Amani M. Marzouk

Bioactive microbial metabolites from glycyrrhetinic acid

Biotransformation of 18beta-glycyrrhetinic acid, using Absidia pseudocylinderospora ATCC 24169, Gliocladium viride ATCC 10097 and Cunninghamella echinulata ATCC 8688a afforded seven metabolites, which were identified by different spectroscopic techniques (1H, 13C NMR, DEPT, 1H-1H COSY, HMBC and HMQC). Three of these metabolites, viz. 15alpha-hydroxy-18alpha-glycyrrhetinic acid, 13beta-hydroxy-7alpha,27-oxy-12-dihydro-18beta-glycyrrhetinic acid and 1alpha-hydroxy-18beta-glycyrrhetinic acid are new. The 13C NMR data and full assignment for the known metabolite 7beta, 15alpha-dihydroxy-18beta-glycyrrhetinic acid are described here for the first time. The major metabolites were evaluated for their hepatoprotective activity using different in vitro and in vivo models. These included protection against FeCl3/ascorbic acid-induced lipid peroxidation of normal mice liver homogenate, induction of nitric oxide (NO) production in rat macrophages and in vivo hepatoprotection against CCl4-induced hepatotoxicity in albino mice.

Hepatoprotective triterpenes from hairy root cultures of Ocimum basilicum L.

Six triterpene acids identified as betulinic, oleanolic, ursolic, 3-epimaslinic, alphitolic and euscaphic acids have been isolated from a dichloromethane extract of hairy root cultures of Ocimum basilicum L. (Lamiaceae). These cultures were obtained by genetic transformation using Agrobacterium rhizogenes. The extract as well as the isolated compounds were evaluated for their hepatoprotective activity by measuring their effect on the oxidative stress status of liver, induced by carbon tetrachloride, in albino rats and in liver homogenate in vitro. All tested compounds displayed hepatoprotective activity comparable to oleanolic and ursolic acids.

A new pregnane glycoside from Gomphocarpus fruticosus growing in Egypt

Abstract Phytochemical investigation of Gomphocarpus fruticosus (L.) Ait. of Egyptian origin afforded the new pregnane glycoside lineolon-3-O-[β-D-oleandropyranosyl-(1–4)-β-D-cymaropyranosyl-(1–4)-β-D-cymaropyranoside], along with six known compounds. The structures of the isolated compounds were elucidated on the basis of extensive spectroscopic evidences derived from 1D, 2D NMR experiments, mass spectrometry and by comparing their physical and spectroscopic data to literature. These included the triterpenoids 3β-taraxerol, 3β-taraxerol acetate and betulinic acid, which are identified for the first time in G. fruticosus and the cardenolides uzarigenin, gomphoside and calotropin.

A new acylated flavonoid tetraglycoside with anti-inflammatory activity from Tipuana tipu leaves

A new acylated kaempferol glycoside, kaempferol 3-O-α-l-rhamnopyranosyl-(1 → 6)-O-[β-d-glucopyranosyl-(1 → 2)-4-O-acetyl-α-l-rhamnopyranosyl-(1 → 2)]-β-d-galactopyranoside, has been isolated from the leaves of Tipuana tipu (Benth.) Lillo growing in Egypt, along with three known flavonol glycosides, kaempferol 3-O-rutinoside, quercetin 3-O-rutinoside (rutin) and kaempferol 3-O-[α-l-rhamnopyranosyl-(1 → 6)]-[α-l-rhamnopyranosyl-(1 → 2]-β-d-glucopyranoside. Structure elucidation was achieved through different spectroscopic methods. Structure relationship with anti-inflammatory activity using carrageenin-induced rat paw oedema model is discussed.

A new lanostane-type triterpene and sesquiterpene lactones from Vernonia leopoldii and their in vitro cytotoxicity

Investigation of the aerial parts of Vernonia leopoldii (Sch. Bip.) Vatke afforded a new lanostane-type triterpene along with known hirsutinolide-type sesquiterpene lactones and flavonoid glycosides, all are identified for the first time in this species. The new compound was identified as lanost-3β, 23S-dihydroxy-22(31)-ene. The structures of the isolated compounds were elucidated based on spectroscopic evidence. The hirsutinolides and the triterpene were evaluated for their cytotoxicity against four human cancer cell lines using MTT assay.

The genus Machaerium (Fabaceae): taxonomy, phytochemistry, traditional uses and biological activities

Machaerium, in the family Fabaceae, predominantly is a genus of a Neotropical distribution of trees, shrubs, and lianas occurring from southern Mexico to Brazil and northern Argentina and as far as South America. Several Machaerium species are widely used in traditional medicine and are considered to have multiple medicinal properties. This review aims to provide up-to-date and comprehensive information on the taxonomy, phytochemistry, traditional uses and biological activities of plants in the genus Machaerium.

Microbial metabolism of danazol: a contribution to doping analysis.

Microbial metabolism of danazol (17α-pregna-2,4-dien-20-yno[2,3-d]isoxazol-17ß-ol) by Beauveria bassiana ATCC 7159 and Glyocladium viride ATCC 10097 afforded four metabolites. The isolated metabolites were identified by different spectroscopic techniques as 6ß- hydroxy danazol, which is a not yet reported danazol metabolite, 17ß-hydroxy-17α-pregn-4-en- 20-yn-3-one (ethisterone) and 17ß-hydroxy-2α-(hydroxymethyl)-17α-pregn-4-en-20-yn-3-one (2α- hydroxymethyl ethisterone), which represent the major danazol metabolites detected in human urine. The last metabolite, 6ß,17ß-dihydroxy-2-(hydroxymethyl)-17α-pregna-1,4-dien-20-yn-3-one, is also a minor human metabolite, for which the NMR data are described here for the first time. The metabolites were isolated in quantities that allowed their use for direct comparison in routine doping analysis

Transformed Root Cultures of Solanum dulcamara L.: A Model for Studying Production of Secondary Metabolites

Solanum dulcamara L. (dogwood or bitter sweet), Solanaceae, is one of the recommended species for growing in the temperate regions as a source of steroidal alkaloids. These alkaloids are suggested to be alternatives for diosgenin in the commercial production of steroidal pharmaceuticals (Mathe et al., 1986). Steroidal alkaloids like solasodine and its C25 epimer tomatidenol can be easily converted to pregdienolone which is an important intermediate in the synthesis of steroids (Sato et al., 1951). Solanum dulcamara L. exists in three chemovarieties that contain either solasodine, soladulcidine or tomatidenol glycosides (Willuhn, 1966). These Solanum alkaloids are always accompanied by varying quantities of their corresponding oxygen analogues, i.e. the neutral saponins. So, these chemovarities can be relisted as tomatidenol/yamogenin, solasodine/diosgenin and soladulcidine/tigogenin types (Hegnauer, 1989). The tomatidenol-producing taxa are found in the humid Atlantic climate of Western Europe, the soladulcidine type occurs in the drier continental climates while the solasodine variety is comparatively rare (J.R Mathe & I. Mathe, 1979). Only the solasodine and tomatidenol-producing varieties are of interest, but their productivity would not be comparable to that of other tropical or subtropical species as S. laciniatum. So, if this steroidal alkaloids content could be boosted by manipulation, S. dulcamara could be of interest for commercial growing due to its other qualities like fair cold hardiness, good growth on poor soils and perennial life cycle. An alternative approach was to produce these alkaloids intensively in vitro. Several Solanum species including S. dulcamara were the subject of many in vitro manipulations, but attempts, which involved techniques like cell suspension and callus cultures failed to achieve the target. Secondary metabolites production, in general, needs a certain degree of tissue differentiation, something that is obviously lacking in those in vitro systems (Ehmke & Eilert, 1993; Rhodes et al., 1987). A more promising technique has been introduced as an alternative to the classical cell