated for cytotoxicity against the human cholangiocarcinoma cell line KKU-M213 using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assays. The chemical composition of E. succirubrum leaf extract was analyzed using GC/MS. RESULT: The ethanolic leaf extract of E. succirubrum reduced the viability of KKU-M213 cells in a dose- and time-dependent manner. It showed high cytotoxicity, with IC50 values of 65.22 ± 1.18 µg/mL and 1.19 ± 1.38 µg/mL at exposure times of 24 and 96 h, respectively. GC/MS analysis of the ethanolic leaf extract of E. succirubrum identified 22 components. The main constituents identified were Cyclohexanone, 2-[2-nitro-1-(2-naphthyl)ethyl]-(14.79%) followed by allomycin (14.65%), mome inositol (14.30%), campesterol (11.80%) and ethyl linolenate (10.83%), respectively. CONCLUSION: Five major groups of compounds were found, with lipids dominating, followed by carbohydrates, benzenoids, phenylpropanoids, polyketides and organoheterocyclic compounds. Many of the bioactive components discovered in the ethanolic leaf extract of E. succirubrum might be responsible for its cytotoxic properties.

Phytochemical studies on Stemona aphylla: isolation of a new stemofoline alkaloid and six new stemofurans.

A new stemofoline alkaloid, (2'S)-hydroxy-(11S,12R)-dihydrostemofoline (3), new stemofurans M-R (8-13), and known compounds stemofoline (1), (2'S)-hydroxystemofoline (2), stemofuran E (4), stemofuran F (5), stemofuran J (6), and stilbostemin F (7) have been isolated from the root extracts of Stemona aphylla. The structures and relative configurations of these new compounds have been determined by spectroscopic data interpretation and from semisynthetic studies. These natural and semisynthetic alkaloids were tested for acetylcholinesterase inhibitory activities and were found to be 10-20 times less active than 1',2'-didehydrostemofoline itself. Stemofurans 4, 6, 8, 11, and 13 were tested for their antibacterial and antifungal activities. Three of these showed antibacterial activities against MRSA with MIC values of 15.6 µg/mL.

Phytochemical investigations of Stemona curtisii and synthetic studies on stemocurtisine alkaloids.

The isolation of two new Stemona alkaloids, 1-hydroxyprotostemonine and stemocurtisine N-oxide, and a new benzofuran, stemofuran L, from the root extracts of Stemona curtisii is reported. The major known alkaloids from this plant extract, stemocurtisine, stemocurtisinol, and oxyprotostemonine, were also isolated along with oxystemokerrine N-oxide. The nonalkaloid components of this extract included a new benzofuran derivative, stemofuran L, the known stemofurans F, J, and K, dihydro-γ-tocopherol, and stigmasterol. Stemocurtisine and stemocurtisinol were converted to their respective N-oxides by oxidation. Stemocurtisine was converted to a tetracyclic derivative by oxidative cleavage of the γ-butyrolactone ring, while stemocurtisinol gave a novel lactam derivative by oxidative cleavage of the C-4 side chain under basic conditions. The acetylcholinesterase inhibitory activities of some known and new alkaloids and their derivatives are also reported. All were 10-20 times less active as acetylcholinesterase inhibitors than the pyrrolo[1,2-a]azepine Stemona alkaloids stemofoline and 1',2'-didehydrostemofoline. None of the stemofuran compounds showed significant antibacterial or antifungal activities.

Alkaloids from the roots of Stemona aphylla.

Three known compounds, stemofoline (1), (2'S)-hydroxystemofoline (2), and (11Z)-1',2'-didehydrostemofoline (3), along with two new alkaloids, stemaphylline (4) and stemaphylline-N-oxide (5), have been isolated from a root extract of Stemona aphylla. The structures of these alkaloids were determined on the basis of their spectroscopic data. The analysis of the crude dichloromethane extract by GC-MS in the EIMS mode showed the presence of alkaloids 1-4, the alkaloid 11, and stilbostemin R (12). The crude dichloromethane extract and 4 were tested for their comparative biological activities. The results of their acetylcholinesterase (AChE) inhibitory activities showed that the crude extract had higher activity than that of 4. The insecticidal properties of the crude extract and 4, using a topical application, showed that 4 had an activity similar to the positive control, methomyl, whereas the crude extract had much lower activity. Their antimicrobial activity against Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, Pseudomonas auruginosa ATCC 27853, and Candida albicans ATCC 90028 was weak (MIC 62.5-125 microg/mL, MBC 125-250 microg/mL, MFC 125 microg/mL) but much higher than that of the crude extract.