Background Highly diluted and succussed solutions interact with solvatochromic dyes, indicating that changes in solvent and solute polarity could be related to their mechanism of action. It is not known, however, how the activity associated with succussed high dilutions is transferred to untreated water and what the limits of this process are. Aims The aims of the present study were to ascertain whether a succussed high dilution of phosphorus (1.5 × 1−59 M; Phos 30cH) seeded into a natural water source that fed a fjord and two connected lakes could propagate itself through the lake system (total volume 2200 m3) and, moreover, whether the process could be tracked using solvatochromic dyes. Methods Samples of water were collected before and after seeding, at different times and places throughout the lake system. Controls comprised water taken from an untreated and adjacent, but independent, lake (1385 m3). Results Water samples taken up to 72 hours after the source treatment produced significant increases (p ≤ 0.03) in the absorbance of the solvatochromic dye methylene violet (MV), while samples from the control lake produced no changes. Conclusions The study indicates that activity associated with Phos 30c can propagate itself through large volumes of water, causing changes throughout a whole connected lake system, and that these changes can be tracked using the solvatochromic dye MV. This in turn means the use of homeopathic medicines in large volumes of drinking water, in farming and ecological contexts, now has the potential to be assessed with physico-chemical monitoring.

The essential oils (EOs) obtained from the leaves of Iryanthera polyneura Ducke trees was chemically Assessed and tested for the ability of inhibiting the growth of Candida albicans, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus mutans and S. sanguinis. The oil was also tested against breast (MCF‐7) and prostate (PC‐3) cancer cell lines. Minimum bactericidal concentrations (MBCs) and 50 % inhibition concentrations (IC50) values were obtained. EOs were active against Gram‐positive bacteria. Spathulenol, α‐cadinol and τ‐muurolol were major components of EOs. The oils showed a higher cytotoxicity against PC‐3 than MCF‐7 cells, although the oils were active against both cell types. Oils obtained from leaves collected in the dry season were more active against E. faecalis, S. aureus and PC‐3, while the oils obtained from leaves collected in the rainy season were more active against S. mutans, S. sanguinis and MCF‐7. The antibacterial and cytotoxic activities of the essential oils from the leaves of I. polyneura are related to the seasonal climate variation and are influenced by compounds that are minor components of the oils.

Cover Picture. Iryanthera polyneura Ducke (cumala‐colorada) is native to Brazil, although not endemic, and occurs in terra firme within the Amazon rain forest. The antimicrobial and cytotoxic activity of the essential oils of the species were evaluated, as well as the relationship between the biological activities of the oils and seasonal variation. Significant antibacterial activity against the Gram‐positive bacteria Staphylococcus aureus and Streptococcus mutans was observed. The oils were more toxic to prostate than to breast cancer cells. The EOs obtained from leaves collected in the rainy season were more active against microorganisms and were more cytotoxic to the breast cancer cells than those collected in the dry season. The antibacterial and cytotoxic activities of the EOs from the leaves of I. polyneura are dependent on seasonal influences that produce changes in the terpene composition of EOs, as reported by Martins et al. in their full paper at 10.1002/cbdv.201900374.

Aims: Malassezia spp. are involved in a wide range of mammalian skin diseases. The introduction of new drugs is a need. Natural products are known to be effective in the treatment of microbial pathogens. The present study analyzed the O. platyspermum leaf essential oils (EOs) antifungal activity. Study Design: 18 terpenes from 13 O. platyspermum leaf EOs are related to seasonal and climatic variations occurring during the dry (DS) and rainy (RS) seasons in the Amazon Rain-Forest, verified by means of multivariate analyses. Place and Duration of the Study: the study was conducted at the Center for Research in Biodiversity (Microbiology Laboratory and Cell Culture Laboratory), Paulista University, biological activity evaluations occurred between January/2019 and December 2019). Methodology: microdilution broth assay was used in the minimal bactericidal concentration (MBC). Multivariate analyses were used to access the relationship among MBC, seasonality and terpene composition of the EOs. Results: Malassezia pachydermatis showed higher sensitivity to the EOs than M. furfur or C. albicans. The DS EOs were linked to the presence of limonene, myrcene, α-terpineol, linalool, terpinen-4-ol, cubenol-1-epi, influenced by insolation, temperature and evaporation, while β-elemene, γ-elemene, neo-intermedeol, elemol, α-cadinol, spathulenol, isospathulenol, viridiflorol, δ-amorphene and ledol were linked to the RS EOs, and were influenced by precipitation, relative humidity and wind velocity. DS EOs showed better antifungal activity against both Malassezia species, and the presence of the six discriminative terpenes was essential for the antifungal activity. Conclusions: The DS EOs are a potential source of new leads to defeat animal dermatological microbes.