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Chemistry and Pharmacology of Naturally Occurring Flavoalkaloids
Published in Namrita Lall, Medicinal Plants for Cosmetics, Health and Diseases, 2022
Rashmi Gaur, Jyoti Gaur, Nikhilesh Kumar
In both the tonkinensines, the alkaloid part is derived from a cytosine unit. The absolute configuration of compounds 105 and 106 was established with the help of X-ray crystallography, CD spectra and their biogenetic origin. When tested against human breast cancer (MDA-MB-231) and cervical carcinoma (HeLa) cell lines, only (-)-tonkinensine B (106) showed moderate activity (IC50 of 24.3 µM against HeLa and 48.9 µM against MDA-MB-231) (Li et al., 2008a). Dejon et al. (2013) isolated a racemate compound, (-)-11-Azamedicarpin (107), from the roots of Robinia pseudoacacia, Linn., commonly known as the black locust tree, and is an aza-analog of the pterocarpan medicarpin (Dejon et al., 2013). Compound 107 showed modest activity against human promyelocytic leukemia cells (HL-60) (cell survival of 72% at 40 µM and 27% survival at 200 µM). Oxidation of 107 to its corresponding indole improved cytotoxicity, and the total synthesis of this compound was performed by Dejon and co-workers (2013).
Chemopreventive Agents
Published in David E. Thurston, Ilona Pysz, Chemistry and Pharmacology of Anticancer Drugs, 2021
The coumestans represent a group of natural products produced by plants through the oxidation of pterocarpan. Found in a variety of species, one of the best-known members of the group is coumestrol (described below), which is thought to be associated with some health benefits. Other members with related structures include wedelolactone and plicadin. Food sources containing high levels of coumestans include pinto and lima beans and split peas, but clover sprouts and alfalfa are particularly rich in these compounds.
Total Synthesis of Some Important Natural Products from Brazilian Flora
Published in Luzia Valentina Modolo, Mary Ann Foglio, Brazilian Medicinal Plants, 2019
Leonardo da Silva Neto, Breno Germano de Freitas Oliveira, Wellington Alves de Barros, Rosemeire Brondi Alves, Adão Aparecido Sabino, Ângelo de Fátima
In 2017, Yang et al. presented an interesting example of an asymmetric synthesis for the pterocarpan (+)-medicarpin (16; Figure 12.6), a type of isoflavonoid; the synthesis was performed in 12 steps with a 9% overall yield. (+)-Medicarpin 16 has already been isolated from several species of plants, among them some of Brazilian occurrence, and can be found in the petroleum extract of the roots of Muellera montana (Fabaceae; basionym: Lonchocarpus montanus; cabelouro, or carrancudo) (Magalhães et al., 2007; Santos, Braga, et al., 2009), in the benzene extract of the core of Dalbergia decipularis (Fabaceae; Sebastião-de-arruda) (de Alencar et al., 1972), and found in the Brazilian red propolis (Li et al., 2008). The strategy presented by Yang et al. for the asymmetric synthesis of 16 made use of a chiral oxazolidone auxiliary group to construct the two chiral centers in one step; reacting 17 with (R)-4-benzyl-2-oxazolidinone using n-butyllithium as a base gave 18 in good yield, which was then converted to 20via an Evans asymmetric aldol addition with the aldehyde 19.
Antimicrobial activity of flavonoids glycosides and pyrrolizidine alkaloids from propolis of Scaptotrigona aff. postica
Published in Toxin Reviews, 2023
T. M. Cantero, P. I. Silva Junior, G. Negri, R. M. Nascimento, R. Z. Mendonça
Quercetin methyl ethers, and methoxy chalcones, similar than that detected in young and adult leaflets of Mimosa tenuiflora, were detected in propolis from Apis mellifera and geopropolis from Scaptotrigona aff. depilis, collected in the state of Rio Grande do Norte, Brazil, indicating M. tenuiflora as resin source (Ferreira et al. 2017a, 2017b). Stigmasterol, taraxasterol, vanilic acid, caffeic acid, quercetin, luteolin, and apigenin were detected in propolis sample from Scaptotrigona depilis collected in the state of Mato Grosso do Sul, Brazil (Bonamigo et al. 2017). Flavonoid aglycones (mainly neoflavonoids, isoflavonoids) and pterocarpans were detected in extracts of propolis from Apis mellifera and Trigona sp (Okińczyc et al. 2020). Propolis samples from Tetragonisca angustula (Carneiro et al. 2016) and from Scaptotrigona species (Sawaya et al. 2009) independently of their geographic origin, presented diterpenic and triterpenic acids similar than that detected in flowers from Schinus terebinthifolius Raddi (Anacardiaceae) (Sawaya et al. 2009, Carneiro et al. 2016).
Antiproliferative Effect of Trifolium Pratens L. Extract in Human Breast Cancer Cells
Published in Nutrition and Cancer, 2019
Mozafar Khazaei, Mona Pazhouhi
A study documented the chemical profile of T. pratense extract using the high-performance liquid chromatography–ultraviolet (HPLC-UV) chromatogram. The results showed that T. pratense extract was composed of isoflavones, flavonoids, pterocarpans, coumarins and tyramine (21). Its main isoflavones are biohanin A, formononetin, daizdein, genistein, pratensein, prunetin, pseudobaptigenin, calycosin, methylorobol, afrormosin, texasin, irilin B, and irilone (22). Dietary flavonoids are the most abundant polyphenols in plant sources. Several plant-derived flavonoids (silymarin, genistein, quercetin, daidzein, luteolin, kaempferol, apigenin, and epigallocatechin 3-gallate) have been reported to have an antiproliferative effect on various cancers such as prostate, colorectal, breast, thyroid, lung, and ovarian. Their anticancer effect is mediated by activation of apoptosis, cell cycle arrest at G1 or G2/M phase, inhibition of metabolizing enzymes, reactive oxygen species formation, vascular endothelial growth factor and basic fibroblast growth factor. Also, some flavonoids have been reported to reduce cancer cells drug resistance. Genistein and daidzein, two member of flavonoid family, have noticeable antiproliferation effect against breast cancer, due to their structural similarity with estrogen. Anticancer effect quercetin, another member of flavonoid family, against colon cancer and glioma tumors is mediated by activation of autophagy signaling pathway. Nowadays, a variety of these flavonoids are used in dietary supplements, but none of them have been approved for clinical use (23). From pterocarpans family Indigocarpan, showed antiproliferative activity in human cancer cell lines via induction of Caspase dependent apoptosis pathway (24). Anticancer activity of coumarins is mediated by various pathways including inhibition of kinase, cell cycle progression, angiogenesis, heat shock protein (HSP90), telomerase, mitotic activity, carbonic anhydrase, monocarboxylate transporters, aromatase, and sulfatase (25).