C. Mallikarjuna Rao

Synthesis and antitumor activity of optically active thiourea and their 2-aminobenzothiazole derivatives: a novel class of anticancer agents.

A novel series of optically active 2-aminobenzothiazole derivatives were synthesized by reaction of optically active amine (I) with thiophosgene to obtain optically active isothiocyanates (IIa-h) which on condensation with 4-fluoro-3-chloro aniline (III) yielded various optically active thioureas (IVa-h). Further oxidative cyclisation in the presence of bromine and chloroform yielded title compounds (Va-h). The structures of these compounds were established by IR, (1)H NMR, (13)C NMR, Mass and HRMS. The compounds (IVa-h and Va-h) were evaluated for in vitro cytotoxicity against mouse Ehrlich Ascites Carcinoma (EAC) and two human cancer cell lines (MCF-7 and HeLa). In preliminary MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] cytotoxicity studies the optically active thiourea derivatives (IVe, IVf and IVh) were found most effective. In EAC cells the IC(50) values for IVe, IVf, IVh and Vg were found in the range of 10-24 microM, whereas in MCF-7 and HeLa cells the IC(50) values were observed in the range of 15-30 microM and 33-48 microM, respectively. In alkaline comet assay the compounds (IVe and IVf) showed dose-dependent DNA damaging activity.

Epigenetics in cancer: Fundamentals and beyond

Activation of oncogenes or the deactivation of tumor suppressor genes has long been established as the fundamental mechanism leading towards carcinogenesis. Although this age old axiom is vastly accurate, thorough study over the last 15years has given us unprecedented information on the involvement of epigenetic in cancer. Various biochemical pathways that are essential towards tumorigenesis are regulated by the epigenetic phenomenons like remodeling of nucleosome by histone modifications, DNA methylation and miRNA mediated targeting of various genes. Moreover the presence of mutations in the genes controlling the epigenetic players has further strengthened the association of epigenetics in cancer. This merger has opened up newer avenues for targeted anti-cancer drug therapy with numerous pharmaceutical industries focusing on expanding their research and development pipeline with epigenetic drugs. The information provided here elaborates the elementary phenomena of the various epigenetic regulators and discusses their alteration associated with the development of cancer. We also highlight the recent developments in epigenetic drugs combining preclinical and clinical data to signify this evolving field in cancer research.

Silymarin liposomes improves oral bioavailability of silybin besides targeting hepatocytes, and immune cells

BACKGROUND Silymarin, a hepatoprotective agent, has poor oral bioavailability. However, the current dosage form of the drug does not target the liver and inflammatory cells selectively. The aim of the present study was to develop lecithin-based carrier system of silymarin by incorporating phytosomal-liposomal approach to increase its oral bioavailability and to make it target-specific to the liver for enhanced hepatoprotection. METHODS The formulation was prepared by film hydration method. Release of drug was assessed at pH 1.2 and 7.4. Formulation was assessed for in vitro hepatoprotection on Chang liver cells, lipopolysaccharide-induced reactive oxygen species (ROS) production by RAW 267.4 (murine macrophages), in vivo efficacy against paracetamol-induced hepatotoxicity and pharmacokinetic study by oral route in Wistar rat. RESULTS The formulation showed maximum entrapment (55%) for a lecithin-cholesterol ratio of 6:1. Comparative release profile of formulation was better than silymarin at pH 1.2 and pH 7.4. In vitro studies showed a better hepatoprotection efficacy for formulation (one and half times) and better prevention of ROS production (ten times) compared to silymarin. In in vivo model, paracetamol showed significant hepatotoxicity in Wistar rats assessed through LFT, antioxidant markers and inflammatory markers. The formulation was found more efficacious than silymarin suspension in protecting the liver against paracetamol toxicity and the associated inflammatory conditions. The liposomal formulation yielded a three and half fold higher bioavailability of silymarin as compared with silymarin suspension. CONCLUSIONS Incorporating the phytosomal form of silymarin in liposomal carrier system increased the oral bioavailability and showed better hepatoprotection and better anti-inflammatory effects compared with silymarin suspension.

Normal and delayed wound healing is improved by sesamol, an active constituent of Sesamum indicum (L.) in albino rats

UNLABELLED ETHNO-PHARMACOLOGICAL RELEVANCE: The seeds of Sesamum indicum Linn. (Pedaliaceae) has been used traditionally for the treatment of wounds in Buldhana district of Maharashtra state. Sesamol is the main anti-oxidative constituent contained mainly in the processed sesame seed oil which has not been explored scientifically for its wound healing activity. AIM OF THE STUDY To investigate the influence of sesamol (SM) on wound repair, both in normal and dexamethasone (DM) delayed healing processes in albino rats. MATERIALS AND METHODS Incision, excision and dead space wounds were inflicted on albino rats (180-220 g) of either sex, under ketamine anaesthesia. Group I served as control, group II received SM 50 mg/kg i.p., group III was treated with dexamethasone (DM) i.m. (0.17 mg/kg) and SM+DM was given to group IV. The tensile strength, wound contraction, hydroxyproline, lysyl oxidase and total RNA and DNA levels (in granulation tissue) were measured. RESULTS The tensile strength significantly (p<0.05) increased with SM at 471.40±14.66 g when compared to control at 300.60±9.16 g in normal and DM suppressed healing. No significant change was observed in duration of wound contraction and lysyl oxidase when compared to control at 2.98±0.10 mg. SM treated rats showed a significant (p<0.05) rise in hydroxyproline levels at 6.45±0.45 mg when compared to control at 1.75±0.20 mg. CONCLUSION These results indicate that sesamol could be a promising drug in normal as well as delayed wound healing processes.

Impact of caffeic acid on aluminium chloride-induced dementia in rats

Literature favours the in vitro neuroprotective role of caffeic acid, a naturally derived polyphenolic compound. This study was aimed to investigate the role of caffeic acid in experimental model of Alzheimers disease.

Antioxidant, anti-inflammatory and anti-hyperglycaemic activities of heterocyclic homoprostanoid derivatives

A series of 19 heterocyclic homoprostanoids were synthesized from easily available oleic and ricinoleic acids and evaluated for their possible antioxidant, anti-inflammatory and anti-hyperlipidaemic activities. Compounds with thioxo- and oxoimidazole ring (1) and (2) have shown potent antioxidant activity with IC(50) values 0.23±0.09 and 0.41±0.01mM comparable with standard ascorbic acid. Compound (3) with a quinoxaline ring showed maximum inhibition of BSA denaturation at 1mM concentration and comparable with standard diclofenac. Incorporation of electron withdrawing substitutions like chloro- and nitro-groups in the quinoxaline ring has resulted in an increase anti-inflammatory activity. Test compounds (3), (3a) and (3c) showed modest inhibition of DPP-IV in vitro. However, the unsubstituted quinoxaline (3) and substituted quinoxalines (3b and 3c) reduced plasma glucose levels indicating the presence of hypoglycemic activity.

Oral Antidiabetic Activities of Different Extracts of Caesalpinia bonducella Seed Kernels

Caesalpinia bonducella F. (Leguminosae) is a medicinal plant, widely distributed throughout India and the tropical regions of the world. Its seed kernels are used in the management of diabetes mellitus, in the folklore medicine of Andaman and Nicobar as well as the Caribbean Islands. The seed kernel powder was reported to have hypoglycaemic activity in experimental animals. Four extracts (petroleum ether, ether, ethyl acetate and aqueous) of the seed kernels were prepared and tested for their hypoglycaemic potentials in normal as well as alloxan induced diabetic rats. In normal rats, only ethyl acetate and aqueous extracts showed a minimum significant hypoglycaemic effect, compared to that of glibenclamide. In diabetic rats, both the polar extracts (ethyl acetate and aqueous) as well as glibenclamide, showed significant hypoglycaemic effect, besides, reversing the diabetes induced changes in lipid and liver glycogen levels. As far as the non-polar extracts were concerned, the ether extract showed a marginal antidiabetic activity, while the petroleum ether extract failed to show any. Since both the polar extracts were, chemically, found to contain triterpenoidal glycosides, we presume that they might be the active principles contributing to the antidiabetic actions. In in vitro antioxidant studies, the aqueous extract was found to be devoid of any free radical scavenging activity, while the ethyl acetate extract showed a maximum of 49% activity at the end of 1 h. Although the antioxidant potential of ethyl acetate extract may contribute to overcome the diabetes linked oxidative stress, it needs not necessarily contribute to its hypoglycaemic activity.

In Vitro and in Vivo Evaluation of Novel Cinnamyl Sulfonamide Hydroxamate Derivative Against Colon Adenocarcinoma

The potential of cinnamic acid as an anti-inflammatory and anti-cancer agent has been studied previously. In our investigation, novel bio-isosters of cinnamyl sulfonamide hydroxamate were synthesized, characterized and confirmed for their structure and evaluated for cytotoxicity. Three NCEs namely, NMJ-1, -2 and -3 showed cell-growth inhibition in 6 human cancer cell lines with IC50 at the range of 3.3±0.15-44.9±2.6 μM. The hydroxamate derivatives of cinnamyl sulfonamide are reported inhibitors of HDAC enzyme. Thus, the effectiveness of these molecules was determined by whole cell HDAC assay in HCT 116 cell line. NMJ-2 (0.41±0.01 μM) exhibited better enzyme inhibition (IC50) compared to SAHA (2.63±0.07). In order to evaluate induction of apoptosis by treatment, Hoechst 33342 and AO/EB nuclear staining methods were used. Further, cell cycle analysis, Annexin V binding and caspase 3/7 activation assays were performed by flow cytometry where NMJ-2 significantly arrested the cell cycle at G2/M phase, increased Annexin V binding to the cell surface and activation of caspase-3/7. Bax/Bcl-2 ratio was observed by Western blot and showed an increase with NMJ-2 treatment. This was comparable to standard SAHA. The acute toxicity study (OECD-425) showed that NMJ-2 was safe up to 2000 mg/kg in rats. 1,2-Dimethyl hydrazine (DMH) was used to produce experimental colon adenocarcinoma in Wistar rats. 5-FU and NMJ-2 (100 mg/kg p.o. and 10 mg/kg i.p. once daily for 21 days, respectively) were administered to the respective groups. Both treatments significantly reduced ACFs, adenocarcinoma count, TNF-α, IL-6, nitrite and nitrate levels in colonic tissue. Our findings indicate that NMJ-2 has potent anti-cancer activity against colon cancer, by acting through HDAC enzyme inhibition and activation of intrinsic mitochondrial apoptotic pathway, with additional anti-inflammatory activity.

Glycosmis pentaphylla (Retz.) DC arrests cell cycle and induces apoptosis via caspase-3/7 activation in breast cancer cells.

ETHNOPHARMACOLOGICAL RELEVANCE Glycosmis pentaphylla (Retz.) DC belonging to the family Rutaceae has been traditionally used for the treatment of rheumatism, anaemia, jaundice, skin diseases, bronchitis etc. The plant is traditionally considered as anti-cancer medicine and used by the healers of Bangladesh to treat all types of cancers. Perhaps the key to many of its medicinal applications is its inherent anti-inflammatory property. AIM OF THE STUDY The present study is aimed at evaluating the effect of various fractions of G. pentaphylla (Retz.) DC leaves on the cell cycle and apoptosis of breast cancer cells viz. MCF-7 and MDA-MB-231. MATERIALS AND METHODS Various extracts and fractions of the leaves of G. pentaphylla (Retz.) DC were studied for their cytotoxicity with the help of Sulforhodamine B assay, in MCF-7, MDA-MB-231 and Vero cell lines. The most active fractions were studied for their effect on the cell cycle of MCF-7 and MDA-MB-231 cells. Apoptotic studies were done using Hoechst staining, DNA fragmentation, Annexin V staining and caspase-3/7 activation assay in breast cancer cells. HPLC and HPTLC profiling of the active fractions were done. RESULTS HPTLC and HPLC profiling revealed the presence of lupeol, chrysin, quercetin, β-sitosterol and kaempferol as components in active fractions. Lupeol and chrysin are being reported in this plant for the first time. The studies showed that the selected fractions possess cell cycle inhibitory and apoptosis inducing effect on both MCF-7 and MDA-MB-231 cells. Apoptotic effect of the fractions on MCF-7 and MDA-MB-231 cells may be through the mitochondrial pathway by the activation of caspase-3/7.

Caffeic acid attenuates lipopolysaccharide-induced sickness behaviour and neuroinflammation in mice

Accumulating data links inflammation, oxidative stress and immune system in the pathophysiology of major depressive disorders. Sickness behaviour is a set of behavioural changes that develop during infection, eventually leading to decrease in mobility and depressed behaviour. Lipopolysaccharide (LPS) induces a depression-like state in animals that mimics sickness behaviour. Caffeic acid, a naturally occurring polyphenol, possesses antioxidant and anti-inflammatory properties. The present study was designed to explore the potential of caffeic acid against LPS-induced sickness behaviour in mice. Caffeic acid (30mg/kg) and imipramine (15mg/kg) were administered orally one hour prior to LPS (1.5mg/kg) challenge. Behavioural assessment was carried out between 1 and 2h and blood samples were collected at 3h post-LPS injection. Additionally, cytokines (brain and serum) and brain oxidative stress markers were estimated. LPS increased the systemic and brain cytokine levels, altered the anti-oxidant defence and produced key signs of sickness behaviour in animals. Caffeic acid treatment significantly reduced the LPS-induced changes, including reduced expression of inflammatory markers in serum and whole brain. Caffeic acid also exerted an anti-oxidant effect, which was evident from the decreased levels of oxidative stress markers in whole brain. Our data suggests that caffeic acid can prevent the neuroinflammation-induced acute and probably the long term neurodegenerative changes.