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The Widening Panorama of Natural Products Chemistry in Brazil
Published in Luzia Valentina Modolo, Mary Ann Foglio, Brazilian Medicinal Plants, 2019
Maria Fátima das Graças Fernandes da Silva, João Batista Fernandes, Moacir Rossi Forim, Michelli Massaroli da Silva, Jéssica Cristina Amaral
Fruit waste provides an opportunity to obtain useful and valuable chemicals. For example, 15 million tons of citrus waste accumulates annually from the food and drink processing industry and other minor contributors. Often simply disposed of or incorporated into animal feed, this huge and naturally occurring resource is not being fully taken advantage of, although the means to do so have been successfully demonstrated. It has long been recognized that orange peel represents a promising source of hesperidin, a flavonoid. One million metric tons of peel residues are generated as a result of fruit processing, and thus, an extract of this residue could be considered for the isolation of hesperidin, other flavonoids, and many other compounds. Bellete et al. (2018) showed that several flavonoids present in citrus waste can be isolated using a faster and greener methodology. They observed the presence of flavonoids hesperitin (31), narigenin (32), nobiletin (33), chrysoerythol (34), sinensetin (35), isosakuranetin (36), 3,5,6,7,3′,4′- hexamethoxylflavone (37), 3,5,6,7,8,3′,4′-heptamethoxyflavone (38), 3,5,6,7,4′-pentamethoxyflavone (39) and 5-methoxysalvigenin (40) (Figure 3.8). This class of compounds presents a broad spectrum of biological activities as antioxidant, antimicrobial, antiviral, anti-inflammatory, etc. (Cao et al., 1997; Cushnie and Lamb, 2005). Lani et al. (2016) showed the potential of certain flavonoids against the Chikungunya virus, making this study a good example of the potential of agro-industrial waste to produce bioactive substances.
Nobiletin Alone or in Combination with Cisplatin Decreases the Viability of Anaplastic Thyroid Cancer Cell Lines
Published in Nutrition and Cancer, 2020
Diana P. Sousa, Marta Pojo, Ana T. Pinto, Valeriano Leite, Ana Teresa Serra, Branca M. Cavaco
Finally, the therapeutic relevance of natural extracts enriched in different bioactive compounds could be further explored in ATC, since the co-existence of distinct compounds may have additive or synergistic effects. With that in consideration, an OPE, enriched in PMFs such as nobiletin (10,30), was investigated in this study, and shown to inhibit metabolic viability of ATC cells more efficiently than nobiletin as an isolated compound, thus suggesting the presence of other compounds in the extract that may also have cytotoxic effects. However, OPE showed a similar toxicity in normal thyroid cells. Therefore, it will be important to perform further studies to explore the potential therapeutic application of these extracts and its isolated compounds (e.g., tangeretin and sinensetin) in ATC.
Polymethoxylated Flavones from Orange Peels Inhibit Cell Proliferation in a 3D Cell Model of Human Colorectal Cancer
Published in Nutrition and Cancer, 2018
Inês Silva, Marta F. Estrada, Carolina V. Pereira, Andreia Bento da Silva, Maria R. Bronze, Paula M. Alves, Catarina M.M. Duarte, Catarina Brito, Ana Teresa Serra
The effect of extraction time on the selectivity of PMF was evaluated by collecting different fractions of OPE each 30 min during 2 h. HPLC profiles evidenced that the PMFs were the main bioactive compounds extracted from orange peels (Fig. 1). Among all, OPE-F1 presented the highest PMF content, indicating that the first 30 min of the extraction was the most selective condition. The main compounds identified included sinensetin, nobiletin, and tangeretin that have been highlighted for their promising anticancer effect (8). Our results showed that in all fractions, sinensetin and nobiletin were present in higher quantity being up to 10 times higher than tangeretin (Table 1). This is in accordance with the study of Toledo-Guillén and co-authors that reported the same variation in PMF composition of citrus extracts (24). The antiproliferative effect of OPE fractions in HT29 cell monolayer was evaluated and all extracts inhibited cancer cell growth in a dose dependent manner (data not shown). OPE-F1 exhibited the highest antiproliferative activity presenting the lowest EC50 value (0.43 ± 0.02 mg extract/mL) and this effect is probably related with the highest PMF content of this fraction (Table 1). Since the main aim of this study was to investigate the antiproliferative effect of PMF-enriched extract in a 3D cell model of colorectal cancer, OPE-F1 was selected for further studies on HT29 cell spheroids.
Anticlastogenic, antimutagenic, and cytoprotective properties of Orthosiphon stamineus ethanolic leaves extract
Published in Drug and Chemical Toxicology, 2022
Dhamraa W. Al-Dulaimi, Aman Shah Abdul Majid, Hussein M. Baharetha, Mohamed B. Khadeer Ahamed, Sarah Furqan Faisal, Raghdaa Hamdan Al Zarzour, Chern Ein Oon, Amin Malik Shah Abdul Majid, Loiy E. Ahmed Hassan
HPLC analysis of 50% ethanolic extract of O. stamineus was performed by a previously reported method (Ahamed et al. 2012). About 100 mg of the extract was dissolved in 25 mL 50% methanol and sonicated for 20 min. All samples were filtered through a 0.5 µm Whatman filter. Similarly, all reference compounds (5 mg) were dissolved in 5 mL of methanol and then filtered. Contents of sinensetin, eupatorin, 3′-hydroxy-5, 6, 7, 4′-tetramethoxyflavone, and rosmarinic acid were detected and quantified using HPLC analysis techniques.