Polyphenolic Composition and Hypotensive Effects of Parastrephia quadrangularis (Meyen) Cabrera in Rat

A new oxime synthesized from Senecio nutans SCh. Bip (chachacoma) reduces calcium influx in the vascular contractile response in rat aorta

Senecio nutans Sch. Bip is an endemic plant commonly employed in the Andes culture to counteract the effects of mountain sickness, and its bioactive molecules could provide new drugs for treating hypertension. The purpose was to determine whether the vascular response of the plant bioactive molecules, such as (5-acetyl-6-hydroxy-2-isopropenyl-2,3-dihydrobenzofurane; Sn-I), could be improved by a simple structural modification to synthesize oximes (Ox-Sn-I). We characterized both compounds using IR and NMR spectroscopy and Heteronuclear Multiple Quantum Coherence (HMQC). We investigated vascular relaxation mechanisms in response to Sn-I and Ox-Sn-I using rat aorta and vascular smooth muscle cells (A7r5) as experimental models. Preincubation of aortic rings with Sn-I (10-5 M) significantly (p < 0.001) decreased the contractile effect in response to phenylephrine (PE) and potassium chloride (KCl). The sensitivity (EC50) to PE significantly (p < 0.01) decreased in the presence of Sn-I (10-5 M), but not with Ox-Sn-I. Sn-I significantly (p < 0.001) reduced the PE-induced contraction under calcium-free conditions. When A7r5 cells were preincubated with Sn-I and Ox-Sn-I (10-5 M), both compounds blunted the increase in intracellular Ca2+ induced by KCl. 2,3-Dihydrobenzofurane derived from S. nutans (Sn-I) reduces the contractile response probably by blocking Ca2+ entry through voltage-gated Ca2+ channels (VGCC) in vascular smooth cells. This effect also causes relaxation in rat aorta mediated by reduction of intracellular Ca2+ concentration, rather than an increase of NO generation in endothelial vascular cells.

Promising Natural Medicines for the Treatment of High-Altitude Illness

Li Li, Lin Lin, Bo Wen, Peng-cheng Zhao, Da-sheng Liu, Guo-ming Pang, Zi-rong Wang, Yong Tan, and Cheng Lu. Promising natural medicines for the treatment of high-altitude illness. High Alt Med Biol. 24:175-185, 2023.-High-altitude illness (HAI) is a dangerous disease characterized by oxidative stress, inflammatory damage and hemodynamic changes in the body that can lead to severe damage to the lungs, heart, and brain. Natural medicines are widely known for their multiple active ingredients and pharmacological effects, which may be important in the treatment of HAI. In this review, we outline the specific types of HAI and the underlying pathological mechanisms and summarize the currently documented natural medicines applied in the treatment of acute mountain sickness and high-altitude cerebral edema, high-altitude pulmonary edema, chronic mountain sickness, and high-altitude pulmonary hypertension. Their sources, types, and medicinal sites are summarized, and their active ingredients, pharmacological effects, related mechanisms, and potential toxicity are discussed. In conclusion, natural medicines, as an acceptable complementary and alternative strategy with fewer side effects and more long-term application, can provide a reference for developing more natural antialtitude sickness medicines in the future and have good application prospects in HAI treatment.

UHPLC-ESI-OT-MS Phenolics Profiling, Free Radical Scavenging, Antibacterial and Nematicidal Activities of "Yellow-Brown Resins" from Larrea spp

This research was designed to investigate the metabolite profiling, phenolics and flavonoids content and the potential antioxidant, antibacterial and nematicidal activities of "yellow-brown resins" from Larrea divaricata Cav (LdRe) and L. nitida Cav (LnRe). Metabolite profiling was obtained using an ultrahigh resolution liquid chromatography orbitrap MS analysis (UHPLC-ESI-OT-MS). The antioxidant properties were screened by four methods: 2,2-diphenyl-1-picrylhydrazyl assay (DPPH), trolox equivalent antioxidant activity assay (TEAC), ferric-reducing antioxidant power assay (FRAP) and lipid peroxidation in erythrocytes (LP). The antibacterial activity was evaluated according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. In addition, the potential combinatory effect was analyzed with the fractional inhibitory concentration index (FICI) values using the checkerboard design. The nematicidal activity was carried out according to a standardized protocol. LdRe and LnRe showed a strong capture of the DPPH radical withvalues around 8.4 µg resin/mL; FRAP (1.69-1.94 mgTE/ g resin), TEAC (1.08-1.09 mgTE/g resin) and LP (81-82% at 100 µg of resin/mL) assays. A strong antimicrobial activity was displayed by both resins against methicillin-sensitive Staphylococcus aureus ATCC 25923(MSSA) and methicillin-resistant S. aureus ATCC 43300(MRSA) (MICs = 16-32 µg resin/mL). Additionally, the combination of LdRe or LnRe with the antibiotic cefotaxime showed an indifferent effect (FICI values = 1-1.25), however, this combinationcould be a potential strategy to reduce the drug doses, and in this way can be a potential alternative to reduce bacterial resistance. On the other hand, the resins showed a scarce nematicidal potential toward J2 Meloidogyne incognita; an important nematode infecting horticultural crops. Phenolics compounds were identified by UHPLC-PDA-OT-MS analysis, updating the knowledge on the chemical profile of these species. These results, together with the high content of quantified phenolics and flavonoids, allow the phenolics-enriched resins of these two Larrea species to be considered as a promising sustainable source of compounds of pharmacological interest.

UHPLC-HESI-OT-MS-MS Biomolecules Profiling, Antioxidant and Antibacterial Activity of the "Orange-Yellow Resin" from Zuccagnia punctata Cav

This research was designed to investigate the metabolite profiling, phenolics, and flavonoids content as well as the potential antioxidant and antibacterial, properties of orange-yellow resin from Zuccagnia punctata Cav (ZpRe). Metabolite profiling was obtained by a ultrahigh resolution liquid chromatography orbitrap MS analysis (UHPLC-ESI-OT-MS-MS). The antioxidant properties were screened by four methods: 2,2-diphenyl-1-picrylhydrazyl assay (DPPH), trolox equivalent antioxidant activity assay (TEAC), ferric-reducing antioxidant power assay (FRAP), and lipid peroxidation in erythrocytes (LP)). The antibacterial activity was evaluated according to the Clinical and Laboratory Standards Institute (CLSI) rules. The resin displayed a strong DPPH scavenging activity (IC₅₀ = 25.72 µg/mL) and showed a percentage of inhibition of LP close to that of the reference compound catechin (70% at 100 µg ZpRe/mL), while a moderated effect was observed in the FRAP and TEAC assays. The resin showed a content of phenolic and flavonoid compounds of 391 mg GAE/g and 313 mg EQ/g respectively. Fifty phenolics compounds were identified by ultrahigh resolution liquid chromatography orbitrap MS analysis (UHPLC-PDA-OT-MS) analysis. Thirty-one compounds are reported for the first time, updating the knowledge on the chemical profile of this species. The importance of the biomolecules identified support traditional use of this endemic plant. Furthermore, additional pharmacological data is presented that increase the potential interest of this plant for industrial sustainable applications.

Fast Isolation of Flavonoids from the Endemic Species Nolana ramosissima I.M. Johnst and Its Endothelium-Independent Relaxation Effect in Rat Aorta

The infusion of the desertic plant Nolana ramosissima I.M. Johnst showed vascular smooth muscle relaxation in rat aorta and the presence of several phenolic compounds, which were detected by high resolution UHPLC-Orbitrap-HESI-MS. In addition, five flavonoids were rapidly isolated from a methanolic extract using high-performance counter-current chromatography (HPCCC). The N. ramosissima extract showed endothelium-independent relaxation effect in rat aorta. Sixty-one compounds were detected in the infusion, mainly glycosylated flavonoids, flavanones and several oxylipins, suggesting that a synergistic effect between the compounds in the extracts could be responsible for the relaxation activity. Vascular activity experiments were done in isolated organ bath. In rat aorta, a nitric oxide inhibitor did not prevent the relaxation effects of the extract; however, a selective guanylyl cyclase inhibitor partially blunted this effect. The compound 5,3′-dihydroxy-4′7-dimethoxyflavone presented higher relaxation effect than 100 μg/mL of N. ramosissima extract. The extract and the isolated metabolites from N. ramosissima can show relaxation effects on rat aorta by a mechanism that is independent of the endothelium.