Synergistic Combination of NAPROC-13 and NMR 13C DFT Calculations: A Powerful Approach for Revising the Structure of Natural Products.

This article describes the structure revision of nine triterpenoids that have been reported corresponding to the same 13C NMR data set. In addition, 13C NMR calculation shows that some chemical shift assignments must be swapped. Our analysis improves the fit between the experimental and calculated data. Correcting misassigned structures and correctly assigning each signal is essential for elucidating new structurally related compounds. Furthermore, the ambiguity of several compounds, the structure of which differs in the literature and the Sci-Finder database, has been eliminated. Misassigned structures were found by chemical shift searches in NAPROC-13, and the results provide two or more different compounds with the same 13C NMR data. The process to determine the correct, most likely structural proposal in agreement with the experimental 13C NMR data was carried out by DFT calculations.

Academic stress, hair and saliva cortisol, and their relationship with body mass index and fat percentage in first year medical students.

Introduction: Although a large part of the population may be exposed to various pressures that can lead to mental or eating problems and increased perceived stress, the transition from adolescence to adulthood has been shown to be a crucial stage. Medical students are particularly vulnerable during the transition period as they must adapt to new circumstances, which may contribute to increased perceived stress. Cortisol plays an important role between stress, weight gain, and the development of obesity. We designed a study to investigate the association between stress, eating behaviour, cortisol, and body weight in a sample of first-year medical students. Methods: We determined 75 first-year medical students' hair and salivary cortisol concentrations by ELISA and related it to self-reported stress, eating behaviour, and anthropometric measurements throughout the academic period. The prevalence of overweight and obesity in females was 25% and 10%, and in males was 35% and 6%, respectively. We report an increase in hair cortisol, higher self-reported stress scores, and BMI mainly in females. Finally, we found evidence of positive associations between hair cortisol and BMI in females (r = 0.348) and males (r = 0.423). Conclusion: There is a low association between short-term single-point cortisol measures and long-term cortisol, mainly in males. Hence, short-term cortisol reactivity is moderately associated with long-term cortisol reactivity when both are evaluated simultaneously. These results support the previous evidence of positive associations between cortisol with body fat percentage and BMI, and finally, that eating behaviours are modified by academic stress perception, mainly in females.

Computational Structural Revision of Elaeophorbate and Other Triterpenoids with the Help of NAPROC-13. A New Strategy for Structural Revision of Natural Products.

A considerable number of natural products have been published in recent years with misassigned structure, even though they had been correctly elucidated in the past. The availability of databases containing revised structures can prevent the amplification of errors in structural elucidation. NAPROC-13, a dereplication tool based on the 13C chemical shift, has been used to search for substances that, possessing the same chemical shifts, have been described with different structures. The correct structure of these different structural proposals is verified by computational chemistry. This paper reports the structural revision of nine triterpenoids following this methodology.

Caracterización química y actividad biológica de las hojas y semillas de Chrysobalanus icaco L. (Icaco) / Chemical characterization and biological activity of leaves and seeds of Chrysobalanus icaco L. (icaco)

Introducción: Chrysobalanus icaco L. (Chrysobalanaceae) es un arbusto utilizado en la fitoterapia tradicional latinoamericana, pero en la provincia de Chiriquí se ha registrado el uso de su fruto para hacer conservas, no de forma medicinal. Objetivo: Caracterizar los metabolitos secundarios presentes en las hojas y semillas de Chrysobalanus icaco y evaluar su actividad biológica in vitro. Métodos: Los metabolitos secundarios presentes en los extractos de las hojas, semilla inmadura y madura de Chrysobalanus icaco, se detectaron a través de tamizaje fitoquímico y purificación por técnicas cromatográficas. Posteriormente se evaluó el contenido de polifenoles totales y la actividad antioxidante total de la infusión de las hojas, semillas y pulpa de esta especie, así como la actividad antibacteriana in vitro. Resultados: En las hojas se identificaron por tamizaje fitoquímico, flavonoides, glucósidos cardiotónicos, triterpenos y esteroides. Para la semilla inmadura se encontró presencia mayoritaria de mezclas de azucares, mientras que para la semilla madura se detectaron ácidos grasos en el endocarpio (almendra). Los datos de polifenoles totales en extractos de Icaco mostraron alto contenido de estos metabolitos en la infusión de hojas secas, y la inhibición del radical DPPH fue mayor también para las hojas secas de icaco, seguido de la infusión de semilla inmadura. Por otro lado, la infusión de hojas secas y el licuado de la pulpa fueron los que mostraron una mayor inhibición contra la cepa de Staphylococcus spp. en el ensayo de actividad antibacteriana. Conclusión: Las hojas secas de Chrysobalanus icaco mostraron alto contenido de polifenoles, asociado a su potencial actividad antioxidante y antibacteriana. Además, se aportaron nuevos datos de composición química de la semilla, se observó que los azúcares detectados inicialmente en la semilla inmadura se pierden considerablemente con la maduración del fruto.

Introduction: Chrysobalanus icaco L. (Chrysobalanaceae) is a shrub used in Latin American traditional phytotherapy, but in the province of Chiriquí its fruit has been reported to be used in food preserves, not for medicinal purposes. Objective: Characterize the secondary metabolites present in Chrysobalanus icaco leaves and seeds and evaluate their in vitro biological activity. Methods: The secondary metabolites present in extracts from leaves and immature and mature seeds of icaco were detected by phytochemical screening and purification with chromatographic techniques. Evaluation was then conducted of total polyphenolic content and total antioxidant activity of the leaf, seed and pulp infusion as well as its antibacterial activity in vitro. Results: Phytochemical screening of the leaves found flavonoids, cardiotonic glycosides, triterpenes and steroids. Sugar mixtures were the most abundant components in immature seeds, whereas fatty acids were found in the endocarp (almond) of mature seeds. Total polyphenolic data about icaco extracts showed high contents of these metabolites in the dry leaf infusion. DPPH radical inhibition was also greater for icaco dry leaves, followed by immature leaf infusion. The dry leaf infusion and the pulp shake displayed the greatest inhibition against the Staphylococcus spp. strain in the antibacterial activity test. Conclusion: Icaco dry leaves exhibited a high polyphenolic content, associated to their antioxidant and antibacterial activity. Fresh data were also contributed about the chemical composition of the seed. It was observed that the sugars initially detected in immature seeds are considerably lost as the fruit ripens.

Assessment of the antinociceptive and anti-inflammatory activities of the stem methanol extract of Diplotropis purpurea.

Context: Since there is still a great need to search for plant species with antinociceptive and anti-inflammatory activities, Diploptropis purpurea (Rich.) Amshoff (Fabaceae) is studied for the first time. Objective: This evaluates the analgesic and anti-inflammatory activities of the stem methanol extract of Diplotropis purpurea (MEDP). Material and methods: The anti-inflammatory and analgesic effects of MEDP of D. purpurea were evaluated in vivo. The antinociceptive activity was assessed in CD1 male mice were treated by oral gavage with 500 mg/kg of MEDP 30 min before submitting to acetic acid-induced abdominal writhing, hot-plate, and formalin tests. Paws oedema induced by carrageenan, histamine or serotonin were performed in male Sprague-Dawley rats to determinate the anti-inflammatory activity. Results: Oral administration of MEDP produced significant antinociceptive effects on the inflammatory phase in the formalin test [12.0 s versus 72.5 s in carboxymethyl cellulose (CMC) control group]. MEDP produced an analgesic effect in the hot-plate model, although the effect was modest compared to tramadol (40 and 60%, respectively). The oral administration of MEDP in a dose of 500 mg/kg showed maximum inhibition (75.1%) after 0.5 h in carrageenan-induced oedema, but it did not modify histamine or serotonin-induced oedemas. Discussion and conclusion: In the peripheral nociception model, acetic acid-induced abdominal writhing, the MEDP did not show a protective effect, but its analgesic effects were evident in the inflammatory phase of the formalin test and in the hot-plate model. These results show that the anti-inflammatory effect was accompanied by a reduction in the perception of painful stimuli.

Vasorelaxant effects in aortic rings of eight diterpenoids isolated from three Venezuelan plants

Vasorelaxant activity Vasorelaxant effects of eight diterpenoids isolated from three Venezuelan plants [(+)-manool [(+)-labda-8(17),14-dien-13-ol], (+)-manoyl oxide, (+)-2-oxomanoyl oxide, sandaracopimara-8(14), 15-dien-3β, 19-diol, jhanidiol acetate (18-acetoxy-1βhydroxymanoyl oxide), jhanidiol (1β,18-dihydroxymanoyl oxide), ent-kaur-16-en-19ol and grandiflorenic acid (ent-kaur-9(11),16-dien-19-oic acid)] aortic rings were assessed in intact endothelium and endothelium-denuded isolated rat. Thw cumulative addition (10-6 to 10-4 M) of each product were carried out after contraction with phenylephrine (10-6 M). Jhanidiol acetate and ent-kaur-9,16-en-19-oic acid at 10-4 M dose concentration, exhibit the maximal vasorelaxant effect in endothelium-intact rings (51.61 ± 7.62% and 79.27 ± 7.41%, respectively). In endothelium-denuded aortic rings, the maximum vascular response exerted by both compounds was not abolished (64.14 ± 5.64% and 84.84 ± 3.62%, respectively). In denuded aortic rings, the half-maximal inhibitory concentration (IC50) Jhanidiol was obtained by the ethyl less than those obtained in rings endothelium (1.09 × 10-4 vs 7.29 × 10-5 M, respectively), although this difference was not significant. These results suggested that the mechanism behind the vasorelaxant effect of the two diterpene is mediated by endothelium-independent pathways.

Vasoactive effects of different fractions from two Panamanians plants used in Amerindian traditional medicine.

ETHNOPHARMACOLOGICAL RELEVANCE: Cecropia obtusifolia (Cecropiaceae) and Psychotria poeppigiana (Synonym: Cephaelis elata, Rubiaceae) are two Latin American plants broadly used in traditional Amerindian medicine. The former, together with many other species of the genus Cecropia, share the folk reputation of curing heart failure, cough, asthma and bronchitis. The latter is used in Panama by Kuna and Ngäbe Buglé (Guaymies) native Indians for the treatment of dyspnea. AIM OF THE STUDY: Based on screening of selected medicinal Panamanian plants by radioligand-binding techniques by Caballero-George et al. (2001), the present study was carried out in order to investigate the vasoactive effects of different fractions from both P. poeppigiana and C. obtusifolia on rat thoracic aorta and identify active fractions and their chemical constituents. MATERIALS AND METHODS: Both acid and neutral methanol fractions (P-AMeOH and P-NMeOH) and acid and neutral dichlorometane fractions (P-ADCM and P-NDCM) were obtained from P. poeppigiana crude methanolic and dichlorometane extracts, respectively. Identical fractionation was carried out for C. obtusifolia (C-AMeOH, C-NMeOH, C-ADCM and C-NDCM. Vasorelaxant effect of all fractions, and their inhibition of contractile responses to angiotensin II were evaluated in isolated aortic rings. RESULTS: P-AMeOH, P-NMeOH and P-ADCM fractions induced a concentration-dependent relaxation (43.9+/-1.8%, 35.3+/-4.7% and 52.9+/-3.5%, respectively) in the endothelium-intact aorta precontracted by phenylephrine (PE, 10(-6)M). The relaxation produced by C-AMeOH and C-NMeOH (57.3+/-2.5% and 53.3+/-3.3%, respectively) was greater than the effect produced by C-ADCM and C-NDCM (42.2+/-3.4% and 21.8+/-0.8%, respectively). Only the incubation of the aortic rings with P-AMeOH reduced the maximum contraction induced by angiotensin II at 20.08+/-0.55%. CONCLUSIONS: The direct vasorelaxation effect observed could explain in part the ethnomedical use of these plants in Amerindian traditional medicine. The most active fractions contain phenolic and aromatic acid compounds. Furthermore, P-AMeOH, the only fraction that showed both vasorelaxant effect and inhibition of contractile responses to angiotensin II, is the most rich in aromatic acids compounds and the only one that contains scopoletin.

Vasorelaxant properties of acid and neutral fractions of Dimerocostus strobilaceus Kuntze used by Kuna Indians of Panama.

ETHNOPHARMACOLOGICAL RELEVANCE: Dimerocostus strobilaceus is used by the Kuna Indians of Panama for the treatment of hypertension and other cardiovascular diseases. AIM OF THE STUDY: We investigated the vascular effects of acid and neutral fractions obtained from methanol and dichloromethane extracts of Dimerocostus strobilaceus. MATERIALS AND METHODS: The acid and neutral methanol fractions (A-MeOH and N-MeOH) or acid and neutral dichlorometanic fractions (A-DCM and N-DCM) were tested using isolated rat aortic rings with or without endothelium pre-contracted by phenylephrine. We examined the ability of these different fractions at different concentrations to modify vascular responses induced by angiotensin II using endothelium-denuded aortic rings from Spontaneously Hypertensive Rats (SHR). RESULTS: In aortic rings with intact endothelium A-MeOH, N-MeOH and A-DCM fractions produced a concentration-dependent vasorelaxation (62.4 +/- 5.2, 64.5 +/- 5.0 and 63.7 +/- 5.0%, respectively), whereas the N-DCM fraction did not produce any vasorelaxant effect. Maximal relaxation evocated by vasoactive fractions was substantially inhibited on aortic rings without endothelium.Our study demonstrates that A-MeOH, N-MeOH, A-DCM and N-DCM significantly reduce contractile responses induced by angiotensin-II on aortic rings. CONCLUSIONS: Our findings may contribute to a better understanding of the potential link between vascular properties observed with Dimerocostus strobilaceus and their ethnobotanical use.