Veselin Ivanov

The protective effects of herbal feed additives Withania somnifera, Silybum marianum, Centella asiatica, and silymarin (administered at feed levels of 4000 ppm, 5000 ppm, 4600 ppm, and 25,000 ppm, respectively) against the toxic effects of ochratoxin A (OTA) (administered at 2 ppm) were investigated in 48 New Zealand White rabbits (37 days old) over an 80-day experimental period. A decrease in body weight was seen in rabbits exposed to OTA alone, but that decrease was less pronounced in rabbits receiving herbal supplements. The most severe lesions in OTA-treated rabbits were found in the liver, kidneys and spleen, while milder lesions were seen in the heart, intestine and lungs. The intensity of macroscopic, histopathological and biochemical changes was highest in rabbits exposed to OTA alone, followed by rabbits additionally supplemented with herbal additives, as evidenced by histopathological findings and serum levels of blood urea nitrogen (BUN), creatinine, aspartate aminotransferase (AST), and alanine aminotransferase (ALT). The most pronounced protective effects of the herbal additives were observed in the kidneys and liver. Oxidative stress was significantly increased in rabbits exposed to OTA alone, as evidenced by elevated reactive oxygen species (ROS), nitric oxide (●NO), ascorbyl radicals (●Asc), protein oxidation (PO), procollagen type I alpha 1 (COL1A1), malondialdehyde (MDA), kidney injury molecule-1 (KIM-1), hydroxyproline (Hyp), advanced glycation end products (AEGs), heme oxygenase-1 (HO-1), catalase (CAT), and 8-hydroxy-2′-deoxyguanosine (8-OHdG), as well decreased superoxide dismutase (SOD) and glutathione peroxidase-1 (GPx-1) activities, while protective effects were seen for all herbal additives, and better expressed for Centella asiatica and Silybum marianum.

Silymarin—a standardized extract from the seeds of milk thistle (Silybum marianum L. Gaertn.)—is mainly used for the treatment of hepatitis and other liver diseases. In recent years, the attention of researchers has been directed to its use in dermatology and wound treatment. Despite the promising results, there are still many unresolved issues in this area. The aim of the present study is to develop and characterize hydrogel chitosan–pectin films containing silymarin as an active ingredient with potential medical application. Six variants of hydrogel films (control and silymarin-loaded) were obtained from chitosan and pectin solutions by the casting method and analyzed in terms of their physicochemical, structural, mechanical and optical properties, as well as the in vitro dissolution profile of silymarin. The highest tensile strength was measured for the chitosan-based films—23.35 ± 1.74 MPa (control) and 22.01 ± 2.67 MPa (silymarin-loaded), while the barrier properties to UV and visible light were the strongest for chitosan–pectin films with silymarin. The antioxidant potential of the films was determined by DPPH assay and it was found that the variants with silymarin have over 20 times higher antioxidant activity (from 2.020 ± 0.048 to 2.106 ± 0.190 mg TE/g) than the corresponding controls. The results showed that chitosan–pectin films with incorporated silymarin could find application as potential hydrogel dressings in the therapy of wounds and superficial burns.

The protective effects of the herbal feed supplements Silybum marianum, Silymarin, Withania somnifera, and Centella asiatica against ochratoxin A (OTA) toxicity were studied in 48 New Zealand White rabbits (37-day-old) during an 80-day experiment. OTA was given at 2 ppm, whereas Silybum marianum, Silymarin, Withania somnifera, and Centella asiatica were given at feed levels of 5000 ppm, 25,000 ppm, 4000 ppm, and 4600 ppm, respectively. All rabbits were immunized against Rabbit Hemorrhagic Disease Virus (RHDV). OTA was found to induce an immunosuppressive effect on the humoral immune response. Reliable protection against OTA-provoked immunosuppression by Silimarin and Withania somnifera was found. The OTA-induced immunosuppression was responsible for secondary bacterial infection (pasteurellosis) and the death of two rabbits from the OTA-exposed group and one rabbit each from the groups protected with Silybum marianum and Centella asiatica. A decreased body weight was found in rabbits exposed to OTA, but the decrease was slighter in the rabbits protected with herbal supplements. The target organs damaged by OTA exposure were the liver, kidneys, and spleen, while weaker lesions were found in other internal organs, except in the cases of secondary pasteurellosis, in which the strongest damage was found in the lung. All investigated herbal supplements appeared to have stronger protective effects against OTA-induced damage to the kidneys and liver, with slightly protective effects observed in the lungs, myocardium, spleen, brain, intestine, testicles, and ovaries.