Modulation by Acanthospermum australe extracts of the tumor induced hematopoietic changes in mice

Antiviral activity of two Acanthospermum species against herpes simplex virus 1

ETHNOPHARMACOLOGICAL RELEVANCE

Acanthospermum species are used in traditional medicine for treating various pathologies, including bacterial and viral infections. In a screening study, we identified the activity of the ethanolic extracts of Acanthospermum australe and Acanthospermum hispidum against herpes simplex virus 1 (HSV-1).

AIM OF THE STUDY

In this work, we analyzed the phytochemical profile and antiviral activity of the chemical fractionation products of Acanthospermum australe and Acanthospermum hispidum. Additionally, we identified the effect of these fractions on different steps of the viral cycle.

MATERIALS AND METHODS

Acanthospermum samples were extracted with methanol and further partitioned with solvents of increasing polarities: hexane, chloroform, ethyl acetate, and butanol. Cytotoxicity and antiviral activity were analyzed for each fraction. The active fractions were tested to identify the virucidal effect and the inhibition of virus-cell binding. Further, the effect of these fractions on the replication and viral gene was quantitated by qPCR, and the expression of gD protein was evaluated by Western blot.

RESULTS

The chloroform and hexane fractions of Acanthospermum hispidum and Acanthospermum australe showed dose-dependent antiviral activity. The chloroform fraction inhibited the virus-cell binding and virus cycle in a post-entry mechanism by decreasing replication and the expression of early and late viral genes. The hexane fraction did not inhibit virus binding; however, it showed antiviral activity in post-entry events by inhibiting the immediate-early, early, and late genes. We identified in both species the presence of 3.6-dimetoxiapigenin, axillarin, and penduletin in the chloroform fraction and methyl-(Z,Z)-9,12-octadecadienoate and phytol in the hexane fraction.

CONCLUSIONS

Acanthospermum hispidum and Acanthospermum australe possess antiviral activity against HSV-1 and affect different steps of the viral cycle. These characteristics make them good candidates for developing phytotherapeutic products against HSV-1.

Activation of cytotoxic T lymphocyte responses and attenuation of tumor growth in vivo by Andrographis paniculata extract and andrographolide

The stimulatory effect of Andrographis paniculata extract and andrographolide on cytotoxic T lymphocyte (CTL) production was determined in BALB/c mice by Winn's neutralization assay using CTL sensitive EL4 thymoma cells as target cell. Extract and andrographolide showed a significant increase in CTL production in both the in vivo and in vitro models. The survival time of EL4 cells alone in animals was only 27.1 days and it was increased to 51.1 and 44.5 days in extract- and andrographolide treated animals with percentage increase in life span (%ILS) of 88.5 and 64.2, respectively. The survival rate of animals administered EL4 cells incubated with alloimmunized spleen cells (effector cells) from normal BALB/c mice was 35.8 (%ILS 32.1). When this group was treated with 10 doses of extract and andrographolide the life span was further increased to 52.1 days (%ILS 92.2 ) and 48.1 days (%ILS 77.4). Survival days of animal carrying EL4 cells incubated with alloimmunized spleen cells (effector cells) from extract and andrographolide treated animals were 55.5 and 50.3 days respectively. When these animals continued with extract and andrographolide treatment for 10 days their life spans were significantly increased to 62 and 53.8 days, respectively. The level of cytokines such as Interlevkin (IL)-2 and Interferon (IFN)-gamma also was enhanced in these animals when they were treated with extract and andrographolide. This study demonstrated that A. paniculata extract and andrographolide stimulate the CTL production through enhanced secretion of IL-2 and IFN-gamma by T cells and thereby inhibit the tumor growth.

Effects produced by Royal Jelly on haematopoiesis: relation with host resistance against Ehrlich ascites tumour challenge

Royal jelly (RJ) was shown to exhibit immunomodulatory properties, although its biological activity is still unclear. In order to elucidate the mechanism whereby RJ activates the immunological system, we examined the role of this substance on the haematopoietic response of Ehrlich ascites tumour (EAT)-bearing mice. Our results demonstrated that RJ prevented the myelosupression induced by the temporal evolution of the tumour and abrogated the splenic haematopoiesis observed in EAT-bearing mice. The stimulating effect of RJ was also observed in vitro on the multipotent bone marrow stem cells, evaluated by the long-term bone marrow cultures (LTBMCs). The study of survival clearly showed the antitumour activity of RJ. Treatment was given prophylactically for 20 days and therapeutically for 3, 8 and 13 days. Except for the treatment with the lower dose of 500 mg/kg, given for 23 days, all the other dose schedules were able to prolong survival. A more effective antitumoural response was observed with the more prolonged treatment regimen. In this regard, the administration of RJ for 33 days produced the highest protection reaching an extension of survival at about 38%, 71% and 85% for the doses of 500, 1000 and 1500 mg/kg, respectively, whereas with the 23 and 28 days treatment schedules, survival increased at a rate of 19% and 23%, respectively, and comparable results were found among the effective doses of RJ. Increased survival rate might be related to the decreased Prostaglandin E2 (PGE2) levels observed in EAT-bearing mice after RJ treatment. These results point to RJ as a promising modifier of biological response leading to myeloprotection and antitumour activity.

Ehrlich Ascites Tumor as a Tool in the Development of Compounds with Immunomodulatory Properties

In previous works, we have demonstrated that the myeloprotective properties of several natural and synthetic compounds are partly responsible for their antitumor activity in the Ehrlich ascites tumor (EAT) model. In this work, we present information that may be useful to the study of pharmacological and toxicological properties of compounds that affect the hematological compartment. Clonogenic studies in EAT-inoculated mice demonstrated a rapid decrease in bone marrow CFU-GM, whereas a progressive increase in splenic CFU-GM and cellularity was observed, followed by splenomegaly. Bone marrow cellularity declined on the third day after tumor challenge, returning to normal values thereafter. Serum from EAT-bearing mice produced detectable colony-stimulating activity in vitro. Similar results were observed with the conditioned medium from Ehrlich tumor cell cultures, but not with the cell-free Ehrlich tumor ascitic fluid. Tumor inoculation also resulted in a more striking depletion in the number of non-adherent cells in long-term bone marrow cell cultures (LTBMCs) with no bone marrow stroma formation. We speculate that the physiological alterations induced by the EAT growth can be used to assess the ability of compounds to modulate the hematopoietic response.