Biotechnology
N. Nematshahi; P. Abrishamchi; T. Radjabian; S.A. Salami
Abstract
Salvia leriifolia Benth. is one of the native Iranian medicinal plants which has been received attention in recent years due to its numerous therapeutic properties. The pharmaceutical properties of this species have been attributed to the presence of phenolic compounds, especially phenolic acids. The ...
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Salvia leriifolia Benth. is one of the native Iranian medicinal plants which has been received attention in recent years due to its numerous therapeutic properties. The pharmaceutical properties of this species have been attributed to the presence of phenolic compounds, especially phenolic acids. The present study investigated the effect of plant age (phenology) on the gene expression and activity of phenolic acid-biosynthetic enzymes. Plant seeds were collected from Torbat-e-Heydariyeh (Khorasan Razavi province, Iran) and planted under greenhouse conditions. Leaves were sampled at 8-, 16- and 24-leaf stages of the growth period. Total contents of phenols, flavonoids, and phenolic acids were measured using spectrophotometry, and the phenolic acid profile was determined by high-performance liquid chromatography (HPLC). The activities of phenylalanine ammonia-lyase (PAL) and tyrosine aminotransferase (TAT) were measured by spectrophotometry, and the activity of rosmarinic acid synthase (RAS) was evaluated by HPLC. The relative expression of the corresponding genes was quantified by RT-PCR. The results showed that the content of all phenolic compounds and the activities of TAT and RAS enzymes/genes increased significantly (p < /em>≤0.05) with increasing plant age. At the 24-leaf stage, the total content of phenols, flavonoids, and phenolic acids were 3.47-, 2.80-, and 7.78-fold of those measured at the 8-leaf stage, respectively. The concentration of rosmarinic acid and caffeic acid (0.69 and 0.36 mg/g DW at the 8-leaf stage, respectively) increased by 3.41- and 4.05-fold during the vegetative growth, respectively. Lithospermic acid and salvianolic acids had a smaller share of total phenolic acids (0.01-0.06 mg/g DW at the 8-leaf stage), and their contents increased 2- to 10-fold with increasing plant age. Also, a strong positive correlation was observed between plant age and phenolic acid accumulation and between plant age and the activity and gene expression of TAT and RAS. TAT enzyme might play the main role in the biosynthesis of rosmarinic acid compared to PAL.
S. Abbaszadeh; T. Radjabian; M. Taghizadeh
Abstract
Phytosterol, a general term applied to a large number of plant-derived sterols, is found exclusively in all organs of higher plants and are often enriched in oilseeds. Phytosterols have wide bioactivity in humans, in particular as an efficacious cholesterol-lowering agent and consequently may have a ...
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Phytosterol, a general term applied to a large number of plant-derived sterols, is found exclusively in all organs of higher plants and are often enriched in oilseeds. Phytosterols have wide bioactivity in humans, in particular as an efficacious cholesterol-lowering agent and consequently may have a preventive role against cardiovascular disease and also a variety of cancers. Phytosterols occur in high concentrations in vegetable oils such as the Echium (Boraginaceae family). In Iran, four species of Echium have been identified so far. In respect of unique roles of phytosterols in human health, the aim of the present study was determination and quantification of sterols in seeds of two Iranian Echium. Seeds were collected from six populations of two Iranian Echium species (E. italicum and E. amoenum) from their natural habitats. After extraction with appropriate solvents, the existence of sterols in seeds was characterized by TLC and then their contents were measured using GC and spectrophotometeric methods. Total phytosterol contents were determined using the standard curve equation obtained from the changes in the absorption of solutions at a wavelength of 640 nm. Results from GC analyses showed that total phytosterol contents based on total seed dry weight were also significant, as the highest amount (399/4 mg/100g D.W) was detected in seeds of E. italicum (Alamute Qazvin population) and the lowest (112 mg/100g D.W) was measured in seeds of E. amoenum species (Hezarjarib population). Also, campesterol (20-50% of total phytosterol) and β-sitosterol (more than 50% of total phytosterol) were the main constituents of the phytosterols in all seeds. Accordingly, seeds of E.amoenum (Behshahr population) with 141 mg/100g β-sitosterol and seeds of E. italicum (Alamute Qazvin population) with 212 and 141/4 mg/100g campesterol and β-sitostanol were respectively identified as the richest samples.
