Hepatoprotective and cytotoxic activities of Anvillea garcinii and isolation of four new secondary metabolites

Polyphenols of the Inuleae-Inulinae and Their Biological Activities: A Review

Polyphenols are ubiquitous plant metabolites that demonstrate biological activities essential to plant-environment interactions. They are of interest to plant food consumers, as well as to the food, pharmaceutical and cosmetic industry. The class of the plant metabolites comprises both widespread (chlorogenic acids, luteolin, quercetin) and unique compounds of diverse chemical structures but of the common biosynthetic origin. Polyphenols next to sesquiterpenoids are regarded as the major class of the Inuleae-Inulinae metabolites responsible for the pharmacological activity of medicinal plants from the subtribe (Blumea spp., Dittrichia spp., Inula spp., Pulicaria spp. and others). Recent decades have brought a rapid development of molecular and analytical techniques which resulted in better understanding of the taxonomic relationships within the Inuleae tribe and in a plethora of data concerning the chemical constituents of the Inuleae-Inulinae. The current taxonomical classification has introduced changes in the well-established botanical names and rearranged the genera based on molecular plant genetic studies. The newly created chemical data together with the earlier phytochemical studies may provide some complementary information on biochemical relationships within the subtribe. Moreover, they may at least partly explain pharmacological activities of the plant preparations traditionally used in therapy. The current review aimed to systematize the knowledge on the polyphenols of the Inulae-Inulinae.

Anti-inflammatory potential of some eudesmanolide and guaianolide sesquiterpenes

Ten sesquiterpene lactones isolated from Anvillea garcinii (Burm.f.) DC ethanolic extract were assessed for their anti-inflammatory potential by myeloperoxidase (MPO) activity assignment, and mice paw swelling model. 3α,4α-10β-trihydroxy-8α-acetyloxyguaian-12,6α-olide (1), epi-vulgarin (3), 9a-hydroxyparthenolide (4), garcinamine C (7), garcinamine D (8), garcinamine E (9), and 4, 9-dihydroxyguaian-10(14)-en-12-olide (10) showed explicit anti-inflammatory activity in rodent paw edema and MPO assignment. The findings of this study showed that the α-methylene γ-lactone moiety does not always guarantee an anti-inflammatory effect, but the presence of proline at the C3 of the lactone ring improves the binding of sesquiterpene lactones with MPO isoenzymes, resulting in a more potent inhibition.

Sesquiterpene Lactones from Vernonia tufnelliae: Structural Characterization and Biological Evaluation

The genus Vernonia is an extremely rich source of biologically active sesquiterpene lactones. The present report describes the spectroscopic structure elucidation and the cytotoxic and antimicrobial properties of five hitherto unknown germacranolide-like sesquiterpenoids and several known compounds. These new derivatives include a compound (1) with an unprecedented 10/5/5/6 tetracyclic framework featuring a hexahydro-1H,3H,7H-furo[3',4':3,4]furo[3,2-c]pyridin-1-one core resulting from an intramolecular cyclization cascade involving a methacrylate substituent and a low molecular weight amine. Furthermore, an elemane-germacranolide hybrid (2) and three amino acid-derived lactones (3-5) were characterized. A plausible biosynthetic pathway to the key alkaloid is presented, while shielding tensor calculations using DFT in combination with the DP4+ method were applied to elucidate its stereostructure. The newly characterized compounds along with ten known sesquiterpene lactones and phenolic compounds have been isolated from Vernonia tufnelliae, a medicinal plant from the western region of Cameroon. Their structures were consistent with spectroscopic and spectrometric data recorded. The present report is the first investigation of the chemistry and biology of V. tufnelliae.

Antimicrobial and Cytotoxic Activities of Selected Hieracium L. s. str. (Asteraceae) Extracts and Isolated Sesquiterpene Lactones

Antimicrobial and cytotoxic activities were tested for dried MeOH extracts of Hieracium calophyllum (CAL), H. coloriscapum (COL), H. pseudoschenkii (PSE), H. valdepilosum (VAL) and H. glabratum (GLA) herbs (flowering aerial parts), their 2 sesquiterpene lactones (SLs) 8-epiixerisamine A and crepiside E, and dried CH₂ Cl₂ extract of H. scheppigianum (SCH) herb. In microdilution test, extracts showed activity on all tested microorganisms (8 bacteria, 10 fungi). The best effect was exhibited by SCH and CAL on Salmonella Typhimurium (MIC=1.7-2.5 mg/mL MBC=3.4-5.0 mg/mL), and SCH and VAL on Candida albicans (MIC=2.5 mg/mL MFC=5.0 mg/mL). SLs showed notable effect on all tested fungi Aspergillus ochraceus, Penicillium funiculosum, C. albicans and C. krusei (MIC=0.15-0.4 mg/mL MFC=0.3-0.8 mg/mL). In MTT test, extracts inhibited growth of all tested cancer cells (HeLa, LS174 and A549), with the best effect on HeLa (IC₅₀ =148.1 μg/mL for SCH, and 152.3-303.2 μg/mL for MeOH extracts); both SLs were active against HeLa cells (IC₅₀ =46.2 μg/mL for crepiside E and 103.8 μg/mL for 8-epiixerisamine A). Extracts and SLs showed good safety profile on normal MRC-5 cells.

Phytochemical Analysis of Anvillea garcinii Leaves: Identification of Garcinamines F-H and Their Antiproliferative Activities

Anvillea garcinii is a medicinal plant used in the Arab region for intestinal diseases, lung and liver diseases, digestive problems, and as an antidiabetic agent. Repeated chromatographic purifications of A. garcinii leaves led to the isolation of three undescribed guaiane sesquiterpene derivatives, named garcinamines F-H, characterized by the presence of an amino acid unit, along with five known sesquiterpene lactones (garcinamines B-E and 9β-hydroxyparthenolide). The structures of the new compounds were established using spectroscopic (1D and 2D NMR) and spectrometric methods (ESIMS). Garcinamine H possesses a double bond at the Δ^1,10 position, a structural feature rarely reported in guaianolide-type sesquiterpenes. The antiproliferative activity of the isolated sesquiterpenes was screened against three different cancer cell lines, and 9β-hydroxyparthenolide and garcinamines C and D displayed significant effects against lung carcinoma (A549), colon carcinoma (LoVo), and breast carcinoma (MCF7) cell lines.

Phytochemical Composition and Biological Activities of Scorzonera Species

The genus Scorzonera comprises nearly 200 species, naturally occurring in Europe, Asia, and northern parts of Africa. Plants belonging to the Scorzonera genus have been a significant part of folk medicine in Asia, especially China, Mongolia, and Turkey for centuries. Therefore, they have become the subject of research regarding their phytochemical composition and biological activity. The aim of this review is to present and assess the phytochemical composition, and bioactive potential of species within the genus Scorzonera. Studies have shown the presence of many bioactive compounds like triterpenoids, sesquiterpenoids, flavonoids, or caffeic acid and quinic acid derivatives in extracts obtained from aerial and subaerial parts of the plants. The antioxidant and cytotoxic properties have been evaluated, together with the mechanism of anti-inflammatory, analgesic, and hepatoprotective activity. Scorzonera species have also been investigated for their activity against several bacteria and fungi strains. Despite mild cytotoxicity against cancer cell lines in vitro, the bioactive properties in wound healing therapy and the treatment of microbial infections might, in perspective, be the starting point for the research on Scorzonera species as active agents in medical products designed for miscellaneous skin conditions.

Antibacterial and Antifungal Sesquiterpenoids from Aerial Parts of Anvillea garcinii

Two new sesquiterpenoids belonging to the guaiane, 4α,9α,10α-trihydroxyguaia-11(13)en-12,6α-olide (1), and germacrane, 9β-hydroxyparthenolide-9-O-β-D-glucopyranoside (2), classes have been isolated from the leaves of the Saudi medicinal plant Anvillea garcinii along with seven known compounds (3–9). The structures of the new metabolites were elucidated by spectroscopic analysis, including one-dimensional (1D) and two-dimensional (2D) Nuclear Magnetic Resonance (NMR) and high-resolution electrospray ionization mass spectrometry (HR-ESIMS). The antimicrobial properties of 1–9 were screened against seven different pathogenic microbes, and compounds 1–3 showed a potent antifungal activity.

Montbresides A-D: antibacterial p-coumaroyl esters of a new sucrose-based tetrasaccharide from Crocosmia × crocosmiiflora (montbretia) flowers

Crocosmia × crocosmiiflora (montbretia) flowers yielded four esters (montbresides A-D) of a new sucrose-based tetrasaccharide, 3-O-β-d-glucopyranosyl-4´-O-α-d-rhamnopyranosyl-sucrose [β-d-Glc-(1 → 3)-α-d-Glc-(1↔2)-β-d-Fru-(4 ← 1)-α-d-Rha]. All four possess O-p-coumaroyl residues on C-3 of fructose and C-4 of α-glucose, plus O-acetyl residues on C-2 and C-3 of rhamnose and C-6 of fructose. Montbresides A and B are additionally O-acetylated on C-1 of fructose. The p-coumaroyls are trans- in montbresides A and C and cis- in B and D. Elemental compositions were determined from MS data, and structures from 1D and 2D NMR spectra. Monosaccharide residues were identified from selective 1D TOCSY spectra and TLC, and acylation sites from 2D HMBC spectra. Enantiomers were distinguished by enzymic digestion. Montbretia flower extracts were cytotoxic against six human cancerous cell-lines, but purified montbresides lacked cytotoxicity. Each montbreside displayed antibacterial activity against Staphylococcus aureus (minimal inhibitory concentration ~6 μg/ml). Montbretia is a potential source of new cytotoxins and antibacterial agents.

Sesquiterpene lactones from the methanol extracts of twenty-eight Hieracium species from the Balkan Peninsula and their chemosystematic significance

Four sesquiterpene lactones (SLs), including three undescribed proline-SL conjugates, the guaianolides calophyllamine A and 8-epiixerisamine A, and the eudesmanolide calophyllamine B, were isolated from the methanol extract of Hieracium calophyllum R. Uechtr. (Compositae) flowering heads. Another known guaianolide, crepiside E, was detected in Hieracium L. species for the first time. Their structures were elucidated using extensive 1D and 2D NMR spectroscopy in combination with HRMS. The isolated SLs were used as external standards for qualitative and quantitative LC-MS analysis of the dry methanol extracts of the flowering aerial parts of 28 Hieracium species from the Balkan Peninsula. Guaianolides were the dominant SLs in 27 species studied. The chemosystematic significance of detected SLs was evaluated using multivariate statistics (PCA, nMDS and UPGMA). Differentiation between the main groups was well supported. All four compounds significantly and equally contributed to the differences between the species. In addition, the eudesmanolide calophyllamine B could be a significant chemosystematic marker for H. sect. Villosa (Griseb.) Gremli s.l. and Glauciformia (Freyn) Zahn-Italica (Fr.) Av. Touv.

Antiulcer Activity of Different Extracts of Anvillea garcinii and Isolation of Two New Secondary Metabolites

Anvillea garcinii (AG, Asteraceae) commonly called “nougd” in Arabic is traditionally used for the treatment of different gastrointestinal disorders. This study evaluates the effects of ethanol, chloroform and n-butanol extracts of AG on ulcerative colitis induced by various ulcerogens in rats and the isolation of new secondary metabolites. Ethanol extracts of the leaf of the AG demonstrated a powerful anti-ulcer activity which could be attributed to the synergistic effect of its constituents. Therefore, our results would be the first proof of traditional use of AG as an antiulcer ailment.