The use of terpenes and derivatives as a new perspective for cardiovascular disease treatment: a patent review (2008–2018)

Introduction: Terpenes are a class of secondary metabolites that can be found in a variety of animal and plants species. They are considered the most structurally diversified and abundant of all natural compounds. Several studies have shown the application of terpenes, such as carvacrol, linalool, and limonene in many pharmaceutical and medicinal fields, including cardiovascular disorders, the leading cause of death worldwide. Areas covered: In this review, the authors outlined patents from the last 10 years relating to the therapeutic application of terpenes for the treatment and/or prevention of cardiovascular diseases found in different databases, emphasizing the possibility of these compounds becoming new drugs that may help to decrease the burden of these disorders. Expert opinion: There has been a growing awareness over recent years of the therapeutic use of terpenes and their derivatives as new pharmaceutical products. Patents involving the use of terpenes have been especially important in the technological development of new strategies for the treatment of cardiovascular diseases by bringing new scientific knowledge into the pharmaceutical industry. Therefore, the development of biotechnologies using natural products should be encouraged in order to increase the variety of drugs available for the treatment of cardiovascular diseases.     

Biochemical analysis of a multifunctional cytochrome P450 (CYP51) enzyme required for synthesis of antimicrobial triterpenes in plants

Members of the cytochromes P450 superfamily (P450s) catalyze a huge variety of oxidation reactions in microbes and higher organisms. Most P450 families are highly divergent, but in contrast the cytochrome P450 14α-sterol demethylase (CYP51) family is one of the most ancient and conserved, catalyzing sterol 14α-demethylase reactions required for essential sterol synthesis across the fungal, animal, and plant kingdoms. Oats (Avena spp.) produce antimicrobial compounds, avenacins, that provide protection against disease. Avenacins are synthesized from the simple triterpene, β-amyrin. Previously we identified a gene encoding a member of the CYP51 family of cytochromes P450, AsCyp51H10 (also known as Saponin-deficient 2, Sad2), that is required for avenacin synthesis in a forward screen for avenacin-deficient oat mutants. sad2 mutants accumulate β-amyrin, suggesting that they are blocked early in the pathway. Here, using a transient plant expression system, we show that AsCYP51H10 is a multifunctional P450 capable of modifying both the C and D rings of the pentacyclic triterpene scaffold to give 12,13β-epoxy-3β,16β-dihydroxy-oleanane (12,13β-epoxy-16β-hydroxy-β-amyrin). Molecular modeling and docking experiments indicate that C16 hydroxylation is likely to precede C12,13 epoxidation. Our computational modeling, in combination with analysis of a suite of sad2 mutants, provides insights into the unusual catalytic behavior of AsCYP51H10 and its active site mutants. Fungal bioassays show that the C12,13 epoxy group is an important determinant of antifungal activity. Accordingly, the oat AsCYP51H10 enzyme has been recruited from primary metabolism and has acquired a different function compared to other characterized members of the plant CYP51 family—as a multifunctional stereo- and regio-specific hydroxylase in plant specialized metabolism.Higher plants produce a huge array of low molecular weight specialized compounds (natural products) that have important functions in biotic and abiotic stress tolerance (1, 2) and that also provide a matchless starting point for drug and agrochemical discovery (3). The cytochrome P450 (P450) superfamily is the largest family of plant metabolic enzymes. The majority of plant P450 families are highly divergent, reflecting diversification and neofunctionalization as new metabolic pathways evolve (4–6). In contrast, the cytochrome P450 14α-sterol demethylase (CYP51) family is one of the most ancient of the P450 families, and the function of CYP51 enzymes is highly conserved across fungi, plants, and animals (7, 8). These enzymes are sterol demethylases required for the synthesis of essential sterols (9–14). Although different sterol substrates are used (e.g., lanosterol in mammals and yeast and obtusifoliol in plants), the reaction mechanism—14α-demethylation and subsequent formation of a Δ14–15 double bond—is preserved. In plants, CYP51 enzymes with sterol 14α-demethylase activity are known as obtusifoliol 14α-demethylases and constitute the CYP51G subfamily (7).The triterpenes are one of the largest classes of plant-derived natural products. Previously we reported the discovery of a gene encoding a divergent plant CYP51 (AsCyp51H10) that is dispensable for the synthesis of essential sterols but is required for production of specialized antimicrobial triterpene glycosides known as avenacins that confer disease resistance in oats (15). AsCyp51H10 (also known as Saponin-deficient 2 or Sad2) was first identified in a screen for mutants of diploid oat that were unable to make avenacins (16). Subsequent analysis revealed that this gene forms part of a metabolic gene cluster for avenacin synthesis (15). AsCYP51H10 (SAD2) belongs to a newly defined and as yet functionally uncharacterized subfamily of CYP51 enzymes, the CYP51H subfamily, which also includes nine members of unknown function from rice (7, 15, 17). The first committed step in the synthesis of avenacins is the cyclization of 2,3-oxidosqualene to β-amyrin, catalyzed by the oat β-amyrin synthase AsbAS1 (also known as SAD1) (18, 19). Biochemical analysis has shown that sad2 mutants accumulate β-amyrin, suggesting that β-amyrin may be the substrate for AsCYP51H10 (15, 20). Partial characterization of AsCYP51H10 in yeast is consistent with this observation (21). However, full characterization of the biochemical function of AsCYP51H10 has not yet been carried out.Triterpenes have a wide range of commercial applications as agrochemicals, food additives, and pharmaceuticals and as foaming agents in the beverage, food, and cosmetics industries (22). Commercial exploitation of triterpenes has been limited thus far by their recalcitrance to synthetic chemistry and their occurrence in low abundance in complex mixtures in plants (23). The availability of enzymes that can stereo- and regio-specifically functionalize triterpene scaffolds will open opportunities for the production of novel triterpenes using synthetic biology approaches. Several triterpene-modifying P450s from eudicots have been characterized recently by heterologous expression in yeast. These include CYP93E1 from soybean, which hydroxylates β-amyrin and sophoradiol at position C24 (24); two P450s from liquorice, one (CYP88D6) that converts β-amyrin to 11-oxo-β-amyrin and a second (CYP72A154) that converts 11-oxo-β-amyrin to glycyrrhizin acid (25, 26); and CYP716A12 from Medicago truncatula, a β-amyrin 28-oxidase that converts β-amyrin to oleanolic acid (27, 28). These enzymes belong to different P450 families, indicating that the ability to oxygenate β-amyrin has arisen multiple times during evolution.Here we show that AsCYP51H10 is a multifunctional CYP51 that is able to convert β-amyrin to a product that we determined by NMR spectrometry (NMR) to be 12,13β-epoxy-3β,16β-dihydroxy-oleanane (12,13β-epoxy-16β-hydroxy-β-amyrin). Molecular modeling and docking experiments indicate that C16 hydroxylation is likely to occur first, followed by C12,13 epoxidation. Our computational modeling in combination with mutant analysis has yielded insights into the structural features that are important for AsCYP51H10 function. We further show that the C12,13 epoxy group is critical for antifungal activity, a discovery that has important implications for triterpene metabolic engineering for food, health, and industrial biotechnology applications.     

Central Properties and Chemical Composition of Ocimum basilicum. Essential Oil

Abstract

Ocimum basilicum. L. (Lamiaceae) is an Egyptian plant used as a folkloric remedy in Egyptian traditional medicine. In the current study, the aerial part of this plant was used, and its essential oil was obtained by hydrodistillation. The essential oil of Ocimum basilicum. (OB) was screened for its composition and some CNS activities (viz., sedative, hypnotic, anticonvulsant, local anesthetic). When tested in mice, OB essential oil had no effect on motor activity up to a dose of 1.2 mL kg^?1 at 90 min postadministration. However, higher doses produced motor impairment at all time intervals. Pentobarbitone sleeping time tested in mice was significantly increased by all doses of the essential oil higher than 0.2 mL kg^?1. Intraperitoneal administration of OB essential oil significantly increased in a dose-dependent manner the latency of convulsion and percent of animals exhibiting clonic seizures. Likewise, it reduced lethality in response to different convulsive stimulus used in this study. The ED₅₀ values of the essential oil of OB were 0.61 mL kg^?1, 0.43 mL kg^?1, and 1.27 mL kg^?1, against convulsions induced by pentylenetetrazole, picrotoxin, and strychnine, respectively. A study of the local anesthetic activity of the OB essential oil by using a nerve block model employing in frog revealed that it had no local anesthetic effect. The LD₅₀ of the essential oil was 3.64 mL kg^?1 [correlation coefficient r = 0.961 and linear regression y. = 147 ln(x.) ? 141.7]. Gas chromatography (GC)/mass spectrometry (MS) analysis of the essential oil revealed the presence of linalool (44.18%), 1,8-cineol (13.65%), eugenol (8.59%), methyl cinnamate (4.26%), iso. caryophyllene (3.10%), and α.-cubebene (4.97%) as the main components. The observed anticonvulsant and hypnotic activities in this study could be related to the presence of a variety of terpenes in the essential oil.     

Air oxidation increases skin irritation from fragrance terpenes

Background:  Linalool and limonene are common fragrance terpenes that autoxidize on air exposure. The pure compounds are not allergenic but their oxidation products can cause contact allergy. Little has been investigated regarding the irritancy of oxidized terpenes.
Aim:  The aim of this study was to investigate the irritating effect of pure and oxidized R- limonene and linalool in concentration series and to study the MNIC (Maximum Non Irritant Concentration) of autoxidized linalool and limonene.
Patients/methods:  Patch testing was performed in dermatitis patients and controls with sequentially diluted concentrations of oxidized and non-oxidized linalool, and oxidized and non-oxidized R -limonene. Readings were made with visual assessment and using laser Doppler imaging.
Results:  The non-oxidized terpenes were non-irritating in all tested concentrations. Both linalool and especially R -limonene were more irritating after oxidation compared with the pure compounds. No difference in response was seen between dermatitis patients and controls.
Conclusion:  Autoxidation of the fragrance terpenes linalool and R -limonene increases irritation. Oxidized linalool is less irritating than oxidized R -limonene. In this study, we found no advantages in using laser Doppler technique compared with visual assessment.     

海洋中药厚藤的化学成分及药理活性研究进展

厚藤Ipomoea pes-caprae为旋花科(Convolvulaceae)番薯属植物,是一种生长于滨海滩涂的海洋植物药,不仅是我国南方沿海民间常用海洋中药和京族习用植物药,同时,也是澳大利亚、墨西哥、泰国、巴西、巴基斯坦等多个热带及亚热带国家的传统药用植物。其资源丰富,应用广泛。其化学成分主要包括树脂糖苷类、萜类、黄酮类、酚酸类、挥发性成分、甾体类等。现代药理研究表明厚藤具有抗肿瘤、抗菌、抗炎镇痛、抗胶原酶、抗氧化、免疫调节等多种药理活性。深入总结厚藤的化学成分及药理活性的研究现状,以期为该海洋中药的临床应用、质量控制和产品开发等提供参考。     

Colophonium and Compositae mix as markers of fragrance allergy: cross-reactivity between fragrance terpenes, colophonium and compositae plant extracts

The aim of this study was to assess the strength of any association between sensitization to 'new' fragrance compounds and sensitization to Compositae, fragrance mix, Myroxylon pereirae resin and colophonium, respectively. Consecutive eczema patients were tested with a series of essential oils and selected fragrance compounds and another series of oxidized terpenes in connection with European multicentre fragrance projects. Contact allergy to either series was frequently detected, in 5% of 318 and 4.6% of 262 persons tested, and both had a statistically significant association with Compositae, colophonium and fragrance mix sensitization. The individual results indicated that simultaneously occurring positive reactions to essential oils, colophonium and Compositae were based on cross-reactivity rather than concomitant sensitization. Thus, all patients with positive reaction to the rare fragrance sensitizer beta-caryophyllene had positive colophonium reactions, and cross-reactivity between essential oils and Compositae was related to the Compositae plant extracts of the Compositae mix and not the pure sesquiterpene lactones of the standard series. The implication is that Compositae mix and colophonium may be markers of fragrance allergy, which is important to know when assessing the relevance of positive reactions to Compositae plant extracts and colophonium.     

人参芦头脂溶性成分的研究

从人参（ＰａｎａｘＧｉｎｓｅｎｇＣ．Ａ．Ｍｅｙｅｒ）芦头的醚溶性成分中，用硅胶柱层析法，分得４种单体化合物。经ＩＲ，ＭＳ，ＮＭＲ，ＧＣ及化学降解等方法分别鉴定为二十九烷（１）、三棕榈酸甘油酯（２）、人参萜醇（３）及β－谷甾醇（４），其中化合物（１），（２），（３）为首次从人参芦头中分离得到的已知成分。     

Impacts of chemical enhancers on skin permeation and deposition of terbinafine

Abstract

Context/Objective: The addition of chemical enhancers into formulations is the most commonly employed approach to overcome the skin barrier. The objective of this work was to evaluate the effect of vehicle and chemical enhancers on the skin permeation and accumulation of terbinafine, an allylamine antifungal drug.

Methods: Terbinafine (1% w/w) was formulated as a Carbopol 934?P gel formulation in presence and absence of three chemical enhancers, nerolidol, dl-limonene and urea. Terbinafine distribution and deposition in stratum corneum (SC) and skin following 8-h ex vivo permeation study was determined using a sequential tape stripping procedure. The conformational order of SC lipids was investigated by ATR-FTIR spectroscopy.

Results and discussion: Nerolidol containing gel formulation produced significantly higher enhancement in terbinafine permeation through skin and its skin accumulation was increased. ATR-FTIR results showed enhancer induced lipid bilayer disruption in SC. Urea resulted in enhanced permeation of terbinafine across the skin and a balanced distribution to the SC was achieved. But, dl-limonene could not minimize the accumulation of terbinafine in the upper SC.

Conclusion: Nerolidol dramatically improved the skin permeation and deposition of terbinafine in the skin that might help to optimize targeting of the drug to the epidermal sites as required for both of superficial and deep cutaneous fungal infections.     

野菊花中萜类和黄酮类化合物保肝作用研究

目的 研究野菊花中萜类和黄酮类化合物对刀豆蛋白A（Con A）诱导的小鼠免疫性肝损伤的保护作用。方法 将小鼠随机分成对照组,模型组,野菊花各提取部位（CIF-A,主要含萜类化合物;CIF-B,主要含萜类和黄酮类化合物;CIF-C,主要含黄酮类化合物）高、中、低剂量组,联双酯滴丸阳性对照组。小鼠首日上下午和次日下午各ig给药1次,以后每天给药1次,连续7 d,末次给药后,除对照组外,其他组小鼠尾iv Con A制备小鼠免疫性肝损伤模型。检测小鼠血清中天冬氨酸转氨酶（AST）、丙氨酸转氨酶（ALT）、肿瘤坏死因子-α（TNF-α）、γ干扰素（IFN-γ）的水平;测定肝组织中MDA的量,观察肝脏病理组织学变化。结果 与模型组比较,CIF-A、CIF-B均抑制血清中AST、ALT、TNF-α水平的升高;CIF-C抑制AST、ALT、IFN-γ水平的升高;CIF-B可降低肝组织中MDA的量,明显改善肝组织病变,作用优于CIF-A和CIF-C。结论 野菊花中萜类和黄酮类化合物对Con A致小鼠免疫性肝损伤均具有一定的保肝作用,CIF-B作用更强。     

地笋属植物化学成分研究进展

检索ScienceDirect,ACS,Wiley Online及CNKI等数据库中有关地笋属植物在化学成分的文献,对该属植物化学成分研究进行整理分析.该属植物化学成分结构类型较多,主要为挥发油、萜类、黄酮、酚酸和甾体类化合物.其中,已经分离鉴定的黄酮类化合物31个,萜类化合物20个,酚酸类化合物20个和甾体类化合物3个.通过文献总结发现,该属植物在我国资源丰富,但仅有少数植物进行了化学成分的研究报道,提示该属植物值得深入研究.