Tanshinones and their Derivatives: Heterocyclic Ring-Fused Diterpenes of Biological Interest.

The available scientific literature regarding tanshinones is very abundant, and after its review, it is noticeable that most of the articles focus on the properties of tanshinone I, cryptotanshinone, tanshinone IIA, sodium tanshinone IIA sulfonate and the dried root extract of Salvia miltiorrhiza (Tan- Shen). However, although these products have demonstrated important biological properties in both in vitro and in vivo models, their poor solubility and bioavailability have limited their clinical applications. For these reasons, many studies have focused on the search for new pharmaceutical formulations for tanshinones, as well as the synthesis of new derivatives that improve their biological properties. To provide new insights into the critical path ahead, we systemically reviewed the most recent advances (reported since 2015) on tanshinones in scientific databases (PubMed, Web of Science, Medline, Scopus, and Clinical Trials). With a broader perspective, we offer an update on the last five years of new research on these quinones, focusing on their synthesis, biological activity on noncommunicable diseases and drug delivery systems, to support future research on its clinical applications.

Inhibition of squalene synthase of rat liver by abietane diterpenes derivatives.

In the current study, chemical composition of cultivated Salvia canariensis L was determined. Carnosol was the main product isolated. We prepared more lipophilic derivatives from carnosol, and both isolated and semisynthetic abietane diterpenes were evaluated in vitro as inhibitors of squalene synthase. Among the compounds tested, carnosol was the most potent inhibitor (IC50 = 17.6 µM). These results highlight the great potential of this species for the production of new ingredients in nutritional supplements for the treatment of hyperlipidemia.

In vitro antimicrobial activity of mexican plants on bovine mastitis bacteria: preliminary studies / Atividade antimicrobiana in vitro de plantas mexicanas sobre bactérias de mastite bovina: estudos preliminares

The present study aimed to evaluate the efficacy of traditionally used antibacterial plants (Euphorbia prostrata, Schinus molle, Brickellia veronicaefolia and Lepidium virginicum) in Santa Rosa Range in Guanajuato against major mastitis-causing pathogens. The selected plants were phytochemically screened for alkaloids, flavonoids, polyphenols, saponins, anthraquinone, cardiac glycosides, steroids and terpenoids. Moreover, to achieve the main purpose of the present research, extracts of selected plants were tested for in vitro antibacterial activity against Staphylococcus aureus, Escherichia coli, Shigella spp., Bacillus subtilis, Clavibacter spp., Proteus vulgaris and Salmonella spp. All these bacterial were isolated from clinical mastitis in dairy cows. The results indicated that the ethanolic extract of the aerial part of L. virginicum exhibited the strongest antimicrobial activity, and it could be potential candidate specie for the development of novel veterinary drugs with low cost and fewer side effects.

O presente estudo teve como objetivo investigar a eficácia de plantas antibacterianas tradicionalmente usadas (Euphorbia prostrata, Schinus molle, Brickellia veronicaefolia e Lepidium virginicum) na cordilheira Santa Rosa, em Guanajuato, contra os principais patógenos causadores de mastite. As plantas selecionadas foram rastreadas fitoquimicamente quanto a alcalóides, flavonóides, polifenóis, saponinas, antraquinona, glicosídeos cardíacos, esteróides e terpenóides. Além disso, para atingir o objetivo principal da presente pesquisa, extratos de plantas selecionadas foram testados quanto à atividade antibacteriana in vitrocontra Staphylococcus aureus, Escherichia coli, Shigella spp., Bacillus subtilis, Clavibacter spp., Proteus vulgaris e Salmonella spp. Todas essas bactérias foram isoladas de mastite clínica em vacas leiteiras. Os resultados indicaram que o extrato etanólico da parte aérea de L. virginicum exibia a atividade antimicrobiana mais forte e poderia ser uma espécie potencial candidata ao desenvolvimento de novos medicamentos veterinários com baixo custo e menos efeitos colaterais.

Coumarin heterocyclic derivatives: chemical synthesis and biological activity.

This review highlights the broad range of science that has arisen from the synthesis of coumarin-linked and fused heterocycle derivatives. Specific topics include their synthesis and biological activity.

Rapid access to ketones related to oleanolic and ursolic acids.

We describe in this article a process with which to obtain different ketones related to oleanolic and ursolic acids from a natural source, Salvia canariensis L., with minimal use of chromatography columns. Amongst the isolated compounds was 12α-bromo-3-oxo-olean-13, 28-olide (3), which was fully characterised, including a characterisation of its molecular configuration by X-ray crystallographic analysis by 1 and 2-dimensional NMR techniques.

Semisynthesis and biological evaluation of abietane-type diterpenes. Revision of the structure of rosmaquinone.

The new aromatic diterpenes 7beta-O-benzylrosmanol (3), 7beta-O-benzyl-11,12-di-O-methylrosmanol (4), and 7alpha-thiophenylcarnosic acid (5) have been obtained by partial synthesis from carnosol (1), an abundant natural diterpene present in Salvia species. The structures of these compounds were established from their physical and spectroscopic data. The known diterpenes sagequinone methide A (6), 7beta-O-methylrosmanol (7), 7-O-methylrosmanol (8), and rosmaquinone B (9) were obtained from rosmanol (2). The spectroscopic data of these semisynthetic diterpenes were identical to data reported in the literature. In addition, the new semisynthetic isorosmaquinone (10) was obtained from isorosmanol (12). The proton resonances of rosmaquinone (11) are reassigned based on 2D NMR spectroscopy. These compounds, as well as eight known analogues, were evaluated for cytotoxic and antimicrobial activities.

Semisynthesis of rosmanol and its derivatives. Easy access to abietatriene diterpenes isolated from the genus Salvia with biological activities.

The known diterpenes rosmanol (3), rosmaquinone (4), 7-methoxyrosmanol (5), 7-ethoxyrosmanol (6), galdosol (7), and epirosmanol (8) have been obtained by partial synthesis from carnosol (2), an abundant natural product present in Salvia species. The physical and spectroscopic data of these semisynthetic diterpenes were identical to those of authentic natural samples and with data reported in the literature. These abietane diterpenes have very interesting biological activities and are present in the genus Salviain low quantities; thus, the semisynthetic approach described here represents an efficient alternative method to obtain these compounds. Additionally, the known diterpene 16-hydroxyrosmanol (10) and a new aromatic diterpene 11 were obtained from 16-hydroxycarnosol (9) by reaction with Ph3P/NBS in CH2Cl2. The structure of the new compound 11 was established from its spectroscopic data as 12,16-epoxycarnosol.