Toxicological Screening of Four Bioactive Citroflavonoids: In Vitro, In Vivo, and In Silico Approaches.

Many studies describe different pharmacological effects of flavonoids on experimental animals and humans. Nevertheless, few ones are confirming the safety of these compounds for therapeutic purposes. This study aimed to investigate the preclinical safety of naringenin, naringin, hesperidin, and quercetin by in vivo, in vitro, and in silico approaches. For this, an MTT-based cytotoxicity assay in VERO and MDCK cell lines was performed. In addition, acute toxicity was evaluated on Wistar rats by OECD Guidelines for the Testing of Chemicals (Test No. 423: Acute Oral Toxicity-Class Method). Furthermore, we used the ACD/Tox Suite to predict toxicological parameters such as hERG channel blockade, CYP450 inhibition, and acute toxicity in animals. The results showed that quercetin was slightly more cytotoxic on cell lines (IC50 of 219.44 ± 7.22 mM and 465.41 ± 7.44 mM, respectively) than the other citroflavonoids. All flavonoids exhibited an LD50 value > 2000 mg/kg, which classifies them as low-risk substances as OECD guidelines established. Similarly, predicted LD50 was LD50 > 300 to 2000 mg/kg for all flavonoids as acute toxicity assay estimated. Data suggests that all these flavonoids did not show significant toxicological effects, and they were classified as low-risk, useful substances for drug development.

Airway smooth muscle relaxant activity of Cordia dodecandra A. DC. mainly by cAMP increase and calcium channel blockade.

ETHNOPHARMACOLOGICAL RELEVANCE: The fight against chronic respiratory diseases needs the exploration of new active compounds with properties that contribute to diminish the symptoms or resolve the disease alongside current therapy. MATERIALS AND METHODS: Eight extracts obtained from the bark and leaves of a Mayan medicinal plant used to treat asthma, Cordia dodecandra A. DC., were investigated for their relaxant effect on rat isolated tracheal rings pre-contracted with carbachol [1 µM]. The underlying functional mode of action of the most effective extract was assessed and the chromatographic fingerprints of more active extracts were analyzed. RESULTS: The dichloromethane bark extract (DECd-b) was the most effective and potent (Emax= 87.57 ±â€¯1.32 %; EC50 = 392.7 ±â€¯5.18 µg/mL). DECd-b relaxant effect was maximized in presence of isoproterenol (ß-adrenergic agonist, [10 µM]) and theophylline (phosphodiesterase unspecific inhibitor, [10 µM]). DECd-b also showed efficient relaxation of KCl [80 mM]-induced contraction and inhibition of CaCl2-induced contraction. Pre-incubation with propranolol (non-selective ß-adrenergic antagonist, [10 µM]), SQ22536 (adenylyl cyclase inhibitor; [100 µM]), ODQ (guanylyl cyclase inhibitor; [10 µM]), l-NAME (nitric oxide synthase inhibitor; [10 µM]), indomethacin (a cyclooxygenase unspecific inhibitor; [10 µM]), glibenclamide (ATP-sensitive potassium channel blocker; [10 µM]) and 2-aminopyridine (voltage-gated potassium channel blocker [100 µM]) did not modify the DECd-b relaxant-effect curve. The chromatographic analysis of DECd-b suggests the cordiaquinones presence with double conjugated bounds such as menaquinone. CONCLUSIONS: Results suggest that DECd-b induces relaxation mainly by cAMP increase and Ca2+ channel blockade. The chromatographic profiles and UV spectrum of DECd-b and HECd-l suggest the presence of molecules with structure of meroterpenoid naphthoquinones. This work report scientific evidence of C. dodecandra medicinal specie, which contributes to the pharmacological and phytochemical background of C. dodecandra providing an added value to the traditional use of this specie.

Spasmolytic and Antibacterial Activity of Two Citrus sinensis Osbeck Varieties Cultivated in Mexico.

Antibacterial activity on ATCC strains of Escherichia coli, Salmonella enterica, Salmonella enteritidis, and Salmonella choleraesuis and spasmolytic effect on contraction on rat ileum trips were determinate. Eight organic extracts (hexanic and methanolic) of albedo (mesocarp) and flavedo (pericarp) of two varieties (Valencian and National) of Citrus sinensis (L.) Osbeck of Yucatán, México, were studied. Additionally, chromatographic fingerprints were obtained and correlated with their pharmacological effects. MAN, MAV, and HFN extract caused inhibition against S. choleraesuis (MIC: 1000 µg/mL) and S. enteritidis (MIC: 1000 µg/mL). Regarding the spasmolytic effect, the Valencian extracts variety was more efficient on spontaneous contraction, HAV (Emax = 51.98 ± 1.98%), MAV (Emax = 35.98 ± 1.42%), HFV (Emax = 68.91 ± 4.14%), and MFV (Emax = 51.28 ± 2.59%), versus National variety, HAN (Emax = 43.80 ± 6.32%), MAN (Emax = 14.62 ± 1.69%), HFN (Emax = 64.87 ± 3.04%), and MFN (Emax = 31.01 ± 3.92%). Chromatographic fingerprints of HFV and HFN were found to have some similar signals that belong to monoterpenes, whereas for HAN and HAV similar signals were found belonging to fatty acids and triterpenoids. Methanolic extracts showed signals of (1) furfural, (2) furfural acetone (3) furfuraldehyde and (4) ß-sitosterol compounds. Flavedo portion of C. sinensis possessed spasmolytic effect on rat ileum strips and antibacterial activity against Salmonella strains. This species is source for obtaining bioactive compounds with therapeutic potential in the treatment of infectious diarrhea.

Comparative fingerprint analyses of extracts from the root bark of wild Hippocratea excelsa and "Cancerina" by high-performance liquid chromatography.

A simple high-performance liquid chromatography method was developed for the identification and comparison of quinone-methide triterpenes in wild Hippocratea excelsa and "cancerina" to establish the chromatographic profile of these compounds in root bark. The essential chromatographic conditions for this method are based on a gradient system with a reversed-phase column (C18 ) using proportions of water, methanol, and tetrahydrofuran as mobile phases to correctly separate the signals at 254 and 420 nm and compare the signals to those reported in the literature. The chromatograms exhibit good resolution and precision. Statistical analysis showed that the chromatographic profiles of wild H. excelsa and cancerina do not exhibit significant differences (p≥0.05) in their area proportions or relative retention times. The method developed in this study is suitable for the identification of the major chemotaxonomic markers of the Celastraceae family and can be used for quality control of this herbal root bark, which has uses today in Mexican folk medicine.