Bioassay-guided identification of antithrombotic compounds from Cnidoscolus aconitifolius (Mill.) I. M. Jhonst.: molecular docking, bioavailability, and toxicity prediction.

Cardiovascular diseases (CVDs) are the leading cause of death worldwide. Conventional antithrombotic therapy has reported hemorrhagic accidents. Ethnobotanical and scientific reports point to Cnidoscolus aconitifolius as an antithrombotic adjuvant. Previously, C. aconitifolius leaves ethanolic extract displayed antiplatelet, anticoagulant, and fibrinolytic activities. This work aimed to identify compounds from C. aconitifolius with in vitro antithrombotic activity through a bioassay-guided study. Antiplatelet, anticoagulant, and fibrinolytic tests guided the fractionation. Ethanolic extract was subjected to a liquid-liquid partitioning, followed by vacuum liquid, and size exclusion chromatography to obtain the bioactive JP10B fraction. The compounds were identified through UHPLC-QTOF-MS, and their molecular docking, bioavailability, and toxicological parameters were determined computationally. Kaempferol-3-O-glucorhamnoside and 15(S)-HPETE were identified; both showed affinity for antithrombotic targets, low absorption, and safety for human consumption. Further in vitro and in vivo evaluations will better understand their antithrombotic mechanism. This bioassay-guided fractionation demonstrated that C. aconitifolius ethanolic extract has antithrombotic compounds.Communicated by Ramaswamy H. Sarma.

Using 13 C-NMR dereplication to aid in the identification of xanthones present in the stem bark extract of Calophyllum brasiliense.

INTRODUCTION: Xanthones are metabolites with a variety of biological properties. The Clusiaceae family, which until recently included the genus Calophyllum, is recognised for its production of monohydroxylated and polyhydroxylated xanthones. Presently, C. brasiliense is the only Calophyllum spp. known to occur in the Yucatan peninsula. OBJECTIVE: To use a combination of traditional phytochemical methods and carbon-13 nuclear magnetic resonance (13 C-NMR) dereplication analysis to identify xanthones in the stem bark of C. brasiliense. MATERIAL AND METHODS: Initial fractionation and purification of the stem bark extract of C. brasiliense produced macluraxanthone (1). Additional xanthones, together with chromanones and terpenoids, were identified using 13 C-NMR dereplication analysis in different semipurified fractions obtained from the low and medium polarity fractions of the stem bark extract of C. brasiliense. RESULTS: Initial identification of macluraxanthone (1) was confirmed by 13 C-NMR dereplication analysis; additionally, 13 C-NMR dereplication analysis allowed the identification of a number of monohydroxylated and polyhydroxylated xanthones, together with chromanones and terpenoids. CONCLUSION: This study confirms C. brasiliense as a rich source of xanthones and the 13 C-NMR dereplication analysis as a suitable method to quickly identify the presence of different families of secondary metabolites in semipurified fractions.

Bioactive dicaffeoylquinic acid derivatives from the root extract of Calea urticifolia

ABSTRACT Calea urticifolia (Mill.) DC., Asteraceae, is a native plant of the Yucatan Peninsula used in traditional medicine to treat inflammation and pain. The bioassay-guided purification of the ethanol root extract allowed the isolation of the main bioactive metabolites, which were identified as an inseparable mixture of thymol (1) and 3-methyl-4-isopropylphenol (2), together with 3,4-O-dicaffeoylquinic acid methyl ester (3), 3,4-O-dicaffeoyl-epi-quinic acid methyl ester (4), 3,5-O-dicaffeoyl-epi-quinic acid methyl ester (5) and 3,5-O-dicaffeoylquinic acid (6). The results showed that the analgesic activity detected in the root extract of C. urticifolia could be attributed mainly to the mixture of 1 and 2 and to the novel 3,4-O-dicaffeoyl-epi-quinic acid methyl ester (4). Alternatively, the similarity on the antiinflammatory and antioxidant activities of the dicaffeoylquinic acid derivatives 3-5 suggests that the former might be related to their ability as radical scavengers.

Effects of polyphenol removal methods on the in vitro exsheathment inhibitory activity of Lysiloma latisiliquum extracts against Haemonchus contortus larvae.

It has been suggested that the anthelmintic (AH) activity of tannin-rich forages is related to their tannin content. However, reports on tropical fodders such as Lysiloma latisiliquum describe the same AH activity after the addition of tannin-blocking agents, suggesting that the activity either depends on the method of tannin blocking/removal or is due to other type of secondary metabolites. This study compared both the effect of the drying process of the plant material and the effect of different polyphenol removal methods on the AH activity of L. latisiliquum acetone-water extracts when tested against Haemonchus contortus. The results showed that the extraction of oven-dried (OD) leaves of L. latisiliquum yielded a CT-free extract with high AH activity. However, polyphenol-free fractions showed similar or lower AH activity levels as of those original OD extract. HPLC analysis confirmed that common polyphenolic metabolites are not responsible for the AH activity of L. latisiliquum.

Anti-Advanced Glycation End-product and Free Radical Scavenging Activity of Plants from the Yucatecan Flora.

BACKGROUND: Formation and accumulation of advanced glycation end-products (AGE) is recognized as a major pathogenic process in diabetic complications, atherosclerosis and cardiovascular diseases. In addition, reactive oxygen species and free radicals have also been reported to participate in AGE formation and in cell damage. Natural products with antioxidant and antiAGE activity have great therapeutic potential in the treatment of diabetes, hypertension and related complications. Objective: to test ethanolic extracts and aqueous-traditional preparations of plants used to treat diabetes, hypertension and obesity in Yucatecan traditional medicine for their anti-AGE and free radical scavenging activities. MATERIALS AND METHODS: ethanolic extracts of leaves, stems and roots of nine medicinal plants, together with their traditional preparations, were prepared and tested for their anti-AGE and antioxidant activities using the inhibition of advanced glycation end products and DPPH radical scavenging assays, respectively. RESULTS: the root extract of C. fistula (IC50= 0.1 mg/mL) and the leaf extract of P. auritum (IC50= 0.35 mg/mL) presented significant activity against vesperlysine and pentosidine-like AGE. Although none of the aqueous traditional preparations showed significant activity in the anti-AGE assay, both the traditional preparations and the ethanolic extracts of E. tinifolia, M. zapota, O. campechianum and P. auritum showed significant activity in the DPPH reduction assay. CONCLUSIONS: the results suggest that the metabolites responsible for the detected radical-scavenging activity are different to those involved in inhibiting AGE formation; however, the extracts with antioxidant activity may contain other metabolites which are able to prevent AGE formation through a different mechanism. SUMMARY: Ethanolic extracts from nine plants used to treat diabetes, hypertension and obesity in Yucatecan traditional medicine were tested for their anti-AGE and free radical scavenging activities.Significant activity against vesperlysine and pentosidine-like AGE was detected in the root extract of Cassia fistula and the leaf extract of Piper auritum.Traditional preparations and the ethanolic extracts of Ehretia tinifolia, Manilkara zapota, Ocimum campechianum and Piper auritum showed significant activity in the DPPH reduction assay.Results suggest that the metabolites responsible for the detected radical-scavenging activity are different to those involved in inhibiting AGE formation. Abbreviations Used: AGE: Advanced glycation end-product; DPPH: 2,2-Diphenyl-1-picrylhydrazyl; DM: Diabetes mellitus; ROS: Reactive oxygen species; BSA: Bovine serum albumin; EtOH: Ethanol; EtOAc: Ethyl acetate; ANOVA: Analysis of variance; BA: Brosimum alicastrum; BS: Bunchosia swartziana; CF: Cassia fistula; CN: Cocos nucifera; ET: Ehretia tinifolia; MZ: Manilkara zapota; OC: Ocimum campechianum; PA: Piper auritum; RM: Rhizophora mangle; L: Leaves; S: Stems; R: Roots; T: traditional preparation; I: Inflorescences; W: Water.

Spatio-Temporal Variation of Terpenoids in Wild Plants of Pentalinon andrieuxii.

Pentalinon andrieuxii (Müll.Arg.) B.F.Hansen & Wunderlin (Apocynaceae) is a vine native to the Yucatan peninsula, where it is widely used in Mayan traditional medicine to treat, among other ailments, the wounds caused by cutaneous leishmaniasis. Among the secondary metabolites isolated from P. andrieuxii are the triterpene betulinic acid and the chemically unusual tri-norsesquiterpene urechitol A; however, to date, there is no existing knowledge about the accumulation dynamics of the ubiquitous betulinic acid or the novel urechitol A in the plant. In this article, we report on the accumulation of both secondary metabolites in wild individuals of P. andrieuxii; our results show that while the content of betulinic acid in plant leaves bears no apparent relation to plant ontogeny, the content of urechitol A in root tissue is clearly related to plant development.

Chemometrics-enhanced high performance liquid chromatography-ultraviolet detection of bioactive metabolites from phytochemically unknown plants.

This work describes the use of Colubrina greggii as a model to investigate the use of chemometric analysis combined with data from a leishmanicidal bioassay, using Principal Component Analysis (PCA) and Orthogonal Projections to Latent Structures (O-PLS), to detect biologically active natural products in crude extracts from plants having little or no phytochemical information. A first analysis of the HPLC-UV profiles of the extract and its semi-purified fractions using both Principal Component Analysis (PCA) and Orthogonal Partial Least Squares (O-PLS) indicated that the components at tR 48.2, 48.7, 51.8min correlated with the variation in bioactivity. However, a further O-PLS analysis of the HPLC-UV profiles of fractions obtained through a final semi-preparative HPLC purification showed two components at tR 48.7 and 49.5min which correlated with the variation of the bioactivity in a high performance predictive model, with high determination coefficient, high correlation coefficient values (R(2) and Q(2)=0.99) and a low root mean square error (RMSE=0.018). This study demonstrates that the association of chemometric analysis with bioassay results can be an excellent strategy for the detection and isolation of bioactive metabolites from phytochemically unknown plant crude extracts.

Salvinorin A content in legal high products of Salvia divinorum sold in Mexico.

Salvia divinorum (Lamiaceae) is a herb native to Mexico where it is used by Mazatec shamans for spiritual and divination purposes. S. divinorum products are easily available to consumers and are used worldwide as legal highs because of the hallucinogenic effects caused mainly by salvinorin A. Highly popular videos and websites on the internet depicting the use of S. divinorum products have contributed to an increase in their consumption. Recent reports have highlighted the potential of these products to induce psychosis in consumers. In Mexico, dried leaf extracts of S. divinorum are sold in different strengths, claiming to correlate with increasing amounts of salvinorin A. In order to determine the variability of salvinorin A content between brands and to investigate possible correlation between brand strengths, this study sought to quantify salvinorin A in commercial products available in Mexico using an HPLC method. The HPLC analytical method showed a correlation coefficient R(2)>0.99, with LOD of 0.44 µg/mL and LOQ of 1.34 µg/mL. The retention time for salvinorin A was 23.09±0.95 min and the measured concentrations ranged between 8.32±0.65 and 56.52±3.77 mg/g dried leaf. The results for brand c did not show an agreement between the declared and the calculated amount of salvinorin A. Additionally, the emergence in Mexico of high strength salvia products (100×), the lack of regulation and the observed variability of salvinorin A content between brands of commercial legal highs products of S. divinorum could result in a health problem for consumers.

Isotopologue profiling of triterpene formation under physiological conditions. Biosynthesis of lupeol-3-(3'-R-hydroxy)-stearate in Pentalinon andrieuxii.

The biosynthesis of lupeol-3-(3'R-hydroxy)-stearate (procrim b, 1) was investigated in the Mexican medicinal plant Pentalinon andrieuxii by (13)CO2 pulse-chase experiments. NMR analyses revealed positional enrichments of (13)C2-isotopologues in both the triterpenoid and the hydroxystearate moieties of 1. Five of the six isoprene units reflected a pattern with [1,2-(13)C2]- and [3,5-(13)C2]-isotopologues from the respective C5-precursors, IPP and DMAPP, whereas one isoprene unit in the ring E of 1 showed only the [3,5-(13)C2]-connectivity of the original C5-precursor, due to rearrangement of the dammarenyl cation intermediate during the cyclization process. The presence of (13)C2-isotopologues was indicative of [(13)C2]acetyl-CoA being the precursor units in the formation of the fatty acid moiety and of the triterpene via the mevalonate route. The observed labeling pattern was in agreement with a chair-chair-chair-boat conformation of the (S)-2,3-oxidosqualene precursor during the cyclization process, suggesting that the lupeol synthase from P. andrieuxii is of the same type as that from Olea europea and Taraxacum officinale, but different from that of Arabidopsis thaliana. The study shows that (13)CO2 pulse-chase experiments are powerful in elucidating, under in vivo conditions and in a single experiment, the biosynthesis of complex plant products including higher terpenes.

Bioactive metabolites from Cnidoscolus souzae and Acmella pilosa.

The bioassay-guided purification of the ethanol extracts of Acmella pilosa and Cnidoscolus souzae, two plants of the native flora of the Yucatan Peninsula used in traditional medicine to treat inflammation and pain, resulted in the identification of rosmarinic acid (1) and caffeic acid (2) as the bioactive metabolites from A. pilosa, and of 7-deoxynimbidiol (4) as the major bioactive metabolite from C. souzae. Metabolites 1, 2, and 4 proved to be responsible for the antioxidant activity originally detected in the corresponding organic crude extracts; 7-deoxynimbidiol (4) showed good analgesic and anti-inflammatory activities, inhibiting the pain induced by PGE2 and reducing the edema induced by carrageenan, respectively.

Synergistic Effect of Lupenone and Caryophyllene Oxide against Trypanosoma cruzi.

The in vitro trypanocidal activity of a 1 : 4 mixture of lupenone and caryophyllene oxide confirmed a synergistic effect of the terpenoids against epimastigotes forms of T. cruzi (IC50 = 10.4 µ g/mL, FIC = 0.46). In addition, testing of the terpenoid mixture for its capacity to reduce the number of amastigote nests in cardiac tissue and skeletal muscle of infected mice showed a reduction of more than 80% at a dose level of 20.8 mg·kg(-1)·day(-1).

Metabolites from the leaf extract of Serjania yucatanensis with trypanocidal activity against Trypanosoma cruzi.

The bioassay-guided phytochemical investigation of the leaf extract of Serjania yucatanensis, a woody climbing plant endemic to the Yucatan peninsula, led to the identification of a mixture of a triterpene [lup-20(29)-en-3-one] and an oxygenated sesquiterpene (ß-caryophyllene oxide), as that responsible for the originally detected trypanocidal activity in the organic crude extract. Results showed that the mixture of lup-20(29)-en-3-one and ß-caryophyllene oxide is active against trypomastigotes of Trypanosoma cruzi (IC(50) =80.3 µg/mL) and inhibits the egress of trypomastigotes from infected Vero cells (when tested at 100 µg/mL) without being cytotoxic.

In vitro and in vivo trypanocidal activity of native plants from the Yucatan Peninsula.

Ethanol extracts of Senna villosa, Serjania yucatanensis, Byrsonima bucidaefolia, and Bourreria pulchra were evaluated for their in vitro activity against epimastigotes and trypomastigotes of Trypanosoma cruzi. Results showed that the leaf extracts of S. yucatanensis and B. pulchra were the most active against epimastigotes (IC(100) = 100 µg/mL) and trypomastigotes of T. cruzi (95% or more reduction in the number of parasites at 100 and 50 µg/mL). However, only the leaf extract of S. yucatanensis showed significant trypanocidal activity when tested in vivo, reducing 75% of the parasitemia in infected mice at 100 mg/kg. This same extract inhibited the egress of trypomastigotes from infected cells and proved not to be cytotoxic (IC(50) = 318.8 ± 2.3 µg/mL).

Antioxidants from the leaf extract of Byrsonima bucidaefolia.

The radical scavenging assay-guided fractionation of the leaf extract of Byrsonima bucidaefolia Standl. yielded two metabolites with antioxidant activity, identified as methyl gallate (1) and methyl m-trigallate (2) on the basis of their spectroscopic data. Both 1 and 2 were identified as artifacts of the extraction and/or the purification process, possibly resulting from transesterification of precursor gallotannins. Evaluation of the antioxidant activity of both the isolated metabolites 1 and 2 and three of their derivatives (3-5), showed that 1 and 2 have a stronger antioxidant activity than vitamin C when tested using the DPPH reduction assay.