Academic literature on the topic 'Taraxerol'

<p class="Abstract">Taraxerol is known to exhibit anti-inflammatory and anti-cancer activity. However, cytoprotective effect of taraxerol on hepatocytes has not been reported. In the present study, we investigated the hepatoprotective effect of taraxerol in the human hepatic L02 cells injured by hydrogen peroxide (H₂O₂). Taraxerol decreased H₂O₂-induced cell viability loss and lactate dehydrogenase release. Taraxerol also inhibited H₂O₂-induced cell apoptosis. Further, taraxerol attenuated H₂O₂-induced increase in cleaved-caspase-3 and cleaved-PARP. H₂O₂-activated p38 and JNK were also inhibited by taraxerol. These data suggest that taraxerol could protect the L02 cells against H₂O₂-induced apoptosis via suppression of p38 and JNK. Taraxerol may be an effective protective agent against oxidative stress-induced liver injury.</p>

A phytochemical investigation of the crude chloroform bark extract of Neolitsea dealbata from Paluma, north Queensland, Australia, revealed the two common triterpenoids, taraxerone and taraxerol, as well as three furanogermacranolide sesquiterpenoids, linderadine, linderalactone, and pseudoneolinderane. These compounds are reported for the first time from this plant. An ab initio investigation (DFT, B3LYP/6-31G* and post HF, MP2/6-31G**) of the Cope rearrangement of linderalactone has been carried out.

A novel oleanane-type triterpene, 15-chloro-β-amyrone (1), was isolated from Trichilia hirta, together with the known compounds taraxer-3-one (2) and β-taraxerol (3), along with two novel esters, 3-(isobutyryloxy)-2,2,4-trimethylpentyl palmitate (4) and 3-(isobutyryloxy)-2,2,3-trimethylpentyl stearate (5), and the known 3-hydroxy-2,2,4-trimethylpentyl isobutyrate (6). These compounds were characterized on the basis of their spectroscopic and HRSEIMS data and by comparison with literature data.

Jatropha tanjorensis leaves were collected, air dried and pulverised. The pulverised sample was extracted with solvents (n-hexane, ethylacetate and ethanol) of varying polarity to obtain the crude extracts.Repeated column and thin layer chromatographic separation of the crude extracts afforded two compounds which were characterised by their IR, MS, 1H and 13C-NMR spectral data. Comparison of the data withliterature confirmed the compounds to be taraxerol and taraxer-14-en-3-one.

Column chromatography of the acetone extract of the lichen Cladina macaronesica (Sephadex LH-20, silica gel and silver nitrate-im pregnated silica gel) afforded eight triterpenes identified by chemical and spectral m eans. α-Amyrenone, lupenone, taraxerol, taraxerone and /so-arborinol acetate were isolated for the first time from lichens and (-)-usnic acid and five mononuclear phenolic compounds were also obtained, four for the first time as natural products. The possible transformation of perlatolic acid into these phenolic compounds is briefly outlined.

A new 3β- O-vanilloyl-taraxerol, microcisin (1) and eight known compounds, 3β-taraxerol acetate (2), 3β-taraxerol (3), cholest-4-en-3-one (4), cholest-4-en-6β-ol-3-one (5), β-sitosterol (6), 7-hydroxycadalene (7), mellein (8) and vanillin (9), were isolated from the roots of Microcos tomentosa. The structures were determined by extensive analysis of their spectroscopic data. All isolated compounds were evaluated for their cytotoxicity against KB and HeLa cells.

Abstract The chemical composition of the leaf surface wax of Euphorbia lathyris L. was analysed using TLC, GC, GC-MS and NMR. A predominance of pentacyclic triterpenoids and primary alcohols was observed. They together constituted 60% of the total wax. Seven triterpenols: taraxerol, β-amyrin, lupeol, isomotiol, a-fernenol, simiarenol. Ψ-taraxasterol and eight triterpenones: taraxerone, β-amyrinone, lupenone, isomotione, a- and β-fernenone, simiarenone and filicanone were isolated. Among them , β-amyrin and lupeol were found esterified with homologous series of fatty acids. The minor part of wax was formed by long chained and predominantly saturated alkanes, wax esters, aldehydes and free fatty acids.

Hyperpigmentation is considered by many to be a beauty problem and is responsible for photoaging. To treat this skin condition, medicinal cosmetics containing tyrosinase inhibitors are used, resulting in skin whitening. In this study, taraxerol methyl ether (1), spinasterol (2), 6-hydroxyflavanone (3), (+)-dihydrokaempferol (4), 3,4-dihydroxybenzoic acid (5), taraxerol (6), taraxerone (7), and lupeol acetate (8) were isolated from Manilkara zapota bark. Their chemical structures were elucidated by analysis of their nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS) data, and by comparing them with data found in the literature. The in vitro antityrosinase, antioxidant, and cytotoxic activities of the isolated compounds (1–8) were evaluated. (+)-Dihydrokaempferol (4) exhibited higher monophenolase inhibitory activity than both kojic acid and α-arbutin. However, it showed diphenolase inhibitory activity similar to kojic acid. (+)-Dihydrokaempferol (4) was a competitive inhibitor of both monophenolase and diphenolase activities. It exhibited the strongest 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), and ferric reducing antioxidant power (FRAP) activities of the isolated compounds. Furthermore, (+)-dihydrokaempferol (4) also demonstrated potent cytotoxicity in breast carcinoma cell line (BT474), lung bronchus carcinoma cell line (Chago-K1), liver carcinoma cell line (HepG2), gastric carcinoma cell line (KATO-III), and colon carcinoma cell line (SW620). These results suggest that M. zapota bark might be a good potential source of antioxidants and tyrosinase inhibitors for applications in cosmeceutical products.

The main aim of this study was to isolate and characterise antifungal and antibacterial compounds from leaf extracts of Combretum molle which belonging to the Combretaceae family. C. molle is one of the commonly used medicinal plants in southern Africa for numerous ailments. Three animal fungal pathogens, namely, Candida albicans, Cryptococcus neoformans, Aspergillus fumigatus and five plant fungal pathogens, namely, Aspergillus niger, Aspergillus parasiticus, Fusarium oxysporum, Penicillium janthinellum, Rhizoctonia solani and four nosocomial bacteria Staphylococcus aureus, Enterococcus faecalis, Escherichia coli and Pseudomonas aeruginosa were used as test microorganisms for bioactive compounds in leaf extracts of C.molle. Experiments for phytochemical analysis were done using different C. molle leaf extracts which were made using acetone, methanol, ethanol, ethyl acetate, chloroform, butanol and hexane as extractants. Thin Layer Chromatography (TLC) fingerprints of different leaf extracts were developed in three mobile phase systems, EMW, CEF and BEA and detected with vanillin-sulphuric acid spraying agent. The different extracts of C. molle showed the presence of many different compounds with distinct retardation factors (Rf), separated according to their polarities. Bioautography was carried out to determine the number of active compounds and their Rf values. The TLC plates were developed in three mobile systems, each sprayed with either fungal or bacterial strains. In BEA bioautograms of A. fumigatus, clear zones of inhibition were observed at Rf values of 0.12, 0.23, and 0.40. In EMW bioautogram of C. albicans, clear zones of inhibition were observed at Rf value of 0.73, 0.81, 0.87. C. neoformans had weak growth inhibition. Most of the fungal and bacterial strains tested in the bioautography displayed susceptibility to the active compounds, with P. janthinellum and P. aeruginosa showing exceptional sensitivity. The minimum inhibitory concentrations (MIC) values ranged from 0.02 to 2.5 mg/ml against the tested pathogens. The acetone and ethyl acetate extracts had the best inhibitory activity against P. janthinellum with an MIC value of 0.02 mg/ml. The acetone extract of C. molle gave the highest total activity (775 ml/g) against P. janthinellum. C. albicans was the most resistant pathogen with an average MIC value of 0.56 mg/ml compared with the other tested strains. Extracts were active against both Gram-positive and Gram-negative strains. P. aeruginosa extracts had the highest average MIC value (0.24 mg/ml) among the tested bacterial strains. In general, there was good overall inhibitory activity by different extracts of C. molle. Bioassay-guided fractionation of DCM extract of the leaves of C. molle yielded 32 fractions. Further fractionation led to the isolation of five compounds (C1, C2, C3, C4 and C5). Compound C1 was selected for structure elucidation due a larger quantity isolated and higher antimicrobial activity compared with the other isolated compounds. Nuclear magnetic resonance (NMR) spectroscopy and mass spectroscopy (MS) was used to show that compound C1 was taraxerol, belonging to the taraxerane group. Antimicrobial activity of the isolated compound against P. janthinellum had an MIC value of 0.08 ug/ml. Although the compound taraxerol have been discovered in other plant species, it is reported for the first time from C. molle in the study. The results illustrate that crude extracts and compound taraxerol from C. molle can be used as either an antibacterial or antifungal, and warrants further investigation.
Dissertation (MSc)--University of Pretoria, 2017.
Paraclinical Sciences
MSc
Unrestricted