Curcumane C and (±)-curcumane D, an unusual seco-cadinane sesquiterpenoid and a pair of unusual nor-bisabolane enantiomers with significant vasorelaxant activity from Curcuma longa

Five new bisabolane-type sesquiterpenoids with oxygen-containing heterocyclic systems from Curcuma longa

Five new bisabolane-type sesquiterpenoids (1-5) were isolated from the rhizomes of Curcuma longa, and all of them were oxygen-containing heterocyclic compounds. The structures of the compounds were elucidated using comprehensive spectroscopic techniques, and their absolute configurations were confirmed through electronic circular dichroism (ECD) calculations. All of the compounds were evaluated for their vasorelaxant and anti-inflammatory activities. The results showed that only compound 4 exhibited a vasorelaxant effect against KCl-induced contraction of rat aortic rings, and it achieved a diastolic ratio that exceeded 25 % at a concentration of 25 μM.

New Bisabolane-Type Sesquiterpenoids from Curcuma longa and Their Anti-Atherosclerotic Activity

To explore the sesquiterpenoids in Curcuma longa L. and their activity related to anti-atherosclerosis. The chemical compounds of the rhizomes of C. longa were separated and purified by multiple chromatography techniques. Their structures were established by a variety of spectroscopic experiments. The absolute configurations were determined by comparing experimental and calculated NMR chemical shifts and electronic circular dichroism (ECD) spectra. Their anti-inflammatory effects and inhibitory activity against macrophage-derived foam cell formation were evaluated by lipopolysaccharide (LPS) and oxidized low-density lipoprotein (ox-LDL)-injured RAW264.7 macrophages, respectively. This study resulted in the isolation of 10 bisabolane-type sesquiterpenoids (1-10) from C. longa, including two pairs of new epimers (curbisabolanones A-D, 1-4). Compound 4 significantly inhibited LPS-induced nitric oxide (NO), interleukin-1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and prostaglandin E2 (PGE2) production in RAW264.7 cells. Furthermore, compound 4 showed inhibitory activity against macrophage-derived foam cell formation, which was represented by markedly reducing ox-LDL-induced intracellular lipid accumulation as well as total cholesterol (TC), free cholesterol (FC), and cholesterol ester (CE) contents in RAW264.7 cells. These findings suggest that bisabolane-type sesquiterpenoids, one of the main types of components in C. longa, have the potential to alleviate the atherosclerosis process by preventing inflammation and inhibiting macrophage foaming.

Curcumanes E and F, two rare sesquiterpenoids with a dicyclo[3.3.1]nonane moiety, from Curcuma longa and their vasorelaxant activities

Two new sesquiterpenoids, curcumanes E (1) and F (2), were isolated from the rhizome of Curcuma longa, and their structures and absolute configurations were examined using extensive spectroscopic analyses and ECD calculations. Interestingly, compounds 1 and 2 are diastereoisomers possessing a rare sesquiterpenoid skeleton that has been reported only once before. Both curcumanes E and F exhibit significant vasorelaxant effects against KCl-induced contraction of rat aortic rings, with EC50 values of 5.10 ± 0.79 and 5.58 ± 1.77 μM, respectively. These findings enrich the data concerning this rare type of sesquiterpenoids and further indicate that these rare sesquiterpenoids can effectively reduce blood pressure.

Vasorelaxant effect of curcubisabolanin A isolated from Curcuma longa through the PI3K/Akt/eNOS signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Curcuma longa L. (Zingiberaceae) is a known blood-activating and stasis-removing traditional Chinese medicine and has relevant pharmacological properties. The rhizomes of C. longa have been used for the treatment of cardiovascular disease (CVD) in China. Previous studies have shown that sesquiterpenoids from C. longa have significant vasorelaxant effects, which are closely associated with the prevention and treatment of CVD.

AIM OF THE STUDY

To explore the sesquiterpenoids with vasorelaxant effects from C. longa and investigate the underlying mechanisms.

MATERIALS AND METHODS

The compound was isolated from C. longa by multiple chromatography technologies. Its structure was determined by extensive spectroscopic analyses, nuclear magnetic resonance (NMR) data calculations, electronic circular dichroism (ECD) data calculations, and optical rotation (OR) data calculations. The vasorelaxant effect of the isolated compound was evaluated by KCl- or phenylephrine (PHE)-inducing contraction of the rat thoracic aortic rings. Endothelial removal and L-NAME pretreatment experiments were used to verify the endothelium-dependent vasorelaxant effect of the isolated compound in rat thoracic aortic rings. NO production was monitored in human umbilical vein endothelial cells (HUVECs). Western blot was carried out in HUVECs to elucidate the potential mechanisms.

RESULTS

A new bisabolane-type sesquiterpenoid, curcubisabolanin A [(+)-(1S,7S,9E)-bisabola-2(3),4(15),9(10)-trien-11-ol], was isolated from the rhizomes of C. longa. curcubisabolanin A exhibited endothelium-dependent relaxation on rat thoracic aortic rings, while pre-treatment of intact aortic rings with an eNOS inhibitor (L-NAME) attenuated the vasorelaxant response of curcubisabolanin A. In addition, curcubisabolanin A induced intracellular NO production and significantly increased the levels of phosphorylated PI3K (p-PI3K), phosphorylated Akt (p-Akt), and phosphorylated eNOS (p-eNOS) in HUVECs. LY294002 (a blocker of PI3K) and MK-2206 (a highly selective inhibitor of Akt) significantly decreased these effects of curcubisabolanin A.

CONCLUSIONS

These findings demonstrated that the vasorelaxant effect of curcubisabolanin A was partially endothelium-dependent and was related to regulation of NO production in vascular endothelial cells through the PI3K/Akt/eNOS signaling pathway.

Natural Enantiomers: Occurrence, Biogenesis and Biological Properties

The knowledge that natural products (NPs) are potent and selective modulators of important biomacromolecules (e.g., DNA and proteins) has inspired some of the world's most successful pharmaceuticals and agrochemicals. Notwithstanding these successes and despite a growing number of reports on naturally occurring pairs of enantiomers, this area of NP science still remains largely unexplored, consistent with the adage "If you don't seek, you don't find". Statistically, a rapidly growing number of enantiomeric NPs have been reported in the last several years. The current review provides a comprehensive overview of recent records on natural enantiomers, with the aim of advancing awareness and providing a better understanding of the chemical diversity and biogenetic context, as well as the biological properties and therapeutic (drug discovery) potential, of enantiomeric NPs.

Bisabolane-type sesquiterpenoids: Structural diversity and biological activity

Bisabolane-type sesquiterpenoids, a class of monocyclic sesquiterpenoids, are widely distributed in nature and have a variety of biological activities. To provide a reference for the further research and development of these compounds, the phytochemical and biological properties of natural bisabolane-type sesquiterpenoids (356 compounds in total) isolated between 1985 and 2020 from 24 families, primarily Compositae, Zingiberaceae, Aspergillaceae, Halichondriidae, and Aplysiidae were reviewed. In vitro and in vivo studies have indicated that antibacterial, anti-inflammatory, and cytotoxic effects are the most commonly reported pharmacological properties of bisabolane-type sesquiterpenoids. Owing to their extensive significant effects, a lot of traditional medicines containing this type of compounds have been used for a long history. Thus, bisabolane-type sesquiterpenoids are a rich source of important natural products, which show great potential for the development of new drugs.

Chemical composition and uterine smooth muscle relaxant activity of essential oils from 10 kinds of blood-activating and stasis-resolving Chinese medicinal herbs

ETHNOPHARMACOLOGICAL RELEVANCE

Dysmenorrhea is one of the most common gynecological problems among menstruating females. Blood-activating and stasis-resolving herbs (BASRHs) have been employed to be the first choice for treating dysmenorrhea in China. Especially, the essential oils of some BASRHs have been confirmed to play important roles in the treatment of dysmenorrhea, but the constituents and uterine smooth muscle relaxant activity of some commonly used BASRH essential oils have not been fully assessed, and whether there are differences in the constituents and anti-dysmenorrhea effect among BASRH essential oils has not been evaluated.

AIM OF THE STUDY

This study aims to systematically investigate the chemical constituents of 10 BASRH essential oils and assess their uterine smooth muscle relaxant activity and the preliminary mechanism of the most effective essential oil.

MATERIALS AND METHODS

The chemical constituents of 10 BASRH essential oils were analyzed by Gas Chromatography-Mass Spectrometer. A rat model of dysmenorrhea in vitro was established to investigate the uterine smooth muscle relaxant activity of 10 kinds of essential oils. Rat isolated uterus strips were given different dose of 10 kinds of essential oils (0.04, 0.08, 0.16 mg/mL). The contractile responses were recorded with Power Lab recording system, and contractile tension, contractile frequency, and contractile activity were evaluated. The preliminary mechanism of the essential oil of the rhizomes of Curcuma phaeocaulis Valeton (CPEO) was assessed using a rat model of dysmenorrhea in vivo and in vitro, and rats were given the CPEO (15, 30, and 60 mg/kg) by gavage. The level of Ca2+ in uterine tissue of rats was determined by methyl thyme phenol blue colorimetric and Bradford methods. The effects of CPEO on extracellular Ca2+ influx and intracellular Ca2+ release were evaluated using the isolated uterus.

RESULTS

The results of Gas Chromatography-Mass Spectrometer analysis showed that more than 81 components (content: 1% max appearance) were identified. The main components of the 10 BASRH essential oils were found to be monoterpenoids, sesquiterpenoids, diterpenoids, aromatics, aliphatics, and phthalides. The study of in vitro smooth muscle relaxant activity demonstrated that all the essential oils except the essential oil of the roots of Cyathula officinalis K.C.Kuan markedly decrease the contractile activity, tension, and frequency (P < 0.05 or P < 0.01). Among these oils, CPEO has the most pronounced effect. Further in vivo studies indicated that CPEO can significantly decrease the level of Ca2+ in uterine tissue when compared with the model group (P < 0.05 or P < 0.01). In vitro studies indicated that CPEO can inhibit the extracellular Ca2+ influx and intracellular Ca2+ release in favor of uterine relaxation.

CONCLUSIONS

BASRH essential oils play an important role in inhibiting uterine smooth muscle contractions, and sesquiterpenoids and phthalides in BASRH essential oils are important active compounds for relaxing uterine smooth muscle. CPEO is a favorable candidate for developing anti-dysmenorrhea drugs.

Review of Natural Resources With Vasodilation: Traditional Medicinal Plants, Natural Products, and Their Mechanism and Clinical Efficacy

For decades, chronic diseases including cardiovascular and cerebrovascular diseases (CCVDs) have plagued the world. Meanwhile, we have noticed a close association between CCVDs and vascular lesions, such as hypertension. More focus has been placed on TMPs and natural products with vasodilation and hypotension. TMPs with vasodilatory and hypotensive activities are mainly from Compositae, Lamiaceae, and Orchidaceae (such as V. amygdalina Del., T. procuinbens L., M. glomerata Spreng., K. galanga L., etc.) whereas natural products eliciting vasorelaxant potentials were primarily from flavonoids, phenolic acids and alkaloids (such as apigenin, puerarin, curcumin, sinomenine, etc.). Furthermore, the data analysis showed that the vasodilatory function of TMPs was mainly concerned with the activation of eNOS, while the natural products were primarily correlated with the blockage of calcium channel. Thus, TMPs will be used as alternative drugs and nutritional supplements, while natural products will be considered as potential therapies for CCVDs in the future. This study provides comprehensive and valuable references for the prevention and treatment of hypertension and CCVDs and sheds light on the further studies in this regard. However, since most studies are in vitro and preclinical, there is a need for more in-depth researches and clinical trials to understand the potential of these substances.

Secondary Metabolites of Plants as Modulators of Endothelium Functions

According to the World Health Organization, cardiovascular diseases are the main cause of death worldwide. They may be caused by various factors or combinations of factors. Frequently, endothelial dysfunction is involved in either development of the disorder or results from it. On the other hand, the endothelium may be disordered for other reasons, e.g., due to infection, such as COVID-19. The understanding of the role and significance of the endothelium in the body has changed significantly over time—from a simple physical barrier to a complex system encompassing local and systemic regulation of numerous processes in the body. Endothelium disorders may arise from impairment of one or more signaling pathways affecting dilator or constrictor activity, including nitric oxide–cyclic guanosine monophosphate activation, prostacyclin–cyclic adenosine monophosphate activation, phosphodiesterase inhibition, and potassium channel activation or intracellular calcium level inhibition. In this review, plants are summarized as sources of biologically active substances affecting the endothelium. This paper compares individual substances and mechanisms that are known to affect the endothelium, and which subsequently may cause the development of cardiovascular disorders.