Triterpenoids from Salvia argentea var. aurasiaca (Pomel) Batt. & Trab. and their chemotaxonomic significance

A new triterpene saponin and known compounds from the polar extract of Salvia argentea L. and evaluation of their antioxidant activity

A new triterpene saponin, 2, 3, 21, 23-tetrahydroxyolean-12-en-28-oic-acid-28-O-β-D- glucosyl-(2''→1')-β-D-glucoside (1), was isolated from the n-butanol extract of dried aerial parts of Salvia argentea L. (Lamiaceae) in addition to two known flavonoids, apigenin 7-O-β-D-glucoside (2), threo-guaiacylglycerol 3-O-[6-O-p-hydroxybenzoyl]-β-D-glucoside (3), luteolin 7-O-β-D-glucoside (4), verbascoside (5) and rosmarinic acid (6). The structure elucidation of these compounds was based on analyses of spectroscopic data including 1D-, 2D-NMR and HR-ESI-MS techniques and by comparing their NMR data with those reported in the literature. Compound 6 exhibited the highest antioxidant activity in DPPH assay (IC50<3.00 µg/mL) which was better than the standards BHA, BHT, Trolox and ascorbic acid.

Salvirrane A-F, six undescribed nordrimane sesquiterpene derivatives from Salvia castanea Diels f. tomentosa Stib and their cytotoxic activities

Six undescribed nordrimane sesquiterpene derivatives, salvirrane A-F (1-6), were isolated from the roots and rhizomes of Salvia castanea Diels f. tomentosa Stib. Comprehensive spectral analysis and a quantum chemical calculation strategy were employed to determine their structures. These compounds represent four previously unreported nordrimane carbon skeletal types in Salvia genus, including 15-nor-drimane, 11,15-di-nor-drimane, 14,15-di-nor-drimane, and 11,14,15-tri-nor-drimane sesquiterpenes. All compounds were evaluated for their cytotoxic activities against several human cancer cell lines (A549, H460, Hep3B, MCF7, PC3, and HeLa). The results showed that 3 exhibited low activity against MCF7 cells (IC50,72.72 ± 6.95 μM) and moderate activity against HeLa cells (IC50, 9.80 ± 0.64 μM). Moreover, the EdU (5-ethynyl-2'-deoxyuridine) assay demonstrates that 3 displays dose-dependent efficacy in suppressing the proliferation of HeLa cells. Network pharmacology and molecular docking technology implied that 3 may potentially bind to Src (proto-oncogene tyrosine-protein kinase) to exert anti-proliferative activity.

New triterpenoids from the aerial parts of the Uygur medicine Salvia deserta

Phytochemical investigation on the aerial parts of Salvia deserta led to the isolation of eight new pentacyclic triterpenoids including three oleanane- (1 - 3) and five ursane-type (4 - 8) triterpenoids, whose structures were elucidated based on extensive spectroscopic analysis and quantum chemical calculation. Weak immunosuppressive potency was observed for compounds 1, 2, and 4 - 8 via inhibiting the secretion of cytokines TNF-α and IL-6 in LPS-induced macrophages RAW264.7 at 20 μM. In addition, compounds 1, 2, and 4 - 6 exhibited moderate protective activity on t-BHP-induced oxidative injury in HepG2 cells.

Triterpenoid saponins from Anagallis monelli ssp. linifolia (L.) Maire and their chemotaxonomic significance

Thirteen undescribed triterpenoid saponins named monellosides A-M, were isolated from the aerial parts of Anagallis monelli ssp. linifolia (L.) Maire, together with ten known oleanane-type glycosides. Their structures were elucidated by 1D and 2D-NMR spectroscopy (COSY, TOCSY, HSQC, HMBC and ROESY) as well as high resolution mass spectrometry (HR-ESI-MS) and acid hydrolysis. Monellosides A-M have a carbohydrate chain linked on the C-3 of the aglycone with a common β-d-glucopyranosyl-(1 → 4)-α-l-arabinopyranosyl sequence which was further glycosylated by a glucose and/or a xylose. The sequence β-d-xylopyranosyl-(1 → 2)-β-d-glucopyranosyl-(1 → 4)-[β-d-glucopyranosyl-(1 → 2)-]α-l-arabinopyranosyl was common to all the 13,28-epoxy-oleanane core skeleton except one compound. In order to discuss the reclassification of Anagallis in Primulaceae, we compared saponins from species of Myrsinaceae and Primulaceae families and showed that these species were characterized by a pentacyclic triterpenoid saponin with a 13,28-epoxy bridge skeleton. Our phytochemical results increase the knowledge of saponins of the genus Anagallis, their chemotaxonomy and stimulate the evaluation of the biological activities of these saponins.

Microbial transformation and inhibitory effect assessment of uvaol derivates against LPS and HMGB1 induced NO production in RAW264.7 macrophages

For the discovery of new pentacyclic triterpenes as a potential anti-inflammatory agent, microbial transformation of uvaol by Penicilium griseofulvum CICC 40293 and Streptomyces griseus ATCC 13273 was investigated. Stereoselective hydroxylation and epoxidation reactions were observed in the biotransformation. Moreover, six new metabolites were isolated and structurally elucidated by HR-ESI-MS and NMR spectrum. All the compounds were evaluated upon the inhibitory effects of nitric oxide (NO) release in RAW 264.7 cells induced by lipopolysaccharide (LPS) and high-mobility group box 1 (HMGB1). Among them, compound 3 (13, 28-epoxy-3β, 7β, 21β-trihydroxy-urs-11-ene) with the unique epoxy structure and compound 5 (3β, 21β, 24, 28-tetrahydroxy-urs-12-en-30-oic acid), exhibited a considerable inhibitory effect on both models while compound 2 (urs-12-ene-3β, 7β, 21β, 28-tetraol) showed a significant bias in the LPS-induced inflammatory response with IC₅₀ value of 2.22 μM. Therefore, this study could provide some insights on the discovery of the pentacyclic triterpene leads for the treatment of either DAMPs or PAMPs triggered inflammation.

Brahucins A and B, new triterpene lactones from Spiraea brahuica

Brahucins A (1) and B (2), the new oleanane-type triterpene lactones, have been isolated from the EtOAc-soluble fraction of Spiraea brahuica Boiss, along with betulinic acid (3), oleanolic acid (4), 3-O-(β-D-glucopyranosyl) oleanolic acid (5), vanillic acid (6) and caffeic acid (7), reported for the first time from this species. The structures of these compounds were elucidated by spectroscopic studies including MS, IR, 1D and 2D NMR.

Plant triterpenoid saponins: biosynthesis, in vitro production, and pharmacological relevance

The saponins are a diverse class of natural products, with a broad scale distribution across different plant species. Chemically characterized as triterpenoid glycosides, they posses a 30C oxidosqualene precursor-based aglycone moiety (sapogenin), to which glycosyl residues are subsequently attached to yield the corresponding saponin. Based on the chemically distinct aglycone moieties, broadly, they are divided into triterpenoid saponins (dammaranes, ursanes, oleananes, lupanes, hopanes, etc.) and the sterol glycosides. This review aims to present in detail the biosynthesis patterns of the different aglycones from a common precursor and their glycosylation patterns to yield the functionally active glycoside. The review also presents recent advances in the pharmacological activities of these saponins, particularly as potent anti-neoplastic pharmacophores, antioxidants, or anti-viral/antibacterial agents. Since alternate production pedestals for these pharmacologically important triterpenes via cell and tissue cultures are an attractive option for their sustainable production, recent trends in the variety and scale of in vitro production of plant triterpenoids have also been discussed.

Triterpenes from Salvia argentea var. aurasiaca and their antibacterial and cytotoxic activities

Five undescribed ursane-type triterpenes, identified as 1β,3β,15α-trihydroxy-urs-9(11)-12-diene (1), 1β,3β,15α,28-tetrahydroxy-urs-9(11),12-diene (2), 1β,3β-dihydroxy-urs-9(11),12-dien-28-al (3), 1β,3β,7β,15α,28-pentahydroxy-urs-12-ene (4), and 1β,3β,15α-trihydroxy-urs-11-en-28-al (5), together with five known compounds (6-10), were isolated from the acetone extract of the dried aerial parts of Salvia argentea L. var. aurasiaca (Pomel) Batt. et Trab. (Lamiaceae). Structures were elucidated on the basis of extensive spectroscopic analysis including HR-ESI-MS, 1D- and 2D-NMR techniques and comparison with literature data. The antibacterial evaluation of compounds 1-10 of the acetone extract of the dried aerial parts, in addition to nine compounds (11-19) previously isolated from the extract of the fresh aerial parts, by bioautography on Staphylococcus aureus followed by the determination of MIC values of active compounds by serial dilution technique against five bacteria, revealed that two compounds have an antibacterial effect comparable to antibiotics. The cytotoxic activity evaluation of compounds 1-19 showed that Six compounds exhibited an antiproliferative activity against K562 and HT1080 cells with IC₅₀ values ranging from 30.25 to 70.32 μM.

Triterpenic Acid Content and Cytotoxicity of Some Salvia Species From Iran

For prosperous domestication, breeding, and cultivation of a herbal species, it is important to screen its medicinally valuable compounds as well as its referred biological activity. Salvia L. species (Lamiaceae), distributed throughout the world, contain a wide range of secondary metabolites including terpenoids and phenolic derivatives. Betulinic acid (BA), oleanolic acid (OA), and ursolic acid (UA) are highly valuable triterpenic acids (TAs) because of their wide range of biological activities. The objective of the present work was to evaluate the BA, OA, and UA contents among 22 Salvia species native to Iran. TA content in the studied Salvia species was compared with that in Salvia officinalis as a commercial species. High-performance liquid chromatography with photodiode array detector results showed that the maximum content of BA (3.12 ± 0.03 mg/g dry weight [DW]) and OA (1.96 ± 0.05 mg/g DW) was determined in Salvia multicaulis. The highest content of UA (4.34 ± 0.1 mg/g DW) was quantified in S. officinalis L. followed by S. multicaulis (3.71 ± 0.08 mg/g DW). Salvia multicaulis exhibited significantly higher agro-morphological values than S. officinalis in traits related to plant width, leaf length, internode length, and inflorescence length. The cytotoxicities of both species were determined against human cancer cell lines using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The methanolic extract of S. multicaulis and S. officinalis showed cytotoxic effects against SH-SY5Y and MCF-7 cell lines, respectively. Both species were equally cytotoxic against the HL-60 cell line. This study provides scope for the selection of high-yielding species and genetic improvement through breeding and biotechnological programs in the future.

Triterpenoids

Covering 2014. Previous review: Nat. Prod. Rep., 2017, 34, 90-122 This review covers the isolation and structure determination of triterpenoids reported during 2014 including squalene derivatives, lanostanes, holostanes, cycloartanes, cucurbitanes, dammaranes, euphanes, tirucallanes, tetranortriterpenoids, quassinoids, lupanes, oleananes, friedelanes, ursanes, hopanes, serratanes, isomalabaricanes and saponins; 374 references are cited.

Bioactive Triterpenes from the Root of Salvia miltiorrhiza Bunge

Danshen (Salvia miltiorrhiza) is a well-known medicinal herb in the oriental medicine. The current study on bioactive triterpenoid in the root of S. miltiorrhiza led to the isolation of a new highly hydroxylated ursane-type triterpene, urs-12-ene-2α,3β,7β,16α-tetraol (1) and five known ones including 2β-hydroxypomolic acid (2), maslinic acid (3), asiatic acid (4), ursolic acid (5), and oleanolic acid (6). Their structures were elucidated on the basis of extensive spectroscopic analyses and comparison with literature data. The antiproliferative testing against HL-60 cells revealed that the new compound 1 and ursolic acid (5) showed weak and moderate activities with IC50 values of 42.2 and 11.7 μM. In addition, compounds 1-3 showed inhibitory effect on ghrelin activity. Copyright © 2017 John Wiley & Sons, Ltd.

Characterization and function of the 3-hydroxy-3-methylglutaryl-CoA reductase gene in Alisma orientale (Sam.) Juz. and its relationship with protostane triterpene production

Protostane triterpenes from Alisma orientale (Sam.) Juz. have exhibited distinct pharmacological properties that are currently in high demand. 3-Hydroxy-3-methylglutaryl-CoA reductase (HMGR) is considered the first rate-limiting enzyme in isoprenoid biosynthesis via the mevalonic acid (MVA) pathway. In this study, we cloned a full-length cDNA of A. orientale (Sam.) Juz. HMGR (AoHMGR; 2252 bp; GenBank accession no. KP342318) with an open reading frame (ORF) of 1809 bp. The deduced protein sequence contained four conserved motifs and exhibited homology with HMGR proteins from other plants. We next expressed the cloned gene in Escherichia coli BL21 (Rosetta) cells, collected the expressed products, and incubated those with 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) to determine enzymatic activity. GC/MS analysis revealed that the products were able to catalyze HMG-CoA and NADPH to form MVA. The purified protein was used to immunize New Zealand rabbits and prepare an antibody against AoHMGR. Western blot results demonstrated that the antibodies specifically recognized AoHMGR protein in A. orientale (Sam.) Juz. We then established a rapid test to detect AoHMGR protein in the plant, and found the tuber to be the most AoHMGR protein-abundant organ in A. orientale (Sam.) Juz. Furthermore, we detected the expression level of AoHMGR and contents of the main active component, Alisol B 23-acetate, at different growth phases of A. orientale (Sam.) Juz. A significant positive correlation was identified, indicating that AoHMGR represents a key enzyme in the synthetic pathway of protostane triterpenes.

The chemistry and biological activities of natural products from Northern African plant families: from Ebenaceae to Solanaceae

Traditional medicinal practices significantly affect the livelihoods of populations in countries with developing economies.