Chemical analyses and in vitro and in vivo toxicity of fruit methanol extract of Sechium edule var. nigrum spinosum.

CONTEXT: Sechium edule (Jacq.) Sw. (Cucurbitaceae) is used in ethnomedicine, but the diversity of the varietal groups of this species has not often been considered. This is important because we previously reported that different variety of species exhibit different activities across different tumor cell lines. OBJECTIVE: This study investigates the chemical composition and biological activities of extracts obtained from S. edule var. nigrum spinosum. MATERIALS AND METHODS: The leukemia P388 cell line and mononuclear bone marrow cells (MNCBMs) were treated with the extract at a concentration ranging from 40 to 2370 µg/mL for cytotoxicity and viability assays. CD-1 mice were treated with 8-5000 mg/kg extract and monitored every hour for the first 24 h and subsequently for seven days for signs of toxicity (LD50). In addition, the chromatographic profile of the extract was determined by HPLC. RESULTS: The extract inhibits the proliferation of both P388 cells and MNCBMs, with IC50 values of 927 and 1911 µg/mL, respectively, but reduced the viability and induced the apoptosis of only leukemia cells. The LD50 was higher than 5000 mg/kg, and this concentration did not alter the blood chemistry or cell count but doubled the mitotic index in the bone marrow. The HPLC showed the presence of cucurbitacins, phloridzin, naringenin, phloretin, apigenin, and gallic, chlorogenic, vanillic, p-hydroxybenzoic, caffeic, and p-coumaric acids. DISCUSSION AND CONCLUSION: Sechium edule var. nigrum spinosum contains bioactive compounds that explain the antiproliferative and nutraceutical activities, and its lack of physiological side effects constitutes an added value to a widely consumed vegetable.

Fruit extract from a Sechium edule hybrid induce apoptosis in leukaemic cell lines but not in normal cells.

The antiproliferative potential of a crude extract from the chayote hybrid H-837-07-GISeM® and its potential for apoptosis induction were assessed in leukaemic cell lines and normal mouse bone marrow mononuclear cells (BM-MNCs). The extract strongly inhibited the proliferation of the P388, J774, and WEHI-3 cell lines (with an IC50 below 1.3 µg·mL(-1)), reduced cell viability, and induced apoptotic body production, phosphatidylserine translocation, and DNA fragmentation. However, the extract had no effect on BM-MNCs. We postulate that these properties make the extract a good candidate for an anti-tumour agent for clinical use.

Photocytotoxicity of a 5-nitrofuran-ethenyl-quinoline antiseptic (Quinifuryl) to P388 mouse leukemia cells.

Quinifuryl (MW 449.52), 2-(5'-nitro-2'-furanyl)ethenyl-4-[N-[4'-(N,N-diethylamino)-1'-methylbutyl]carbamoyl] quinoline, is a water soluble representative of a family of 5-nitrofuran-ethenyl-quinoline drugs which has been shown to be highly toxic to various lines of transformed cells in the dark. In the present study, the toxicity of Quinifuryl to P388 mouse leukemia cells was compared in the dark and under illumination with visible light (390-500 nm). Illumination of water solutions of Quinifuryl (at concentrations ranging from 0.09 to 9.0 microg/ml) in the presence of P388 cells resulted in its photodecomposition and was accompanied by elevated cytotoxicity. A significant capacity to kill P388 cells was detected at a drug concentration as low as 0.09 microg/ml. The toxic effect detected at this drug concentration under illumination exceeded the effect observed in the dark by more than three times. Moreover, the general toxic effect of Quinifuryl, which included cell proliferation arrest, was nearly 100%. Both dose- and time-dependent toxic effects were measured under illumination. The LC50 value of Quinifuryl during incubation with P388 cells was approximately 0.45 microg/ml under illumination for 60 min and >12 microg/ml in the dark. We have demonstrated that the final products of the Quinifuryl photolysis are not toxic, which means that the short-lived intermediates of Quinifuryl photodecomposition are responsible for the phototoxicity of this compound. The data obtained in the present study are the first to indicate photocytotoxicity of a nitroheterocyclic compound and demonstrate the possibility of its application as a photosensitizer drug for photochemotherapy.

Characterization of chemotherapy-induced morphonuclear modifications in the P388 leukaemia and the MXT mammary tumour models of the mouse.

Chemotherapy-induced morphonuclear modifications were monitored in vivo by means of the digital cell image analysis of Feulgen-stained nuclei. Two experimental models were used, i.e. the P388 mouse leukaemia and the MXT mouse mammary carcinoma. The drugs used were doxorubicin, etoposide and cyclophosphamide. The results indicate that the chemotherapy induced a significant decrease in the MXT tumour growth and a significant increase in the survival of the P388 leukaemic mice. These effects were accompanied at the morphonuclear level by an increase in the nuclear area, by modifications in the DNA content in accordance with the effects of the drugs on the cell cycle and by several modifications in the chromatin texture in accordance with the model or the drugs studied. While there were neither homogeneous morphonuclear changes in all treatment groups nor clearcut correlations between the morphonuclear changes and tumour growth or the survival of the animals, the present study nevertheless shows that it is possible, at least partly, to monitor in vivo certain chemotherapy-induced effects occurring at the morphonuclear level, and subsequently to obtain information on the mode of action of the drugs.

Studies on zoapatle, II. Leucanthanolide, a novel sesquiterpene lactone from Montanoa leucantha ssp. leucantha.

PIP: A sesquiterpene lactone given the trivial name leucanthanolide, from the Mexican zoapatle plant (Montanoa leucantha), long used as an herbal remedy, was isolated and was found to have cytotoxicity but no uterine activity. The compound was isolated from the fraction containing zoapatanol, a substance being investigated for its ability to induce menses, abortion and labor. The compound has a molecular formula of C19H2606, a 5-membered lactone ring, an ester group, and a germacradienolide skeleton. It was evaluated for abortifacient activity in pregnant guinea pigs by intraperitoneal injection on day 22 of gestation. 3 of 5 animals had abnormal fetuses, but there was no evidence of early uterine activity. Cytotoxic testing in vitro was done on KB and P-388 test systems in cell culture. The ED50 of leucanthanolide was 0.57 mcg/ml (KB) and 0.93 (P-388). In comparison, the ethyl acetate fraction had an ED50 of 1.35 mcg/ml and 5.2 mcg/ml respectively.^ieng