Antiplasmodial activities of indole alkaloids from Tabernaemontana penduliflora K. Schum (Apocynaceae).

Five undescribed carboxy-indole alkaloids with corynanthe skeleton, penduflorines A-E (1-3) as well as a voacangine-N-oxide alkaloid, tabernaemontine (4), were isolated along with eight other known compounds (5-12) from the trunk bark of Tabernaemontana penduliflora K. Schum (Apocynaceae). Their structures were determined by means of spectroscopic and spectrometric methods such as UV, IR, NMR and HR-ESI-MS. Antiplasmodial activities of new isolates were evaluated against two strains of Plasmodium falciparum 3D7 and Dd2 by the Sybr green I-based fluorescence assay setup. Those compounds showed good in vitro activities. Among them, penduflorines A and B (1a and 1b) as well as tabernaemontine (4) showed significant inhibitory activities against the two strains with IC50 values ranged between 1.85 and 7.88 µg/mL. This is the first report of quaternary-N-indole alkaloids (1a, 1b, 2, 3a, 3b and 4) occurring in the form of zwitterion from Tabernaemontana genus.

Experimental and computational studies of an antiplasmodial derivative of allantoin; antimycobacterial essential oil from Cordia batesii WERNHAM (Boraginaceae).

BACKGROUND: Chemical and pharmacological investigations were performed on the stems of Cordia batesii (Boraginaeae); chemical studies included quantum calculations applied on a newly described compound. RESULTS: A new derivative of allantoin (1) named batesiin (2) was characterized. Thirteen other known compounds involving allantoin (1) were either isolated or identified. GC-MS enabled the identification of six compounds from a fraction containing essential oil. MeOH extract and some isolated compounds were tested in vitro against Pf7G8 CQS and Pf Dd2 CQR strains of Plasmodium falciparum; extract disclosed a moderate antiplasmodial activity (IC50 = 50 µg mL-1). Meantime, the CH2Cl2 extract and essential oil fraction were tested on a resistant mycobacterial strain of Mycobacterium tuberculosis; a potent antimycobacterial activity with a MIC = 9.52 µg mL-1 was deduced from essential oil. Density functional theory (DFT) calculations were carried on batesiin (2). Calculated chemical shifts at B3LYP/6-31G(d,p) and MPW1PW91/6-31G+(d,p) showed much better correlations with the experimental data. Time dependent DFT at B3LYP/6-31G+(d,p) displayed a major absorption band 3.01 nm higher than the experimental value. CONCLUSION: Cordia batesii can be considered as promising in search of compounds with antimalarial and antitubercular properties. DFT studies are very helpful when trying to learn more about the spectroscopic insights of a derivative of allantoin (1).

Antiplasmodial and antileishmanial inhibitory activity of triterpenes and steroidal alkaloid from the leaves of Funtumia elastica (Preuss) Stapf (Apocynaceae).

The phytochemical study of leaves of Funtumia elastica led to the isolation of three undescribed ursane derivatives, funtumic acids A, B and C (1-3), as well as one steroidal alkaloid, elasticine (4) and five other known compounds (5-9). Their structures were elucidated on the basis of NMR, MS, IR, UV spectroscopic data as well as by comparison with the literature. The compound 5-hydroxypyridine-3-carboxamide (9) was isolated for the first time from the Apocynaceae family. All the isolated compounds were evaluated for their antiparasitic effects against 3D7 and Dd2 strains of Plasmodium falciparum and promastigotes of Leishmania donovani (MHOM/SD/62/1S). Compounds 1-4 possessed good in vitro antimalarial activities against CQR Dd2 with IC50 values ranging from 4.68 to 5.36 µg/mL and moderate on CQS 3D7. Only compounds 1 and 2 showed leishmanicidal activities with IC50 values ranging between 10.49 and 13.21 µg/mL. In addition, crude extract exhibited potent antiplasmodial (IC50 0.91 and 3.12 µg/mL) and antileishmanial (IC50 3.32 µg/mL) activities, thus demonstrating their potential synergistic action.

Antileishmanial activity of long chain alkyl benzene and other constituents from seeds of Sesamum indicum. L (Pedaliaceae).

The methanolic extract of the waste seeds of Sesamum indicum L. (Pedaliaceae) was subjected to chromatographic fractionation; it led to the isolation of an alkyl benzene identified as 1,3-bis (pentadecyl)benzene (1) along with three known fatty acids: oleic acid (2), linoleic acid (3), and palmitic acid (4); one monosaturated cardanol, 3-pentadecylphenol (5) and two phytosteroids identified as sitostanol (6) and campestanol (7). The structures of these compounds were elucidated by chemical and spectroscopic analyses. Compounds 1, 5 and 6 were evaluated against protozoan parasites. Compound 1 moderately inhibited the promastigote form of Leishmania donovani LG13 with IC50 equal to 16.9 µM.

In vitro antitubercular activity of extract and constituents from the stem bark of Disthemonanthus benthamianus

ABSTRACT A new C-glycosylflavone, apigenin 7-methyl ether 6-C-[β-xylopyranosyl-(1→3)-β-glucopyranoside] named distemonanthoside was isolated from the stem bark of Distemonanthus benthamianus Baill., Fabaceae, along with six known compounds, sitosterol 3-O-β-D-glucopyranoside, 4-methoxygallic acid, syringic acid, quercetin, 6"-O-acetylvitexin, quercetin 3-O-β-D-glucopyranoside. The structures of those compounds and others were determined through spectral analyses. Compounds distemonanthoside, sitosterol 3-O-β-D-glucopyranoside, 4-methoxygallic acid and quercetin were tested against a clinical isolate strain of Mycobacterium tuberculosis AC 45; they exhibited good to moderate antitubercular activities with MIC values ranged from 31.25 to 125 µg/ml.