Effect of Diterpene Manool on the Arterial Blood Pressure and Vascular Reactivity in Normotensive and Hypertensive Rats

Geographical variation in metabolite profiles and bioactivity of Thesium chinense Turcz. revealed by UPLC-Q-TOF-MS-based metabolomics

Introduction

This study aims to investigate the impact of geographical origin on the metabolite composition and bioactivity of Thesium chinense Turcz. (TCT), a member of the Apiaceae family renowned for its wide range of pharmacological properties, including antioxidant, antimicrobial, and anti-inflammatory effects. In this study, we investigated the whole plants of TCT from different regions in China, aiming to explore the geographical variation of TCT.

Methods

A non-targeted metabolomics approach was employed using ultra-high-performance liquid chromatography combined with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were utilized to identify and differentiate the metabolite profiles. We investigated the bioactivity, antioxidant activity, total flavonoid content (TFC), and the content of characteristic compounds from TCT sourced from different regions. This aims to further explore the metabolic differences and quality characteristics of TCT from various origins.

Results

PCA and PLS-DA analyses indicated that samples from different origins could be clearly distinguished. The analysis revealed 54 differential metabolites, predominantly flavonoids and alkaloids. KEGG pathway analysis indicated significant variations in the biosynthesis pathways of flavonoids and flavanols among the samples. TCT from Anhui province exhibited the highest TFC and strongest antioxidant and anti-inflammatory activities, while samples from Jilin province showed the lowest.

Discussion

A strong correlation was observed between metabolite content and geographical origins, suggesting that the bioactivity of TCT is significantly influenced by its provenance. Additionally, the antioxidant and anti-inflammatory activities of TCT were validated, showing a strong predictive relationship with TFC. This research highlights the potential of metabolomics in discerning the subtleties of plant metabolomes, contributing to the advancement of traditional Chinese medicine and its integration into modern healthcare practices.

Cistus albidus L.-Review of a Traditional Mediterranean Medicinal Plant with Pharmacological Potential

Cistus albidus L. (Cistaceae) is a medicinal plant that has been used therapeutically since ancient times in the Mediterranean basin for its important pharmacological properties. The ability of C. albidus to produce large quantities of a wide range of natural metabolites makes it an attractive source of raw material. The main constituents with bioactive functions that exert pharmacological effects are terpenes and polyphenols, with more than 200 identified compounds. The purpose of this review is to offer a detailed account of the botanical, ethnological, phytochemical, and pharmacological characteristics of C. albidus with the aim of encouraging additional pharmaceutical investigations into the potential therapeutic benefits of this medicinal plant. This review was carried out using organized searches of the available literature up to July 2023. A detailed analysis of C. albidus confirms its traditional use as a medicinal plant. The outcome of several studies suggests a deeper involvement of certain polyphenols and terpenes in multiple mechanisms such as inflammation and pain, with a potential application focus on neurodegenerative diseases and disorders. Other diseases such as prostate cancer and leukemia have already been researched with promising results for this plant, for which no intoxication has been reported in humans.

Antimelanoma effect of manool in 2D cell cultures and reconstructed human skin models

Melanoma is the most aggressive and lethal type of skin cancer, characterized by therapeutic resistance. In this context, the present study aimed to investigate the cytotoxic potential of manool, a diterpene from Salvia officinalis L., in human (A375) and murine (B16F10) melanoma cell lines. The analysis of cytotoxicity using the XTT assay showed the lowest IC₅₀ after 48 h of treatment with the manool, being 17.6 and 18.2 µg/ml for A375 and B16F10, respectively. A selective antiproliferative effect of manool was observed on the A375 cells based on the colony formation assay, showing an IC₅₀ equivalent to 5.6 µg/ml. The manool treatments led to 43.5% inhibition of the A375 cell migration at a concentration of 5.0 µg/ml. However, it did not affect cell migration in the B16F10 cells. Cell cycle analysis revealed that the manool interfered in the cell cycle of the A375 cells, blocking the G2/M phase. No changes in the cell cycle were observed in the B16F10 cells. Interestingly, manool did not induce apoptosis in the A375 cells, but apoptosis was observed after treatment of the B16F10 cells. Additionally, manool showed an antimelanoma effect in a reconstructed human skin model. Furthermore, in silico studies, showed that manool is stabilized in the active sites of the tubulin dimer with comparable energy concerning taxol, indicating that both structures can inhibit the proliferation of cancer cells. Altogether, it is concluded that manool, through the modulation of the cell cycle, presents a selective antiproliferative activity and a potential antimelanoma effect.

Biologically Active Diterpenoids in the Clerodendrum Genus-A Review

One of the key areas of interest in pharmacognosy is that of the diterpenoids; many studies have been performed to identify new sources, their optimal isolation and biological properties. An important source of abietane-, pimarane-, clerodane-type diterpenoids and their derivatives are the members of the genus Clerodendrum, of the Lamiaceae. Due to their diverse chemical nature, and the type of plant material, a range of extraction techniques are needed with various temperatures, solvent types and extraction times, as well as the use of an ultrasound bath. The diterpenoids isolated from Clerodendrum demonstrate a range of cytotoxic, anti-proliferative, antibacterial, anti-parasitic and anti-inflammatory activities. This review describes the various biological activities of the diterpenoids isolated so far from species of Clerodendrum with the indication of the most active ones, as well as those from other plant sources, taking into account their structure in terms of their activity, and summarises the methods for their extraction.

Novel Labdane Diterpenes-Based Synthetic Derivatives: Identification of a Bifunctional Vasodilator That Inhibits CaV1.2 and Stimulates KCa1.1 Channels

Sesquiterpenes such as leucodin and the labdane-type diterpene manool are natural compounds endowed with remarkably in vitro vasorelaxant and in vivo hypotensive activities. Given their structural similarity with the sesquiterpene lactone (+)-sclareolide, this molecule was selected as a scaffold to develop novel vasoactive agents. Functional, electrophysiology, and molecular dynamics studies were performed. The opening of the five-member lactone ring in the (+)-sclareolide provided a series of labdane-based small molecules, promoting a significant in vitro vasorelaxant effect. Electrophysiology data identified 7 as a Ca_V1.2 channel blocker and a K_Ca1.1 channel stimulator. These activities were also confirmed in the intact vascular tissue. The significant antagonism caused by the Ca_V1.2 channel agonist Bay K 8644 suggested that 7 might interact with the dihydropyridine binding site. Docking and molecular dynamic simulations provided the molecular basis of the Ca_V1.2 channel blockade and K_Ca1.1 channel stimulation produced by 7. Finally, 7 reduced coronary perfusion pressure and heart rate, while prolonging conduction and refractoriness of the atrioventricular node, likely because of its Ca²⁺ antagonism. Taken together, these data indicate that the labdane scaffold represents a valuable starting point for the development of new vasorelaxant agents endowed with negative chronotropic properties and targeting key pathways involved in the pathophysiology of hypertension and ischemic cardiomyopathy.

Antitumor Effect of Manool in a Murine Melanoma Model

The manool diterpene, found in abundance in Salvia officinalis L., showed a selective cytotoxic effect against murine melanoma cells. Therefore, the present study aimed to evaluate the antitumor potential of manool in a murine melanoma model, administered by three routes: oral, subcutaneous, and intraperitoneal. In addition, the antimelanoma effect of manool (orally) combined with cisplatin (subcutaneous) was evaluated. The results obtained revealed that manool, administered by the three routes, was able to significantly decrease the mass and frequency of mitosis of the tumor tissue. The data obtained revealed that manool, at a dose of 20 mg/kg, was able to significantly decrease the tumor mass when administered by the three routes, with the percentages of reduction being equivalent to 62.4% (oral), 48.5% (intraperitoneal), and 38.8% (subcutaneous), without toxic effects. The treatment of manool plus cisplatin led to 86.7% reduction in tumor mass, higher than that observed in treatment with manool or cisplatin alone (50.7%), although signs of toxicity have been observed. The results also showed that treatments with manool (20 mg/kg orally) and/or cisplatin did not alter the activity of caspase 3 cleaved in tumor tissue. Therefore, manool revealed a promising antimelanoma effect, but without involvement of the caspase 3 cleaved pathway.