The effects of Piper sarmentosum aqueous extracts on zebrafish (Danio rerio) embryos and caudal fin tissue regeneration

Antioxidant, Pro-Survival and Pro-Regenerative Effects of Conditioned Medium from Wharton's Jelly Mesenchymal Stem Cells on Developing Zebrafish Embryos

Conditioned media harvested from stem cell culturing have the potential to be innovative therapeutic tools against various diseases, due to their high content of growth, trophic and protective factors. The evaluation in vivo of the effects and biosafety of these products is essential, and zebrafish provides an ideal platform for high-throughput toxicological analysis, concurrently allowing the minimization of the use of mammalian models without losing reliability. In this study, we assessed the biological effects elicited by the exposure of zebrafish embryos to a conditioned medium derived from Wharton's jelly mesenchymal stem cells. By a multiparametric investigation combining molecular, embryological, behavioural and in vivo imaging techniques, we found that exposure to a conditioned medium at a non-toxic/non-lethal dosage triggers antioxidant, anti-apoptotic and pro-regenerative effects, by upregulation of a set of genes involved in antioxidant defence (nrf2, brg1, sirt1, sirt6, foxO3a, sod2 and cat), glycolysis (ldha) and cell survival (bcl2l1, mcl1a and bim), coupled to downregulation of pro-apoptotic markers (baxa, caspase-3a and caspase-8). To our knowledge, this is the first study comprehensively addressing the effects of a conditioned medium on a whole organism from a developmental, molecular and behavioural perspective, and we are fairly confident that it will pave the way for future therapeutic application.

Osteogenic Potential and Bioactive Profiles of Piper sarmentosum Ethanolic Extract-Treated Stem Cells

Piper sarmentosum is a well-known traditional herbal plant in various diseases treatments. Multiple scientific studies have also reported various biological activities exhibited by the plant's extract, such as antimicrobial, anticarcinogenic and antihyperglycemic activities, and, in addition, a bone protective effect in ovariectomized rats has been reported. However, no known Piper sarmentosum extract is involved in osteoblast differentiation using stem cells. Our study aims to identify the potential of P. sarmentosum ethanolic extract to induce osteoblast differentiation of human peripheral blood stem cells. Prior to the assay, the proliferation ability of the cells was observed for 14 days and the presence of hematopoietic stem cells in the culture was determined by the expression of SLAMF1 and CD34 genes. During the differentiation assay, the cells were treated with P. sarmentosum ethanolic extract for 14 days. Osteoblast differentiation was examined using an (alkaline phosphatase) ALP assay, by monitoring the expression of osteogenic gene markers and by von Kossa staining. The untreated cells served as the negative control, while cells treated with 50 µg/mL ascorbic acid and 10 mM β-glycerophosphate acted as the positive control. Finally, the determination of the compound profile was performed using a gas chromatography-mass spectrometry (GC-MS) analysis. The isolated cells were able to proliferate for 14 days during the proliferation assay. The expression of hematopoietic stem cell markers was also upregulated during the 14 days assay. Following the differentiation induction, the ALP activity exhibited a significant increase (p < 0.05) from day 3 of the differentiation assay. A molecular analysis also showed that the osteogenic markers ALP, RUNX2, OPN and OCN were upregulated compared to the positive control. The presence of mineralized cells with a brownish-stained morphology was observed, indicating the mineralization process increased in a time-dependent manner regardless of the concentration used. There were 54 compounds observed in the GC-MS analysis, including β-asarones, carvacrol and phytol, which have been shown to possess osteoinductive capacities. Our results demonstrate that the ethanolic extract of P. sarmentosum can induce osteoblast differentiation of peripheral blood stem cells. The extract contains potent compounds which can potentially induce the differentiation of bone cells, i.e., osteoblasts.

Current Trends in Toxicity Assessment of Herbal Medicines: A Narrative Review

Even in modern times, the popularity level of medicinal plants and herbal medicines in therapy is still high. The World Health Organization estimates that 80% of the population in developing countries uses these types of remedies. Even though herbal medicine products are usually perceived as low risk, their potential health risks should be carefully assessed. Several factors can cause the toxicity of herbal medicine products: plant components or metabolites with a toxic potential, adulteration, environmental pollutants (heavy metals, pesticides), or contamination of microorganisms (toxigenic fungi). Their correct evaluation is essential for the patient’s safety. The toxicity assessment of herbal medicine combines in vitro and in vivo methods, but in the past decades, several new techniques emerged besides conventional methods. The use of omics has become a valuable research tool for prediction and toxicity evaluation, while DNA sequencing can be used successfully to detect contaminants and adulteration. The use of invertebrate models (Danio renio or Galleria mellonella) became popular due to the ethical issues associated with vertebrate models. The aim of the present article is to provide an overview of the current trends and methods used to investigate the toxic potential of herbal medicinal products and the challenges in this research field.

A Spatiotemporal Characterisation of Redox Molecules in Planarians, with a Focus on the Role of Glutathione during Regeneration

A strict coordination between pro- and antioxidative molecules is needed for normal animal physiology, although their exact function and dynamics during regeneration and development remains largely unknown. Via in vivo imaging, we were able to locate and discriminate between reactive oxygen species (ROS) in real-time during different physiological stages of the highly regenerative planarian Schmidtea mediterranea. All ROS signals were strong enough to overcome the detected autofluorescence. Combined with an in situ characterisation and quantification of the transcription of several antioxidant genes, our data showed that the planarian gut and epidermis have a well-equipped redox system. Pharmacological inhibition or RNA interference of either side of the redox balance resulted in alterations in the regeneration process, characterised by decreased blastema sizes and delayed neurodevelopment, thereby affecting tails more than heads. Focusing on glutathione, a central component in the redox balance, we found that it is highly present in planarians and that a significant reduction in glutathione content led to regenerative failure with tissue lesions, characterised by underlying stem cell alterations. This exploratory study indicates that ROS and antioxidants are tightly intertwined and should be studied as a whole to fully comprehend the function of the redox balance in animal physiology.