Screening genotypes and optimizing ultrasonic extraction of phenolic antioxidants from Rheum ribes using response surface methodology.

The flowers and stems of Rhubarb (Rheum ribes L.) are known to contain effective antioxidant compounds that have potential antidiarrheal properties in traditional medicine. This study was conducted to screen various genotypes of Rhubarb for their phytochemical and antioxidant activity and optimize the extraction parameters using the response surface methodology (RSM). The study found high diversity among the different genotypes (G1-G13) in terms of their flowers and stems. The total phenolic content (TPC) in the flowers of R. ribes varied significantly, showing values between 9.80 and 81.53 mg GAE g-1 DW. In the stems, TPC ranged from 2.87 to 16.33 mg GAE g-1 DW. Similarly, the total flavonoid content (TFC) in the flowers ranged from 0.33 to 1.32 mg Qu g-1 DW, while in the stems, it was between 0.05 and 0.38 mg Qu g-1 DW. The antioxidant activity, indicated as µmol Fe2+ g-1 DW, varied from 7.42 to 59.87 in the flowers and from 0.14 to 15.99 in the stems. Hierarchical cluster analysis (HCA) identified five distinct clusters among the collected genotypes. Subsequent analysis of variance and principal components analysis (PCA) revealed that the flowers of G8 (G8F) from Tehran to Lavasan exhibited the highest total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity (FRAP). Given these findings, G8F was chosen for further optimization in the study. The RSM was designed based on a Box-Behnken design (BBD) to determine the optimal extraction conditions, including extraction temperature (30-80 °C), extraction time (5-15 min), and ethanol concentration (25-75%, ethanol to water, v/v). The responses measured were total phenolic content (TPC), total flavonoid content (TFC), total anthocyanin content (TAC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging, and Ferric reducing/antioxidant power (FRAP) assays. The optimal extraction conditions for all responses or desirability indices were X1: 80 °C, X2: 15 min, and X3: 53.14%, which resulted in TPC (99.32 mg GAE.g-1 DW), TFC (3.00 mg Qu.g-1 DW), TAC (1.12 mg cyanidin-3-glucoside (Cy-g) g-1 DW), FRAP (110.22 µmol Fe+2/g DW), and DPPHsc (88.20%). The R2 values (0.91-0.99) indicated that the RSM models were acceptable.

Phytochemical properties of essential oil from Artemisia sieberi Besser (Iranian accession) and its antioxidant and antifungal activities.

In this study, the phytochemical profile, the essential oil composition of an Iranian accession of Artemisia sieberi and their antioxidant and antifungal properties were investigated. The amount of essential oil yield was 1.5% (w/v) and twenty two components were identified by GC-MS analysis being camphor (33.64%), 1,8-cineole (25.66%) and chrysanthenone (7.86%) the major compounds. The amount of total polyphenols and flavonoids, total ascorbic acid and carotenoid content of A. sieberi extract were determined, and resulted in 666.26 mg GAE/100g DW, 54.77 mg QUE/100g DW, 153.585 mg/100g DW, and 907.18 mg/100g FW, respectively. Highest antioxidant activity based on DPPH bioassay was recorded in essential oil (84.04%) and extract (89.33%). Furthermore, the essential oil of A. sieberi tested for its antifungal activity, demonstrated to reduce significantly the mycelium growth rate of Botrytis cinerea, that is, no mycelial growth was observed at concentrations 1000 and 1500 µll-1.

Composition, Antifungal, Phytotoxic, and Insecticidal Activities of Thymus kotschyanus Essential Oil.

Essential oils (EOs) are some of the outstanding compounds found in Thymus that can exert antifungal, phytotoxic, and insecticidal activities, which encourage their exploration and potential use for agricultural and food purposes. The essential oils (EO) obtained from Thymus kotschyanus collected in the East Azerbaijan Province (Iran) were characterized using a gas chromatography-mass spectrometry (GC-MS) analysis. Thymol was the most important compound (60.48%), although 35 other active compounds were identified in the EO. Significant amounts of carvacrol (3.08%), p-cymene (5.56%), and γ-terpinene (6.67%) were found in the EO. The T. kotschyanus EO was tested against important phytopathogenic fungi (Botrytis cinerea, Aspergillus niger, and Penicillium expansum). The antifungal assay showed that the use of ≥500 ppm of EO resulted in a fungicidal effect against all funguses tested. In a similar way, the use of ≥500 ppm of EO inhibited the germination of all crop weed seeds (Amaranthus retroflexus L. and Panicum miliaceum L.) and their subsequent growth, which demonstrated its herbicidal effect. Finally, the insecticidal capacity of T. kotschyanus EO was also observed against selected insects (Oryzaephilus surinamensis and Sitophilus oryzae). O. surinamensis was more susceptible to the effect of EO (LC50 = 4.78 µL/L air) than S. oryzae (LC50 = 13.20 µL/L air). The obtained results of the present study can provide new safe resources to the development of new products for the food, agriculture, and pharmaceutical industries.

A new source of oxygenated monoterpenes with phytotoxic activity: essential oil of Cuminum Cyminum L. from Iran.

Chemical constitutes and phytotoxic activity of Cuminum cymiunm L. is investigated in the present study. For this means seeds of C. cyminum L. was harvested from Ilkhchi of Iran. The major components of essential oil (EO) with more than 94% were 3-caren-10-al, cuminal, 2-Caren-10-al, γ-Terpinene, (-)-ß-Pinene and p-Cymene. This study found that cumin EO displayed meaningful inhibitory impacts on germination indices and the growth of the seedlings of Amaranthus retroflexus, Lactuca sativa, and Acroptilon repens. The germination indices showed severely concentration-dependent responses. In the case of A. retroflexus and L. sativa germination indices were controlled in the 500 ppm and in the A. repens were inhibited in the 1500 ppm of EO concentration. Overall, this study suggests that EO derived from C. cyminum L. looks to be a promising candidate for its utilization as a natural herbicide in large scale.[Formula: see text].

Antioxidant and antifungal activities of a new chemovar of cumin (Cuminum cyminum L.).

Chemical composition, antifungal and antioxidant properties of essential oil extracted from Cuminum cyminum from Iran was studied. GC-MS analysis revealed the presence of 18 components, with 3-caren-10-al and cuminal as the principal constituents. Hierarchical cluster analysis and antioxidant capacities showed that this essential oil made a single group at 64 unit distinct from other reported essential oils extracted from cumin in the literature and was with high antioxidant activity [150 µL exhibiting strong reducing power; 2200 (FRAP) µmol/L Fe+2 during 15 min and ~ 89 DPPH % at 60 min]. The antifungal effects of the essential oil against three postharvest fungal pathogens, Botrytis cinerea, Aspergillus niger and Penicillim expansum revealed that at concentrations of ≥ 750 µL/L, the mycelial growth of the tested fungi were completely inhibited. Overall, the essential oil derived from this new cumin chemovar could be a promising candidate for its utilization as a natural preservative.

Bioactivity of malva sylvestris L., a medicinal plant from iran.

OBJECTIVES: Malva sylvestris L. (Malvaceae), an annual plant, has been already commonly used as a medicinal plant in Iran. In the present work, we evaluate some bioactivities of the plant extracts. MATERIALS AND METHODS: The aired-dried plant flowers and leaves were extracted by soxhlet apparatus with n-hexane, dichloromethane and methanol. The antimicrobial, cytotoxic, and phytotoxic of the plant extracts were evaluated using disk diffusion method, MTT, and Lettuce assays, respectively. RESULTS: Both flowers and leaves of M. sylvestris methanol extracts exhibited strong antibacterial effects against Erwinia carotovora, a plant pathogen, with MIC value of 128 and 256 µg/ml, respectively. The flowers extract also showed high antibacterial effects against some human pathogen bacteria strains such as Staphylococcus aureus, Streptococcus agalactiae, Entrococcus faecalis, with MIC value of 192, 200 and 256 µg/ml, respectively. The plant methanol extracts had relatively high cytotoxic activity against MacCoy cell line. CONCLUSION: We concluded that Malva sylvestris can be candidated as an antiseptic, a chemopreventive or a chemotherapeutic agent.