Repellent and Lethal Activities of Extracts From Fruits of Chinaberry (Melia azedarach L., Meliaceae) Against Triatoma infestans

Ecotoxicological evaluation of an aqueous phytoextract of Melia azedarach L

Melia azedarach L. is a Meliaceae that has shown important insecticidal activities. However, few researchers have extensively studied the toxicology of aqueous extracts of M. azedarach (MAE). Therefore, the main objective of this study was to characterize the phyto-eco-toxicological profile of MAE. First, a botanical and phytochemical characterization of MAE was performed using a histological, and metabolomic multi-analytical approach. Second, the toxicological effects on pollinating insects (Apis mellifera ligustica) and soil collembola (Folsomia candida) were evaluated. In addition, acute toxicity was evaluated in zebrafish (Danio rerio) to assess effects on aquatic fauna, and toxicity was determined in human neuroblastoma (SH-SY5Y) and fibroblast (FB-21) cell models. Finally, phytotoxic effects on germination of Cucumis sativus L., Brassica rapa L. and Sorghum vulgare L. were considered. Metabolomic analyses revealed the presence of not only limonoids but also numerous alkaloids, flavonoids and terpenoids in MAE. Histological analyses allowed us to better localize the areas of leaf deposition of the identified secondary metabolites. Regarding the ecotoxicological data, no significant toxicity was observed in bees and collembola at all doses tested. In contrast, severe cardiac abnormalities were observed in zebrafish embryos at concentrations as low as 25 μg/mL. In addition, MAE showed toxicity at 1.6 μg/mL and 6.25 μg/mL in FB-21 and SH-SY5Y cells, respectively. Finally, MAE inhibited seed germination with inhibitory concentrations starting from 5.50 μg/mL in B. rapa, 20 μg/mL in S. vulgare, and 31 μg/mL in C. sativus. Although M. azedarach extracts are considered valuable natural insecticides, their ecological impact cannot be underestimated. Even the use of an environmentally friendly solvent (an aqueous solution), for the first time, is not without side effects. Therefore, the data collected in this study show the importance of evaluating the dosages, modes of administration and production methods of M. azedarach phytoextracts in agricultural settings.

Phytochemical and Antioxidant Profile of the Medicinal Plant Melia azedarach Subjected to Water Deficit Conditions

Environmental stress triggered by climate change can alter the plant’s metabolite profile, which affects its physiology and performance. This is particularly important in medicinal species because their economic value depends on the richness of their phytocompounds. We aimed to characterize how water deficit modulated the medicinal species Melia azedarach’s lipophilic profile and antioxidant status. Young plants were exposed to water deficit for 20 days, and lipophilic metabolite profile and the antioxidant capacity were evaluated. Leaves of M. azedarach are rich in important fatty acids and oleamide. Water deficit increased the radical scavenging capacity, total phenol, flavonoids, and catechol pools, and the accumulation of β-sitosterol, myo-inositol, succinic acid, sucrose, d-glucose and derivatives, d-psicofuranose, d-(+)-fructofuranose, and the fatty acids stearic, α-linolenic, linoleic and palmitic acids. These responses are relevant to protecting the plant against climate change-related stress and also increase the nutritional and antioxidant quality of M. azedarach leaves.

Plant-Derived Antimicrobial Peptides as Potential Antiviral Agents in Systemic Viral Infections

Numerous studies have led to a better understanding of the mechanisms of action of viruses in systemic infections for the development of prevention strategies and very promising antiviral therapies. Viruses still remain one of the main causes of human diseases, mainly because the development of new vaccines is usually challenging and drug resistance has become an increasing concern in recent decades. Therefore, the development of potential antiviral agents remains crucial and is an unmet clinical need. One abundant source of potential therapeutic molecules are plants: they biosynthesize a myriad of compounds, including peptides which can have antimicrobial activity. Our objective is to summarize the literature on peptides with antiviral properties derived from plants and to identify key features of these peptides and their application in systemic viral infections. This literature review highlights studies including clinical trials which demonstrated that plant cyclotides have the ability to inhibit the growth of viruses causing human diseases, defensin-like peptides possess anti-HIV-1 activity, and lipid transfer proteins and some lectins exhibit a varied antimicrobial profile. To conclude, plant peptides remain interesting to explore in the context of emerging and re-emerging infectious diseases.