Farouk S. El-Feraly

Carbazole alkaloids from Clausena lansium

Abstract Three new carbazole alkaloids, 3-formyl-6-methoxycarbazole, methyl 6-methoxycarbazole-3-carboxylate and 3-formyl-1,6-dimethoxycarbazole and two carbazole derivatives, 3-formyl carbazole and methyl carbazole-3-carboxylate, reported for the first time from Nature, have been isolated from the root of Clausena lansium along with three previously reported carbazole alkaloids, murrayanine, glycozoline and indizoline. All isolated compounds except glycozoline have a carbonyl group at C-3 with different substitution patterns at C-1, C-2 and C-6.

Antiparasitic, nematicidal and antifouling constituents from Juniperus berries

A bioassay‐guided fractionation of Juniperus procera berries yielded antiparasitic, nematicidal and antifouling constituents, including a wide range of known abietane, pimarane and labdane diterpenes. Among these, abieta‐7,13‐diene (1) demonstrated in vitro antimalarial activity against Plasmodium falciparum D6 and W2 strains (IC50 = 1.9 and 2.0 µg/mL, respectively), while totarol (6), ferruginol (7) and 7β‐hydroxyabieta‐8,13‐diene‐11,12‐dione (8) inhibited Leishmania donovani promastigotes with IC50 values of 3.5–4.6 µg/mL. In addition, totarol demonstrated nematicidal and antifouling activities against Caenorhabditis elegans and Artemia salina at a concentration of 80 µg/mL and 1 µg/mL, respectively. The resinous exudate of J. virginiana afforded known antibacterial E‐communic acid (4) and 4‐epi‐abietic acid (5), while the volatile oil from its trunk wood revealed large quantities of cedrol (9). Using GC/MS, the two known abietanes totarol (6) and ferruginol (7) were identified from the berries of J. procera, J. excelsa and J. phoenicea. Copyright

Antibacterial constituents from the rhizomes of Ferula communis

The rhizomes of Ferula communis yielded three antibacterial sesquiterpenes, namely, the new daucane ester 14‐(o‐hydroxycinnamoyloxy)‐dauc‐4,8‐diene (1), ferulenol (2) and ferchromone (3). Compound 1 exhibited significant activity against Gram‐positive bacteria, while 3 was found to be less active. Compound 2, on the other hand, demonstrated potent activity against Mycobacterium organisms, and its corresponding C‐4‐acetoxy derivative 9 was found to retain the same activity as well. In addition, the rhizomes yielded a number of inactive compounds, including 2‐nor‐1,2‐secoferulenol, elemicin, colladonin, feselol and compounds 4 and 5. Structural assignments were largely based on the spectral data, especially the 2D NMR COSY and HETCOR experiments.

On the possible role of qinghao acid in the biosynthesis of artemisinin

Abstract Artemisinin (qinghaosu), a seco -sesquiterpene peroxide, is the clinically established antimalarial principle isolated from the leaves of the Chinese medicinal herb, Artemisia annua . Recent studies have suggested that arteannuin B, another metabolite of this plant, could serve as a precursor for artemisinin. In the present study, qinghao acid, the major sesquiterpene constituent of A . annua , was converted to arteannuin B by singlet oxygen ( 1 O 2 ) generated by sensitized photo-oxygenation. The formation of this compound was monitored by high-pressure liquid chromatographic analysis, and the identity of the isolated material was established by direct comparison. Since 1 O 2 is known to play a role in biogenetic reactions, it appears that qinghao acid can serve as a biogenetic precursor for artemisinin.

Effects of artemisinin, dihydroartemisinin and arteether on immune responses of normal mice

Artemisinin (Qinghaosu) is a potent antimalarial sesquiterpene lactone isolated from the Chinese herb Artemisia annua. Arteether, a potent semisynthetic analogue of dihydroartemisinin is being developed by the World Health Organization as the artemisinin derivative of choice for the treatment of malaria. All three agents in doses of 400 and 600 mg/kg body weight were found to exhibit marked suppression of humoral responses, as measured by the hemolytic plaque assay, with arteether being the most potent. These agents did not alter the delayed-type hypersensitivity response to sheep erythrocytes at the same dose levels. In addition, all three agents were found not to possess any anti-inflammatory activity when tested on carrageenan-induced oedema. These results indicated that these agents have a selective immunosuppressive activity. They did not exhibit immunostimulating activity in contrast to what has been reported for sodium artesunate.

Melampolides from Magnolia grandiflora

Abstract Two isomeric melampolides, melampomagnolide A and melampomagnolide B, were isolated from the newly formed leaves of Magnolia grandiflora . Their stereochemical structures were established by spectroscopic means, and by chemical correlation with soulangianolide A and parthenolide, respectively.

Microbial transformation of parthenolide

Abstract Microbial transformation of the germacranolide parthenolide using Rhizopus nigricans , Streptomyces fulvissimus and Rhodotorula rubra yielded three new compounds: 11αH-dihydroparthenolide, 9β-hydroxy-11βH-dihydroparthenolide and 14-hydroxy-11βH-dihydroparthenolide. 11βH-dihydroparthenolide was the only common metabolite produced by all microorganisms.

Additional Antibacterial Diterpenes from the Bark of Juniperus procera

The bark of Juniperus procera yielded the diterpene 7β‐hydroxyabieta‐8,13‐dien‐11,12‐dione (1) with strong activity against Mycobacterium species, and the hitherto unreported bisnorlabdane derivative 14,15‐bisnor‐13‐oxolabd‐8(17),11(E)‐dien‐19‐oic acid (4). In addition, the bark yielded the known compounds crypotrienolic acid, isocupressic acid and sugiol. Structural assignments were largely based on the spectral data, including those derived from 2D NMR COSY and HETCOR experiments.

9-Deoxy drimane sesquiterpenes from Canella winterana

Abstract The stem bark of Canella winterana collected in Florida yielded three new drimane sesquiterpenes. Their structures were elucidated from their spectral data as: 9-deoxymuzigadial, 9-deoxyisomuzigadial and 3β-acetoxypolygodial. The first two compounds, which are double bond isomers, could only be separated from each other on silver nitrate-impregnated silica gel.

3β,12-dihydroxyabieta-8,11,13-triene-1-one and other constituents from Juniperus excelsa leaves

Abstract The leaves of Juniperus excelsa yielded the hitherto unreported diterpenoid 3β,12-dihydroxyabieta-8,11,13- triene-1-one together with the known compounds 4- epi -abietal, 4- epi -abietic acid, 4-epi-abietol, (+)-8α-hydroxyelemol and (−)-4- epi -catechin. The structural assignments were largely based on the spectral data including those derived from 2D NMR experiments together with chemical derivation.