New substituted benzoxazine derivatives as potent inducers of membrane permeability and cell death.

The search for new agents targeting different forms of cell death is an important research focus for developing new and potent antitumor therapies. As a contribution to this endeavor, we have designed and synthesized a series of new substituted 3,4-dihydro-2H-1,4-benzoxazine derivatives. These compounds have been evaluated for their efficacy against MCF-7 breast cancer and HCT-116 colon cancer cell lines. Overall, substituting this heterocycle led to improved antiproliferative activity compared to the unsubstituted derivative 1. The most active compounds, 2b and 4b, showed IC50 values of 2.27 and 3.26 µM against MCF-7 cells and 4.44 and 7.63 µM against HCT-116 cells, respectively. To investigate the mechanism of action of the target compounds, the inhibition profile of 8 kinases involved in cell signaling was studied highlighting residual activity on HER2 and JNK1 kinases. 2b and 4b showed a consistent binding mode to both receptor kinases, establishing significant interactions with known and catalytically important domains and residues. Compounds 2b and 4b exhibit potent cytotoxic activity by disrupting cell membrane permeability, likely triggering both inflammatory and non-inflammatory cell death mechanisms. This dual capability increases their versatility in the treatment of different stages or types of tumors, providing greater flexibility in clinical applications.

Digital Health-Enabled Clinical Trials in Stroke: Ready for Prime Time?

As stroke continues to represent a major global health care problem, advancing our knowledge of new effective and safe stroke interventions represents a public health priority. The identification of these therapies requires the conduct of high-quality and well-powered randomized clinical trials. Despite its potential to inform clinical practice, traditional randomized clinical trial models have their drawbacks, including elevated costs, long completion times, failure to recruit the target sample sizes, lack of diversity, and complex operational procedures. Therefore, improving the participants' experience and trials' overall efficiency constitutes an important unmet need. Innovative models such as virtual and decentralized patient-centric trials have been proposed as a valuable strategy in this pursuit. In this narrative review, we discuss the limitations of traditional randomized clinical trial models and present the concept, advantages, and challenges of decentralized digitally enabled approaches to the conduct of stroke clinical trials.

Bioactive imidamide-based compounds targeted against nitric oxide synthase.

The selective inhibition of inducible nitric oxide synthase (iNOS) has become an interesting goal for the treatment of diseases where the immune and inflammatory response of the organism is involved. Septic shock is one prominent example of this type of affections. In this paper, the design and synthesis of twelve substituted pyridinyl- imidamide derivatives is described, together with their biological evaluation as NOS inhibitors. The most potent and selective compound was N-(3-hydroxy-3-(pyridin-3-yl)propyl)acetimidamide 9a (IC50 = 4.6 µM, against iNOS). Pharmacological assays in aortic rat tissue, have confirmed its inhibitory activity on iNOS and the absence of undesired cardicovascular effects. In silico analysis of the most promising compounds (9a, 9b, 9e and 9g) have predicted good drug-likeness properties. Furthermore, they have shown an adequate cell viability. Docking studies carried out on 9a suggest a particular binding mode that involves the essential residue Glu377, and might explain its iNOS selectivity. From a chemical point of view, the article describes an unusual cyclization to obtain pyridinyl-pyrimidine derivatives with high yield.

Synthesis, bioevaluation and docking studies of new imidamide derivatives as nitric oxide synthase inhibitors.

In search of new Nitric Oxide Synthase (NOS) inhibitor agents, two isosteric series of derivatives with an imidamide scaffold (one of them with a hydroxyl group and the other with a carbonyl one) were synthesized and evaluated on inducible (iNOS) and neuronal (nNOS) isoforms. These compounds have been designed by combining a kynurenamine framework with an amidine moiety in order to improve selectivity for the inducible isoform. In general, the in vitro inhibitory assays exhibited better inhibition values on the iNOS isoform, being the N-(3-(2-amino-5-methoxyphenyl)-3-hydroxypropyl)-4-(trifluoromethyl)benzimidamide 4i the most active inhibitor with the highest iNOS selectivity, without inhibiting eNOS. Docking studies on the two most active compounds suggest a different binding mode on both isozymes, supporting the experimentally observed selectivity towards the inducible isoform. Physicochemical in silico studies suggest that these compounds possess good drug-likeness properties.

Adapting the Accelerated Solvent Extraction Method for Resin and Rubber Determination in Guayule Using the BÜCHI Speed Extractor.

Guayule (Parthenium argentatum Gray) is a promising alternative source to Hevea brasiliensis for the production of natural rubber, which can reach levels of 8-9% under industrialized farming conditions. The most common method for determining rubber concentration is by accelerated solvent extraction (ASE), a technique developed by the Dionex Corporation and almost exclusively performed with the Dionex ASE-200 or 350 systems. Herein, it is sought to apply and adapt the most common methods used in the literature for the Dionex system to another extraction platform, the BÜCHI Speed Extractor E-914. Results showed that using a sand sandwich method to confine the sample in the center and exploiting a larger cell volume (80 mL) for extraction prevents the occurrence of overpressure and problems with clogging. Under optimized conditions, the coefficient of variation was <15% for both resin quantification for samples containing 5.0-15.8% of resin and for rubber quantification for samples with 1.7-10.3% rubber content. The extraction time for resin (2 cycles of 5 min each) was smaller than for rubber (2 cycles of 20 min each). It would be interesting to carry out interlaboratory comparisons to standardize the method at an international level.

A Bayesian framework for the inference of gene regulatory networks from time and pseudo-time series data.

Motivation: Molecular profiling techniques have evolved to single-cell assays, where dense molecular profiles are screened simultaneously for each cell in a population. High-throughput single-cell experiments from a heterogeneous population of cells can be experimentally and computationally sorted as a sequence of samples pseudo-temporally ordered samples. The analysis of these datasets, comprising a large number of samples, has the potential to uncover the dynamics of the underlying regulatory programmes. Results: We present a novel approach for modelling and inferring gene regulatory networks from high-throughput time series and pseudo-temporally sorted single-cell data. Our method is based on a first-order autoregressive moving-average model and it infers the gene regulatory network within a variational Bayesian framework. We validate our method with synthetic data and we apply it to single cell qPCR and RNA-Seq data for mouse embryonic cells and hematopoietic cells in zebra fish. Availability and implementation: The method presented in this article is available at https://github.com/mscastillo/GRNVBEM. Contact: mscastillo@ugr.es.

Strong Influence of the Ancillary Ligand over the Photodynamic Anticancer Properties of Neutral Biscyclometalated IrIII Complexes Bearing 2-Benzoazole-Phenolates.

In this paper, the synthesis, comprehensive characterization and biological and photocatalytic properties of two series of neutral IrIII biscyclometalated complexes of general formula [Ir(C^N)2 (N^O)], where the N^O ligands are 2-(benzimidazolyl)phenolate-N,O (L1, series a) and 2-(benzothiazolyl)phenolate-N,O (L2, series b), and the C^N ligands are 2-(phenyl)pyridinate or its derivatives, are described,. Complexes of types a and b exhibit dissimilar photophysical and biological properties. In vitro cytotoxicity tests conclusively prove that derivatives of series a are harmless in the dark against SW480 cancer cells (colon adenocarcinoma), but express enhanced cytotoxicity versus the same cells after stimulation with UV or blue light. In contrast, complexes of type b show a very high cytotoxic activity in the dark, but low photosensitizing ability. Thus, the ancillary N^O ligand is the main factor in terms of cytotoxic activity both in the dark and upon irradiation. However, the C^N ligands play a key role regarding cellular uptake. In particular, the complex of formula [Ir(dfppy)2 (L1)] (dfppy=2-(4,6-difluorophenyl)pyridinate) [3 a] has been identified as both an efficient photosensitizer for 1 O2 generation and a potential agent for photodynamic therapy. These capabilities are probably related to a combination of its notable cellular internalization, remarkable photostability, high photoluminescence quantum yield, and long triplet excited-state lifetime. Both types of complexes exhibit notable catalytic activity in the photooxidation of thioanisole and S-containing aminoacids with full selectivity.

Cationic Bis(cyclometalated) Ir(III) Complexes with Pyridine-Carbene Ligands. Photophysical Properties and Photocatalytic Hydrogen Production from Water.

Precursors of chelate pyridine-N-heterocyclic carbene (N^C:) ligands with methyl- or benzyl-substituted imidazolylidene fragments were synthesized. They were used to obtain 12 iridium bis-cyclometalated complexes of the type [Ir(C^N)2(N^C:)]+ (C^N = 2-(phenyl)pyridinato-C2,N, ppy, 2-(4,6-difluorophenyl)pyridinato-C2,N, dfppy). The ancillary N^C: ligands contain different structural modifications. The aim of the work was to analyze the effect that changes in the two types of ligands have on the photophysical and electrochemical properties and also on the behavior of these materials as photosensitizers. The X-ray crystal structures of five complexes were determined. The complexes emitted in the blue-green region. It was expected that the frontier orbitals and thus the photophysical and electrochemical properties would be controlled by the main C^N ligands, and it was demonstrated that the effect of the modifications in the N^C: ligand, especially the presence of a nitro group in the pyridine ring or the interruption of conjugation between the two rings, also affected these properties. The quenching with O2 and photostability studies were also performed. Density functional theory calculations were used to explain the behavior of some derivatives. The complexes and other previously reported compounds were employed as photosensitizers (PS) in preliminary studies on the production of H2 from water using [Co(bpy)3]Cl2 (bpy = 2,2'-bipyridine) as catalyst and triethanolamine (TEOA) as the sacrificial reductant. The absence of quenching of the PS with TEOA allowed us to propose an oxidative quenching mechanism.

(1) H and (13) C NMR spectral assignment of N,N'-disubstituted thiourea and urea derivatives active against nitric oxide synthase.

The (1) H and (13) C NMR resonances of seventeen N-alkyl and aryl-N'-[3-hydroxy-3-(2-nitro-5-substitutedphenyl)propyl]-thioureas and ureas (1-17), and seventeen N-alkyl or aryl-N'-[3-(2-amino-5-substitutedphenyl)-3-hydroxypropyl]-thioureas and ureas (18-34), designed as NOS inhibitors, were assigned completely using the concerted application of one- and two-dimensional experiments (DEPT, HSQC and HMBC). NOESY studies confirm the preferred conformation of these compounds. Copyright © 2016 John Wiley & Sons, Ltd.

Quinazolinones, Quinazolinthiones, and Quinazolinimines as Nitric Oxide Synthase Inhibitors: Synthetic Study and Biological Evaluation.

The synthesis of different compounds with a quinazolinone, quinazolinthione, or quinazolinimine skeleton and their in vitro biological evaluation as inhibitors of inducible and neuronal nitric oxide synthase (iNOS and nNOS) isoforms are described. These derivatives were obtained from substituted 2-aminobenzylamines, using diverse cyclization procedures. Furthermore, the diamines were synthesized by two routes: A conventional pathway and an efficient one-pot synthesis in a continuous-flow hydrogenator. The structures of these heterocycles were confirmed by (1) H and (13) C nuclear magnetic resonance and high-resolution mass spectroscopy data. The structure-activity relationships of the target molecules are discussed in terms of the effects of both the R radical and the X heteroatom in the 2-position. In general, the assayed compounds behave as better iNOS than nNOS inhibitors, with the quinazolinone 11e being the most active inhibitor of all tested compounds and the most iNOS/nNOS selective one.

Transoral robotic surgery of the central skull base: preclinical investigations.

In this study we explored possible applications of the da Vinci system in approaching the skull base at optic chiasm level on two cryopreserved cadavers, using an entirely transoral robotic technique (TORS). We used a standard 12 mm endoscopy and 8 mm terminals. Bone drilling was performed manually. The da Vinci system is equipped with very good illumination and 3D viewing, thus providing excellent vision and great maneuverability even in the less accessible areas of the skull. Our experience demonstrates that an entirely transoral skull base robotic approach to this complex anatomical region has many advantages as compared to traditional techniques.

Statins use for primary prevention of cardiovascular disease: A population-based digitally enabled real-world evidence cross-sectional study in primary care in Brazil.

BACKGROUND: Statins are the main strategy to reduce dyslipidemia-related cardiovascular risk. Nevertheless, there is scarce evidence on the real-world statins use in primary care settings in low-middle-income countries. OBJECTIVE: We conducted a cross-sectional retrospective study using anonymized data routinely collected by community health workers in Brazil aimed to evaluate statin use and associated factors in a primary prevention population with cardiovascular risk enhancers. METHODS: Study population consisted of adults with hypertension, diabetes, and/or dyslipidemia. The primary and secondary outcomes were the proportion of individuals self-reporting statins use on any dose and high-dose statins/high-intensity lipid-lowering therapy (LLT), respectively. RESULTS: Of the 2,133,900 adult individuals in the database, 415,766 (19.5%) were included in the study cohort. From this cohort, 89.1% had hypertension, 28.9% diabetes, and 5.5% dyslipidemia. The mean age was 61.5 (standard deviation 14.5) years, 63.4% were female, and 61.0% were of mixed-race. Only 2.6% and 0.1% of individuals self-reported the use of statins and high-dose statins/high-intensity LLT, respectively. Older age (odds ratio [OR] 1.96; 95% confidence interval [CI] 1.88, 2.05, p < 0.001), living in the South region of Brazil (OR 4.39; 95% CI 3.97, 4.85, p < 0.001), heart failure (OR 2.60; 95% CI 2.33, 2.89, p < 0.001), chronic kidney disease (OR 1.49; 95% CI 1.35, 1.64, p < 0.001), and anti-hypertensive medications use (OR 4.38; 95% CI 4.07, 4.71, p < 0.001) were independently associated with statin use. CONCLUSION: In a real-world evidence study analyzing data routinely collected in a digitized primary care setting, we observed a very low use of statins in a primary prevention population with cardiovascular risk enhancers in Brazil. Socio-demographic factors and co-morbidities were associated with higher statins use rates.

Anticancer activity and DNA binding of a bifunctional Ru(II) arene aqua-complex with the 2,4-diamino-6-(2-pyridyl)-1,3,5-triazine ligand.

The synthesis and full characterization of the new aqua-complex [(η(6)-p-cymene)Ru(OH2)(κ(2)-N,N-2-pydaT)](BF4)2, [2](BF4)2, and the nucleobase derivative [(η(6)-p-cymene)Ru(9-MeG)(κ(2)-N,N-2-pydaT)](BF4)2, [4](PF6)2, where 2-pydaT = 2,4-diamino-6-(2-pyridyl)-1,3,5-triazine and 9-MeG = 9-methylguanine, are reported here. The crystal structures of both [4](PF6)2 and the chloro complex [(η(6)-p-cymene)RuCl(κ(2)-N,N-2-pydaT)](PF6), [1](PF6), have been elucidated by X-ray diffraction. The former provided relevant information regarding the interaction of the metallic fragment [(η(6)-p-cymene)Ru(κ(2)-N,N-2-pydaT)](2+) and a simple model of DNA. NMR and kinetic absorbance studies have proven that the aqua-complex [2](BF4)2 binds to the N7 site of guanine in nucleobases, nucleotides, or DNA. A stable bifunctional interaction (covalent and partially intercalated) between the [(η(6)-p-cymene)Ru(κ(2)-N,N-2-pydaT)](2+) fragment and CT-DNA has been corroborated by kinetic, circular dichroism, viscometry, and thermal denaturation experiments. The reaction mechanism entails the very fast formation of the Ru-O-(PO3) linkage prior to the fast intercalation of the 2-pydaT fragment. Then, a Ru-N7-(G) covalent bond is formed at the expense of the Ru-O-(PO3) bond, yielding a bifunctional complex. The dissociation rate of the intercalated fragment is slow, and this confers additional interest to [2](BF4)2 in view of the likely correlation between slow dissociation and biological activity, on the assumption that DNA is the only biotarget. Furthermore, [2](BF4)2 displays notable pH-dependent cytotoxic activity in human ovarian carcinoma cells (A2780, IC50 = 11.0 µM at pH = 7.4; IC50 = 6.58 µM at pH = 6.5). What is more, complex [2](BF4)2 is not cross-resistant with cisplatin, exhibiting a resistance factor, RF(A2780cis), of 0.28, and it shows moderate selectivity toward the cancer cell lines, in particular, A2780cis (IC50 = 3.0 5 ± 0.08 µM), relative to human lung fibroblast cells (MRC-5; IC50 = 24 µM), the model for healthy cells.

Synthesis and biological evaluation of 4,5-dihydro-1H-pyrazole derivatives as potential nNOS/iNOS selective inhibitors. Part 2: Influence of diverse substituents in both the phenyl moiety and the acyl group.

In a preliminary article, we reported a series of 4,5-dihydro-1H-pyrazole derivatives as neuronal nitric oxide synthase (nNOS) inhibitors. Here we present the data about the inhibition of inducible nitric oxide synthase (iNOS) of these compounds. In general, we can confirm that these pyrazoles are nNOS selective inhibitors. In addition, taking these compounds as a reference, we have designed and synthesized a series of new derivatives by modification of the heterocycle in 1-position, and by introduction of electron-donating or electron-withdrawing substituents in the aromatic ring. These derivatives have been evaluated as nNOS and iNOS inhibitors in order to identify new compounds with improved activity and selectivity. Compound 3r, with three methoxy electron-donating groups in the phenyl moiety, is the most potent nNOS inhibitor, showing good selectivity nNOS/iNOS.

Comparison of static and dynamic respirometry for the determination of stoichiometric and kinetic parameters of a nitrifying process.

Respirometry consists in the measurement of the biological oxygen consumption rate under well-defined conditions and has been used for the characterization of countless biological processes. In the field of biotechnology and applied microbiology, several respirometry methods are commonly used for the determination of process parameters. Dynamic and static respirometry, which are based on oxygen measurements with or without continuous aeration, respectively, are the methods most commonly used. Additionally to several respirometry methods, different methods have also been developed to retrieve process parameters from respirometric data. Among them, methods based on model fitting and methods based on the injection of substrate pulse at increasing concentration are commonly used. An important question is then; what respirometry and data interpretation methods should be preferably used? So far, and despite a growing interest for respirometry, relatively little attention has been paid on the comparison between the different methods available. In this work, both static and dynamic respirometry methods and both interpretation methods; model fitting and pulses of increasing concentration, were compared to characterize an autotrophic nitrification process. A total of 60 respirometry experiments were done and exhaustively analysed, including sensitivity and error analyses. According to the results obtained, the substrate affinity constant (K S ) was better determined by static respirometry with pulses of increasing concentration and the maximum oxygen uptake rate (OUR ex.max ) was better determined by dynamic respirometry coupled to fitting procedure. The best method for combined K S and OUR ex.max determination was static respirometry with pulses of increasing concentration.

Extruded flaxseed meal enhances the nutritional quality of cereal-based products.

Human consumption of flaxseed is increasing due to its health benefit properties and extrusion processes can enhance its nutritional quality. Extruded flaxseed meal (EFM) obtained in a pilot plant was characterized and incorporated in flour mixes and cereal-based bars to demonstrate its nutritious usefulness. Amino acid content was not affected by extrusion and, despite lysine was the limitating amino acid, the chemical score (CS) was 83 %. Thiamin and riboflavin decreased slightly as consequence of extrusion, phytic acid did not change and trypsin inhibitor activity was undetectable. Proximate composition and nutritional quality determined by biological and chemical indexes were compared among EFM, flour mixes (FM) and cereal bars (CB). They presented high protein levels (26, 20 and 17 %, respectively), good biological value (BV) (80, 79 and 65, respectively), acceptable true protein digestibility (TD) (73, 79 and 78, respectively), and high dietary fiber (33, 20.5 and 18 %, respectively). The ratio of ω6:ω3 for CB was within the WHO/FAO recommendations. These results open a new venue for the usefulsess of nutritious/healthy extruded flaxseed flours into ready-to-eat cereal-based products with improved nutritional quality.

[Drug treatment adjustment to the clinical guidelines in octagenarians with acute myocardial infarction]. / Ajuste del tratamiento farmacológico a las guías de práctica clínica en pacientes octogenarios con infarto agudo de miocardio.

OBJECTIVES: To determine whether there is a linear association of age and aspirin, betablockers, angiotensin-converting enzyme inhibitors and statins; the extent to which elderly patients receive these treatments; and whether age is independently associated with these treatments. DESIGN: A prospective cohort study. SETTING: Coronary Unit of two hospitals in the Region of Murcia (Spain). PATIENTS: Consecutive patients admitted with the diagnosis of acute myocardial infarction between January 1998 and January 2008. INTERVENTIONS: None. MAIN OUTCOMES: Those related to the administration of aspirin, betablockers, angiotensin-converting enzyme inhibitors and statins during stay in the Coronary Care Unit. RESULTS: Regarding the remaining patients, octogenarians received a similar proportion of angiotensin-converting enzyme inhibitors (70.8% vs. 69.3%, p=0.41) and less often aspirin (90.4% vs. 94.6%, p<0.001), betablockers (44.4% vs. 69.4%, p<0,001) and statins (47.6% vs. 64.7%, p<0.001). We were only able to demonstrate an abrupt and significant decrease in the use of statins after 80 years of age. Patient age was independently associated with the use of betablockers (OR 0.59; 95%CI 0.47 - 0.73) and statins (OR 0.78; 95%CI 0.65 - 0.95). The lesser administration of these drugs was also associated with early mortality (OR 0.17, 95%CI 0.09 to 0.33 and OR 0.14; 95%CI 0.08 to 0.23, respectively). CONCLUSIONS: Octogenarians less often receive aspirin, betablockers and statins, though old age was not an independent factor associated with lesser aspirin use.

Microcapsules of Sacha Inchi seed oil (Plukenetia volubilis L.) obtained by spray drying as a potential ingredient to formulate functional foods.

Sacha Inchi seed oil (SIO) is rich in omega 3, 6, and 9 fatty acids with important health benefits, but is temperature sensitive. Spray drying is a technology that improves the long-term stability of bioactive compounds. This work aimed to study the effect of three different homogenization techniques on some physical properties and bioavailability of microcapsules of Sacha Inchi seed oil (SIO) emulsions obtained by spray drying. Emulsions were formulated with SIO (5%, w/w), maltodextrin:sodium caseinate as wall material (10%, w/w; 85:15), Tween 20 (1%, w/w) and Span 80 (0.5%, w/w) as surfactants and water up to 100% (w/w). Emulsions were prepared using high-speed (Dispermat D-51580, 18,000 rpm, 10 min), conventional (Mixer K-MLIM50N01, Turbo speed, 5 min), and ultrasound probe (Sonics Materials VCX 750, 35% amplitude, 750 W, 30 min) homogenization. SIO microcapsules were obtained in a Mini Spray B-290 (Büchi) using two inlet temperatures of the drying air (150 and 170 °C). Moisture, density, dissolution rate, hygroscopicity, drying efficiency (EY), encapsulation efficiency (EE), loading capacity, and oil release in digestive fluids in vitro were studied. Results showed that the microcapsules obtained by spray-drying had low moisture values and high encapsulation yield and efficiency values (greater than 50% and 70%, respectively). The thermogravimetric analysis indicates that heat protection was assured, enhancing the shelf life and the ability to withstand thermal food processing. Results suggest that spray-drying encapsulation could be a suitable technology to successfully microencapsulate SIO and enhance the absorption of bioactive compounds in the intestine. This work highlights the use of Latin American biodiversity and spray drying technology to ensure the encapsulation of bioactive compounds. This technology represents an opportunity for the development of new functional foods, improving the safety and quality of conventional foods.

New amidine-benzenesulfonamides as iNOS inhibitors for the therapy of the triple negative breast cancer.

Triple negative breast cancer (TNBC) is a specific breast cancer subtype, and poor prognosis is associated to this tumour when it is in the metastatic form. The overexpression of the inducible Nitric Oxide Synthase (iNOS) is considered a predictor of poor outcome in TNBC patients, and this enzyme is reported as a valuable molecular target to compromise TNBC progression. In this work, new amidines containing a benzenesulfonamide group were designed and synthesized as selective iNOS inhibitors. An in vitro biological evaluation was performed to assess compounds activity against both the inducible and constitutive NOSs. The most interesting compounds 1b and 2b were evaluated on MDA-MB-231 cells as antiproliferative agents, and 1b capability to counteract cell migration was also studied. Finally, an in-depth docking study was performed to shed light on the observed potency and selectivity of action of the most promising compounds.

New strategies to analyze argentatins A and B in guayule (Parthenium argentatum, A. Gray).

There is considerable interest in the exploitation of compounds belonging to the triterpenoid family from guayule (Parthenium argentatum, A. Gray), as they offer several beneficial effects to human health. The most abundant triterpenoids in guayule resin are the argentatins, which are currently analyzed by labor-intensive and time-consuming techniques. The purpose of the present study was to estimate argentatins and isoargentatins A and B in guayule using near-infrared spectroscopy (NIRS) and flow injection analysis (FIA). Results revealed that the best partial least squares regression model exhibited excellent correlation with the values estimated by NIRS calibration (r2c = 0.99-1.00) and cross-validation (r2cv = 0.94-0.99), and the residual predictive deviation was >3 in all cases. After optimization of the liquid chromatography-mass spectrometry and FIA parameters, the FIA mode could reliably collect data for argentatin A and B after applying a calculated coverage factor. In sum, NIRS and FIA appear to be a robust option for the estimation and routine analysis of argentatins in guayule stems and resin, respectively.