Medicinal Plants
Rahele Ghanbari Moheb Seraj; Mehdi Behnamian; Asadollah Ahmadikhah; Vahid Shariati; Sara Dezhestan
Abstract
Introduction
Plant growth and yield are affected often by stress conditions, especially drought, which is the most important factor in reducing crop production worldwide. Silybum marianum is an important pharmaceutical crop with great potential as a multipurpose plant for low-input cropping systems ...
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Introduction
Plant growth and yield are affected often by stress conditions, especially drought, which is the most important factor in reducing crop production worldwide. Silybum marianum is an important pharmaceutical crop with great potential as a multipurpose plant for low-input cropping systems of the arid and semiarid regions.
Materials and Methods
In this experiment, the effect of drought stress (full irrigation at field capacity; no stress, irrigation at 70% of field capacity; mild stress and irrigation at 40% of field capacity; severe stress) on physiologic traits, the amount of silybin a and b and 1000 seed weight in milk thistle was studied in the research field of Shahid Beheshti University in 2017-2018. The experimental site is located in Shahid Beheshti University, Tehran, Iran (51.23°N, 35.48°E, and 1769 m above mean sea level). It has a moderate and mountainous climate with a mean annual rainfall of 145.2 mm and a mean temperature of 22ºC. This experiment was performed in a completely randomized block design with 3 replications. Milk thistle seeds were prepared from Isfahan Pakanbazr Company. The soil composition consisted of 1/3 clay, 1/3 sand, and 1/3 leaf composts. The field area was 150.0 m2. Furrows were created to implement this study. The space of plants on rows was 0.5 m and between rows was 1 m. In general, 15 furrows were created and 15 plants were cultured on each furrow, so the total number of plants cultivated on the field was 225. Drought stress was applied at flowering stage. Soil moisture was measured by the weighing method. The soil samples were taken from various areas (randomly) of the field, three samples each day. After measuring the water content at F.C, based on that, the amount of 70%F.C and 40%F.C was also calculated. At the time of stress, F.C irrigation was performed every two days, 70% F.C irrigation every 4 days, and 40% F.C irrigation every 6 days. After 8 days, leaf sampling was performed to measure catalase, ascorbate peroxidase, proline and malondialdehyde content and seed sampling was performed to 1000 seed weight and extract analysis. For physiologic measurements, 3 plants were randomly assigned to each stack and their leaves were separated and transferred to the laboratory. Then, in the next step, their physiologic parameters (include Catalase and ascorbate peroxidase, proline and malondialdehyde content) were measured according to the relevant protocol. In order to measure silybin, 4 plants were randomly considered to each stack and their seeds were harvested and combined and dried in shade condition in the laboratory for one month. The dried seed samples were completely powdered using a mill, then 10 g of the powders weighed and the oil extract of them was isolated by Soxhlet using n-hexane solvent. The extraction temperature was 70 °C and the extraction time was 6 h. After the extraction was completed, the extract was poured into dark glass. Next, the oil-free powder was dried in an incubator at 37 ° C. Methanol extract of oil-free powder was extracted using methanol solvent. For this purpose, 2 g of samples powder was weighed and 200 ml of 80% methanol was added to each of them and the mixture stirred for two days by Shaker. The mixture was then passed from a filter paper and after that, 200 ml of 80% methanol was added to the sample precipitate (on filter paper) and placed again on the shaker. After 24 h, extraction was performed by the same method and were added to the previous extract. The extracts were then concentrated in the environment temperature for two weeks. Concentrated extracts (powder) as well as standard silymarin with certain concentrations were dissolved in methanol solvent and used for injection into HPLC (Model: Infinity1260, Manufacturer: Agilent) using syringe filters with a diameter of 0.2 μm. After receiving the HPLC results, the data and peaks were analyzed and the amounts of silybin a and b were determined and compared at different levels of water stress. Statistical analysis of data was performed using R 3.6.1 and RStudio 1.1.463 software. Mean data were compared using Duncan's test with agricolae package at a significance level of 0.05.
Results and Discussion
The results showed that with increasing water stress intensity, the amount of silybin a and silybin b increased by 24% and 26%, respectively. The amount of these compounds in 40% were significantly higher than other treatments, so that its amount compared to F.C treatment (26.07 mg/g Grain DW in silybin a and 40.74 mg/g Grain DW in silybin b) and compared to the 70%F.C (25.32 mg/g Grain DW in silybin a and 34.64 mg/g Grain DW in silybin b) was higher. This indicates carbon assimilation from photosynthesis to produce secondary metabolites in this treatment. Also, the amount of silybin b compared to silybin a in all treatments was (0.8: 1.2), in which 1.2 is related to silybin b and 0.8 is related to silybin a. In severe stress treatment (40% of field capacity), the amount of silybin a and b (67.30 and 98.92 mg/g, respectively) increased significantly compared to other treatments. According to the mean comparison results, the highest activity of catalase (5.16 U/ml) and ascorbate peroxidase (2.26 U/ml) was observed in mild stress treatment. Proline content gradually increased with increasing stress intensity and reached its peak in severe stress (3.36 µM/gr). Lipid peroxidation also had their maximum in severe stress (8.35 nmol/grFW). The 1000 seeds weight was reduced by 6.8 g in severe stress treatment (40%F.C) compared to the control (F.C).
Conclusion
According to the results, the amount of milk thistle flavonoids can be increased for medicinal purposes including the treatment of liver disease and hepatitis by applying dehydration stress.
Farnoosh Malekshahi; Ali Ashraf Mehrabi; Elahe Tavakol; Khosro Mehdikhanlo; Vahid Shariati
Abstract
Introduction: Basil genus (Ocimum) contains 30 to 150 species which grown in tropical and subtropical regions of Asia, Africa, Central and South America and found as a wild plant in these areas. In India, around 25,000 ha is under cultivation of Ocimum spp., with an annual production of about 250–300 ...
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Introduction: Basil genus (Ocimum) contains 30 to 150 species which grown in tropical and subtropical regions of Asia, Africa, Central and South America and found as a wild plant in these areas. In India, around 25,000 ha is under cultivation of Ocimum spp., with an annual production of about 250–300 tonnes of essential oil. Ocimum gratissimum L., a dicotyledonous shrub plant, which belongs to the Lamiaceae family, stands out for the quality, quantity and chemical diversity of the essential oils. These oils have been used in the pharmaceutical, cosmetic and food industries. Some of the essential oil compounds have antibacterial, insecticidal and antioxidant properties with high demand on the international market of the fine perfumery industry. It is also popularly used in herbal medicine for treating several diseases, such as upper respiratory tract infection, fever, cough, diarrhea and pneumonia. Being a short-duration economically viable medicinal and aromatic crop, clove basil has huge potential for large scale cultivation. Plant genetic has an important role in determining the type and amount of secondary metabolites of medicinal plants. Moreover, the recognition of species and genotypes with high genetic capability in the production of desired metabolites has been at the top of the plant breeding plans of medicinal plants. In addition, essential oil composition of plants may be affected by harvest time which is due to the impact of weather conditions on plant growth and development. The present study was aimed to evaluate the oil composition of two genotypes in two harvests. Materials and Methods: The research was conducted in the research farm of the college of agriculture, shahid Chamran University, Ahvaz, Iran during 2019. Two valuable genotypes of Ocimum gratissimum L. (278 and 296), with two different essential oil profiles, were investigated in two harvests; spring and autumn seasons. The aboveground parts of the plants were collected on June and November and dried on shade at room temperature. The essential oils of the plants were extracted by water distillation through Clevenger apparatus and the quantity and quality of the essential oils were analyzed by GC and GC-MS. Results and Discussion: The results of present study showed that the essential oil content of two genotypes was not affected by the harvest season while its amount was different in two genotypes. The essential oil content of genotype 296 was 2-fold of 278. According to the qualitative analysis of the essential oils, fifty compounds were identified in the essential oils of 278 and 296 genotypes. More than 98% of the identified compounds (in the essential oils of these two genotypes) were classified into five chemical classes; including hydrocarbon and oxygenated monoterpens, and hydrocarbon and oxygenated sesquiterpene and phenylpropanoids. The major constituent of the essential oil of genotype 278 was oxygenated monoterpene, thymol, on June (35.48 %) and November (45.85 %), which was not found in genotype 296. Gamma-terpinene was also significantly increased from June (13.15 %) to November (25.80 %). P-cymene (11.31-3.56 %), alpha- thujone (4.76-2.94 %), Germacrene D (3.73-2.76 %), caryophyllene E (3.66-1.51 %), myrcene (2.93-3.01 %), alpha-terpinene (2.63-3.38 %) and bourneol (2.28-0.71 %) were the remains of oil composition. Dihydro eugenol, which belongs to the chemical class of phenylpropanoids, was identified as the main essential oil components of genotype 296 which its amount was not affected by the harvest time. The other oil constituents were Beta (Z)-Ocimene (11.89-3.40 %), Germacrene D (3.58-2.80 %), and caryophyllene E (0.52-2.68 %). Conclusion: Terpenoids such as thymol are synthesized via the mevalonic acid pathway, and phenylpropanoid compounds such as dihydroeugenol and eugenol are synthesized via the shikimic acid pathway. The metabolite diversity across different species could be explained by the differential gene expression pattern. According to the results of the present study, thymol was identified as the main oil components of genotype 278. This may be due to the increased expression of mevalonate enzymes. The monoterpene was replaced by phenylpropanoid; dihydrogenugenol, in the oil of genotype 296 which might be due to more expression of the enzymes of the phenylpropanoid pathway. In the other hand, Thymol, P-cymene and gamma-terpinene in genotype 278 varied significantly in different harvesting times, indicating the effect of temperature on the activity of enzymes involved in the synthesis of essential oil components. On the contrary, the amount of dihydrogenugenol in genotype 278 on June and November is not affected by the environmental conditions in two seasons. With regard to the conclusions to the proper growth of genotype 278 and 296, as well several harvests annually, essential oil content and thymol and dihydrogenugenol, therefore, it is suggested that further research should be carried out for developing plant cultivation in Khuzestan and southern provinces which is not suitable for basil growth.
