Exposure of Food Samples to Pulsed Microwave Radiation to Increase their Microbiological Safety and Shelf Life

The aim of the study was to increase the efficiency of decontamination of biological material and media (by the example of food products) by pulsed (non-thermal) radio emission and asses the prospects of its application in medicine and biology.Materials and methods. To achieve the goal an experimental setup has been designed, manufactured and tested, which makes it possible to study the process of exposure of biological materials and media to pulsed (non-thermal) radio emission, in particular, by the example of food products. The basis of the method is optimum control of the electro-physical parameters of the irradiating radio signal, depending on the type of the irradiated object. We used pulsed magnetrons with operating frequency of (2.45±0.05) GHz, authorized for bio-medical research, generating pulsed radiation with an adjustable power within the range of 0.1...10 kW. The pulse repetition rate with a duty cycle of 500...10000 is 0.1...5 kHz. The setup has an operating chamber into which the test sample is placed, as well as additional elements of magnetron protection and measuring the parameters of the microwave power incident on biological object.Results and discussion. The setup has been successfully used to irradiate various food samples with pathogenic micro flora (Salmonella spp. etc.) with pulsed microwave radiation. In particular, as shown by the studies, the arithmetic mean number of pathogenic bacteria in the irradiated samples of minced meat decreased by 27.5 times after 28 days of storage as compared to the control group of non-irradiated samples. Preliminary conducted experiments in the field of investigating the effect of microwave radiation on the process of cell division and other aspects of electromagnetic field influence on pathological microorganisms confirm the prospects and the expediency of continuing the ongoing studies in medicine and biology

Оценка цитотоксической активности и токсичности производного трополонов с потенциальным противоопухолевым действием

The aim. To study the toxicity of 2-(6,8-dimethyl-5-nitro-4-chloroquinoline-2-yl)-5,6,7-trichloro-1,3-tropolone in vitro and in vivo.Materials and methods. 2-(6,8-dimethyl-5-nitro-4-chloroquinoline-2-yl)-5,6,7-trichloro-1,3-tropolone was synthesized using a method for expanding the o-quinone cycle during the reaction between 5-nitro-2,6,8-trimethyl4-chloroquinoline and 3,4,5,6-tetrachloro-1,2-benzoquinone while boiled in dioxane. An in vitro experiment was carried out in the human A549 cell line. Cell viability was assessed using the MTT colorimetric assay by reducing the optical density of the experimental samples compared with the control ones. Acute toxicity was studied on 20 BALB/c Nude male mice. The test compound was administered once orally as a suspension in 1% starch gel at three doses: 0.0055 (group 1), 0.055 (group 2) and 0.55 mg / g (group 3). The control group (group 4) received a placebo.Results. We synthesized a new compound, 2-(6,8-dimethyl-5-nitro-4-chloroquinoline-2-yl)-5,6,7-trichloro-1,3-tropolone. Its structure was established by 1 H nuclear magnetic resonance (NMR), infrared (IR) spectroscopy, and mass spectrometry. The yield was 19.8 g (52%), the melting point was 205–207 ºС, bright yellow crystals (benzene) were observed. The half-maximal inhibitory concentration (IC50) of 2-(6,8-dimethyl-5-nitro-4-chloroquinoline-2-yl)-5,6,7-trichloro-1,3-tropolone was 0.21 ± 0.01 μM, which was significantly lower (р < 0.05) than the IC50 of cisplatin (3.84 ± 0.23). Following the in vivo experiment, no toxic effect of tropolone was detected when administered once at a dose of 0.0055, 0.055, and 0.55 mg / g. Conclusion. 2-(6,8-dimethyl-5-nitro-4-chloroquinoline-2-yl)-5,6,7-trichloro-1,3-tropolone demonstrated cytotoxic effects on the A549 cell line at a lower IC50 than cisplatin which is widely used in treatment of cancers, including lung cancer. Insolubility of 2-(6,8-dimethyl-5-nitro-4-chloroquinoline-2-yl)-5,6,7-trichloro-1,3-tropolone in water and the absence of its toxic effect in the studied modes determine the scope of its application for further study of cumulative and antitumor effects. Цель – исследование токсичности 2-(6,8-диметил-5-нитро-4-хлорхинолин-2-ил)-5,6,7-трихлор-1,3-трополона in vitro и in vivo.Материалы и методы. Для синтеза 2-(6,8-диметил-5-нитро-4-хлорхинолин-2-ил)-5,6,7-трихлор-1,3-трополона использован метод расширения о-хинонового цикла в процессе реакции между 5-нитро-2,6,8-триметил-4-хлорхинолином и 3,4,5,6-тетрахлор-1,2-бензохиноном при кипячении в диоксане. Эксперимент in vitro проведен на клеточной линии рака легкого человека A549. Оценку жизнеспособности клеток проводили при помощи МТТ-колориметрического теста по уменьшению оптической плотности опытных проб по сравнению с контрольными. Исследование острой токсичности проведено на 20 самках мышей линии Balb/c Nude. Исследуемое соединение вводили однократно перорально в форме суспензии в 1%-м крахмальном геле в трех дозах: 0,0055 (1-я группа), 0,055 (2-я группа) и 0,55 мг/г (3-я группа). Контрольная группа (4-я) получала плацебо.Результаты. Получен 2-(6,8-диметил-5-нитро-4-хлорхинолин-2-ил)-5,6,7-трихлор-1,3-трополон по ранее разработанному методу, его строение установлено данными ядерно-магнитного резонанса 1 Н и инфракрасной и масс-спектрометрии. Выход составил 19,8 г (52%), температура плавления 205–207 º С, ярко-желтые кристаллы (бензол). Ингибирующая концентрация IC50 2-(6,8-диметил-5-нитро-4-хлорхинолин-2-ил)-5,6,7- трихлор-1,3-трополона была равна 0,21 ± 0,01 мкМ, что оказалось статистически значимо меньше (р < 0,05) ингибирующей концентрации IC50 цисплатина равной 3,84 ± 0,23 мкМ. В результате исследования in vivo не выявлено токсического действия трополона при однократном введении в дозах 0,0055; 0,055 и 0,55 мг/г.Заключение. Показано, что 2-(6,8-диметил-5-нитро-4-хлорхинолин-2-ил)-5,6,7-трихлор-1,3-трополон проявляет цитотоксическую активность в отношении клеточной линии A549 в более низкой ингибирующей концентрации IC50, чем цисплатин, широко применяющийся в лечении злокачественных новообразований, в том числе рака легкого. Нерастворимость в воде 2-(6,8-диметил-5-нитро-4-хлорхинолин-2-ил)-5,6,7- трихлор-1,3-трополона и отсутствие его токсического действия в исследованных нами режимах определяют границы его использования для дальнейшего изучения кумулятивных и противоопухолевых эффектов.