Eman G. Haggag

The Effect of a Herbal Water-Extract on Histamine Release from Mast Cells and on Allergic Asthma

A water extract of a mixture of eight herbs (chamomile, saffron, anise, fennel, caraway, licorice, cardomom and black seed) was tested for its inhibitory effect on histamine released from rat peritoneal mast cells stimulated either by compound 48/80 or by IgE/anti-IgE. The effect of the herb extract was compared to that of the flavonoid quercetin. The herbal water-extract inhibited histamine release from chemically-and immunologically-induced cells by 81% and 85%, respectively; quercetin treated cells were inhibited by 95% and 97%, respectively. The clinical results showed significant improvements of sleep discomfort, cough frequency and cough intensity in addition to increased percentages of FEV1/FVC in patients suffering from allergic asthma, who used the herbal tea compared to those who used the placebo tea.

Quercetin-induced expression of rat mast cell protease II and accumulation of secretory granules in rat basophilic leukemia cells

Rat basophilic leukemia (RBL) cells are considered to be similar to bone-marrow derived mast cells and to mucosal mast cells (MMC), the latter of which may be involved in inflammatory bowel diseases. RBL cells are not able to accumulate histamine and secretory granules under regular growing conditions. Here we show that the flavonoid quercetin, which inhibits mast cell secretion of histamine, also inhibited RBL cell proliferation and constitutive histamine release while it induced synthesis of rat mast cell protease (RMCP) II and triggered processes leading to accumulation of secretory granules. Cell viability was also retained in the presence of quercetin, whereas untreated cells did not survive past 6 days of growth. Quercetin did not affect the expression of mRNA for alpha-subunit of immunoglobulin E (IgE) receptor, but led to increased expression of mRNA for, and synthesis of RMCP II, which is a marker protein for MMC. Many of these granules showed metachromasia with toluidine blue after 3 days of growth, stained red with alcian blue counterstained with safranin after 8 days of growth, and contained electron dense material. Our results suggest that RBL cells have the capacity to progress to a more mature state and may lend themselves to further analysis of a growth regulator(s) with action similar to that of quercetin.

Discovery, Optimization, and Pharmacophore Modeling of Oleanolic Acid and Analogues as Breast Cancer Cell Migration and Invasion Inhibitors Through Targeting Brk/Paxillin/Rac1 Axis

Bioassay‐guided fractionation of Terminalia bentzoe L. leaves methanol extract identified the known triterpene oleanolic acid (1) as its major breast cancer cell migration inhibitor. Further chemical optimization afforded five new (9–12 and 15) and seven known (4–8, 13, and 14) semisynthetic analogues. All compounds were tested for their ability to inhibit human breast cancer MDA‐MB‐231 cells migration, proliferation, and invasion. The results revealed that 3‐O‐[N‐(3′‐chlorobenzenesulfonyl)‐carbamoyl]‐oleanolic acid (11) and 3‐O‐[N‐(5′‐fluorobenzenesulfonyl)‐carbamoyl]‐oleanolic acid (12) were the most active hits at low μm concentration. Western blot analysis indicated the activity of 1, 11, and 12 might be related, at least in part, to the suppression of Brk/Paxillin/Rac1 signaling pathway. Pharmacophore modeling study was conducted to better understand the common structural binding epitopes important for the antimigratory activity. The sulfonyl carbamoyl moiety with an optimal bulkiness electron‐deficient phenyl ring is associated with improved activity. This study is the first to discover the antimigratory and anti‐invasive activities of oleanolic acid and analogues through targeting the Brk/Paxillin/Rac1 axis.

Antioxidant and cytotoxic activity of polyphenolic compounds isolated from the leaves of Leucenia leucocephala

Context: Cancer is a serious clinical problem to the health care system. Anticancer drugs have been extracted from plants containing phenolic compounds. Leucenia species (Fabaceae) contain a variety of bioactive components of numerous biological and pharmacological properties. Objective: This study explored the constitutive polyphenols of Leucenia leucocephala Lam. growing in Egypt and evaluated the antioxidant and cytotoxic activity. Materials and methods: Chemical structures of the isolated compounds from the leaves of L. leucocephala were established by spectral techniques (UV, 1H, and 13C NMR, MS). Results: Chromatographic separation of 80% MeOH extract of the leaves of L. leucocephala have resulted in a novel flavonoid-galloyl glycoside [myricetin 3-O-(2′,3′4′-tri-O-galloyl)-α-l-rhamnopyranoside] with three known polyphenolic compounds isolated for the first time from this species (apigenin 7-O-β-d-glucuronopyranoside methyl ester, luteolin 7-O-β-d-glucuronopyranoside methyl ester, and 1,3,6-tri-O-galloyl-β-d-glucopyranose) and seven known previously isolated compounds. Also, 80% methanol extract exhibited high antioxidant activity (SC50 = 3.94 µg/ml), which is correlated with its phenolic content. The extract also showed cytotoxic activity against Hep G2 (IC50 value 1.41 µg/ml) confirming its anticancer activity against hepatocellular carcinoma. Among the tested compounds (4–8) for antioxidant property, compound 7 was the most active compound (SC50 = 2.49 µg/ml). Also compounds 7 and 8 exhibited high cytotoxic activity (IC50 = 2.41 and 2.81 µg/ml, respectively). Discussion and conclusion: These findings demonstrate that the leaves of L. leucocephala contain a considerable amount of polyphenolic compounds with high antioxidant properties, thus it has great potential as a source for natural health products.

3-O-[N-(p-fluorobenzenesulfonyl)-carbamoyl]-oleanolic acid, a semisynthetic analog of oleanolic acid, induces apoptosis in breast cancer cells.

Oleanolic acid (OA), a pentacyclic triterpene acid widely distributed in food and traditional herbal remedies, exhibits diverse therapeutic effects. OA has been subjected to various chemical modifications to optimize its anticancer effect. Among other analogs, 3-O-[N-(p-fluorobenzenesulfonyl)-carbamoyl]-oleanolic acid (PFOA) was semisynthesized from OA. This study evaluates the cytotoxic effects of PFOA on MDA-MB-231, MCF-7, BT-474, and T-47D human breast cancer cells. Acute treatment of PFOA inhibited breast cancer cell viability in a dose-dependent manner. Treatment of PFOA at cytotoxic doses significantly induced apoptosis in cancer cells as shown by flow cytometry analysis. Activation of apoptosis in MCF-7 and BT-474 cells seemed to be initiated through induction of Fas ligand, which resulted in activation of caspase-8 and PARP-1, whereas apoptosis in MDA-MB-231 cells was initiated by the activation of caspase-9, caspase-3 and PARP-1. The mechanism of apoptosis induction in T-47D involves activation of PARP-1. PFOA decreased the expression of EGFR, HER-2, MET and ERα in human breast cancer cell lines. These findings suggest that PFOA inhibits cell growth, activates apoptosis, and decreases the expression of key proteins involved in progression of breast cancer.

The indole alkaloid meleagrin, from the olive tree endophytic fungus Penicillium chrysogenum, as a novel lead for the control of c-Met-dependent breast cancer proliferation, migration and invasion

Fungi of the genus Penicillium produce unique and chemically diverse biologically active secondary metabolites, including indole alkaloids. The role of dysregulated hepatocyte growth factor (HGF) and its receptor, c-Met, in the development and progression of breast carcinoma is documented. The goal of this work is to explore the chemistry and bioactivity of the secondary metabolites of the endophytic Penicillium chrysogenum cultured from the leaf of the olive tree Olea europea, collected in its natural habitat in Egypt. This fungal extract showed good inhibitory activities against the proliferation and migration of several human breast cancer lines. The CH2Cl2 extract of P. chrysogenum mycelia was subjected to bioguided chromatographic separation to afford three known indole alkaloids; meleagrin (1), roquefortine C (2) and DHTD (3). Meleagrin inhibited the growth of the human breast cancer cell lines MDA-MB-231, MDA-468, BT-474, SK BR-3, MCF7 and MCF7-dox, while similar treatment doses were found to have no effect on the growth and viability of the non-tumorigenic human mammary epithelial cells MCF10A. Meleagrin also showed excellent ATP competitive c-Met inhibitory activity in Z-Lyte assay, which was further confirmed via molecular docking studies and Western blot analysis. In addition, meleagrin treatment caused a dose-dependent inhibition of HGF-induced cell migration, and invasion of breast cancer cell lines. Meleagrin treatment potently suppressed the invasive triple negative breast tumor cell growth in an orthotopic athymic nude mice model, promoting this unique natural product from hit to a lead rank. The indole alkaloid meleagrin is a novel lead c-Met inhibitory entity useful for the control of c-Met-dependent metastatic and invasive breast malignancies.

Anti-inflammatory of pyrrolizidine alkaloids from Heliotropium digynum

One new and six known pyrrolizidine alkaloids (1–7) were isolated from the 70% ethanol extract of the aerial parts of Heliotropium digynum (Forssk.) C. Chr. The chemical structure of the new compound, 7-Angeloylsincamidine N-Oxide (4) was determined by extensive 1D and 2D NMR spectroscopic analysis and HRESIMS. The absolute configuration of 4 was elucidated by comparing the experimental and electronic circular dichroism spectra. The anti-inflammatory activity of the ethanolic extract and compounds 1, 2, 4, and 6 were evaluated against the Nitric oxide production in lipopolysaccharide induced murine macrophages RAW 264.7 cells. The IC50 values of the tested compounds were 52.4, 85.1, 105.1, and 7.9 µM, respectively, while the % inhibition of the ethanolic extract at 25 µg/mL was 78.7%. A docking study was conducted to provide more explanation about the activity of the tested compounds.

Rutin as A Novel c-Met Inhibitory Lead for The Control of Triple Negative Breast Malignancies

ABSTRACT Triple negative breast cancer (TNBC) has high metastatic and mortality potential and lacks effective and selective therapeutic options. Aberrant dysregulation of the receptor tyrosine kinase c-Met promotes TNBC progression, motility and survival and therefore considered a valid therapeutic target. Among various identified anticancer agents, plant polyphenols (PPs) including flavonoids, have been shown to be safe and proven for their antitumor activity through modulating diverse macromolecular targets. This study reports the bioassay-guided identification of the common flavonol glycoside rutin as breast cancer cell proliferation, migration and invasion inhibitor. The cell free Z′-LYTE kinase assay, Western blot and in silico docking experiments uncovered, for the first time, c-Met kinase as a potential mechanistic target for rutin-mediated anticancer effects on TNBC cell lines. Likewise, the intraperitoneal injection of rutin at 30 mg/kg, 3X/week, significantly reduced the growth of the TNBC MDA-MB-231/GFP orthotopic xenograft in nude mouse model. These results clearly designate the functional dietary flavonoid rutin as a potential lead for the prevention and control of c-Met-dependent breast malignancies.