Sameh AbouZid

Hepatoprotective and antioxidant activities of Tamarix nilotica flowers

Context: Tamarix nilotica (Ehrenb.) Bunge (Tamaricaceae) is used in the Egyptian traditional medicine as an antiseptic agent. This plant has been known since pharaonic times and has been mentioned in medical papyri to expel fever, relieve headache, to draw out inflammation, and as an aphrodisiac. No scientific study is available about the biological effect of this plant. Objective: This study aimed to evaluate the hydro-alcoholic extract (80%) of T. nilotica flowers for hepatoprotective and antioxidant activities. Materials and methods: Hepatoprotective activity was assessed using carbon tetrachloride–induced hepatic injury in rats by monitoring biochemical parameters. Antioxidant activity was evaluated in alloxan-induced diabetic rats. Biochemical markers of hepatic damage such as serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT), alkaline phosphatase (ALP), and tissue glutathione were determined in all groups. Results and conclusion: Carbon tetrachloride (5 mL/kg body weight) enhanced the SGOT, SGPT, and ALP levels. There was a marked reduction in tissue glutathione level in diabetic rats. The hydro-alcoholic extract of T. nilotica (100 mg/kg body weight) ameliorated the adverse effects of carbon tetrachloride and returned the altered levels of biochemical markers near to the normal levels.

Solamargine production by a fungal endophyte of Solanum nigrum

The aim was to isolate, identify and characterize endophytes from Solanum nigrum L. as a new source of the cytotoxic steroidal alkaloid solamargine.

Chemical and biological investigation of some Clerodendrum species cultivated in Egypt.

Context: Phytochemical investigation of Clerodendrum chinense (Osbeck) Mabberley (Lamiaceae) cultivated in Egypt and evaluation for anti-inflammatory, analgesic, and antipyretic effects of the methanol and chloroform extracts of Clerodendrum chinense, Clerodendrum indicum (L.) Kuntze, Clerodendrum glabrum E. Meyer. Objective: The objective of this study was to investigate the anti-inflammatory, analgesic, and antipyretic effects of the methanol and chloroform extracts of Clerodendrum species under investigation. Materials and methods: Air-dried powdered leaves of C. chinense were extracted with MeOH 80%. This extract was fractionated with successive portions of chloroform, ethyl acetate and n-butanol. By further fractionation through silica gel, polyamide and reversed phase column chromatography several compounds were isolated which were elucidated by nuclear magnetic resonance (NMR) and mass spectroscopy. For biological study, the powdered leaves of C. chinense, C. indicum and C. glabrum were extracted by chloroform and then extracted with methanol. The acute anti-inflammatory effect of tested extracts of the leaves of Clerodendrum species under investigation was estimated by carrageenan-induced rat paw edema. Antipyretic effect was evaluated and compared with that of paracetamol as standard using the yeast-induced hyperthermia method on female albino rats. Analgesic effect was evaluated and compared with that of Novalgin (metamizol sodium) as standard using an electric current anxious stimulus. Results: Verbascoside, isoverbascoside, decaffeoylverbascoside, hispidulin, lupeol and icariside B5 were isolated from the leaves of C. chinense for the first time. Cornoside and rengyolone were also isolated. The methanol extract of the leaves of C. chinense and verbascoside showed significant analgesic, anti-inflammatory and antipyretic effects. Conclusion: The present study provided a scientific validation of the traditional claims suggested for C. chinense.

Steroidal glycoalkaloids from the berries of Solanum distichum.

Two steroidal glycoalkaloids, Solanidine 3-O-[α-L-rhamnopyranosyl-(1″ → 4)-[α-L-rhamnopyranosyl-(1′ → 2)]-β-D-glucopyranoside] (1) and Solanidine 3-O-[α-L-rhamnopyranosyl-(1″ → 4)-β-D-glucopyranoside] (2) commonly known as α-chanonine and β2-chanonine, were isolated from the berries of Solanum distichum. The structures of the isolated compounds were studied by 1D and 2D NMR techniques and FAB MS analysis. The 13C NMR signal assignments and direct elucidation of the glycoside linkages were established. Glycoalkaloids level in the dried berries, determined by a simple colorimetric method, was found to be 5.08 ± 0.18 g%.

Flavonoids of Calligonum polygonoides and their cytotoxicity

Abstract Context Calligonum polygonoides L. subsp. comosum L’ Hér. (Polygonaceae), locally known as “arta”, is a slow-growing small leafless desert shrub. Objective Isolation, structure elucidation and evaluation of cytotoxic activity of flavonoids from C. polygonoides aerial parts. Materials and methods Flavonoids in the hydroalcoholic extract of the of C. polygonoides were isolated and purified using column chromatography and preparative HPLC. The structures of the isolated flavonoids were elucidated on the basis of spectroscopic data including 2D NMR techniques. The cytotoxic activity of the isolated flavonoids (6.25, 25, 50 and 100 μg/mL) was evaluated against liver HepG2 and breast MCF-7 cancer cell lines using sulphorhodamine-B assay. Results A new flavonoid, kaempferol-3-O-β-D-(6″-n-butyl glucuronide) (1), and 13 known flavonoids, quercetin 3-O-β-D-(6″-n-butyl glucuronide) (2), kaempferol-3-O-β-D-(6″-methyl glucuronide) (3), quercetin-3-O-β-D-(6″-methyl glucuronide) (4), quercetin-3-O-glucuronide (5), kaempferol-3-O-glucuronide (6), quercetin-3-O-α-rhamnopyranoside (7), astragalin (8), quercetin-3-O-glucopyranoside (9), taxifolin (10), (+)-catechin (11), dehydrodicatechin A (12), quercetin (13), and kaempferol (14), were isolated from the aerial parts of C. polygonoides. Quercetin showed significant cytotoxic activity against HepG2 and MCF-7 cell lines with IC50 values of 4.88 and 0.87 μg/mL, respectively. Structure–activity relationships were analyzed by comparing IC50 values of several pairs of flavonoids differing in one structural element. Discussion and conclusion The activity against breast cancer cell lines decreased by glycosylation at C-3. The presence of 2,3-double bond in ring C, carbonyl group at C-4 and 3’,4’-dihydroxy substituents in ring B are essential structural requirements for the cytotoxic activity against breast cancer cells.

Antimicrobial activity of some Clerodendrum species from Egypt

Chloroformic and methanolic extracts of four Clerodendrum species cultivated in Egypt were screened for antimicrobial activities. Chloroformic extracts of the flowers of Clerodendrum chinense and Clerodendrum splendens were active against Plasmodium falciparum (IC50 < 10 µg mL−1). Chloroformic extracts of the stem and flowers of C. chinense were active against Trypanosoma cruzi (IC50 = 1.21 and 1.12 µg mL−1, respectively) with marginal cytotoxicity. Chloroformic extracts of the leaves of C. chinense and C. splendens showed promising activities against T. cruzi (IC50 = 3.39 and 1.98 µg mL−1, respectively) without cytotoxic effect on a human cell line. None of the selected plants showed significant activity against Gram-negative or Gram-positive bacteria or Candida albicans. Verbascoside, a phenyl propanoid glycoside isolated from the leaves of C. chinense, showed marginal activity against T. cruzi. Rengyolone, a cyclohexyl ethanoid isolated from the leaves of C. chinense, showed a broad but not specific activity against the tested organisms.

Silymarin Flavonolignans: Structure–Activity Relationship and Biosynthesis

Abstract Silymarin is a well-known hepatoprotective agent having an exceptional safety profile. It exerts its action by antioxidant, anti-inflammatory, immunomodulatory, antiproliferative, antifibrotic, and antiviral activities. Silymarin is composed of an isomeric mixture of seven flavonolignans silybin A, silybin B, isosilybin A, isosilybin B, silychristin A, silychristin B, and silydianin and one flavonoid taxifolin. Silibinin, a mixture of silybin A and silybin B, is considered responsible for the hepatoprotective functions of silymarin. Purification of these compounds in gram scale allowed for testing the hepatoprotective effects of pure compounds in various assays. Some individual flavonolignans showed stronger hepatoprotective functions than silymarin. Only isosilybin B showed high toxicity to human hepatoma cell line. Isosilybin A, taxifolin, and silibinin were the most effective hepatoprotectors. Isosilybin B showed the highest antiproliferative activity against human prostate carcinoma cell lines. Biosynthesis of silymarin flavonolignans occurs by oxidative coupling between the phenylpropanoid coniferyl alcohol and the flavonoid taxifolin. Flavonoid biosynthesis involves phenylpropanoid and polyketide pathways. Plant tissue culture studies have largely contributed to our current understanding of silymarin biosynthesis. Production of silymarin in Silybum marianum cultures can be stimulated by treatment with elicitors such as yeast extract and methyl jasmonate. The components of phenylpropanoid pathway are not modified by elicitation of cell cultures of S. marianum with yeast extract or methyl jasmonate. This was concluded when the overall metabolic changes in elicitor-treated cultures were studied using nuclear magnetic spectroscopy. The flavonoid biosynthesis, not coniferyl alcohol biosynthesis, may be the candidate component of the signaling pathway involved in stimulation of flavonolignan biosynthesis with elicitors. Understanding the basic signaling components in the transduction of the elicitor signal to downstream responses such as silymarin production is mandatory for biotechnological exploitation of this valuable pharmaceutical raw material. Lipoxygenase involvement in the elicitor-induced accumulation of silymarin is well established. Inhibition of external and internal calcium fluxes significantly increases flavonolignan production. Activation of phospholipase D after elicitor treatment mediates silymarin secretion into the culture medium, indicating possible involvement of the enzyme in deposition of silymarin in the external cover of the fruits of S . marianum .

Silybum marianum pericarp yields enhanced silymarin products.

An improved method for the purification of silymarin, the flavonolignan complex from the fruits of milk thistle, Silybum marianum, is reported. The method enables a more efficient extraction of silymarin from the pericarp after it has been separated mechanically from the rest of the fruits. Accelerated solvent extraction (ASE) was employed for each extraction procedure. Quantitation of the eight major silymarin components in the pericarp extract was compared to that of the whole fruit extract using two orthogonal analytical methods. The pericarp extract showed higher silymarin content (2.24-fold by HPLC and 2.12-fold by qHNMR) than whole fruit extract using acetone as an extraction solvent following defatting with hexane. Furthermore, the mg/g recovery of silymarin major components was not diminished by eliminating the hexane defatting step from the pericarp extraction procedure. The efficiencies of acetone, ethanol, and methanol as extraction solvents were compared. Methanol pericarp extract showed the highest content of the silymarin major components, 2.72-fold higher than an extract prepared from the whole fruits using acetone. Finally, all of the major silymarin components showed a higher w/w content in the pericarp extract than in a commercial extract.

Retraction. A new antifungal labdane diterpene from the leaves of Saraca indica.

A new labdane diterpene, along with 10 known sterols and flavonoids, was isolated from the hydroalcoholic extract of the leaves of Saraca indica. The chemical structure of the new compound was identified as 6,9-epoxy marrubiinic acid on the basis of spectroscopic analyses including two-dimensional NMR. The antimicrobial potential of the new compound was evaluated against Gram-positive and Gram-negative bacteria as well as fungi. It showed a significant antifungal activity against Geotrichum candidum with MIC 0.48 μg/mL. It also showed potential cytotoxicity against human cancer cell lines with IC50 ranging from 1.07 to 1.29 μg/well.

Secondary metabolites from fungal endophytes of Solanum nigrum

Abstract Three endophytic fungi, Aspergillus sp. (SNFSt), Aspergillus sp. (SNFL) and Lasiodiplodia theobromae (SNFF) were isolated from stems, leaves and fruits of Solanum nigrum L, respectively. The static fermentation of the three fungal strains led to the characterization of nine known metabolites (1–9) using HRESIMS and NMR analyses.