M.C. Courrèges

Antiviral activity of sandalwood oil against Herpes simplex viruses-1 and -2

Sandalwood oil, the essential oil of Santalum album L., was tested for in vitro antiviral activity against Herpes simplex viruses-1 and -2. It was found that the replication of these viruses was inhibited in the presence of the oil. This effect was dose-dependent and more pronounced against HSV-1. A slight diminution of the effect was observed at higher multiplicity of infections. The oil was not virucidal and showed no cytotoxicity at the concentrations tested.

In vitro and in vivo activity of eugenol on human herpesvirus

Eugenol (4‐allyl‐1‐hydroxy‐2‐methoxybenzene) was tested for antiviral activity against HSV‐1 and HSV‐2 viruses. In vitro, it was found that the replication of these viruses was inhibited in the presence of this compound. Inhibitory concentration 50% values for the anti‐HSV effects of eugenol were 25.6 µg/mL and 16.2 µg/mL for HSV‐1 and HSV‐2 respectively, 250 µg/mL being the maximum dose at which cytotoxicity was tested. Eugenol was virucidal and showed no cytotoxicity at the concentrations tested. Eugenol–acyclovir combinations synergistically inhibited herpesvirus replication in vitro. Topical application of eugenol delayed the development of herpesvirus induced keratitis in the mouse model. Copyright

Immunomodulatory activities of Cedrela tubiflora leaf aqueous extracts

Human peripheral blood monocytes and polymorphonuclear leukocytes treated with leaf aqueous extracts of the Meliaceae tree Cedrela tubiflora showed a diminution in both their phagocytic and respiratory burst activities. Besides, the extract inhibited the proliferation of Concanavalin A stimulated lymphocytes. A decrease in the hemolytic capacity of the human complement was also observed. The significance of the inhibitory effect observed over some components of the human immune system closely related with the inflammatory process is discussed.

Effect of Melia azedarach L. leaf extracts on human complement and polymorphonuclear leukocytes

The effect of the water extract of Melia azedarach L. (Meliaceae) leaves on human complement and polymorphonuclear leukocytes was investigated. This extract showed a strong anticomplementary activity, which was more pronounced in the classical pathway assay. The extract did not affect the phagocytic activity of polymorphonuclear leukocytes, nor the respiratory burst of these cells as measured by the nitro blue tetrazolium reduction assay.

Nitric oxide and HSV vaginal infection in BALB/c mice

Here we study the role of nitric oxide in the vaginal infection of Balb/c mice with herpes simplex virus type 2. Inducible nitric oxide synthase (iNOS) mRNA was detected by RT-PCR in vaginal tissue and inguinal lymph nodes early postinfection. iNOS was also found to be activated in cells recovered from vaginal washings of infected animals. Animals treated with aminoguanidine (AG), an iNOS inhibitor, showed a dose-dependent increase in vaginal pathology after viral infection compared to controls. Viral titers in vaginal washings and vaginas were higher in AG-treated mice. Treated animals presented higher PMN counts in vaginal washings compared to controls. Histopathology studies revealed a profound inflammatory exudate in vaginal tissue of treated animals. Finally, RT-PCR analysis showed increased expression of the chemokines MIP-2 and RANTES in vaginal tissue and inguinal lymph nodes of these animals.

Immunomodulatory activities of Cedrela lilloi and Trichilia elegans aqueous leaf extracts

The effects of Cedrela lilloi and Trichilia elegans (Meliaceae) aqueous leaf extracts on several parameters of the mouse immune system were studied. Both extracts showed a strong anticomplementary activity and inhibited the phagocytosis of opsonized sheep erythrocytes and the activation of the oxidative metabolism by opsonized zymosan on peritoneal macrophages. The in vitro proliferation of spleen T-lymphocytes was also impaired. Furthermore, treatment of mice with the extracts diminished the delayed-type hypersensitivity response to sheep erythrocytes. These results suggest that both extracts exert a marked immunomodulatory effect on the mouse immune system.

In vitro antiphagocytic effect of Melia azedarach leaf extracts on mouse peritoneal exudate cells

The effect of Melia azedarach L. (Meliaceae) leaf extract on the phagocytic capability and respiratory burst of mouse peritoneal exudate cells was studied. The extract inhibited the phagocytosis of opsonized sheep erythrocytes. This inhibition was both dose- and time-dependent and reverted 48 h after removing the extract from the culture medium. Furthermore, chemiluminescence in treated cells was also impaired using either receptor (opsonized zymosan) or post-receptor (PMA) stimuli.

Effect of dietary choline deficiency on immunocompetence in Wistar rats

In order to study the effect of dietary choline deficiency on immunity, adult Wistar rats were fed for two months with choline supplemented (CS, 0.35% choline chloride) or deficient (CD) diets and different parameters of immune response against sheep blood red cells or ovoalbumin (OVA) were evaluated. We found a significant reduction of haemagglutinating (HA) antibodies in sera (day 5 post-immunization: CD, 110 ± 12 HAU vs. CS 320 ± 40 HAU, p < 0.05) and only a slight difference in anti-OVA antibodies in CD group. Delayed type hypersensitivity was significantly impaired in CD group (footpad swelling in mm: CD, 0.97 ± 0.51 vs. CS, 2.32 ± 0.53, p < 0.05). In vitro, concanavalin A (Con A) stimulated proliferation of lymphocytes from spleen or lymph nodes of CD rats were diminished to 1:3 of control values while no difference was observed when lipopolisaccharide (LPS) was used as stimulus. So, we can conclude that choline dietary deficiency affects immune response in rats reducing host response to antigens.

In vitro and in vivo activities of Melia azedarach L. aqueous leaf extracts on murine lymphocytes

The effect of Melia azedarach L. aqueous leaf extracts (Ma) on in vitro lymphocyte proliferation and humoral and cellular immune responses in vivo was studied. Proliferation of spleen and lymph node T cells was impaired when these cells were incubated in the presence of the extract using different mitogens as stimuli. Furthermore, treatment of mice with the extracts not only diminished the production of antibodies but also exerted an inhibition on graft vs host and delayed type hypersensitivity reactions. These results suggest that Ma extracts exert a marked immunomodulatory effect on the mouse immune system.

In vitro activities of Cedrela tubiflora aqueous leaf extracts on murine macrophages, polymorphonuclear leukocytes and complement

Cedrela tubiflora aqueous leaf extracts are capable of inhibiting in vitro the activity of some components of the mouse immune system related to inflammatory responses. A significant reduction in the phagocytic capability and respiratory burst response (61.5% and 57.6%, respectively) of murine peritoneal macrophages was observed when these cells were incubated for 24 h with medium containing 1 mg/mL extract. On the other hand, at a concentration of 4 mg/mL, the extract reduced significantly the phagocytic activity of mouse polymorphonuclear leukocytes (87.5%) without altering the oxidative metabolism of these cells. Finally, a concentration of 2 mg/mL was required to inhibit the haemolytic activity of both pathways of mouse complement.