Cytotoxic activity screening of some indigenous Thai plants
The 50% ethanolic extracts from 14 plant species used in Thai traditional folklore were screened for cytotoxic activity against a malignant human hepatoma (HepG2) cell line and a normal African green monkey kidney (Vero) cell line. The extracts of Polyalthia evecta and Erythroxylum cuneatum showed potent anticancer activity in the HepG2 cell line with IC50 of 70 ± 3 µg/ml and 64 ± 4 µg/ml, respectively. P. evecta demonstrated more selectivity to the HepG2 than the Vero cell (selectivity index > 14.3) indicating its potential for biopharmaceutical use. 
MTT colorimetric assay for testing macrophage cytotoxic activity in vitro
The MTT (3-(4,5-dimethylthiazol-2-yl)2,5-diphenyl tetrazolium bromide) cleavage,assay, originally described by Mosmann (1983, J. Immunol. Methods 65, 55) for measuring cell survival/proliferation, has been used successfully to quantitate macrophage-mediated cytotoxicity. Peritoneal macrophages, from control or pyran copolymer MVE2-treated mice and from TU5 and L929 murine cell lines, were used as effectors and targets respectively in a 48 h cytotoxicity test, at three effector: target ratios (10:1, 5:1, 2:1). The amount of MTT reduced by cells to its blue formazan derivative during an additional 4 h of culture was quantified spectrophotometrically at 570 nm using an ELISA reader. A linear relationship between the formazan generated and the number of viable TU5 and L929 cells was demonstrated, together with time-dependent growth characteristics for these cells. The formazan produced by macrophages was independent of their functional state and did not interfere with the target cell signal. MVE2-activated macrophages strongly inhibited the survival/growth of target cells in a dose-related way, whereas the cytotoxic activity of control macrophages was very low. Finally, the MTT method compared favorably with the 3H-TdR uptake method in evaluating macrophage cytotoxicity, and both of them were more sensitive than the 3H-TdR release assay. 
Cytotoxic activity in broth-culture filtrates of Campylobacter pylori
Broth-culture filtrates of Campylobacter pylori induced non-lethal cytopathic effects in vitro in 7 of 9 mammalian cell lines tested. Transmission electronmicroscopy revealed that the response consisted of intracellular vacuolisation. Intestine 407 cells were among the most responsive and were used for routine assay. About 55% of isolates of C. pylori tested, originating from four geographic regions worldwide, produced cytotoxic activity. The activity was neutralisable by specific antisera to broth-culture filtrates or to sonicated bacteria but not by antisera to other bacterial preparations. Cytotoxic activity was heat-labile (70°C for 30 min), was protease-sensitive and ammonium-sulphate precipitable. It did not pass through an ultrafiltration membrane with a nominal mol.-wt limit of 100 x 103. It was concluded that C. pylori can produce a factor that alters cultured cells in vitro. The relevance of this factor to the pathogenesis of gastritis associated with C. pylori remains to be determined. 
An Analysis In-vitro of the Cytotoxic, Antioxidant and Antimicrobial Activity of Aqueous and Alcoholic Extracts of Annona muricata L. Seed and Pulp
Aims: To evaluate the cytotoxic activity of aqueous and alcoholic extracts from Annona muricata L (soursop) seed and pulp on human tumor cell lines of breast, prostate and cervix; as well as the antioxidant and antimicrobial properties of those extracts.
Study Design: For cytotoxic activity, non-linear regressions of the values of IC50 of all extracts were used. For antimicrobial and antioxidant activities, an analysis of variance with multiple range tests, using the Fisher’s LSD method was applied. Each study was replicated 3 times.
Methodology: The methanolic extract of soursop seed was obtained by two methods: Soxhlet apparatus (SSS) and maceration (MSS). The aqueous extracts of both soursop seed (LSS) and pulp (LSP) were obtained by decoction. Human tumor cell lines from breast (MCF-7 and SKBr3), prostate (PC3) and cervix (HeLa), and fibroblasts (as control) were used to determine the cytotoxic activity by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) assay. Antioxidant and antimicrobial activity were determined by the DPPH (1,1-diphenyl-2-picrylhydrazyl) and disc diffusion method, respectively.
Results: Extracts of SSS, MSS, LSP and LSS had a higher cytotoxic activity on the PC3 (0.0024 to 1.275 µg/mL) and HeLa (0.0011 to 7.194 µg/mL) cell lines with low impact on healthy cells (fibroblasts, as control), than in MCF-7 (27.09 to >100 µg/mL) and SKBr3 (20.50 to >100 µg/mL) cells. Antioxidant activity of MSS (83.23%) and LSS (84.41%) extracts were significantly (P < 0.05) higher than those extracts of LSP (69.77%) and SSS (69.43%). Significant (P < 0.05) antimicrobial activity against Listeria monocytogenes, Salmonella enterica ser. Enteritidis and Staphylococcus aureus was only observed for SSS and MSS extracts.
Conclusion: Results obtained in this research suggest that consumption of soursop fruit could be a good alternative to prevent illness such as cancer of prostate and cervix. However, further studies are needed to isolate and characterize the specific compounds of these extracts causing such effects. 
Antioxidant and Cytotoxic Activities of Gmelina arborea ROXB. Leaves
Aims: The leaves of Gmelina arborea (ROXB.) (Family Verbenaceae) are widely used in the folklore to treat various types of diseases. In this study, the antioxidant and cytotoxic activities of different methanolic extracts and the derived subfractions of 90% methanolic extract of this plant were evaluated.
Methodology: The antioxidant activity was carried out via three different quantitative assays as well as qualitative one. Total phenolic was determined via Folin-Ciocalteu and total flavonoid via AlCl3 assays. The cytotoxic activity was carried out via brine shrimp test and toward human cancer cell line; HepG2 using Sulphorhodamine-B assay. The 90% methanolic extract was fractionated using pet. ether then the 90% defatted methanol undergoes fractionation using (CHCl3, EtOAc and n-BuOH).
Results: The antioxidant results showed that the; DPPH antioxidant activity was (19.20, 14.10 and 28.94 µg/ml); total antioxidant capacity was (412.69, 518.45 and 390.41; mg AAE /g extract); reducing power was (0.649, 0.715 and 0.396; 200 mg/ml) and total phenolic was (330.22, 400.66 and 244.76; mg GAE/g extract), respectively for 90% methanol, n-BuOH and EtOAc. The cytotoxic results showed that the; mortality of brine shrimp larvae (LC50) against different dosages of defatted 90% methanol, n-BuOH and EtOAc respectively was (158.48, 39.81 and 199.52; µg/ml) and the results of HepG2 assay showed that n-BuOH fractions have cytotoxic activity with IC50 ≤ 20 µg/ml (IC50 = 17.3 µg/ml) which falls within the American Cancer Institute criteria followed by 90% methanol and EtOAc (IC50 = 22.1 µg/ml).
Conclusion: It was concluded that Gmelina arborea extracts possess a powerful antioxidant and cytotoxic activities. 
 Prayong, P., Barusrux, S. and Weerapreeyakul, N., 2008. Cytotoxic activity screening of some indigenous Thai plants. Fitoterapia, 79(7-8), pp.598-601.
 Ferrari, M., Fornasiero, M.C. and Isetta, A.M., 1990. MTT colorimetric assay for testing macrophage cytotoxic activity in vitro. Journal of immunological methods, 131(2), pp.165-172.
 Leunk, R.D., Johnson, P.T., David, B.C., Kraft, W.G. and Morgan, D.R., 1988. Cytotoxic activity in broth-culture filtrates of Campylobacter pylori. Journal of medical microbiology, 26(2), pp.93-99.
 Raybaudi-Massilia, R., Suárez, A.I., Arvelo, F., Mosqueda-Melgar, J., Zambrano, A. and Calderón-Gabaldón, M.I., 2015. An analysis in-vitro of the cytotoxic, antioxidant and antimicrobial activity of aqueous and alcoholic extracts of Annona muricata L. seed and pulp. Current Journal of Applied Science and Technology, pp.333-341.
 Shoeb, H.A., Madkour, H.M., Refahy, L.A., Mohamed, M.A., Saad, A.M. and Ghareeb, M.A., 2014. Antioxidant and cytotoxic activities of Gmelina arborea ROXB. leaves. Journal of Pharmaceutical Research International, pp.125-144.