Sesterterpenoids and other constituents from Salvia lachnocalyx Hedge

Chemical Profile and Bioactivity Evaluation of Salvia Species from Eastern Europe

The Salvia genus comprises about 1000 species endowed with medicinal, aromatic, cosmetic, and ornamental applications. Even though the genus is one of the most-studied taxa of the Lamiaceae family, data on the chemical composition and biological properties of certain locally used Salvia species are still scarce. The present work aimed to evaluate the phytochemical profile and antimicrobial, antioxidant, and cytotoxic potential of ten Salvia species that grow in Eastern Europe (e.g., the Republic of Moldova). LC-HRMS/MS metabolite profiling allowed for the annotation of 15 phenolic and organic acids, 18 flavonoids, 19 diterpenes, 5 sesterpenes, and 2 triterpenes. Multivariate analysis (e.g., principal component analysis, hierarchical cluster analysis) revealed that S. austriaca, S. nutans, and S. officinalis formed individual clusters, whereas the remaining species had a similar composition. S. officinalis showed the highest activity against Staphylococcus aureus and Streptococcus pneumoniae (MIC = 0.625 mg/mL). As evaluated in DPPH, ABTS, and FRAP assays, S. officinalis was one of the most potent radical scavenging and metal-reducing agents (CE50 values of 25.33, 8.13, and 21.01 μg/mL, respectively), followed by S. verticillata, S. sclarea, S. kopetdaghensis, S. aethiopis, and S. tesquicola. Pearson correlation analysis revealed strong correlations with rosmarinic acid, luteolin-O-glucuronide, and hydroxybenzoic acid. When the cytotoxic activity was evaluated in human breast carcinoma MCF-7 and MDA-MB-231 cells, no significant reduction in cell viability was observed over the concentrations ranging from 25 and 100 μg/mL. The results confirm the potential use of understudied Salvia species as promising sources of antioxidant compounds for developing novel pharmaceutical, nutraceutical, or cosmeceutical products.

Cytotoxic abietane diterpenoids from Salvia leriifolia Benth

The Phytochemical profiling of the root extract of Salvia leriifolia, an endemic plant of Iran, was investigated and 16 abietane diterpenes were isolated, and three were original compounds. 1D and 2D NMR and HRMS performed structural elucidation. The absolute configuration of the previously unreported compounds was determined by circular dichroism (ECD). The cytotoxicity of the isolated compounds was investigated against AGS, MIA PaCa-2, HeLa, and MCF-7 cell lines by the MTT assay. The known diterpene pisiferal possesses high cytotoxicity against all investigated cell lines at a concentration between 9.3 ± 0.6 and 14.38 ± 1.4 μM.

Uncommon Terpenoids from Salvia Species: Chemistry, Biosynthesis and Biological Activities

The search for new bioactive compounds from plant sources has been and continues to be one of the most important fields of research in drug discovery. However, Natural Products research has continuously evolved, and more and more has gained a multidisciplinary character. Despite new developments of methodologies and concepts, one intriguing aspect still persists, i.e., different species belonging to the same genus can produce different secondary metabolites, whereas taxonomically different genera can produce the same compounds. The genus Salvia L. (Family Lamiaceae) comprises myriad distinct medicinal herbs used in traditional medicine worldwide that show different pharmacological activities due to the presence of a variety of interesting specialized metabolites, including mono-, sesqui-, di-, sester-, tri-, tetra-, and higher terpenoids as well as phenylpropanoids, phenolic acid derivatives, lignans, flavonoids, and alkaloids. We herein summarize the research progress on some uncommon terpenoids, isolated from members of the genus Salvia, which are well recognized for their potential pharmacological activities. This review also provides a current knowledge on the biosynthesis and occurrence of some interesting phytochemicals from Salvia species, viz. C₂₃-terpenoids, sesterterpenoids (C₂₅), dammarane triterpenoids (C₃₀), and uncommon triterpenoids (C₂₀+C₁₀). The study was carried out by searching various scientific databases, including Elsevier, ACS publications, Taylor and Francis, Wiley Online Library, MDPI, Springer, Thieme, and ProQuest. Therefore, 106 uncommon terpenoids were identified and summarized. Some of these compounds possessed a variety of pharmacological properties, such as antibacterial, antiviral, antiparasitic, cytotoxic and tubulin tyrosine ligase inhibitory activities. Due to the lack of pharmacological information for the presented compounds gathered from previous studies, biological investigation of these compounds should be reinvestigated.

New Sesterterpenoids from Salvia mirzayanii Rech.f. and Esfand. Stereochemical Characterization by Computational Electronic Circular Dichroism

Phytochemical investigation on the acetone extract of Salvia mirzayanii Rech. f. and Esfand. afforded seven new isoprenoids including six new sesterterpenoids salvimirzacolide A-F (1–6), and one new nor-diterpenoid (7). Their structures were established by comprehensive spectroscopic and spectrometric data analysis (1D and 2D NMR, HRMS) and DP4+ NMR chemical shift probability calculation technique. Moreover, the absolute configuration of compounds was determined by using electronic circular dichroism spectroscopy. Evaluation of antiproliferative properties of compounds isolated against four human melanoma cancer cells displayed no cytotoxic activity at the concentration range used.

The untapped potential of plant sesterterpenoids: chemistry, biological activities and biosynthesis

Covering: 1969 up to 2021Sesterterpenoids, biosynthetically derived from the precursor, namely geranylfarnesyl diphosphate (GFDP) are amongst the rarest of all isoprenoids with approximately 1300 compounds known. Most sesterterpenoids originate from marine organisms (especially sponges), while only about 15% of these compounds are isolated from several families of plants such as Lamiaceae, Gentianaceae, and Nartheciaceae. Many plant sesterterpenoids possess highly oxygenated and complex cyclic skeletons and exhibit remarkable biological activities involving cytotoxic, anti-inflammatory, antimicrobial, and antifeedant properties. Thus, due to their intrinsic chemical complexity and intriguing biological profiles, plant sesterterpenoids have attracted continuing interest from both chemists and biologists. However, the biosynthesis and distribution of sesterterpenoids in the plant kingdom still remain elusive, although substantial progress has been achieved in recent years. This review provides an overall coverage of sesterterpenoids originating from plant sources, followed by a classification of their chemical skeletons, which summarizes the distribution, chemistry, biological activities, biosynthesis and evolution of plant sesterterpenoids, aiming at strengthening the research efforts toward the untapped great potential of these unique natural product resources.

Iranian Salvia species: A phytochemical and pharmacological update

Salvia is the largest genus of the Lamiaceae family, with over 900 species in the world which about 60 species are distributed in Iran, 17 of them are endemic. In Iran, Salvia species have been used to treat various diseases with a wide spectrum of pharmacological activity in vitro and in vivo. The present review summarizes the phytochemistry and pharmacology of medicinal Iranian Salvia species in order to describe their therapeutic potential for a range of diseases. . Phytochemical investigations reveal that the Iranian Salvia has a varied range of metabolites including terpenoids, flavonoids and phenolic acids. The most important pharmacological activities are antidiabetic, antioxidant, antimicrobial, cytotoxic and anti-inflammatory. Iranian Salvia traditionally used as carminatives, analgesics, digestive aids, antiseptics, sedative, anxiolytic, hypnotic, pain reduction and antidiabetic. Among the endemic species, the most interesting for human health are treating a variety of diseases.

Sesterterpenoids: chemistry, biology, and biosynthesis

Covering: July 2012 to December 2019Over the last seven years, expanding research efforts focused on sesterterpenoids has led to the isolation, identification, and characterization of numerous structurally novel and biologically active sesterterpenoids. These newly reported sesterterpenoids provide diverse structures that often incorporate unprecedented ring systems and new carbon skeletons, as well as unusual functional group arrays. Biological activities of potential biomedical importance including suppression of cancer cell growth, inhibition of enzymatic activity, and modulation of receptor signaling, as well as ecologically important functions such as antimicrobial effects and deterrence of herbivorous insects have been associated with a variety of sesterterpenoids. There has also been a rapid growth in our knowledge of the genomics, enzymology, and specific pathways associated with sesterterpene biosynthesis. This has opened up new opportunities for future sesterterpene discovery and diversification through the expression of new cryptic metabolites and the engineered manipulation of associated biosynthetic machinery and processes. In this paper we reviewed 498 new sesterterpenoids, including their structures, source organisms, country of origin, relevant bioactivities, and biosynthesis.

Phytochemical Study of Tanacetum Sonbolii Aerial Parts and the Antiprotozoal Activity of its Components

The genus Tanacetum includes some popular endemic species of the flora of Iran, with important medicinal properties. In a project, directed at structurally interesting bioactive metabolites from Iranian endemic species, we studied Tanacetum sonbolii Mozaff. Eight compounds comprising six phenolic and two terpenoidal compounds were isolated from the ethyl acetate extract of the aerial parts of the plant by normal and reverse phase chromatography. Their structures were established mainly by 1D and 2D NMR spectroscopic techniques, including ¹H-¹H COSY, HSQC and HMBC methods and confirmed by comparing their NMR data with those reported in the literature. The compounds namely: 2,4-dihydroxy-6-methoxyacetophenone (1), apigenin (2), 5-desmethylsinensetin (3), 5-desmethylnobiletin (4), 8-methoxycirsilineol (5), scopoletin (6), ursolic acid (7), and β-sitosterol (8). In-vitro antiprotozoal activity of compounds 1, 3, and 5 were evaluated against Trypanosoma brucei rhodesiense, Trypanosoma cruzi, Leishmania donovani and Plasmodium falciparum parasites and also toxicity against rat myoblast (L6) cells. Compound 5 showed promising activity against T. b. rhodesiense.

Antibacterial and ATP Synthesis Modulating Compounds from Salvia tingitana

A surface extract of the aerial parts of Salvia tingitana afforded a nor-sesterterpenoid (1) and eight new sesterterpenoids (2-̵9), along with five known sesterterpenoids, five labdane and one abietane diterpenoid, one sesquiterpenoid, and four flavonoids. The structures of the new compounds were established by 1D and 2D NMR spectroscopy, HRESIMS, and VCD data and Mosher's esters analysis. The antimicrobial activity of compounds was evaluated against 30 human pathogens including 27 clinical strains and three isolates of marine origin for their possible implications on human health. The methyl ester of salvileucolide (10), salvileucolide-6,23-lactone (11), sclareol (15), and manool (17) were the most active against Gram-positive bacteria. The compounds were also tested for the inhibition of ATP production in purified mammalian rod outer segments. Terpenoids 10, 11, 15, and 17 inhibited ATP production, while only 17 inhibited also ATP hydrolysis. Molecular modeling studies confirmed the capacity of 17 to interact with mammalian ATP synthase. A significant reduction of ATP production in the presence of 17 was observed in Enterococcus faecalis and E. faecium isolates.

Perovskanol, a new sesquiterpenoid with an unprecedented skeleton from Perovskia Abrotanoides

Phytochemical investigation of the aerial parts of Perovskia abrotanoides (Lamiaceae) by normal phase column chromatography resulted in the isolation of perovskanol (1), a novel sesquiterpenoid possessing a 5/7/5 fused carbon ring skeleton. The structure of 1 was established by comprehensive spectroscopic data analysis including 1 D and 2 D NMR and HRESIMS. The antiprotozoal activity of compound 1 was evaluated against Trypanosoma brucei rhodesiense, T. cruzi, Leishmania donovani, Plasmodium falciparum and no promising activities were shown against all parasite tested.

Terpenoids and phenolics of Micromeria persica

Phytochemical investigation of the aerial parts of Micromeria persica led to the isolation of a new oleane type triterpenoid ester (1), together with six known compounds 2-7), comprising one phenyl ethanoid ester, one glycosylated flavonoid, two triterpenoids, and two steroids. Their structures were elucidated by interpretation of their one-dimensional and two-dimensional NMR spectra and completed by the analysis of the HRESIMS data. Compounds 1 and 3 were evaluated for their cytotoxic feature against human breast adenocarcinoma cell line (MDA-MB231) and human prostate cancer cell line (DU145). However, they did not show positive effect (IC₅₀ > 75µM).[Figure: see text].

Antiprotozoal Isoprenoids from Salvia hydrangea

Fractionation of the n-hexane extract of Salvia hydrangea afforded seven isoprenoids including six new compounds (1-6) and salvadione A (7). Their structures were established by comprehensive spectroscopic and spectrometric data analysis (1D and 2D NMR, HRMS). The absolute configuration of salvadione A (7) was established by single-crystal X-ray diffraction analysis with Cu/Kα radiation. In addition, the absolute configuration of all compounds was determined by electronic circular dichroism spectroscopy. A biosynthetic pathway for the formation of the scaffold of 1 is proposed. The antiprotozoal activity of the compounds against Trypanosoma brucei rhodesiense, Trypanosoma cruzi, Leishmania donovani, and Plasmodium falciparum was determined, and cytotoxicity was assessed in rat myoblast L6 cells. Perovskone C (2) exhibited good activity against P. falciparum (IC₅₀ 0.6 μM) and a selectivity index of 62.2.

Phytochemical Study of Salvia leriifolia Roots: Rearranged Abietane Diterpenoids with Antiprotozoal Activity

Phytochemical investigation of the lipophilic extract of the roots of Salvia leriifolia resulted in the isolation of the new rearranged abietane diterpenoids leriifoliol (1) and leriifolione (2), together with 10 known diterpenoids. Structure elucidations were performed via extensive NMR and HRESIMS data, and the absolute configurations of compounds 1 and 3-5 were established by evaluation of experimental and calculated ECD spectra. The antiplasmodial activity of the new isolates was assayed against Trypanosoma brucei rhodesiense, T. cruzi, Plasmodium falciparum, and Leishmania donovani and also toxicity against rat myoblast (L6) cells. Compound 1 displayed antimalarial and low cytotoxic activity with IC₅₀ values of 0.4 and 33.6 μM, respectively, and a selectivity index of 84. Compound 2 displayed activity against T. brucei, T. cruzi, and L. donovani, with IC₅₀ values of 1.0, 4.6, and 1.0 μM, respectively. Putative biosynthetic pathways toward the formation of 1, 2, and 3 are proposed. Leriifoliol (1) is the first 20- nor-9,10- seco-abietane, while 2 exhibits an uncommon 6-6-5 fused-ring system.

Eupatorin and Salvigenin Potentiate Doxorubicin-Induced Apoptosis and Cell Cycle Arrest in HT-29 and SW948 Human Colon Cancer Cells

Background: Cancer persists as one of the world’s most pressing maladies. Notable points about chemotherapy are drug side effects which are almost universally encountered. Emerging knowledge focusing on mechanisms of toxicity due to chemotherapy has led to characterization of novel methods, including the exploitation of natural compounds, in combination therapies. Flavonoids are natural polyphenolic compounds that play protective roles against tumor cell development. The focus of this study was apoptotic effects of two flavonoids, eupatorin and salvigenin, in combination with doxorubicin on a cellular model of colon cancer. Method: Upon establishing a non-effective dose of doxorubicin, and effective doses of eupatorin (100μM) and salvigenin (150μM) via MTT, morphological features of apoptosis were distinguished using DAPI staining and cell cycle blockage in the sub-G1 phase. Apoptosis was determined by annexin/ PI and western blotting. ROS levels and MMP were measured to show any role of mitochondria in apoptosis. Results: Co-administration of flavonoids with doxorubicin induced apoptosis via the mitochondrial pathway as mitochondrial membrane potential and ROS production were changed. Annexin/PI analysis demonstrated that apoptosis frequency was increased with the combination treatments in colon cancer cells. Finally, the combination of these flavonoids with doxorubicin increased the Bax/Bcl-2 ratio, caspase-3 expression and PARP cleavage. Conclusion: Combination of flavonoids with doxorubicin induces apoptosis and enhances effect on cancer cells which might allow amelioration of side effects by dose lowering.

Abietane and nor-abitane diterpenoids from the roots of Salvia rhytidea

Background

The genus Salvia is a rich source of structurally diverse terpenoids. Different species of the Salvia have been used in folk medicine of Iran and therefore attracted the attention of researchers for exploring their chemical constituents. In a project directed at structurally interesting bioactive metabolites from Iranian Lamiaceae, we studied Salvia rhytidea.

Results

Fractionation of the petroleum ether extract of the root of S. rhytidea led to the isolation of a new 20-nor-abietane diterpenoid (1), together with seven known compounds, comprising five abietane diterpenoids (2–6), and two rearranged abietanes (7, 8). Their structures were established by a combination of 1D and 2D NMR.

Conclusions

Our results showed that the root of S. rhytidea could be considered as a new and rich source of different types of abietane and rearranged abietane diterpenoids.