Induction of apoptosis in RKO colon cancer cell line by an aqueous extract of Millingtonia hortensis.

Millingtonia hortensis is an important medicinal plant in Southeast Asia, used for the treatment of asthma, sinusitis and as a cholagogue and tonic. The aim of this study was to compare the effects of aqueous and ethanol extracts of Millingtonia hortensis on the induction of apoptosis in an RKO human colon cancer cell line. Viability of RKO cells was assessed by MTT reduction assay. The aqueous extract, but not the ethanol extract of M. hortensis inhibited cell growth and proliferation in a dose- and time-dependent manner. Apoptotic cells were determined by flow cytometry and DNA fragmentation assay. Apoptotic cell numbers increased in a dose-dependent manner after treatment with aqueous extract. DNA ladders were clearly observed in RKO cells treated with 200, 300 and 400 ?g/ml of the aqueous extract of M. hortensis for 48 h. These results indicate that the aqueous extract of M. hortensis inhibited cell proliferation in an RKO colon cancer cell line via the apoptosis pathway.

Immunomodulatory activities of Centella asiatica and Rhinacanthus nasutus extracts.

Centella asiatica (CA) and Rhinacanthus nasutus (RN )have been used for treatment of various illnesses, but the mechanisms of action remain largely unknown. This study focused on the influence of CA and RN extracts on cell-mediated and humoral immune responses. In human peripheral blood mononuclear cells (PBMCs), CA (water extract) and RN (water and ethanol extracts) significantly increased proliferation and the production of IL-2 and TNF-alpha. In contrast, an ethanol extract of CA inhibited human PBMC mitogenesis and the production of IL-2 and TNF-alpha. BALB/c mice treated with CA extracts (100 mg/kg bw) showed higher responses to both primary and secondary antibodies against BSA when compared with non-treated group. Only the secondary antibody response was increased in RN extract-treated mice. The present study revealed immunomodulating activity of CA and RN extracts with regard to both non-specific cellular and humoral immune responses. The data available to date suggest that they may have chemopreventive or anticancer potential.

Expression of cyclooxygenase-1 and -2 and clinicopathologic features of colorectal cancer in northern Thailand.

Two isoforms of cyclooxygenase, COX-1 and COX-2, have been identified and shown to be involved in tumorigenesis. Although, overexpression of COX-2 in human cancers has been repeatedly reported, no data have hitherto been available for Thai patients. To cast light on the role(s) of COX enzymes in the development and progression of colorectal cancers and to determine the incidence of COX-2 overexpression, the expression levels of COX-1 and COX-2 proteins using Western blot analysis in tumor tissues and adjacent normal tissues obtained from 44 Thai patients with colorectal cancer. Compared with paired normal tissues, COX-2 was overexpressed in 13 of 44 colorectal tumor tissues (29.5%). Overall, COX-2 levels in colorectal tumor specimens were significantly correlated with histological differentiation, in particular in the tumors with poor differentiation (p<0.05). In addition, overexpression of COX-2 was found more frequently in colorectal tumors with lymphatic invasion, regional lymph node metastasis and larger size, although without statistical significance. In contrast to the relatively consistent alteration in COX-2 expression, the level of COX-1 expression was quite varied in tumor tissues. Forty-eight percent of colorectal tumors exhibited a decreased level of COX-1 in comparison to normal tissues and overexpressed in 23%. Thus both isoforms may both play roles in promoting tumorigenesis. However, there was no significant relationship between the alteration of COX-1 protein levels and any pathological features of tumors.