Chemical analysis of a marine-derived Streptomyces sp. (CMB-M0423) isolated from beach sand off Heron Island, Australia, yielded three new members of the rare pyrroloterpene biosynthetic structure class. Identified by detailed spectroscopic analysis as the first reported examples of naturally occurring 2-nitropyrroles, heronapyrroles A-C (1-3) displayed promising biological activity-with low to submicromolar IC(50) activity against Gram-positive bacteria but no cytotoxicity toward mammalian cell lines.

No abstract

Propolis is a non-toxic natural substance with multiple pharmacological properties including anti-cancer, antioxidant, fungicidal, antibacterial, antiviral, and anti-inflammatory among others. The aim of this study was to determine the chemical and botanical characterization of Chilean propolis samples and to evaluate their biological activity against the cariogenic bacteria Streptococcus mutans and Streptococcus sobrinus. Twenty propolis samples were obtained from beekeeping producers from the central and southern regions of Chile. The botanical profile was determined by palynological analysis. Total phenolic contents were determined using colorimetric assays. Reverse phase HPLC and HPLC-MS were used to determine the chemical composition. The minimum inhibitory concentration (MIC) was determined on S. mutans and S. sobrinus. All propolis samples were dominated by structures from native plant species. The characterization by HPLC/MS, evidenced the presence of quercetin, myricetin, kaempferol, rutine, pinocembrin, coumaric acid, caffeic acid and caffeic acid phenethyl ester, that have already been described in these propolis with conventional HPLC. Although all propolis samples inhibited the mutans streptococci growth, it was observed a wide spectrum of action (MIC 0.90 to 8.22 μg mL−1). Given that results it becomes increasingly evident the need of standardization procedures, where we combine both the determination of botanical and the chemical characterization of the extracts. Research conducted to date, describes a promising effectiveness of propolis in the prevention of caries and other diseases of the oral cavity, making it necessary to develop studies to identify and understand the therapeutic targets or mechanisms of molecular action of the various compounds present on them.

The antifungal effect of six commercial extracts of Chilean propolis on Candida spp. Cien. Inv. Agr. 37(1): 75-84. Propolis has been used in traditional medicine for many centuries because of its beneficial health properties, including its antimicrobial capacity. Prosthesis stomatitis affects a significant percentage of users of removable dentures; Candida albicans is the most common fungal species associated with the development of this pathology. Thus, the objectives of this study were: a. To evaluate the antifungal activity of six commercial propolis extracts against Candida spp. that was isolated from the oral cavity of removable dentures users, and b. To determine chemical characteristics of the propolis extracts evaluated. Among the results, we note that these concentrations of polyphenols varied between 9 ± 0.3 and 85 ± 2.1 mg mL-1. Chromatographic analysis was able to detect 35 compounds, among which were caffeic acid, myricetin, quercetin, kaempferol, apigenin, pinocembrin, galangin, and caffeic acid phenyl ester (CAPE). All strains tested were inhibited by the liquid extracts of propolis. The MID ranged between 1:40 and 1:1280, and the MIC for C. albicans ranged from 197 µg mL-1 to 441 µg mL-1. From the results obtained in this investigation, we can conclude that all propolis extracts evaluated are capable of inhibiting the development of Candida spp. However, they show significant differences in the concentration of polyphenols present and in antifungal activity.