Increased vascular eNOS and cystathionine-γ-lyase protein after 6 weeks oral administration of 3, 5, 7, 3', 4'-pentamethoxyflavone to middle-aged male rats

Insights into the formulation properties, biocompatibility, and permeability of poorly water-soluble methoxyflavones with PEG400 and propylene glycol

Herein, thermal and non-thermal techniques were used to elucidate the putative physical and chemical interactions between poorly water-soluble Kaempferia methoxyflavones and PEG400/propylene glycol. Additionally, the biocompatibility of methoxyflavone-glycol solutions was evaluated using Caco-2 cells whereas the absorptive transport was investigated by measuring the apparent permeability coefficient (P app) of the methoxyflavones and transepithelial electrical resistance (TEER) of the Caco-2 cell monolayer. Data from differential scanning calorimetry, Fourier-transform infrared (FTIR), and proton nuclear magnetic resonance (1H NMR) spectroscopic analysis revealed physico-chemical compatibility between the three methoxyflavones and PEG400/propylene glycol. Furthermore, PEG400 and propylene glycol solutions of the methoxyflavones were shown to be compatible with Caco-2 cells at pharmacologically effective concentrations. In vitro transport studies across the Caco-2 cell monolayer revealed high P app values of 24.07 × 10-6 to 19.63 × 10-6 cm s-1 for PEG400 solutions of the methoxyflavones. The TEER values of the Caco-2 cell monolayers indicated that the increased drug transport was partly due to increased tight junction openings, but without compromising the epithelial barrier integrity. The good pharmaceutical and biocompatibility profiles, as well as improved transport of the methoxyflavones in PEG400 and propylene glycol solutions, are suggestive of the worthiness of this approach for further consideration pertaining to the development of these drugs into oral liquid dosage forms.

Kaempferia parviflora and Its Methoxyflavones: Chemistry and Biological Activities

Kaempferia parviflora (KP), a health-promoting herb, has been traditionally used for treating a variety of diseases. Pharmacological studies have claimed the various benefits from KP and its main effective methoxyflavones, including cellular metabolism-regulating activity, anticancer activity, vascular relaxation and cardioprotective activity, sexual enhancing activity, neuroprotective activity, antiallergic, anti-inflammatory, and antioxidative activity, antiosteoarthritis activity, antimicroorganism activity, and transdermal permeable activity. These might be associated with increased mitochondrial functions and activated cGMP-NO signaling pathway. However, the underlying molecular mechanisms of KP and its methoxyflavones are still under investigation. The clinical applications of KP and its methoxyflavones may be limited due to their low bioavailability. But promising strategies are on the way. This review will comprehensively discuss the biological activities of KP and its methoxyflavones.

Vasodilator Activity of Compounds Isolated from Plants Used in Mexican Traditional Medicine

Arterial hypertension is one of the main risk factors in the development of cardiovascular diseases. Therefore, it is important to look for new drugs to treat hypertension. In this study, we carried out the screening of 19 compounds (triterpenes, diterpenes, sesquiterpenes, lignans, and flavonoids) isolated from 10 plants used in Mexican traditional medicine to determine whether they elicited vascular smooth muscle relaxation and, therefore, could represent novel anti-hypertension drug candidates. The vasorelaxant activity of these compounds was evaluated on the isolated rat aorta assay and the results obtained from this evaluation showed that three compounds induced a significant vasodilatory effect: meso-dihydroguaiaretic acid [half maximal effective concentration (EC₅₀), 49.9 ± 11.2 µM; maximum effect (Emax), 99.8 ± 2.7%]; corosolic acid (EC₅₀, 108.9 ± 6.7 µM; Emax, 96.4 ± 4.2%); and 5,8,4′-trihydroxy-3,7-dimethoxyflavone (EC₅₀, 122.3 ± 7.6 µM; Emax, 99.5 ± 5.4%). Subsequently, involvement of the NO/cyclic guanosine monophosphate (cGMP) and H₂S/ATP-sensitive potassium channel (K_ATP) pathways on the vasodilator activity of these compounds was assessed. The results derived from this analysis showed that the activation of both pathways contributes to the vasorelaxant effect of corosolic acid. On the other hand, the vasodilator effect of meso-dihydroguaiaretic acid and 5,8,4′-trihydroxy-3,7-dimethoxyflavone, partly involves stimulation of the NO/cGMP pathway. However, these compounds also showed an important endothelium-independent vasorelaxant effect, whose mechanism of action remains to be clarified. This study indicates that meso-dihydroguaiaretic acid, corosolic acid, and 5,8,4′-trihydroxy-3,7-dimethoxyflavone could be used as lead compounds for the synthesis of new derivatives with a higher potency to be developed as drugs for the prevention and treatment of cardiovascular diseases.