Effects of gamma radiation treatment on three different medicinal plants: Microbial limit test, total phenolic content, in vitro cytotoxicity effect and antioxidant assay

Biochemical and biological studies of irradiated and non-irradiated extracts of Solanum aculeastrum Dunal fruit

This study explores the impact of γ-irradiation on ethanolic extracts of Solanum aculeastrum Dunal. The anti-cancer and antimicrobial properties were investigated. The obtained results revealed that total phenol (TP) and total flavonoid (TF) of total ethanol extract (100%) (FTE) were higher than 70% ethanol extract (SE), and these contents increased after gamma radiation with 5 kGy. The results of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the Solanum aculeastrum extracts suggested that FTE and 5 kGy-irradiated FTE can be used to control and prevent skin infections caused by MRSA and endocarditis, urinary tract infections, and prostatitis caused by Enterococcus faecalis. The FTE sample irradiated at 5 kGy showed cytotoxicity for A431 and Hct-116 cell lines similar to the control sample and higher than the toxicity revealed by the samples irradiated at 10 kGy. In normal cells (Bj-1), the toxicity was decreased after irradiation (IC50 = 31 μg/ml) compared to the non-irradiated extract (IC50 = 26.1 μg/ml). Molecular docking suggested Sortase A to play a role in chlorogenic acid antibacterial activity towards Staphylococcus aureus. In conclusion, γ-irradiation can be used to enhance the phytoconstituents of Solanum aculeastrum fruit extracts and, consequently, its biological properties.

Decontamination technologies for medicinal and aromatic plants: A review

Microbial quality assurance has always been an important subject in the production, trade, and consumption of medicinal and aromatic plants (MAPs). Most MAPs have therapeutic and nutritional properties due to the presence of active substances such as essential oils, flavonoids, alkaloids, etc. However, MAPs can become infected with microorganisms due to poor hygienic conditions during cultivation and postharvest processes. This problem reduces the shelf life and effective ingredients of the product. To overcome these problems, several technologies such as using ethylene oxide gas, gamma irradiation, and steam heating have been used. However, these technologies have disadvantages such as the formation of toxic by-products, low consumer acceptance, or may have a negative effect on the quality of MAPs. This requires a need for novel decontamination technology which can effectively reduce the biological contamination and minimize the food quality losses. In recent years, new technologies such as ozonation, cold plasma, ultraviolet, infrared, microwave, radiofrequency and combination of these technologies have been developed. In this review, biological contamination of MAPs and technologies used for their decontamination were studied. Also, the mechanism of inactivation of microorganisms and the efficacy of decontamination techniques on the qualitative and microbial characteristics of MAPs were investigated.

Effect of gamma irradiation on the caffeoylquinic acid derivatives content, antioxidant activity, and microbial contamination of Pluchea indica leaves

Pluchea indica (L.) Less. leaf has a long history of being used as a food and in traditional medicines. Although gamma irradiation is an effective decontamination method, it must be performed appropriately to preserve the bioactive constituents and biological activities of the plant. This study investigated the influence of gamma irradiation on the caffeoylquinic acid derivatives content, antioxidant capacity, and microbial burden of P. indica leaf. Dried P. indica leaf powder was exposed to gamma rays from cobalt-60 at the absorbed doses of 2.5, 5.0, 7.5, and 10 kGy. After a maceration of P. indica leaf with 70% ethanol, the content of six caffeoylquinic acid derivatives (CQAs) in the extract was assayed using high-performance liquid chromatography. The antioxidant capacity of the ethanolic extract was also determined using the DPPH, ABTS, and ferric reducing antioxidant power (FRAP) methods. The total aerobic bacteria and total yeast and mold counts were investigated using the Petrifilm method at 0 and 3 months after irradiation. Doses of 5–10 kGy significantly increased the CQA level (P < 0.05). The antioxidant activity was enhanced significantly at 2.5–10 kGy (P < 0.05). Doses of 2.5–10 kGy also effectively reduced the microbial load (P < 0.05). Among the irradiation doses, 10 kGy showed the best results. Thus, gamma irradiation at 10 kGy is useful in increasing CQA content and antioxidant capacity as well as reducing the microbial load of P. indica leaf.

Gamma and UV radiations induced treatment of anti-cancer methotrexate drug in aqueous medium: Effect of process variables on radiation efficiency evaluated using bioassays

This studystudy focuses on the effect of radiation treatment and hydrogen peroxide (H₂O₂) on the toxicity of anticancer methotrexate. For cytotoxicity, different bioassays such as Allium cepa, hemolytic, brine shrimp were employed. The Ames test was used for mutagenicity analysis. The solutions having concentrations 5, 10 and 15 ppm were irradiated with UV radiation exposure time 15, 30, 45, 60, 75 and 90 min and gamma radiation absorbed doses 0.3, 0.6, 0.9, 1.2, 2, 3 and 4 kGy in combination with with H₂O₂. There was a clear difference observed for aqueous solution before and after treatment with reference to cytotoxicity and mutagenicity. In Allium cepa test, a 47.07, 44.36 and 38.23% increase in root length (RL), root count (RC) and mitotic index (MI) was observed, respectively, for UV/H₂O₂ treatment and in the case of gamma/H₂O₂ treatment, the RL, RC and MI were increased up to 49.39, 52.63 and 52.38%, respectively. Brine shrimp test has shown 85.95 and 91.30% decrease in toxicity using UV/H₂O₂ and gamma/H₂O₂ respectively, while hemolytic test has shown 19.21 and 26.32% hemolysis using UV/H₂O₂ and gamma/H₂O₂, respectively. The mutagenicity reduced up to 82.3, 86.46 and 89.59% (TA98) and 85.42, 87.5 and 90.63% (TA100) for UV/H₂O₂ while 89.59, 90.63 and 93.75% (TA98) and 84.38, 89.59 and 92.71% (TA100) for gamma/H₂O₂. The UV and gamma radiation along with H₂O₂ based AOPs are promising approaches to detoxify the wastewater which can be extended to real hospital liquid effluent effectively.