Objective: In this work, we evaluated the chemical composition by chromatography coupled to mass spectrometry, antimicrobial and insecticidal activity of essential oils (TrEO) and nanoeffu-sion (NTrEO) of oil from Tetradenia riparia leaves. We also evaluated the acute toxicity in Mus musculus. The results showed that S. aureus showed greater susceptibility to TrEO, with a minimum inhibitory concentration (MIC) of 125 µg.mL-1, when compared to P. aeruginosa, E. coli, which presented a MIC of 250 µg.mL-1. There was a greater toxic effect on TrEO (LC50 = 630.29 µg.mL-1) and NTrEO (LC50 = 713.68 µg.mL-1) larvae, effect on pupae (LC50 = 630.29 µg.mL-1) and NTrEO (LC50 = 713.68 µg.mL-1) and ovicide (LC50 = 631.184 µg.mL-1) and NTrEO (LC50 = 146.701 µg.mL-1) of Ae. aegypti after 24 h of exposure, when compared to other exposure periods. Chemical analysis re-vealed 20 components, aromadendrene oxide (23.47%) being the main component. Female and male mice were used to assess toxicity and oral administration of NTrEO to mice did not result in acute toxicity. Thus, the essential oil of T. riparia and its nanoemulsion have insecticidal and an-timicrobial potential for Ae. aegypti, S. aureus, E. coli, P. aeruginosa, and has a high toxicological safety threshold at the concentrations evaluated in this study.

The prevalence of diabetes mellitus (DM), considered one of the most common metabolic disorders, has dramatically increased and resulted in higher rate of morbidity and mortality around the world, in the past decade. It is well known that insulin resistance in target tissues and a deficiency in insulin secretion from pancreatic β-cells are the main characteristic of type 2 diabetes. The aim of this study was the bio-evaluation of compounds isolated from three selected plant species; namely, Salvia africana-lutea, Leonotis ocymifolia and Plectranthus madagascariensis, for their glucose uptake ability. Methanolic extracts were produced from the arterial part of each plant. Compounds were identified using different spectroscopic techniques. The glucose uptake ability of each compound was then evaluated in mammalian cells using 2-deoxyglucose-6-phosphate. The cytotoxicity of each compound was established via the MTT assay. Chromatographic purification of the three plant species yielded fifteen pure terpenoids. Compounds 1 (p = 0.0031), 8 (p = 0.0053), and 6 (p = 0.0086), showed a marked increase in glucose uptake, with p values of p=0.0031, p=0.0053 and p=0.0086, respectively. Additionally, 1, 4 and 6 exhibited cytotoxicity toward mammalian tissue with a decrease in cell viability of ~70%, ~68% and ~67%, respectively. The results suggested that several compounds demonstrated a marked increase in glucose uptake while two of the compounds exhibited signs of cytotoxicity. It may, therefore, be suggested that these compounds be considered as potential candidates for novel plant-derived alternative therapies in the treatment of type 2 diabetes.

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder that develops as a consequence of different factors such as oxidative stress and accumulation of the protein amyloid β (Aβ) in the brain, resulting in apoptosis of neuronal cells. The search for a treatment for this disorder is essential as current medications are limited to alleviating symptoms and palliative effects. The aim of this study is to investigate the effects of mint extracts on selected mechanisms implicated in the development of AD. To enable a thorough investigation of mechanisms, including effects on -secretase (the enzyme the leads to the formation of A), on Aβ aggregation, and on oxidative stress and apoptosis pathways, a neuronal cell model, SH-SY5Y cells was selected. Six Mentha taxa were investigated for their in vitro β-secretase (BACE) and Aβ-aggregation inhibition activities. Also, their neuroprotective effects on H2O2-induced oxidative stress and apoptosis in SH-SY5Y cells were evaluated through caspase activity. Real-time PCR and Western blot analysis were carried out for the two most promising extracts to determine their effects on signalling pathways in SH-SY5Y cells. All mint extracts had strong BACE inhibition activity. M. requienii extracts showed excellent inhibition of Aβ-aggregation, while other extracts showed moderate inhibition. M. diemenica and M. requienii extracts lowered caspase activity. Exposure of SH-SY5Y cells to M. diemenica extracts resulted in a decrease in the expression of pro-apoptotic protein, Bax, and an elevation in the anti-apoptotic protein, Bcl-xL, potentially mediated by down-regulation of ASK1-JNK pathway. These results indicate that mint extracts could prevent the formation of Aβ and also could prevent their aggregation if they had already formed. M. diemenica and M. requienii extracts have potential to suppress apoptosis at the cellular level. Hence, mint extracts could provide a source of efficacious compounds for a therapeutic approach for AD.

Recent lines of evidence suggest the intriguing hypothesis that consuming common culinary herbs of the mint family might help prevent or treat Covid. Individual citizens could easily explore the hypothesis using ordinary kitchen materials. I offer a philosophical framework to account for the puzzling lack of public health messaging about this interesting idea.