Aruna Bhatia

Reactive oxygen species generation and mitochondrial dysfunction in the apoptotic cell death of human myeloid leukemia HL-60 cells by a dietary compound withaferin A with concomitant protection by N-acetyl cysteine.

Induction of apoptosis in cancer cells has become the major focus of anti-cancer therapeutics development. WithaferinA, a major chemical constituent of Withania somnifera, reportedly shows cytotoxicity in a variety of tumor cell lines while its molecular mechanisms of action are not fully understood. We observed that withaferinA primarily induces oxidative stress in human leukemia HL-60 cells and in several other cancer cell lines. The withanolide induced early ROS generation and mitochondrial membrane potential (Δψmt) loss, which preceded release of cytochrome c, translocation of Bax to mitochondria and apoptosis inducing factor to cell nuclei. These events paralleled activation of caspases −9, −3 and PARP cleavage. WA also activated extrinsic pathway significantly as evidenced by time dependent increase in caspase-8 activity vis-à-vis TNFR-1 over expression. WA mediated decreased expression of Bid may be an important event for cross talk between intrinsic and extrinsic signaling. Furthermore, withaferinA inhibited DNA binding of NF-κB and caused nuclear cleavage of p65/Rel by activated caspase-3. N-acetyl-cysteine rescued all these events suggesting thereby a pro-oxidant effect of withaferinA. The results of our studies demonstrate that withaferinA induced early ROS generation and mitochondrial dysfunction in cancer cells trigger events responsible for mitochondrial -dependent and -independent apoptosis pathways.

Anticancer Potential of Aqueous Ethanol Seed Extract of Ziziphus mauritiana against Cancer Cell Lines and Ehrlich Ascites Carcinoma

Ziziphus mauritiana (Lamk.) is a fruit tree that has folkloric implications against many ailments and diseases. In the present study, anticancer potential of seed extract of Ziziphus mauritiana in vitro against different cell lines (HL-60, Molt-4, HeLa, and normal cell line HGF) by MTT assay as well as in vivo against Ehrich ascites carcinoma bearing Swiss albino mice was investigated. The extract was found to markedly inhibit the proliferation of HL-60 cells. Annexin and PI binding of treated HL-60 cells indicated apoptosis induction by extract in a dose-dependent manner. The cell cycle analysis revealed a prominent increase in sub Go population at concentration of 20 μg/ml and above. Agarose gel electrophoresis confirmed DNA fragmentation in HL-60 cells after 3 h incubation with extract. The extract also exhibited potent anticancer potential in vivo. Treatment of Ehrlich ascites carcinoma bearing Swiss albino mice with varied doses (100–800 mg/kg b.wt.) of plant extract significantly reduced tumor volume and viable tumor cell count and improved haemoglobin content, RBC count, mean survival time, tumor inhibition, and percentage life span. The enhanced antioxidant status in extract-treated animals was evident from decline in levels of lipid peroxidation and increased levels of glutathione, catalase, and superoxide dismutase.

Hypoglycemic activity of Ziziphus mauritiana aqueous ethanol seed extract in alloxan-induced diabetic mice

Ziziphus mauritiana Lamk. (Rhamnaceae) is a fruit tree that has been used as folkloric medicine for many ailments and diseases. In the present study, the hypoglycemic effect of seed extract of Ziziphus mauritiana in alloxan-induced diabetic mice was assessed. Seed extract was administered orally at doses of 100, 400, and 800 mg/kg body weight (bw) and also in combination with glyburide (800 mg/kg seed extract and 10 mg/kg glyburide) to different groups of mice (normal and alloxan-treated diabetic mice). Their blood glucose level (in acute and sub-acute study), body weight, and mortality rate were monitored. Oral glucose tolerance test (OGTT) was also performed. Oral administration of extract alone or in combination with glyburide reduced the blood glucose level in all the diabetic mice after acute and sub-acute (28 days) administration. Administration of the extract reduced the weight loss and mortality rate during the sub-acute study. The results of blood glucose level, loss in body weight, and mortality rate were more pronounced in the group treated with combination (800 mg/kg seed extract and 10 mg/kg glyburide). The extract also augmented the glucose tolerance in both normal and diabetic mice. These results suggest that the extract possesses synergistic hypoglycemic activity.

Sex Hormones and Immune Dimorphism

The functioning of the immune system of the body is regulated by many factors. The abnormal regulation of the immune system may result in some pathological conditions. Sex hormones of reproductive system are one of the major factors that regulate immune system due to the presence of hormone receptors on immune cells. The interaction of sex hormones and immune cells through the receptors on these cells effect the release of cytokines which determines the proliferation, differentiation, and maturation of different types of immunocytes and as a result the outcome of inflammatory or autoimmune diseases. The different regulations of sex hormones in both sexes result in immune dimorphism. In this review article the mechanism of regulation of immune system in different sexes and its impact are discussed.

Augmentation of expression of immunocytes' functions by seed extract of Ziziphus mauritiana (Lamk.).

AIM OF THE STUDY The present study was carried out to evaluate the immunomodulatory potential of Ziziphus mauritiana (Lamk.) seed extract to ascertain the folkloric claim as immunomodulator. MATERIALS AND METHODS The aqueous-ethanolic seed extract (100-400 mg kg(-1)) of Z. mauritiana was investigated for immunomodulatory potential in mice. The extract was standardized with HPLC using betulinic acid as a marker. Functions of various immunocytes in the form of humoral (development of anti-SRBC (sheep red blood cells) antibody titers) and cell-mediated immune response (delayed type hypersensitivity, nitroblue tetrazolium reduction, inducible nitric oxide synthase activity and bactericidal activity) was studied in SRBC immunized mice. The cytokine, IFN-gamma (interferon-gamma) and IL-4 (interleukin-4) secretion was also measured quantitatively by ELISA as the expression of functions of Th-1 and Th-2 respectively. Levamisole (2.5 mg kg(-1)) was used as standard drug. RESULTS The seed extract demonstrated significant (P<0.05-0.001) up-regulation of cell-mediated, humoral immune response and Th-1 mediated cytokine IFN-gamma and decline in Th-2 mediated cytokine IL-4. At higher dose of extract the results were comparable to that of the levamisole. CONCLUSION The immunostimulatory potential of this seed extract is likely to be mediated through its effect on macrophage function and Th-1 mediated immunity confirming the folkloric use of this plant.

Immunomodulatory studies of a bioactive fraction from the fruit of Prunus cerasus in BALB/c mice

In order to evaluate the role of ethyl acetate fraction (PNRS-EtOAC) obtained from the Prunus cerasus fruit in the modulation of immune responses, detailed studies were carried out using a panel of in vivo assays. Oral administration of PNRS-EtOAC (25-100 mg/kg) stimulated the IgM and IgG titre expressed in the form of hemagglutination antibody (HA) titre. Further, it elicited a dose related increase in the delayed type hypersensitivity reaction (DTH) after 24 and 48 h in BALB/c mice. Besides augmenting the humoral and cell mediated immune response, the concentration of cytokines (IFN-γ, IL-4, and TNF-α) in serum with respect to T cell interactions, i.e. the proliferation of lymphocytes were significantly increased at 50 mg/kg compared with the control. The results in these studies demonstrated the immunostimulatory effect of PNRS-EtOAC in a dose-dependent manner with respect to the macrophage activation possibly expressing the phagocytosis and nitrite production by the enhancement of TNF-α production as a mode of action.