Flavonoid Distribution during the Development of Leaves, Flowers, Stems, and Roots ofRosmarinus officinalis. Postulation of a Biosynthetic Pathway

Abstract

The distribution of seven flavonoids, eriocitrin, luteolin 3'-O-beta-d-glucuronide, hesperidin, diosmin, isoscutellarein 7-O-glucoside, hispidulin 7-O-glucoside, and genkwanin, has been studied in Rosmarinus officinalis leaves, flowers, stems, and roots during plant growth. The maximum level reached by luteolin 3'-O-beta-d-glucuronide in leaves during June-August suggests the existence of a delay between the activation of the enzymes involved in the flavanone and flavone biosynthesis. The presence of hesperidin and diosmin in the vascular system is significant, and hesperidin shows even higher levels than the phenolic diterpenes and rosmarinic acid. The distribution of flavonoids observed in R. officinalis suggests a functional and structural relationship between phytoregulators and flavonoids, where flavonoids would be "protectors" of the activity of phytoregulators. A hypothesis for the general pathway of biosynthesis of these compounds in plants of the family Labiatae is proposed.

Revisiting Greek Propolis: Chromatographic Analysis and Antioxidant Activity Study

“…Isosakuranetin is also reported to be biosynthesized from naringenin via an O -methyltransferase enzyme expressed in E. coli [68]. Luteolin’s biosynthesis in Rosmarinus officinalis has been postulated by del Bano et al [69]. In this work, naringenin was proposed to be hydroxylated to eriodictyol and finally converted to luteolin by the enzyme flavone synthase.…”

Effect of Drying on the Antioxidant Capacity and Concentration of Phenolic Compounds in Different Parts of the Erythrina americana Tree

“…Thus, this part of the plant has a higher antioxidant activity. Many reports have suggested that in the leaves, the stress level is high; for this reason more pigments quantity are generated, and this protects the leaf tissues from photochemical damage (del Baño et al 2004;Chew et al 2009). …”

“…As this process is able to trigger the production of highly reactive chemical species at a cellular level, the leaf tissues are responsible for the generation of highly effective antioxidants that are capable of eliminating free radicals and minimizing oxidative damage (del Baño et al 2004;Chew et al 2009). …”

Effects of Herbal Supplements on Drug Glucuronidation. Review of Clinical, Animal, andIn VitroStudies

“…This glycosylated flavonoid is found in citrus, hyssop, and rosemary and is commonly used for its venotonic effects [57][58][59]. In Europe, it is prescribed for treatment of venous insufficiency while in the US, it is marketed as a food supplement [60,61].…”