Diversity of Culturable Bacteria from Endemic Medicinal Plants of the Highlands of the Province of Parinacota, Chile.

Endemic medicinal plants that grow at altitudes in northern Chile have been traditionally used for therapeutic applications by Aymara doctors. Several studies have analyzed the biological properties of these plants for therapeutic purposes. The aim was to characterize at molecular and biochemical levels the bacteria that live in the rhizosphere and roots from endemic medicinal plants that grow between 3681-5104 m.a.s.l. in the province of Parinacota. Thirty-nine bacteria were isolated from nine medicinal plants under our laboratory conditions. These bacteria were characterized by Gram stain, hydrolase production, plant-growth promotion, anti-fungal and antibacterial activities, and 16S rDNA sequencing. A phylogenetic study revealed the presence of three major phyla, Actinomycetota (46.2%), Bacillota (43.6%), and Pseudomonadota (10.3%). The rhizobacteria strains associated with the Aymara medicinal plant exhibited several interesting biological activities, such as hydrolytic enzymes, plant-growth-promoting traits, and antibacterial and antifungal properties, indicating their potential for developing new bio-based products for agricultural or clinical applications. These results are promising and highlight the need to point toward the search for explanations of the bio-molecular basis of the therapeutic effects of medicinal plants.

Effects of LED Light Spectra on the Development, Phytochemical Profile, and Antioxidant Activity of Curcuma longa from Easter Island.

Curcuma longa (C. longa), an herbaceous plant used for medicinal purposes by the indigenous people of Easter Island, has been overexploited in its natural habitat, leading to its conservation status being designated as a vulnerable species. We have recently reported on the use of light-emitting diodes (LEDs) to improve the productivity of C. longa in vitro cultures under a temporary immersion system (TIS), but the effects of light quality on plant growth, phytochemical composition, and antioxidant capacity remained unexplored. Here, we set out to study these three aspects as observed at the end of TIS culture (day 0) and after 30 days of greenhouse acclimation (day 30). Thus, we evaluated plant morphological characteristics, phytochemical profile (polyphenols, tannins, flavonoids, reducing sugars, and curcumin), and radical scavenging activity by DPPH, ORAC, and FRAP assays. The results showed that, during in vitro cultivation under TIS, the red:blue (RB) LED light spectrum promoted C. longa shoot proliferation, with the resulting seedlings exhibiting greater fresh weight and no signs of etiolation. In the acclimation phase, the RB spectrum increased phytochemicals, such as polyphenols, flavonoids, and reducing sugars, and boosted curcumin synthesis. Nevertheless, the antioxidant activity of the plants under the RB light spectrum did not intensify. We surmise that this may be due to the premature intraplant allocation of metabolites to alternative pathways (e.g., curcumin synthesis) under RB light.

Chemistry and Bioactivity of Microsorum scolopendria (Polypodiaceae): Antioxidant Effects on an Epithelial Damage Model.

Microsorum scolopendia (MS), which grows on the Chilean island of Rapa Nui, is a medicinal fern used to treat several diseases. Despite being widely used, this fern has not been deeply investigated. The aim of this study was to perform a characterization of the polyphenolic and flavonoid identity, radical scavenging, antimicrobial, and anti-inflammatory properties of MS rhizome and leaf extracts (RAE and HAE). The compound identity was analyzed through the reversed-phase high-performance liquid chromatography (RP-HPLC) method coupled with mass spectrometry. The radical scavenging and anti-inflammatory activities were evaluated for DPPH, ORAC, ROS formation, and COX inhibition activity assay. The antimicrobial properties were evaluated using an infection model on Human Dermal Fibroblast adult (HDFa) cell lines incubated with Staphylococcus aureus and Staphylococcus epidermidis. The most abundant compounds were phenolic acids between 46% to 57% in rhizome and leaf extracts, respectively; followed by flavonoids such as protocatechic acid 4-O-glucoside, cirsimaritin, and isoxanthohumol, among others. MS extract inhibited and disaggregated the biofilm bacterial formed and showed an anti-inflammatory selective property against COX-2 enzyme. RAE generated a 64% reduction of ROS formation in the presence of S. aureus and 87.35% less ROS in the presence of S. epidermidis on HDFa cells. MS has great therapeutic potential and possesses several biological properties that should be evaluated.

Evidence for the existence of extracellular vesicles in Renibacterium salmoninarum and related cytotoxic effects on SHK-1 cells.

Extracellular vesicles (EVs) in bacteria have been implicated in invasive and, through enzymes, infective processes. One Gram-positive bacterium lacking any EV research, despite having commercial impacts on the aquaculture industry, is Renibacterium salmoninarum. We addressed this gap in knowledge by utilizing scanning electron microscopy to provide the first reported evidence for the production of EVs by R. salmoninarum strain H-2. Dispersive light scattering detected that the EVs were heterogeneous in size, and the protein compositions were similar to the bacterial membrane and contained the virulent protein factors p22 and p57. The EVs additionally had a concentrated negative charge compared with R. salmoninarum H-2, as determined by Z potential. Finally, these particles seemed to play a role in host invasion in vitro in the salmon head kidney cell line, as demonstrated by the occurrence of a cytotoxic effect within the first 48 hr post-infection. Higher EV concentrations (i.e. 52.6 µg/ml) were more toxic than R. salmoninarum H-2. This information serves as a foundation to develop and test possible uses for R. salmoninarum EVs in salmon aquaculture, inspiring future advances against bacterial kidney disease.

Genetic diversity and biological activity of Curcuma longa ecotypes from Rapa Nui using molecular markers.

Curcuma Longa (CL) has been used for hundreds of years by native people from Rapa Nui for the treatment of different illness. Despite this plant was introduced from Polynesia or India, there is still scarce information about its origin. The objective of this study was to analyze the genetic variation of three CL ecotypes based on molecular phylogenetic and genotypification using internal transcribed spacer 2 (ITS2) and simple sequence repeats (SSR). Antioxidant and anti-inflammatory properties of rhizomes and leaves extracts of three CL plants were analyzed by spectrophotometric methods and cyclooxygenase 2 (COX-2) inhibition assay. Complementarily, we predicted the potential binding mode and binding energy of curcuminoids and nonsteroidals anti-inflammatory drugs (NSAIDs) into COX-2 via molecular docking. The ITS2 sequence shows two major clusters (I and II), group I consisted of Curcuma haritha and group II consisted of different species of Curcuma and Rapa Nui samples (MR-1, MR-2 and RK-2). Results of SSR markers show that genotype MR-2 was similar to MR-1 and RK-2 with 70.8 and 42.9% similarity, whereas genotype was similar to RK-2, MR-1 and MR-2 with 63.9, 43.2 and 42.9% similarity, respectively. MR-1 have better antioxidant and autoinflammatory activity than rest of CL samples due to its high concentration of polyphenols (33.68 mg/g) and curcumin (29.69 mg/g). Furthermore, docking results show that three curcuminoids of CL and selective NAIDs, as celecoxib, etodolac and meloxicam, share the same binding pocket into COX-2. However, three curcuminoids have a lower ΔGbinding than other COX-2 selective NAIDs as etodolac and meloxicam, except for Coxib family as valdecoxib, celecoxib and rofecoxib. Our findings suggest MR-1, MR-2 and MK-2 from Germplasm Bank (Mataveri Otai of CONAF) are closely related to Curcuma amada and Curcuma montana even though they have genetic variability.

t-Resveratrol Protects against Acute High Glucose Damage in Endothelial Cells.

Postprandial hyperglycemia in diabetic and nondiabetic subjects is associated with endothelial dysfunction. Evidence shows that high glucose generates oxidative stress and a pro-inflammatory state promoting the development of cardiovascular diseases. trans-Resveratrol (t-RV) has been shown to reduce cardiovascular risk. To determine whether t-RV acts as a protector against acute high glucose (AHG)-induced damage, two in vitro models, rat aortic rings (RAR) and human umbilical vein endothelial cells (HUVEC) were used. RAR pretreated with AHG (25 mM D-glucose) for 3 h dramatically decreased the endothelium-dependent relaxation (EDR) induced by acetylcholine in phenylephrine (PE)-precontracted vessels. However, coincubation with t-RV significantly mitigated the damage induced by AHG on EDR. Pretreatment with AHG did not affect the vasodilation induced by sodium nitroprusside. HUVEC treated with t-RV decreased cytotoxicity and reduced radical oxygen species production induced by AHG. Taken together, these results suggest that t-RV can mitigate the AHG-induced EDR damage through a mechanism involving ROS scavenging and probably an increase in the bioavailability of NO.