Determination of l-(+)-bornesitol, the hypotensive constituent of Hancornia speciosa, in rat plasma by LC-MS/MS and its application on a pharmacokinetic study

Improving the Accuracy of Permeability Data to Gain Predictive Power: Assessing Sources of Variability in Assays Using Cell Monolayers

The ability to predict the rate of permeation of new compounds across biological membranes is of high importance for their success as drugs, as it determines their efficacy, pharmacokinetics, and safety profile. In vitro permeability assays using Caco-2 monolayers are commonly employed to assess permeability across the intestinal epithelium, with an extensive number of apparent permeability coefficient (Papp) values available in the literature and a significant fraction collected in databases. The compilation of these Papp values for large datasets allows for the application of artificial intelligence tools for establishing quantitative structure-permeability relationships (QSPRs) to predict the permeability of new compounds from their structural properties. One of the main challenges that hinders the development of accurate predictions is the existence of multiple Papp values for the same compound, mostly caused by differences in the experimental protocols employed. This review addresses the magnitude of the variability within and between laboratories to interpret its impact on QSPR modelling, systematically and quantitatively assessing the most common sources of variability. This review emphasizes the importance of compiling consistent Papp data and suggests strategies that may be used to obtain such data, contributing to the establishment of robust QSPRs with enhanced predictive power.

Definition of chemical markers for Hancornia speciosa Gomes by chemometric analysis based on the chemical composition of extracts, their vasorelaxant effect and α-glucosidase inhibition

ETHNOPHARMACOLOGICAL RELEVANCE

Hancornia speciosa Gomes (Apocynaceae) is a tree found in the Brazilian savannah, traditionally used to treat several diseases, including diabetes and hypertension. The anti-hypertensive activity of H. speciosa leaves (HSL) has been demonstrated in different models and is credited to the vasodilator effect and ACE (angiotensin-converting enzyme) inhibition. The hypoglycemic effect of HSL has been also reported.

AIM OF THE STUDY

To establish correlations between the biological activities elicited by H. speciosa extracts and the contents of their major compounds, aiming to define chemical markers related to the potential antihypertensive and antidiabetic effects of the species. Additionally, it aimed to isolate and characterize the chemical structure of a marker related to the α-glucosidase inhibitory effect.

MATERIALS AND METHODS

Extracts of a single batch of H. speciosa leaves were prepared by extraction with distinct solvents (ethanol/water in different proportions; methanol/ethyl acetate), employing percolation or static maceration as extraction techniques, at different time intervals. The contents of chlorogenic acid, rutin and FlavHS (a tri-O-glycoside of quercetin) were quantified by a developed and validated HPLC-PDA method. Bornesitol was determined by HPLC-PDA after derivatization with tosyl chloride, whereas total flavonoids were measured spectrophotometrically. Identification of other constituents in the extracts was performed by UPLC-DAD-ESI-MS/MS analysis. The vasorelaxant activity was assayed in rat aortic rings precontracted with phenylephrine, and α-glucosidase inhibition was tested in vitro. Principal component analysis (PCA) was employed to evaluate the contribution of each marker to the biological responses. Isolation of compound 1 was carried out by column chromatography and structure characterization was accomplished by NMR and UPLC-DAD-ESI-MS/MS analyses.

RESULTS

The contents of the chemical markers (mean ± s.d. % w/w) varied significantly among the extracts, including total flavonoids (2.68 ± 0.14 to 5.28 ± 0.29), bornesitol (5.11 ± 0.26 to 7.75 ± 0.78), rutin (1.46 ± 0.06 to 1.97 ± 0.02), FlavHS (0.72 ± 0.05 to 0.94 ± 0.14) and chlorogenic acid (0.67 ± 0.09 to 0.91 ± 0.02). All extracts elicited vasorelaxant effect (pIC₅₀ between 4.97 ± 0.22 to 6.48 ± 0.10) and α-glucosidase inhibition (pIC₅₀ between 3.49 ± 0.21 to 4.03 ± 0.10). PCA disclosed positive correlations between the vasorelaxant effect and the contents of chlorogenic acid, rutin, total flavonoids, and FlavHS, whereas a negative correlation was found with bornesitol concentration. No significant correlation between α-glucosidase inhibition and the contents of the above-mentioned compounds was found. On the other hand, PCA carried out with the areas of the ten major peaks from the chromatograms disclosed positive correlations between a peak ascribed to co-eluted triterpenes and α-glucosidase inhibition. A triterpene was isolated and identified as 3-O-β-(3'-R-hydroxy)-hexadecanoil-lupeol.

CONCLUSION

According to PCA results, the vasorelaxant activity of H. speciosa extracts is related to flavonoids and chlorogenic acid, whereas the α-glucosidase inhibition is associated with lipophilic compounds, including esters of lupeol like 3-O-β-(3'-R-hydroxy)-hexadecanoil-lupeol, described for the first time for the species. These compounds can be selected as chemical markers for the quality control of H. speciosa plant drug and derived extracts.

Pharmacokinetics of Myo-Inositol in a Wistar Rat Animal Model

Myo-inositol is the most popular inositol in living organisms, where it is present as a sugar alcohol, in a free form, and can also be described as a lipid. The aim of this study was to check the concentration change of a myo-inositol solution from the time of oral administration and over a 48 h period in Wistar-type rats. All rats received 2 g/kg of inositol as a solution in distilled water by oral gavage. Estimated parameters were based on the serum concentration of myo-inositol observed in nine individual rats with regard to time. Observations were described as a one-compartment pharmacokinetic model with first-order absorption and zero-order endogenous input of checked inositol. The highest myo-inositol concentration was observed in the first hour after oral administration in the serum of all tested rats. Then, the concentration began decreasing immediately after the maximal peak. The inositol concentration continued to decrease, but after 24 h its level was still higher than before the administration. The plasma profile of the myo-inositol concentration showed a rapid decline over time, possibly due to the metabolism of this compound.

Pharmaceutical, food potential, and molecular data of Hancornia speciosa Gomes: a systematic review

Hancornia speciosa Gomes is a fruit and medicinal tree species native to South America, which in Brazil is considered of potential economic value and priority for research and development. We present a map of the state-of-art, including articles, patents, and molecular data of the species to identify perspectives for future research. The annual scientific production, intellectual, social, and conceptual structure were evaluated, along with the number of patent deposits, components of the plant used, countries of deposit, international classification and assignees, and the accessibility of available molecular data. Brazil has the most significant publications (306) between 1992 and 2020. Technological products (29) have been developed from different tissues of the plant. Most of the articles and patents were developed by researchers from public universities from different regions of Brazil. The molecular data are sequences of nucleotides (164) and proteins (236) of the chloroplast genome and are described to identify the species as DNA barcodes and proteins involved in photosynthesis. The compilation and report of scientific, technological, and molecular information in the present review allowed the identification of new perspectives of research to be developed based on the gaps in knowledge regarding the species and perspectives for the definition of future research.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s10722-021-01319-w.

Paving New Roads Towards Biodiversity-Based Drug Development in Brazil: Lessons from the Past and Future Perspectives

Although Brazil gathers two fundamental features to occupy a leading position on the development of biodiversity-based medicines, the largest flora on earth and a broad tradition on the use of medicinal plants, the number of products derived from the national genetic heritage is so far modest, either as single drugs or as herbal medicines. This article highlights some aspects that may have contributed to the low rates of success and proposes new insights for innovation. We initially approach the use of medicinal plants in Brazil, molded by its ethnic diversity, and the development of the local pharmaceutical industry. A discussion of some governmental initiatives to support plant-based drug development is then presented. Employing the economic concept of “middle-income trap,” we further propose that Brazil is stuck in a “middle-level science trap,” since the increase in the number of scientific publications that launched the country to an intermediate publishing position has not been translated into drug development. Two new approaches to escape from this trap are presented, which may result in innovative drug development. The first is based on the exploitation of the antifragility properties of herbal products aiming to investigate non-canonical pharmacodynamics mechanisms of action, aligned with the concepts of system biology. The second is the manufacture of herbal products based on the circular economy principles, including the use of byproducts for the development of new therapeutical agents. The adoption of these strategies may result in innovative phytomedicines, with global competitiveness.

The development and validation of a sensitive HPLC-MS/MS method for the quantitative and pharmacokinetic study of the seven components of Buddleja lindleyana Fort

Buddleja lindleyana Fort., a traditional Chinese medicine, has demonstrated anti-inflammatory, immunomodulatory, antidementia, neuroprotective, antibacterial, and antioxidant effects. Its flowers, leaves, and roots have been used as traditional Chinese medicines. A simple and rapid high-performance liquid chromatography method coupled with mass spectrometry (HPLC-MS/MS) was applied in the multicomponent determination of Buddleja lindleyana Fort., and the discrepancies in the contents from ten different habitats were analyzed. The present study simultaneously determined the concentrations of seven chemical compounds of Buddleja lindleyana Fort. extract in rat plasma via HPLC-MS/MS, which was applied in the pharmacokinetic (PK) study of Buddleja lindleyana Fort. A C18 column was used for chromatographic separation, and ion acquisition was achieved by multiple-reaction monitoring (MRM) in negative ionization mode. The optimized mass transition ion-pairs (m/z) for quantization were 591.5/282.8 for linarin, 609.4/300.2 for rutin, 284.9/133.0 for luteolin, 300.6/151.0 for quercetin, 268.8/116.9 for apigenin, 283.0/267.9 for acacetin, 623.3/160.7 for acteoside, and 252.2/155.8 for sulfamethoxazole (IS). A double peak appeared in the drug–time curve of apigenin, which was associated with entero-hepatic recirculation. There were discrepancies in the contents of seven chemical compounds from 10 batches of Buddleja lindleyana Fort., which were associated with the growth environments. Herein, the pharmacokinetic parameters of seven analytes in Buddleja lindleyana Fort. extract are summarized. The maximum plasma concentration (C_max) of linarin, rutin, luteolin, quercetin, apigenin, acacetin and acteoside were 894.12 ± 9.34 ng mL⁻¹, 130.76 ± 18.33 ng mL⁻¹, 77.37 ± 25.72 ng mL⁻¹, 20.15 ± 24.85 ng mL⁻¹, 146.42 ± 14.88 ng mL⁻¹, 31.92 ± 17.58 ng mL⁻¹, and 649.78 ± 16.42 ng mL⁻¹, respectively. The time to reach C_max for linarin, rutin, luteolin, quercetin, apigenin, acacetin, and acteoside were 10, 5, 5, 5, 180, 10 and 10 min, respectively. This is the first report on the simultaneous determination of seven active components for 10 different growing environments and the pharmacokinetic studies of seven active components in rat plasma after the oral administration of Buddleja lindleyana Fort. extract. This study lays the foundation for a better understanding of the absorption mechanism of Buddleja lindleyana Fort., and the evaluation of its clinical application.

Quality control and pharmacokinetics of Buddleja lindleyana Fort by HPLC-MS/MS.

Microscopic Analysis Applied to the Quality Control of Hancornia speciosa Gomes

Hancornia speciosa Gomes is popularly known as mangabeira and occurs throughout Brazil. It belongs to the Apocynaceae family and is very important for its food and medicinal uses. The objective of this study was to perform the anatomical and histochemical characterization of the leaves of H. speciosa. Microscope slides were made containing cross sections of petiole and leaf blade, as well as paradermic sections of the leaf blade. The analyses were performed under light and polarized microscopy. For the histochemical analysis, different reagents were used, according to the targeted metabolite. Through microscopic analysis, it was possible to identify the anatomical structures that provide the detailed diagnosis of the studied species. Through histochemistry, the presence of phenolic compounds, tannins, alkaloids, triterpenes and steroids, lipophilic compounds, lignin, starch, and calcium oxalate crystals was evidenced in the leaf blade. Thus, the results presented contribute to the quality control of H. speciosa, as well as to bring unpublished data about the species and to increase knowledge about the Apocynaceae family.