Chemical analysis of amyloid ß aggregation inhibitors derived from Geranium thunbergii.

Amyloid ß (Aß) aggregates in the brains of patients with Alzheimer's disease (AD) and accumulates via oligomerization and subsequent fiber elongation processes. These toxicity-induced neuronal damage and shedding processes advance AD progression. Therefore, Aß aggregation-inhibiting substances may contribute to the prevention and treatment of AD. We screened for Aß42 aggregation inhibitory activity using various plant extracts and compounds, and found high activity for a Geranium thunbergii extract (EC50 = 18 µg/mL). Therefore, we screened for Aß42 aggregation inhibitors among components of a G. thunbergii extract and investigated their chemical properties in this study. An active substance was isolated from the ethanol extract of G. thunbergii based on the Aß42 aggregation inhibitory activity as an index, and the compound was identified as geraniin (1) based on spectral data. However, although geraniin showed in vitro aggregation-inhibition activity, no binding to Aß42 was observed via saturation transfer difference-nuclear magnetic resonance (STD-NMR). In contrast, the hydrolysates gallic acid (2) and corilagin (5) showed aggregation-inhibiting activity and binding was observed via STD-NMR. Therefore, the hydrolysates produced under the conditions of the activity test may contribute to the Aß42 aggregation-inhibition activity of G. thunbergii extracts. Geraniin derivatives may help prevent and treat AD.

LC-ESI-QTOF-MS/MS Analysis, Cytotoxic, Antiviral, Antioxidant, and Enzyme Inhibitory Properties of Four Extracts of Geranium pyrenaicum Burm. f.: A Good Gift from the Natural Treasure.

This study focused on the biological evaluation and chemical characterization of Geranium pyrenaicum Burm. f. Different solvent extracts (hexane, ethyl acetate, methanol, and water extracts) were prepared. The phytochemical profile, antioxidant, and enzyme inhibitory activity were investigated. Cytotoxicity was assessed using VERO, FaDu, HeLa and RKO cells. The antiviral activity was carried out against HSV-1 (Herpes simplex virus 1) propagated in VERO cell line. The aqueous extract, possessing high phenolic content (170.50 mg gallic acid equivalent/g extract), showed the highest reducing capacity (613.27 and 364.10 mg Trolox equivalent/g extract, for cupric reducing antioxidant capacity and ferric reducing antioxidant power, respectively), radical scavenging potential (469.82 mg Trolox equivalent/g extract, against 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)), metal chelating ability (52.39 mg ethylenediaminetetraacetic acid equivalent/g extract) and total antioxidant capacity (3.15 mmol Trolox equivalent/g extract). Liquid chromatography-electrospray ionization-quadrupole time-of-flight-mass spectrometry (LC-ESI-QTOF-MS/MS) alloved to tentatively identify a total of 56 compounds in the extracts, including ellagitannins, gallic acid and galloyl derivatives amongst others. The ethyl acetate extracts substantially depressed cholinesterase enzymes (4.49 and 12.26 mg galantamine equivalent/g extract against AChE and BChE, respectively) and α-amylase enzyme (1.04 mmol acarbose equivalent/g extract). On the other hand, the methanolic extract inhibited tyrosinase (121.42 mg kojic acid equivalent/g extract) and α-glucosidase (2.39 mmol acarbose equivalent/g extract) activities. The highest selectivity towards all cancer cell lines (SI 4.5-10.8) was observed with aqueous extract with the FaDu cells being the most sensitive (CC50 40.22 µg/mL). It can be concluded that the presence of certain bioactive antiviral molecules may be related to the high anti HSV-1 activity of the methanolic extract. This work has generated vital scientific data on this medicinal plant, which is a prospective candidate for the creation of innovative phyto-pharmaceuticals.

Structure of floral nectaries and female-biased nectar production in protandrous species Geranium macrorrhizum and Geranium phaeum.

Nectar is a major floral reward offered to pollinators by plants. In dichogamous plant species, differences in nectar production across sexual phases often occur, but both the male- and female-phase flowers have to attract pollinators to achieve effective pollination. Nectar-producing structures, i.e. floral nectaries, are a key component of floral organisation and architecture, and the knowledge of their structure and function contributes to better understanding of the plant-pollinator interactions. In the present study, we investigated the morphology and structure of nectaries and the nectar production pattern in two protandrous species Geranium macrorrhizum and G. phaeum. The flowers of the studied species have been shown to exhibit varied availability of nectar for insect visitors. Their nectaries differ in the shape, size and thickness. The other differences include the localisation of the stomatal field, the size and number of nectarostomata, the presence of non-glandular and glandular trichomes, the presence of tannin idioblasts, the mode of secretion and the occurrence of plastids functioning probably as autophagosomes and autolysosomes, whose presence in nectary cells has been described for the first time. The flowers of the studied species started nectar secretion in the non-receptive phase before pollen presentation and nectar was produced throughout both sexual phases. The nectar production was gender biased towards the female phase in the nectar amount, nectar sugar concentration and total sugar secreted in the nectar. We postulate that the nectar production patterns in G. phaeum and G. macrorrhizum might have evolved as a response to pollinators' pressure.

Chemical Composition of Volatiles of Eight Geranium L. Species from Vlasina Plateau (South Eastern Serbia).

Geranium species are widely used in traditional medicine of Balkan. The aim of this work was to investigate and compare chemical composition of volatile fractions obtained by hydrodistillation from aerial parts of G. macrorrhizum, G. phaeum, G. sanguineum, G. robertianum, G. palustre, G. pyrenaicum, G. columbinum and G. lucidum as well as from underground parts of G. macrorrhizum and G. phaeum, originated from Vlasina plateau in South Eastern Serbia. The volatiles were analyzed using GC/MS and GC-FID. G. palustre volatiles have been studied for the first time with ß-selinene (18.6 %) as a characteristic compound. The cluster analysis revealed separation of volatiles into two main groups. Volatile fractions of G. macrorrhizum were separated from all other samples due to high sesquiterpene content (92.3 % in aerial and 94.6 % in underground parts). The volatile fractions of other samples were mainly composed of sesquiterpenes (10.8-61.8 %), diterpenes (12.9-43.0 %) and fatty acids and their derivatives (6.6-21.6 %) with the exception of volatile fraction of G. phaeum underground parts which was dominated only by fatty acids and their derivatives (76.6 %). The results presented in this article contribute to the knowledge on the chemistry of this genus and advances the knowledge on flora of southeast Serbia.

Transcriptome mining and in silico structural and functional analysis of ascorbic acid and tartaric acid biosynthesis pathway enzymes in rose-scanted geranium.

Rose-scented geranium (Pelargonium sp.) is widely known as aromatic and medicinal herb, accumulating specialized metabolites of high economic importance, such as essential oils, ascorbic acid, and tartaric acid. Ascorbic acid and tartaric acid are multifunctional metabolites of human value to be used as vital antioxidants and flavor enhancing agents in food products. No information is available related to the structural and functional properties of the enzymes involved in ascorbic acid and tartaric acid biosynthesis in rose-scented geranium. In the present study, transcriptome mining was done to identify full-length genes, followed by their bioinformatic and molecular modeling investigations and understanding of in silico structural and functional properties of these enzymes. Evolutionary conserved domains were identified in the pathway enzymes. In silico physicochemical characterization of the catalytic enzymes revealed isoelectric point (pI), instability index, aliphatic index, and grand average hydropathy (GRAVY) values of the enzymes. Secondary structural prediction revealed abundant proportion of alpha helix and random coil confirmations in the pathway enzymes. Three-dimensional homology models were developed for these enzymes. The predicted structures showed significant structural similarity with their respective templates in root mean square deviation analysis. Ramachandran plot analysis of the modeled enzymes revealed that more than 84% of the amino acid residues were within the favored regions. Further, functionally important residues were identified corresponding to catalytic sites located in the enzymes. To, our best knowledge, this is the first report which provides a foundation on functional annotation and structural determination of ascorbic acid and tartaric acid pathway enzymes in rose-scanted geranium.

Hydrogeochemical and biomedical insights into germanium potential of curative waters: a case study of health resorts in the Sudetes Mountains (Poland).

Germanium is considered to be a non-essential element; however, little is still known about its significance for living organisms. It exerts prophylactic and therapeutic effects in the treatment of serious diseases such as cancer, HIV infection, and others. Germanium does not exhibit acute toxicity, but, as it tends to accumulate in various organs and tissues, undesirable and even dangerous side effects have been reported after prolonged and/or high dosage application. In general, inorganic compounds of germanium are more toxic than its organic compounds. Further studies should be performed to elucidate the exact molecular mechanism of germanium action, to determine the safe and effective dose of germanium via curative/mineral waters, and to understand the applications and benefits of using germanium-enriched waters in balneotherapy. The geochemistry of curative (cold CO2-rich, thermal) waters from spas in the Sudetes (Poland) was clarified in terms of components and mineral phases which might govern germanium. Germanium and silicon in thermal (above 20 °C) waters presumably result from the solubility of silicates in crystalline (granites, gneisses) aquifer rocks and might be controlled by neo-formed quartz. The cold CO2-rich waters revealed a significant diversity of aqueous chemistry and relationships of germanium with iron, silicon, or arsenic. Locally, both in sedimentary (sandstones) and metamorphic (gneisses) aquifer rocks, primary (silicates) and/or secondary (oxides) iron-containing minerals likely release germanium into solution. In the CO2-rich waters of the western part of the Klodzko Region, germanium distinctly correlates with arsenic. It is hypothesized that both elements are co-sourced from crystalline basement and/or migration of substances of post-magmatic origin along deep-seated dislocations related to the seismically active Porící-Hronov fault zone. This area was proposed as the most prospective one for finding waters rich in germanium in the Sudetes.

Further antibacterial Geranium macrorrhizum L. metabolites and synthesis of epoxygermacrones.

4,5- and 1,10-Epoxygermacrones were isolated from the essential oil of aerial parts of Geranium macrorrhizum L. (Geraniaceae). The structures of the epoxy derivatives were deduced from their 1D- and 2D-NMR spectra, molecular modeling, and confirmed by synthesis starting from germacrone. The epoxy compounds were screened for their antimicrobial activities by a microdilution assay, which revealed high activities of both compounds against Bacillus subtilis (minimum inhibitory concentrations (M/Cs) determined were 4.3 and 43 nmol/ml for 1,10- and 4,5-epoxygermacrone, resp.) and Pseudomonas aeruginosa (0.043 and 0.855 µmol/ml for 1,10- and 4,5-epoxygermacrone, resp.). The discovery and observed activity of the two epoxides fills the gap in our knowledge of the active principles in this highly renowned ethnomedicinal plant species.

Antioxidant effects of secondary metabolites from Geranium psilostemon.

An investigation was made of the effects on endogenous antioxidant enzyme activities and H2O2-induced lipid peroxidation inhibition in human red blood cells of the crude MeOH extract and its EtOAc, n-BuOH, and H2O sub-extracts obtained from aerial parts of Geranium psilostemon Ledeb., as well as compounds isolated from the most active EtOAc extract. Gallic acid (1), methyl gallate (2), pusilagin (3), 1,3,6-tri-O-galloyl-beta-glucopyranoside (4), 1,2,3,4,6-penta-O-galloyl-beta-glucopyranoside (5), kaempferol (6), quercetin (7), kaempferol 7-O-alpha-rhamnopyranoside (8), and quercetin 7-O-alpha-rhamnopyranoside (9) were isolated from the aerial parts of the title plant, and their structures identified from spectroscopic (UV, 1D- and 2D- NMR) and spectrometric (TOF-MS) data. All extracts and isolated compounds inhibited H2O2-induced lipid peroxidation and also enhanced the activity of superoxide dismutase (SOD) and catalase (CAT).