Ikram M. Said

A new indole alkaloid, 7-hydroxyspeciociliatine, from the fruits of Malaysian Mitragyna speciosa and its opioid agonistic activity

A new indole alkaloid, 7-hydroxyspeciociliatine (1), was isolated from the fruits of Malaysian Mitragyna speciosa Korth., together with 11 known indole and oxindole alkaloids (3–13). The structure of the new compound was determined by spectroscopic analysis and chemical conversion. The opioid agonistic activity of the new alkaloid was investigated in guinea-pig ileum experiments. The compound was found to have a weak stimulatory effect on μ-opioid receptors.

New indole alkaloids from the leaves of Malaysian Mitragyna speciosa

Abstract Three new monoterpenoid indole alkaloids, i.e., 3,4,5,6-tetradehydromitragynine, mitralactonal, and mitrasulgynine carrying a sulfonate function, were isolated, together with seven known compounds, from the leaves of Mitragyna speciosa native to Malaysia.

Methyl chanofruticosinates from leaves of Kopsia flavida Blume

Three new indole alkaloids with methyl chanofruticosinates skeletal system, viz., methyl 12-methoxy-N1-decarbomethoxychanofruticosinate, methyl 12-methoxychanofruticosinate and methyl 11,12-dimethoxychanofruticosinate, in addition to methyl 11,12-methylenedioxy-N1-decarbomethoxychanofruticosinate, have been isolated from the leaves of Kopsia flavida Blume. The structures of these three new indole alkaloids were assigned by NMR spectral data using various 2D-techniques.

Structure Elucidation and Chiral-Total Synthesis of a New Indole Alkaloid, (−)-9-Methoxymitralactonine, Isolated from Mitragyna speciosa in Malaysia

Abstract A new Corynanthe-type indole alkaloid, (−)-9-methoxymitralactonine ( 1 ), having a highly conjugated system was isolated from the young leaves of Mitragyna speciosa in Malaysia, and its structure was first deduced by spectroscopic analysis and then confirmed by chiral-total synthesis starting from optically pure epoxy-ketone and 5-methoxy-3,4-dihydro-β-carboline. The chiral HPLC analysis demonstrated that the natural 9-methoxymitralactonine contained predominantly the (−)-enantiomer over the (+)-enantiomer in the ratio of 62:38.

Oligostilbenoids from Shorea gibbosa and their cytotoxic properties against P-388 cells

A new oligostilbenoid derivative, diptoindonesin F (1), along with five known oligostilbenoids, (−)-ampelopsin A (2), (−)-α-viniferin (3), ampelopsin E (4), (−)-vaticanol B (5), and (−)-hemsleyanol D (6), were isolated from the methanol extract of the tree bark of Shorea gibbosa. The structure of the new compound was determined based on the analysis of spectroscopic data, including UV, IR, NMR 1-D and 2-D, and mass spectra. Cytotoxic properties of the isolated oligostilbenoids were evaluated against murine leukemia P-388 cells with the result that compounds 2 and 4 showed the highest cytotoxicity.

Cytotoxic Properties of Oligostilbenoids from the Tree Barks of Hopea dryobalanoides

Abstract A new modified stilbene dimer, diptoindonesin D (1), was isolated from the acetone extract of the tree bark of Hopea dryobalanoides, together with seven known compounds, parviflorol (2), (D)-balanocarpol (3), heimiol A (4), hopeafuran (5), (+)-α-viniferin (6), vaticanol B (7) and (D)-hopeaphenol (8). Cytotoxic properties of compounds 1-8 were evaluated against murine leukemia P-388 cells. Compound 8 was found to be the most active with IC50 of 5.7 μm

Structure revision of mitragynaline, an indole alkaloid in Mitragyna speciosa

Abstract The structure of mitragynaline, an indole alkaloid isolated from Malaysian Mitragyna speciosa , was revised as formula 3 by analysis of the NMR spectra measured at low temperature and by chemical transformation with DDQ oxidation from the known alkaloid mitragynine ( 5 ).

Phenolic Constituents from the Wood of Morus australis with Cytotoxic Activity

A new methylated flavonol, 5,7,2 ′,4 ′-tetrahydroxy-3-methoxyflavone (1), had been isolated from the methanol extract of the wood of Morus australis, along with nine known compounds, kuwanon C (2), morusin (3), morachalcone A (4), oxyresveratrol (5), 4 ′-(2-methyl-2-buten- 4-yl)oxyresveratrol (6), moracins M (7) and C (8), alboctalol (9), and macrourin B (10). The structures of these compounds were determined based on spectral evidence, including UV, IR, NMR, and mass spectra. Cytotoxic properties of compounds 1 →10 were evaluated against murine leukemia P-388 cells. The prenylated stilbene 6 and 2-arylbenzofuran 8, and morusin (3) were found to have strong cytotoxic effects with IC50 values of 6.9, 8.7, and 10.1 μM, respectively.

Two new methyl chanofruticosinates from Kopsia flavida blume

Two new indole alkaloids with the methyl chanofruticosinate skeletal system viz., methyl 3-oxo-12-methoxy- N 1 -decarbomethoxy-14,15-didehydrochanofruticosinate ( 1 ) and methyl 3-oxo-11,12-methylenedioxy- N 1 -decarbomethoxy-14,15-didehydrochanofruticosinate ( 2 ), together with four known compounds, methyl 12-methoxy- N 1 -decarbomethoxychanofruticosinate, methyl 12-methoxychanofruticosinate, methyl 11,12-dimethoxychanofruticosinate and methyl 11,12-methylenedioxy- N 1 -decarbomethoxychanofruticosinate, were isolated in continuing studies on the leaves of Kopsia flavida Blume. The structures of the new indole alkaloids were assigned by NMR spectral data using various 2D-techniques.

Molecular cloning and characterization of strictosidine synthase, a key gene in biosynthesis of mitragynine from Mitragyna speciosa

Mitragynine is one of the most dominant indole alkaloids present in the leaves of Mitragyna speciosa , a species of Rubiaceae. This alkaloid is believed to be synthesized via condensation of the amino acid derivative, tryptamine and secologanine by the action of strictosidine synthase (STR). The cDNA clone encoding STR from M. specios a was cloned through reverse-transcription polymerase chain reaction (RT-PCR) and denoted as StrMs1. The clone is a full-length cDNA with a size of 1257 bp, which contains an open reading frame of 1056 bp starting from base pair 18 to 1076. Sequence analysis showed that StrMs1 has high homology with other STRs of TIA-producing plants. Nucleotide sequence of StrMs1 was deposited in GenBank with accession number ADK91432. The deduced amino acid sequence has 352 residues with a predicted molecular weight of 39 kDa and isoelectric point at pH 5.78. Southern blot performed showed that there is only one copy of StrMs1 present in the genome of M. speciosa . Expression pattern on different tissues tested using RT-PCR revealed that besides leaf, the expression was also detected in root, stem and flower. Expression profiles under plant defense signal using salicylic acid (SA) was investigated on leaf tissues and the results showed that the transcript of StrMs1 were detected before and after treatment with salicylic acid. Result obtained from phylogenetic analysis suggested that StrMs1 is the most evolved protein among other STRs. However, the 3-D prediction of StrMs1 showed that there are alpha helices and beta propeller structures, which remain conserved withother STRs. Key word: Strictosidine synthase, Mitragyna speciosa, StrMs1, semiquantitative reverse-transcription polymerase chain reaction (RT-PCR), molecular evolution, protein prediction.