MUTAGENICITY AND ANTIMUTAGENICITY OF MEDICINAL PLANTS, NOM NANG, SUN SOKE AND STEVIA, EXTRACTS IN AMES TEST

Abstract Aqueous and 80% alcohol crude extracts of three medicinal plants, i.e., Nom Nang , Sun Soke and Stevia showed non-genotoxicity in Ames test in the presence or absencc of metabolic enzymes activation. However, the aqueous and 80% alcoholic extracts of Sun Soke or Nom Nang showed antimutagenicity against pyrolysate mutagens, IQ and Trp-P-1, hepatocarcinogen, aflatoxin B1 and a carcinogenic, AF-2. But co-mutagenicity to Trp-P-1 was observed in 80% alcoholic extract of Nom Nang and to AFB1 was in aqueous extract of Sun Soke. Chiang Mai Med Bull 2001;40:(3):147-153.

THE PRODUCTION OF LACTOFERRIN-PRODUCING BACTEROIDES UNIFORMIS

Abstract To construct lactoferin-producing Bacteroides uniformis, the human lactoferrin gene(hLF) was inserted into pVAL-1, a E. coli-Bacteroides shuttle vector, to generate the recombinantplasmid pVLFK. Then, withE. coli HB101 (R751) as a donor either pVAL-1 or pVLFKwas transferred intoB. uniformis BU1001. The erythromycin resistant strains were selected andisolated as a plasmid containing strain. By PCR technique, the lactoferrin gene was detected inthe bacteria cell extract from each strain. The presence ofhLF has been shown as a 2.1 Kbamplicon inB. uniformis strain pVLFK. The expression of hLF was assessed by Northernhybridization and the gene product was detected by Western blot analysis with anti-humanlactoferrin monoclonal antibody. Although the transcription level ofhLF gene was extremelylow in the strain harboring pVLFK, the specific protein was detected by Western blot analysis.However the size of gene product in this strain was higher than that of standard human LF(SIGMA). The results revealed that a lactoferrin gene bearing plasmid could replicate and wasexpressed inB. uniformis strain pVLFK. The properties of this strain will be further study.Chiang Mai Med Bull 2001;40(4):187-194.

CENTELLA ASIATICA EXTRACT INDUCES CELL CYCLE ARREST IN CACO-2 HUMAN COLON CANCER CELLS

Centella asiatica  is traditionally a medicinal plant frequently employed in the practice of Thai folk medicine. This study examined the anti-tumor activity of the crude water extract of C. asiatica using human colon adenocarcinoma-derived Caco-2 cells. C. asiatica extract reduced the proliferation rate of Caco-2 cells significantly in a concentration- and time-dependent manner. The mechanism of cancer cell growth inhibition was shown to occur via cell cycle arrest. The extract induced S and G2-M arrest in Caco-2 cells accompanied apoptosis induction. The extract also increased the accumulation of cyclin B1 protein in the cells. These findings indicate that C. asiatica extract inhibited cell proliferation of Caco-2 cells through modification of the cell cycle events and this cell cycle arrest is associated, at least in part, with increased accumulation of cyclin B1 protein. Chiang Mai Med Bull 2005;44(1):21-28.

IMMUNOMODULATORY EFFECTS OF THAI MEDICINAL PLANTS ON THE MITOGEN STIMULATED PROLIFERATION OF HUMAN PERIPHERAL BLOOD MONONUCLEAR CELLS IN VITRO

The immunomodulatory effects of Thai medicinal plants, including Murdannialoriformis, Cymbopogon citratus, Momornica charantia, Centella asiatica, Alliumsativum, Carthamus tinctorius, Eclipta alba, Cyperus rotundus, lotus pollen (Dee-Buo),and plant embryos in seeds of the lotus (Ke-Sorn-Buo), on the mitogen stimulatedproliferation of human peripheral blood mononuclear cells (PBMCs) were investigated.The results obtained from this study indicated that only water extracts from C. asiaticahad an immunostimulating effect on mitogen-stimulated proliferation of human PBMCs.In contrast, the ethanol extract from this plant showed immunosuppressive activity.Moreover, the water and ethanol extracts of Ke-Sorn-Buo, Dee-Buo, C. rotundus andE. alba had immunosuppressive effects. These extracts strongly decreased PBMCproliferation in a dose-dependent manner. Ethanol extract of C. tinctorius also showedimmunosuppressive activity at a high concentration. Other medicinal plants did not showany mitogenic responses. This in vitro study revealed various effects of Thai medicinalplant extracts on non-specific cellular immune responses. Further investigation should beconsidered on the effect of extracts on other immune parameters such as macrophageactivity, NK cell activity including cell signaling and cytokine production. Chiang MaiMed Bull 2005;44(1):1-12.

MUTAGENICITY OF OUTDOOR AND INDOOR PM 2.5 FROM URBAN AREAS OF CHIANG MAI, THAILAND

Outdoor and indoor air particulate matter samples were measured in urban areas of Chiang Mai from June 2004 to May 2005. Twenty-four hour air particulate matter samples were collected each day with Airmetric Minivol ® portable air samplers and extracted with dichloromethane by ultrasonication. The organic extracts of PM 2.5 were tested by short-term mutagenicity bioassays using Salmonella tester strains TA98 and TA100, with and without metabolic activation (S9). The types of mutations induced by complex environmental mutagens in experimental organisms (such as Salmonella typhimurium) were found to be the same types as those in humans exposed to the same environmental mutagens. The study showed that direct mutagenicity with TA98 and TA100 strains in airborne particulate matter extracts, from outdoor and indoor PM 2.5 in two sampling sites, was detected during the winter months (October to March). Indirect-acting mutagenicities were detected in both sites in all samples. The mutagenicities became positive, and were higher in the presence of enzyme activation (S9 mix).

ANTIPROLIFERATIVE EFFECT ON COLON CANCER CELL LINES BY AQUEOUS EXTRACT FROM THE BARK OF MILLINGTONIA HORTENSIS

Millingtonia hortensis is a traditional medicinal plant widely used in South-East Asia. This study focused on the antiproliferative effect when comparing between aqueous extract and ethanol extract from the bark of M. hortensis using human colon cancer cell lines, DLD-1, HCT15, SW48 and SW480. In in vitro experiments, the MTT method was used to determine the antiproliferative effect of M. hortensis extract on colon cancer cells. An aqueous extract of M. hortensis significantly reduced the proliferation rate of colon cancer cell lines in a dose-dependent manner. However, no antiproliferative effect was observed by ethanol extract of M. hortensis. This finding indicated that only aqueous extract from the bark of M. hortensis is able to inhibit colon cancer cell proliferation, and its mechanism is now under investigation.