Amina H. Abou-Donia

Amaryllidaceae alkaloids belonging to different structural subgroups display activity against apoptosis-resistant cancer cells.

Fifteen Amaryllidaceae alkaloids (1-15) were evaluated for their antiproliferative activities against six distinct cancer cell lines. Several of these natural products were found to have low micromolar antiproliferative potencies. The log P values of these compounds did not influence their observed activity. When active, the compounds displayed cytostatic, not cytotoxic activity, with the exception of pseudolycorine (3), which exhibited cytotoxic profiles. The active compounds showed similar efficacies toward cancer cells irrespective of whether the cell lines were responsive or resistant to proapoptotic stimuli. Altogether, the data from the present study revealed that lycorine (1), amarbellisine (6), haemanthamine (14), and haemanthidine (15) are potentially useful chemical scaffolds to generate further compounds to combat cancers associated with poor prognoses, especially those naturally resistant to apoptosis, such as glioblastoma, melanoma, non-small-cell lung, and metastatic cancers.

SESQUITERPENE LACTONES FROM CHRYSANTHEMUM CORONARIUM

Abstract The flower heads of Chrysanthemum coronarium afforded a new sesquiterpene lactone, dihydrocumambrin A, in addition to the known cumambrin A.

Narciclasine-4-O-β-d-glucopyranoside, a glucosyloxy amidic phenanthridone derivative from Pancratium maritimum

Abstract Bulbs of Pancratium maritimum were found to contain a new glucosyloxy phenolic metabolise as well as 14 known Amaryllidaceae alkaloids. The structure of the phenolic metabolite was elucidated by spectroscopic and chemical methods, and it was identified as narciclasine-4- O -β- d -glucopyranoside. When tested in Artemia salina and potato disc assays the new glucoside showed cytotoxic and antitumour activity very similar to narciclasine.

Phytochemical and biological investigation of Hymenocallis littoralis Salisb

A phytochemical investigation of the bulbs and flowers of Hymenocallis littoralis Salisb., cultivated in Egypt, was carried out, which resulted in the isolation of four alkaloids, lycorine (1), hippeastrine (2), 11‐hydroxyvittatine (3), and (+)‐8‐O‐demethylmaritidine (4), and of two flavonoids, quercetin 3′‐O‐glucoside (5), and rutin (6). The volatile constituents of the plant flowers were analyzed for the first time by GC/MS, which led to the identification of 26 known compounds (Table 1). Finally, the antimicrobial activity of the petroleum ether extract of the flowers of H. littoralis was investigated.

Two betaine-type alkaloids from Egyptian Pancratium maritimum

Abstract Two 2-oxyphenanthridinium alkaloids have been isolated from Egyptian Pancratium maritimum and identified as ungeremine and zefbetaine using spectroscopic and chemical methods. The identification of zefbetaine was supported by its partial synthesis from pseudolycorine and by comparison with its unnatural isomer, iso -zefbetaine, which was in turn prepared from sternbergine.

Nobilisitine a and B, two masanane-type alkaloids from Clivia nobilis

Abstract Two masanane-type lactone alkaloids, named nobilisitine A and B, were isolated from Egyptian Clivia nobilis and characterized by spectroscopic and chemical methods. Both compounds showed contain the same [2]benzopyrano [3,4- g ]indole ring system and therefore belong to the same subgroup of Amaryllidaceae alkaloids. In particular, nobilisitine A and B, reported as two new alkaloids, proved to be the 5 β -hydroxy-3a,11c- epi -masan-7-one and the 3-hydroxybutanoyl ester of clivonine (5a-hydroxy-5a- epi -masan-7-one), the alkaloid previously extracted from Clivia miniata and belonging to the same alkaloid subgroup. Nobilisitine B appears to be an epimer at the acyl side chain of clivatine.

New rapid validated HPTLC method for the determination of galanthamine in Amaryllidaceae plant extracts

The work reported in this paper aims at developing an accurate, specific, repeatable and robust HPTLC method for the determination of galanthamine in different Amaryllidaceae plant extracts.

Sesquiterpene lactones from Centaurea glomerata

Abstract The investigation of the aerial parts of Centaurea glomerata afforded four new sesquiterpene lactones of the germacradienolide type and the lignan lactone arctigenin. Their structures were elucidated by spectroscopic methods.

A new approach to develop a standardized method for assessment of acetylcholinesterase inhibitory activity of different extracts using HPTLC and image analysis

A new, validated, sensitive and cheap method for preliminary quantitative evaluation of acetylcholine esterase inhibitory activity is presented. The proposed method combines HPTLC with data analysis by means of image processing software. An in-situ TLC autobiographic method was employed in which regions of the TLC plate which contain acetylcholinesterase inhibitors show up as white spots against the yellow background. Bleaching of the yellow color, caused by substances with acetylcholinesterase inhibitory activity was observed and recorded using a digital camera. ImageJ, JustTLC and Sorbfil, three image processing programs were evaluated for quantitative measurements. For evaluation of the assay efficiency, acetylcholinesterase inhibitory activity of different Amaryllidaceae plant extracts was expressed as Standard Activity Coefficients (SACs), which are relative measures of the activity to the well known acetylcholinesterase inhibitor eserine. We attempted to validate the method according to the ICH guideline. Different statistical data revealed that all image analysis software are able to detect the acetylcholine esterase inhibitory activity at very low concentration levels with the ImageJ program being the best of all three tested software regarding sensitivity, linearity and precision.

New Rapid Validated HPTLC Method for the Determination of Lycorine in Amaryllidaceae Plants Extracts

A rapid, accurate, specific, repeatable and robust HPTLC method for the determination of lycorine in different Amaryllidaceae plant extracts is presented in this work. No article related to the HPTLC determination of lycorine in plant extracts has been reported in literature. Lycorine, a common alkaloid of family Amaryllidaceae, moreover, there have been some recent reports which reveal the interaction of lycorine with DNA and tRNA. It has, therefore, been to the interest of phytochemists to determine the content of this alkaloid in Amaryllidaceaous plants.