Leucas aspera inhibits the Dalton's ascitic lymphoma in Swiss albino mice: A preliminary study exploring possible mechanism of action

Abstract

Background: North East India is a rich source of medicinal plants and a number of plant extracts are used by tribal peoples living in this area for various disorders. L.aspera is such a plant, traditionally used as an antitumor agent.

Aim: In the present study, aerial parts of L.aspera were investigated for antitumor activity in Dalton's lymphoma (DAL) bearing mice. The ability of plant extract in free radical scavenging, neoangiogenesis inhibition and macrophage stimulation were also checked.

Materials and methods: Based on the preliminary in vitro cytotoxicity studies ethyl acetate fraction of L.aspera (EALA) was selected for the detailed study. DAL ascites tumor model was performed to check the antitumor activity of EALA (200 and 400mg/kg of body weight). Hematological and histopathological parameters were estimated. Antioxidant levels, neoangiogenesis and peritoneal macrophage count were also determined.

Results: In vitro MTT and Trypan blue assay results showed the cytotoxic effect of EALA in DAL cells lines. EALA treatment resulted in significant decrease in ascites tumor volume and viable cell count. Hematological and liver antioxidant parameters were normalised by EALA treatment. It was also found that EALA treatment inhibits neovascularisation and produce macrophage stimulation in treated mice.

Conclusion: The results showed that EALA is a promising anticancer agent and its activity is comparable to the standard drug 5-Flouro uracil (5-FU).

Keywords: Antioxidant; L.aspera; antitumor; macrophage stimulation; neoangiogenesis.

Figure 1

In vitro cytotoxic effect of EALA on DAL cells by trypan blue exclusion assay. All values are mean ± SEM, n=6. IC50 for EALA = 29.4 μg/ml; and 5-FU = 28.2 μg/ml

Figure 2

Effect of EALA and 5-FU on mean survival time in DAL bearing mice. Values are expressed as mean ± SEM (n=6), ^aP<0.001 as compared to DAL control group

Figure 3

Effect of EALA and 5-FU on percentage increase in life span in DAL bearing mice. Values are expressed as mean (n=6)

Figure 4

Effect of EALA and 5-FU on change of body weight in DAL bearing mice. Values are expressed as mean± SEM (n=6), ^aP<0.001 as compared to DAL control group

Figure 5

Effect of EALA and 5-FU on antioxidant parameters (Catalase) in DAL bearing mice. Values are expressed as mean± SEM (n=6). ^aP<0.001 as compared to DAL control group

Figure 6

Histology of liver stained with H and E (×100) of mice from the different groups, on day 15 of the experiment (n=6). A: Hepatocytes, B: lymphocytes, C: Portal area

Figure 7

Effect of EALA on neoangiogenesis in peritoneal tissue of DAL bearing mice

Figure 8

Histopathology of the peritoneal wall sections (×100) of DAL bearing mice treated or untreated with EALA on day 15 of the experiment (n=6). The arrow head indicates neoangiogenesis

Figure 9

Effect of EALA on MVD count of the peritoneal section of tumor bearing mice. Values are expressed as mean± SEM (n=6). ^aP<0.001, ^bP<0.01 as compared to DAL control group

Figure 10

Effect of EALA in macrophage stimulation. Values are expressed as mean± SEM (n=6). ^aP<0.001, ^bP<0.01 as compared to vehicle control group