Bolleddula Jayaprakasam

Insulin Secretion by Bioactive Anthocyanins and Anthocyanidins Present in Fruits

Anthocyanins are responsible for a variety of bright colors including red, blue, and purple in fruits, vegetables, and flowers and are consumed as dietary polyphenols. Anthocyanin-containing fruits are implicated in a decrease in coronary heart disease and are used in antidiabetic preparations. In the present study, we have determined the ability of anthocyanins, cyanidin-3-glucoside (1), delphinidin-3-glucoside (2), cyanidin-3-galactoside (3), and pelargonidin-3-galactoside (4), and anthocyanidins, cyanidin (5), delphinidin (6), pelargonidin (7), malvidin (8), and petunidin (9), to stimulate insulin secretion from rodent pancreatic beta-cells (INS-1 832/13) in vitro. The compounds were tested in the presence of 4 and 10 mM glucose concentrations. Our results indicated that 1 and 2 were the most effective insulin secretagogues among the anthocyanins and anthocyanidins tested at 4 and 10 mM glucose concentrations. Pelargonidin-3-galactoside is one of the major anthocyanins, and its aglycone, pelargonidin, caused a 1.4-fold increase in insulin secretion at 4 mM glucose concentration. The rest of the anthocyanins and anthocyanidins tested in our assay had only marginal effects on insulin at 4 and 10 mM glucose concentrations.

Regulation of hepatic fatty acid elongase and desaturase expression in diabetes and obesity

Fatty acid elongases and desaturases play an important role in hepatic and whole body lipid composition. We examined the role that key transcription factors played in the control of hepatic elongase and desaturase expression. Studies with peroxisome proliferator-activated receptor α (PPARα)-deficient mice establish that PPARα was required for WY14643-mediated induction of fatty acid elongase-5 (Elovl-5), Elovl-6, and all three desaturases [Δ5 desaturase (Δ5D), Δ6D, and Δ9D]. Increased nuclear sterol-regulatory element binding protein-1 (SREBP-1) correlated with enhanced expression of Elovl-6, Δ5D, Δ6D, and Δ9D. Only Δ9D was also regulated independently by liver X receptor (LXR) agonist. Glucose induction of l-type pyruvate kinase, Δ9D, and Elovl-6 expression required the carbohydrate-regulatory element binding protein/MAX-like factor X (ChREBP/MLX) heterodimer. Suppression of Elovl-6 and Δ9D expression in livers of streptozotocin-induced diabetic rats and high fat-fed glucose-intolerant mice correlated with low levels of nuclear SREBP-1. In leptin-deficient obese mice (Lepob/ob), increased SREBP-1 and MLX nuclear content correlated with the induction of Elovl-5, Elovl-6, and Δ9D expression and the massive accumulation of monounsaturated fatty acids (18:1,n-7 and 18:1,n-9) in neutral lipids. Diabetes- and obesity-induced changes in hepatic lipid composition correlated with changes in elongase and desaturase expression. In conclusion, these studies establish a role for PPARα, LXR, SREBP-1, ChREBP, and MLX in the control of hepatic fatty acid elongase and desaturase expression and lipid composition.

Withanolides potentiate apoptosis, inhibit invasion, and abolish osteoclastogenesis through suppression of nuclear factor-κB (NF-κB) activation and NF-κB–regulated gene expression

The plant Withania somnifera Dunal (Ashwagandha), also known as Indian ginseng, is widely used in the Ayurvedic system of medicine to treat tumors, inflammation, arthritis, asthma, and hypertension. Chemical investigation of the roots and leaves of this plant has yielded bioactive withanolides. Earlier studies showed that withanolides inhibit cyclooxygenase enzymes, lipid peroxidation, and proliferation of tumor cells. Because several genes that regulate cellular proliferation, carcinogenesis, metastasis, and inflammation are regulated by activation of nuclear factor-κB (NF-κB), we hypothesized that the activity of withanolides is mediated through modulation of NF-κB activation. For this report, we investigated the effect of the withanolide on NF-κB and NF-κB-regulated gene expression activated by various carcinogens. We found that withanolides suppressed NF-κB activation induced by a variety of inflammatory and carcinogenic agents, including tumor necrosis factor (TNF), interleukin-1β, doxorubicin, and cigarette smoke condensate. Suppression was not cell type specific, as both inducible and constitutive NF-κB activation was blocked by withanolides. The suppression occurred through the inhibition of inhibitory subunit of IκBα kinase activation, IκBα phosphorylation, IκBα degradation, p65 phosphorylation, and subsequent p65 nuclear translocation. NF-κB-dependent reporter gene expression activated by TNF, TNF receptor (TNFR) 1, TNFR-associated death domain, TNFR-associated factor 2, and IκBα kinase was also suppressed. Consequently, withanolide suppressed the expression of TNF-induced NF-κB-regulated antiapoptotic (inhibitor of apoptosis protein 1, Bfl-1/A1, and FADD-like interleukin-1β-converting enzyme–inhibitory protein) and metastatic (cyclooxygenase-2 and intercellular adhesion molecule-1) gene products, enhanced the apoptosis induced by TNF and chemotherapeutic agents, and suppressed cellular TNF-induced invasion and receptor activator of NF-κB ligand-induced osteoclastogenesis. Overall, our results indicate that withanolides inhibit activation of NF-κB and NF-κB-regulated gene expression, which may explain the ability of withanolides to enhance apoptosis and inhibit invasion and osteoclastogenesis. [Mol Cancer Ther 2006;5(6):1434–45]

Anticancer and antiinflammatory activities of cucurbitacins from Cucurbita andreana

Bioassay-guided purification of an extract of Cucurbita andreana fruits yielded cucurbitacins B (1), D (2), E (3), and I (4). These cucurbitacins were evaluated for their inhibitory effects on the growth of human colon (HCT-116), breast (MCF-7), lung (NCI-H460), and central nervous system (CNS) (SF-268) cancer cell lines, cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) enzymes and on lipid peroxidation. Inhibitory activities of cucurbitacins B (1), D (2), E (3) and I (4), respectively, were for colon 81.5, 80.4, 77, and 65% at 0.4 microM, breast 87, 78, 66.5, and 12% at 0.4 microM, lung 96, 43, 37 and 2% at 0.1 microM and CNS 92, 25, 24 and 4% at 0.05 microM. Adriamycin (doxorubicin) was used as a positive control, which showed 64, 47, 45 and 71% inhibition of HCT-116 (colon), MCF-7 (breast), NCI-H460 (lung) and SF-268 (CNS) cell lines, respectively, at 0.3 x 10(-5) M. Compounds 1, 2, 3, and 4 inhibited the COX-2 enzyme by 32, 29, 35, and 27%, respectively, at 100 microg/ml. However these compounds did not inhibit the COX-1 enzyme at this concentration. Ibuprofen, naproxen and vioxx, commercial antiinflammatory drugs, were tested as controls for the inhibition of COX-1 and COX-2 enzymes at concentrations of 2.1, 2.5 and 1.67 microg/ml, respectively. Ibuprofen and naproxen exhibited 59 and 95% COX-1, and 53 and 79% COX-2 inhibitory activities, respectively. Vioxx showed specific COX-2 inhibition by 71%. Also, cucurbitacins 1 and 4 inhibited lipid peroxidation by 59 and 23%, respectively, at 100 microg/ml.

Withanamides in Withania somnifera fruit protect PC‐12 cells from β‐amyloid responsible for Alzheimer's disease

Alzheimers disease (AD) is an irreversible neurodegenerative disorder with symptoms of confusion, memory loss, and mood swings. The β‐amyloid peptide, with 39–42 amino acid residues (BAP), plays a significant role in the development of AD. Although there is no cure for AD, it can be managed with available drugs to some degree. Several studies have revealed that natural antioxidants, such as vitamin E, vitamin C and β‐carotene, may help in scavenging free radicals generated during the initiation and progression of this disease. Therefore, there has been considerable interest in plant phytochemicals with antioxidant property as potential agents to prevent the progression of AD. Our earlier investigations of the Withania somnifera fruit afforded lipid peroxidation inhibitory withanamides that are more potent than the commercial antioxidants. In this study, we have tested two major withanamides A (WA) and C (WC) for their ability to protect the PC‐12 cells, rat neuronal cells, from β‐amyloid induced cell damage. The cell death caused by β‐amyloid was negated by withanamide treatment. Molecular modeling studies showed that withanamides A and C uniquely bind to the active motif of β‐amyloid (25–35) and suggest that withanamides have the ability to prevent the fibril formation. Further understanding of the mechanism of action and in vivo efficacy of these withanamides may facilitate its development as a prophylaxis. Copyright

Acylphloroglucinol derivatives from Hypericum prolificum

Three new acylphloroglucinol derivatives have been isolated from the hexane extract of the aerial parts of Hypericum prolificum L.: prolificin A (1), prolifenone A (2), and prolifenone B (3). The structures were elucidated on the basis of extensive 2D NMR and MS data. All three compounds were evaluated for in vitro cell proliferation inhibitory activity against human breast (MCF-7), lung (NCI-H460), CNS (SF-268), stomach (AGS), and colon (HCT-116) tumor cell lines. Prolificin A showed growth inhibition of all cell lines with IC50 values ranging from 23 to 36 microM. Prolifenones A and B were inactive at the concentrations tested.

Chemical and Cytotoxic Constituents from the Stem of Machilus zuihoensis

Five new compounds, including a novel lactone, machilactone (=rel-(2R,3aR,6E,6aS)-2-heptadecyl-3a-methyl-6-octadecylidene-6,6a-dihydrofuro[2,3-d][1,3]dioxol-5(3aH)-one; 1), a new sesquiterpene, 3,4-dihydroxy-β-bisabolol (=rel-(1R,2S,4R)-1-[(1R)-1,5-dimethylhex-4-enyl]-1-methylcyclohexane-1,2,4-triol; 2), a new secobutyrolactone, methyl (2E)-2-(1-hydroxy-2-oxopropyl)eicos-2-enoate (3), two new butyrolactones, machicolide A (4) and machicolide B (5) (=3E,4R,5R)- and (3Z,4R,5R)-4,5-dihydro-4-hydroxy-5-methoxy-5-methyl-3-octadecylidenefuran-2(3H)-one, resp.) as a mixture, together with known caryophyllene oxide (=4,12,12-trimethyl-9-methylene-5-oxatricyclo[8.2.0.04,6]dodecane), hexacosane, tetracosanoic acid, isomahubanolide-23 (=(3E,4R)-4,5-dihydro-4-hydroxy-5-methylidene-3-octadecylidenefuran-2(3H)-one), and β-bisabolol (=(1S)-1-[(1S)-1,5-dimethylhex-4-enyl]-4-methylcyclohex-3-en-1-ol) were isolated from the stem wood of Machilus zuihoensis. The structures of these compounds were established by spectroscopic studies. The eicos-2-enoate (3) and β-bisabolol exhibited marginal cytotoxicity against NUGC and HONE-1 cancer cell lines in vitro.

Blood–Brain Barrier Permeability of Bioactive Withanamides Present in Withania somnifera Fruit Extract

The neuroprotective effect of Withania somnifera L. Dunal fruit extract, in rodent models, is known. Withanamides, the primary active constituents in W. somnifera fruit extract exhibited neuroprotective effects against β‐amyloid‐induced cytotoxicity in neuronal cell culture studies. Therefore, we investigated the blood–brain barrier permeability of withanamides in W. somnifera fruit extract in mice using HPLC coupled with high resolution quadrupole time of flight mass spectrometer (Q‐TOF/MS) detection. Mice were administered with 250 mg/kg of W. somnifera extract by intraperitoneal injection, and the blood and brain samples analyzed by Q‐TOF/MS detection. Four major withanamides were detected in brain and blood of mice administered with W. somnifera extract. The results suggested that the withanamides crossed the blood–brain barrier. These results may help to develop W. somnifera fruit extract as a preventive or therapeutic botanical drug for stress‐induced neurological disorders. Copyright