The glycosidic precursor of (Z)-5-ethylidene-2(5H)-furanone in Halocarpus biformis juvenile foliage

Arbutin: Occurrence in Plants, and Its Potential as an Anticancer Agent

Arbutin, a hydroquinone glucoside, has been detected in ca. 50 plant families, especially in the plants of the Asteraceae, Ericaceae, Proteaceae and Rosaceae families. It is one of the most widely used natural skin-whitening agents. In addition to its skin whitening property, arbutin possesses other therapeutically relevant biological properties, e.g., antioxidant, antimicrobial and anti-inflammatory, as well as anticancer potential. This review presents, for the first time, a comprehensive overview of the distribution of arbutin in the plant kingdom and critically appraises its therapeutic potential as an anticancer agent based on the literature published until the end of August 2022, accessed via several databases, e.g., Web of Science, Science Direct, Dictionary of Natural Products, PubMed and Google Scholar. The keywords used in the search were arbutin, cancer, anticancer, distribution and hydroquinone. Published outputs suggest that arbutin has potential anticancer properties against bladder, bone, brain, breast, cervix, colon, liver, prostate and skin cancers and a low level of acute or chronic toxicity.

Arbutin Derivatives Isolated from Ancient Proteaceae: Potential Phytochemical Markers Present in Bellendena, Cenarrhenes, and Persoonia Genera

Extensive phytochemical studies of the paleoendemic Tasmanian Proteaceae species Bellendena montana, Cenarrhenes nitida, and Persoonia gunnii were conducted employing pressurized hot water extraction. As part of these studies, six novel glycosides were isolated, including rare examples of glycoside-containing natural products featuring tiglic acid esters. These polar molecules may represent potential phytochemical markers in ancient Proteaceae.

Trichoderpyrone, a Unique Polyketide Hybrid with a Cyclopentenone-Pyrone Skeleton from the Plant Endophytic Fungus Trichoderma gamsii

Trichoderpyrone (1), a unique polyketide with a cyclopentenone-pyrone hybrid skeleton, was isolated from the plant endophytic fungus Trichoderma gamsii. The structure of 1 was determined by detailed analysis of NMR data together with comparison of chemical shift values of similar fragments. The relative and absolute configurations were established by NOESY correlations and CD experiment. Trichoderpyrone (1) displayed weak cytotoxic activities against A549, HepG2, and HeLa cancer cell lines. 1 might originate from a hybrid biosynthetic pathway through two nonreduced (NR) polyketide megasynthetases.

Phytochemical constituents of Mongolian traditional medicinal plants, Chamaerhodos erecta and C. altaica, and its constituents prevents the extracellular matrix degradation factors

Activity-guided isolation of the n-butanol fraction of Chamaerhodos erecta and water soluble fraction of C. altaica resulted in the isolation of 39 compounds, including new compounds identified as 4,5-dihydroxybenzaldehyde-3-O-β-D-glucopyranoside (1) from C. erecta and quercetin-3-O-β-D-glucuronopyranosyl-4'-O-β-D-glucopyranoside (2) from C. altaica. A total of 37 other compounds were identified based on physico-chemical properties and spectroscopic data. Antioxidative activity was evaluated using a DPPH radical-scavenging method, hyaluronidase inhibitory activity, and advanced glycation end products production inhibitory activity of isolated compounds. Some flavonols (4, 6, 9-11, 14, 15), catechins (18, 19), an amino acid (20), a lignan glucoside (23), and tannins (29-39) exhibited potential a free radical scavenging activity while the new compound (1) showed weak activity. A catechin (18) and some of the tannins (32, 33, 35, 36, 38) had moderate hyaluronidase inhibitory activity. Some of flavonoids and tannins prevented advanced glycation end products production, and the IC₅₀ of compounds 3, 9, 14-16, 33, 34, 36, 38, and 39 were determined.

Ranunculin

In the title mol-ecule {systematic name: (5S)-5-[(β-d-gluco-pyranos-yloxy)meth-yl]furan-2(5H)-one}, C(11)H(16)O(8), the five-membered ring is essentially planar, the maximum deviation being 0.0151 (13) Å for the O atom. The six-membered ring adopts a chair conformation with puckering parameters Q = 0.581 (2) Å, θ = 9.0 (2)° and ϕ = 39.7 (13)°, and with all of the substituents of the glucoside unit having normal equatorial orientations. The crystal structure is stabilized by extensive O-H⋯O and C-H⋯O hydrogen bonding, resulting in a three-dimensional network.

Two new compounds from the marine Nigrospora sphaerica

Two new compounds, 1-(5-oxotetrahydrofuran-2-yl)ethyl 2-phenylacetate (1) and 3-hydroxybutan-2-yl 2-hydroxy-3-phenylpropanoate (2), along with three known compounds, harzialactone A (3), benzeneethanol 4-hydroxy-1-acetate (4), and 1,4-dioxane-2,5-dione-3,6-bis(penylmethyl)-homopolymer (5), have been isolated from the fungus Nigrospora sphaerica. Their structures were determined on the basis of chemical and spectroscopic methods.

Arbutin-2′-sulphonyl from the infusion of Ilex theezans leaves

A sulphate arbutin derivative was isolated from the leaves of Ilex theezans, an adulterant of mate (Ilex paraguariensis). The structure was determined by spectral analysis.

Synthesis of furanone-based natural product analogues with quorum sensing antagonist activity

The synthesis of 5- and 3-(1'-hydroxyalkyl)-substituted 5H-furan-2-ones 4a-d and 8a-d as well as 5-alkylidene-5H-furan-2-ones 5a-d is described. A study of the structure-activity relationship of these furanone-based natural product analogues towards two different quorum sensing systems is reported. Although the synthesized compounds are not as potent quorum sensing inhibitors as some natural counterparts and a synthetic analogue hereof, interesting structure-activity relationships are seen.

Flavonoid and benzophenone glycosides from Coleogyne ramosissima

A benzophenone glucoside and two flavonol glycosides were isolated together with 27 known polyphenols from the aerial parts of Coleogyne ramosissima, and their structures were elucidated by spectroscopic and chemical methods as iriflophenone 2-O-beta-glucopyranoside, isorhamnetin 3-O-2G-rhamnopyranosylrutinoside-7-O-alpha-rhamnopyranoside and limocitrin 3-O-rutinoside-7-O-beta-glucopyranoside, respectively.

Antimicrobial and cytotoxic phenolic glycoside esters from the New Zealand tree Toronia toru

Two new compounds, 4-hydroxyphenyl 6-O-(4-hydroxy-2-methylenebutanoyl)-beta-D-glycopyranoside (1) and 4-hydroxyphenyl 6-O-[(3R)-3,4-dihydroxy-2-methylenebutanoyl]-beta-D-glucopyranosid e (2), have been isolated from foliage of Toronia toru. Compound 2 was the main antimicrobial component (7 mg/g of dry foliage) of the crude extract and also showed significant cytotoxic activity against P-388 leukemia cells.