Xanthones, as some of the most active components and widely distributed in various herb medicines, have drawn more and more attention in recent years. So far, 168 species of herbal plants belong to 58 genera, 24 families have been reported to contain xanthones. Among them, Calophyllum, Cratoxylum, Cudrania, Garcinia, Gentiana, Hypericum and Swertia genera are plant resources with great development prospect. This paper summarizes the plant resources, bioactivity and the structure-activity relationships (SARs) of xanthones from references published over the last few decades, which may be useful for new drug research and development on xanthones.

https://www.mdpi.com/1420-3049/22/10/1698/pdf

Chemical and Biological Research on Herbal Medicines Rich in Xanthones

Terpenes are one of the most abundant classes of secondary metabolites produced by plants and can be divided based on the number of isoprene units (C5) in monoterpenes (2 units—C10), sesquiterpenes (3 units—C15), diterpenes (4 units—C20), triterpenes (6 units—C30), etc. Chemically, triterpenes are classified based on their structural skeleton including lanostanes, euphanes, cycloartanes, ursanes, oleananes, lupanes, tirucallanes, cucurbitanes, dammaranes, baccharanes, friedelanes, hopanes, serratanes etc. Additionally, glycosylated (saponins) or highly oxidated/degraded (limonoids) triterpenes could be found in nature. The antiinflammatory effect and action as immunomodulators of these secondary metabolites have been demonstrated in different studies. This review reports an overview of articles published in the last 15 years (from 2006 to 2021 using PubMed and SciFinder database) describing the antiinflammatory effects of different triterpenes with their presumed mechanism of action, suggesting that triterpenes could be appointed as natural products with future pharmaceutical applicability.

Antiinflammatory activity of natural triterpenes—An overview from 2006 to 2021

Context: Parinari excelsa Sabine (Chrysobalanaceae) is an indigenous tree from West and Eastern Africa. This tree is used in Ivory Coast as an antimalaria remedy.Objective: The in vitro antiplasmodial and antileishmanial activities of the stem bark, the leaf and the major compounds from the stem bark were investigated.Materials and methods: The leaves and stem bark from P. excelsa were separately collected, air-dried and powdered. Two extracts (methylene chloride and methanol) were realized for both powders. Every extract was tested for its antiplasmodial and antileishmanial activities. Only the stem bark crude extracts were fractionated by column chromatography and their major components were analyzed by NMR, HRESIMS and IR methods. The compounds were tested for their antiplasmodial and antileishmanial activities.Results: The comparison of the IC50 values of the crude extracts were in this ordrer: 3.41 (IC50 of PeBMc) <4.10 (IC50 of PeBMc) <4.42 (IC50 of PeLMe) against P. falciparum and 5.19 (IC50 of PeB...

https://www.tandfonline.com/doi/pdf/10.3109/13880209.2011.633270

In vitro antileishmanial, antiplasmodial and cytotoxic activities of a new ventiloquinone and five known triterpenes from Parinari excelsa.

The bark of the underground stem of Tontelea micrantha (Mart. ex. Schult.) A. C. Sm., a native Brazilian Cerrado species, is used in folk medicine for treating kidney ailments. The structures of the underground and the aerial stems were examined and their barks were analyzed for the presence of secondary metabolites. Bark fragments were processed according to conventional techniques in plant anatomy and their chemical compositions examined using histochemical and phytochemical tests, thin layer chromatography, and high-efficiency liquid chromatography. The underground stem is a sobol with unusual cambial activity. Laticifers that secrete terpenoids were present in the cortex and phloem of both organs and can contribute to the identification of the species in field. Druses were present in both barks, but mono-crystals were only observed in the sobol. Tannins, flavonoids, alkaloids, and terpenoids occurred in both types of bark, but carotenoids were only detected in the sobol. The similarities between these two organs indicate that the aerial stem bark has potential medicinal use and represents a plausible alternative to harvesting the sobol, which could contribute to the preservation of natural populations of this species.

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Structure, histochemistry and phytochemical profile of the bark of the sobol and aerial stem of Tontelea micrantha (Celastraceae - Hippocrateoideae)

Biochemistry is a discipline offered in undergraduate health courses whose learning depends on previous knowledge in the field of chemistry, which should be learned during basic education. The objective of this study was to analyze the previous knowledge of chemistry that a graduate of the health area must present to favor the learning of biochemistry from the perspective of teachers. A qualitative descriptive research was carried out through semi-structured interviews with 06 biochemistry teachers for undergraduate health courses at a university with a solid tradition in the training of professionals in this area. To analyze the data was used content analysis of the thematic type. Teachers consider that students are not prepared to learn biochemistry, although with difference according to the course. They reported difficulties regarding the lack of previous knowledge about math and chemistry topics, such as oxreduction and thermochemistry topics, areas indicated as the greatest deficiencies of students. Another obstacle factor was the immaturity of the students. As strategies to alleviate the difficulties are used classes of revision and resumption of the topic when necessary. A script for directed study was developed as a product of this research.

Da química à bioquímica: conceitos e pré-requisitos para uma melhor aprendizagem

The chemical investigation of Salacia elliptica allowed to the isolation of 20 constituents: two polyols, one xanthone, a mixture of long chain hydrocarbons, one carboxylic acid, one polymer, two steroidal compounds, one aromatic ester and eleven pentacyclic triterpenes. These triterpenes include 3β-stearyloxy-oleanane, 3β-stearyloxy-ursane, one seco-friedelane, and eight compounds of the friedelane serie. The chemical structure and the relative configuration of a new triterpene 1,3-dioxo-16α-hydroxyfriedelane (15) were established through 1H and 13C NMR including 2D experiments (HMBC, HMQC, COSY and NOESY) and herein reported for the first time.

/pdf/chemical-constituents-of-salacia-elliptica-celastraceae-2n83g5kb9h.pdf

Chemical constituents of Salacia elliptica (Celastraceae)

Anti-inflammatory, antimicrobial and acetylcholinesterase inhibitory activities of friedelanes from Maytenus robusta branches and isolation of further triterpenoids

We live in a context in which knowledge develops continuously and rapidly. This generates a social dynamics that demands constant adaptation from those living in society and also from educational institutions. Education for this new society needs to be rethought. Universities, anchored in tradition, still use a transmission/reception model of education. A data-collecting instrument applied to undergraduate chemistry students at the end of the course in organic chemistry investigated some concepts essential to the education of a chemist, such as interatomic and intermolecular interactions and Lewis structure. We observed that students have difficulty dealing with these concepts, and we believe that this is related to the type of class they had/have and to the way the concepts are presented in the college textbooks.

/pdf/o-ensino-superior-de-quimica-reflexoes-a-partir-de-conceitos-3fkls8msqs.pdf

Salomão Bento Vasconcelos Rodrigues

Papers

Chemical constituents of Salacia elliptica (Celastraceae)

Anti-inflammatory, antimicrobial and acetylcholinesterase inhibitory activities of friedelanes from Maytenus robusta branches and isolation of further triterpenoids

O ensino superior de química: reflexões a partir de conceitos básicos para a química orgânica