Sakuranetin and its therapeutic potentials - a comprehensive review

Biofortified Rice Provides Rich Sakuranetin in Endosperm

Sakuranetin plays a key role as a phytoalexin in plant resistance to biotic and abiotic stresses, and possesses diverse health-promoting benefits. However, mature rice seeds do not contain detectable levels of sakuranetin. In the present study, a transgenic rice plant was developed in which the promoter of an endosperm-specific glutelin gene OsGluD-1 drives the expression of a specific enzyme naringenin 7-O-methyltransferase (NOMT) for sakuranetin biosynthesis. The presence of naringenin, which serves as the biosynthetic precursor of sakuranetin made this modification feasible in theory. Liquid chromatography tandem mass spectrometry (LC-MS/MS) validated that the seeds of transgenic rice accumulated remarkable sakuranetin at the mature stage, and higher at the filling stage. In addition, the panicle blast resistance of transgenic rice was significantly higher than that of the wild type. Specially, the matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) imaging was performed to detect the content and spatial distribution of sakuranetin and other nutritional metabolites in transgenic rice seeds. Notably, this genetic modification also did not change the nutritional and quality indicators such as soluble sugars, total amino acids, total flavonoids, amylose, total protein, and free amino acid content in rice. Meanwhile, the phenotypes of the transgenic plant during the whole growth and developmental periods and agricultural traits such as grain width, grain length, and 1000-grain weight exhibited no significant differences from the wild type. Collectively, the study provides a conceptual advance on cultivating sakuranetin-rich biofortified rice by metabolic engineering. This new breeding idea may not only enhance the disease resistance of cereal crop seeds but also improve the nutritional value of grains for human health benefits.

Interaction of sakuranetin with unsaturated lipids forming Langmuir monolayers at the air-water interface: A biomembrane model

This study investigates the interaction between sakuranetin, a versatile pharmaceutical flavonoid, and monolayers composed of unsaturated phospholipids, serving as a surrogate for cell membranes. The phospholipids were 1-palmitoyl-2-oleoyl-glycero-3-phosphocholine (POPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE). We conducted a series of experiments to comprehensively investigate this interaction, including surface pressure assessments, Brewster angle microscopy (BAM), and polarization-modulated infrared reflection-absorption spectroscopy (PM-IRRAS). Our findings unequivocally demonstrate that sakuranetin interacts with these phospholipids, expanding the monomolecular films. Notably, regarding POPC, the presence of sakuranetin led to a reduction in stability and a decline in surface elasticity, which can likely be attributed to intricate molecular rearrangements at the interface. The visual evidence of aggregations in BAM images reinforces the interactions substantiated by PM-IRRAS, highlighting sakuranetin's interaction with the polar and nonpolar regions of POPC. However, it is worth noting that these aggregations do not appear to contribute significantly to the viscosity of the mixed film, and our investigations did not reveal any substantial hysteresis. In contrast, when examining POPE, we observed a minor reduction in thermodynamic stability, indicative of fewer rearrangements within the monolayer. This notion was further reinforced by the limited presence of aggregations in the BAM images. Sakuranetin also increased the rigidity of the lipid monolayer; nevertheless, the monolayer remained predominantly elastic, facilitating easy re-spreading on the surface, especially for the first lipid. PM-IRRAS analysis unveiled interactions between sakuranetin and POPE's polar and nonpolar segments, compellingly explaining the observed monolayer expansion. Taken together, our data suggest that sakuranetin was more effectively incorporated into the monomolecular layer of POPE, indicating that membranes comprised of POPC might exhibit a greater degree of interaction in the presence of this pharmacologically active compound.

Sakuranetin as a Potential Regulator of Blood Pressure in Spontaneously Hypertensive Rats by Promoting Vasorelaxation through Calcium Channel Blockade

Natural compounds, known for diverse pharmacological properties, have attracted attention as potential sources for hypertension treatment. Previous studies have revealed the hypotensive effect and vascular relaxation of prunetin, a natural compound derived from Prunus yedoensis. However, the potential blood pressure-lowering and vasorelaxant effects of sakuranetin, another representative compound found in plants belonging to the genus Prunus, have remained unexplored. We aimed to fill this gap by investigating the hypotensive and vasorelaxant effects of sakuranetin in rats. Results indicated that sakuranetin, particularly in the sakuranetin 20 mg/kg group, led to significant reductions in systolic blood pressure (SBP) and diastolic blood pressure (DBP) by -14.53 ± 5.64% and -19.83 ± 6.56% at 4 h after administration. In the sakuranetin 50 mg/kg group, the SBP and DBP decreased by -13.27 ± 6.86% and -16.62 ± 10.01% at 2 h and by -21.61 ± 4.49% and -30.45 ± 5.21% at 4 h after administration. In addition, we identified the vasorelaxant effects of sakuranetin, attributing its mechanisms to the inhibition of calcium influx and the modulation of angiotensin II. Considering its hypotensive and vasorelaxant effects, sakuranetin could potentially serve as an antihypertensive agent. However, further research is required to evaluate the safety and long-term efficacy.