José Antonio Del Río

Accumulation of furanocoumarins by Bituminaria bituminosa in relation to plant development and environmental stress

Bituminaria bituminosa (L.) C.H. Stirton (Fabaceae) accumulates high concentrations of the furanocoumarins (FCs) angelicin and psoralen, which protect against infection and herbivory. The effects on FC accumulation of the exposure of two populations of B. bituminosa to abiotic stress (cold, heat and drought) under field conditions were determined, as well as the effect of temperature under controlled conditions, in hydroponic culture. In field conditions, psoralen and angelicin levels in the leaf dry matter were 400-6000 and 1500-11,000 μg g(-), respectively. There were significant effects of population on the psoralen concentration and psoralen:angelicin ratio. In hydroponic culture, exposure to a diurnal temperature of 33 °C increased FC levels in population Calnegre but not in Llano del Beal, compared with plants grown at 22 °C; however, high summer temperatures in the field (>30 °C) did not coincide with the highest leaf FC levels, since the plants accumulated FCs preferentially in the fruits. Hence, leaf FC levels were higher in winter. Irrigation, to alleviate water stress in the semi-arid conditions, increased the fruit psoralen concentration but produced only minor decreases in leaf FC levels. There was a significant, positive correlation (P < 0.001) between the FC and nitrogen concentrations in the plant organs analysed (both increased in the order: fruits > growing leaves > mature leaves), reflecting their respective contributions to plant fitness. The genetically- and developmentally-regulated accumulation of FCs by B. bituminosa is altered by short-term variations in environmental conditions, particularly temperature.

Neodiosmin, a flavone glycoside of Citrus aurantium

Abstract The flavone neodiosmin (5,7,3′-trihydroxy-4′-methoxyflavone 7β-neohesperidoside) has been isolated and identified from the leaves of Citrus aurantium . 1 H and 13 C NMR data are given for this compound.

Furanocoumarins: Biomolecules of Therapeutic Interest

Abstract Furanocoumarins are a subgroup of phenolic compounds included in the coumarins group. They can be subdivided into two types: linear, generically known as psoralens, among which are included psoralen, xanthotoxin, and bergapten, and angular, generically known as angelicins, including angelicin, sphondin, and pimpinellin. Linear furanocoumarins have been identified in a great variety of plant families, the highest concentrations being found in Apiaceae, Rutaceae, Leguminosae, and Moraceae. Angular furanocoumarins are less widely distributed and are principally confined to the Apiaceae and Leguminosae. Psoralen-containing plants have been used for centuries in a popular medicine to treat vitiligo, a skin disease characterized by lack of pigmentation. Different methods have been used for the extraction, separation, and analysis of furanocoumarins: supercritical fluid extraction, solid-phase extraction, thin-layer chromatography, high-performance liquid chromatography, high-performance liquid chromatography–mass spectrometry, high-speed countercurrent chromatography, gas chromatography, gas chromatography–mass spectrometry, capillary electrophoresis, and pressurized capillary electrochromatography. Furanocoumarins are typical phototoxic compounds that produce photodermatitis in combination with UV light exposure and cytotoxic and mutagenic disorders. At molecular level, furocoumarins bind to cellular constituents such as proteins and lipids, damaging lysosomes, leading to the formation of reactive oxygen species and contributing to the formation of novel antigens by covalent modification of proteins. Furocoumarins are well known for interfering with drug metabolism, in particular with cytochrome P450 (CYP). On the other hand, furanocoumarins possess mutagenic and carcinogenic properties due to their ability to intercalate into dsDNA and create covalent cross-links primarily with thymidine residues. Since the discovery of furanocoumarins and other structurally related biomolecules, extensive research on different aspects of therapeutical interest has been realized due to the exclusive behavior of these compounds when irradiated with UVA light. These properties have made possible the use of these molecules in PUVA (combination therapy of psoralen and UVA radiation) or extracorporeal photopheresis for the treatment not only of many skin diseases such as vitiligo or psoriasis but also of several autoimmune diseases (systemic lupus erythematosus, Crohns disease, type 1 diabetes mellitus, or multiple sclerosis) and for the treatment of cutaneous T-cell lymphoma, solid organ transplant rejection, and graft versus host disease. Importantly, these compounds alone or in combination with other drugs represent promising candidates to develop new therapies or improve the existing ones. This chapter looks at the structures of furanocoumarins, their presence in plants, analytic methods, their pharmacological properties, and their therapeutic uses.