Applied Biological Chemistry

Cisplatin often shows the drug resistance which could limit the chemotherapeutic efficacy. Thus, it is necessary to develop anticancer agents against cisplatin-resistant cancer cells. To identify pharmacophores exhibiting the cell growth inhibitory effect against cisplatin-resistant A2780/Cis ovarian cancer cells, we prepared 35 synthetic polyphenols bearing naphthalene skeleton including naphthalenyl chalcones, naphthalenyl flavones, naphthalenyl flavanones, 4,5-dihydro-1H-pyrazol-3-yl)naphthalen-2-ols, naphthalen-1-yl-N-phenyl-4,5-dihydro-1H-pyrazole-1-carbothioamides, and 4,5-dihydro-1H-pyrazol-3-yl)naphthalen-1-ol. The correlation between their inhibitory effects and structural properties was evaluated using hologram quantitative structure activity relationship and comparative molecular field analysis. The pharmacophores derived here can lead us to design new polyphenols against the growth of cisplatin-resistant cells.

The current study was carried out to detect metrafenone residues and estimate the half-lives in lettuce grown under greenhouse conditions using gas chromatography with a micro-electron capture detector. Metrafenone was applied in two and three doses (with a 7-day interval) to two different sites in Naju (distance between sites 1 and 2 = 6.5 km) in different seasons (spring and autumn). Samples were extracted with acetone and matrix components were purified using a silica solid-phase extraction (SPE) cartridge. The calibration curve over the concentration range of 0.02–5.0 mg/L was linear with a determination coefficient (R 2) = 0.9993. The limits of detection and quantification were 0.003 and 0.01 mg/L, respectively. Recoveries at two fortification levels (0.1 and 0.5 mg/kg) ranged from 78.5 to 113.3 % with a relative standard deviation <8 %. The calculated half-lives were 2.3 and 2.2 days and 4.9 and 5.0 days for the double and triple doses at sites 1 and 2, respectively. These results suggest that the method is effective and sensitive for the determination of metrafenone residues in field-incurred lettuce samples, and the difference in the reported half-lives is due to seasonal variation.

Increasing demand for renewable energy has led to the production of biodiesel from microalgae. Microalgae have been regarded as one of the best feedstocks for biodiesel due to their high growth rate and lipid content as compared to other crops and plants. However, use of microalgae is still hindered by technical barriers and high processing costs. The economic viability and environmentally friendly aspects of biodiesel production will be significantly improved by co-producing value-added chemicals and extracting lipids directly from wet biomass without involvement of organic solvents, respectively. In this study, organic solvent-free lipid extraction from wet Aurantiochytrium sp. biomass was developed to co-produce biodiesel and value-added products such as docosahexaenoic acid. Organic solvent-free lipid extraction was performed by applying alkali and heat treatments to wet biomass. Key parameters for the extraction from Aurantiochytrium sp. were optimized to increase extraction yields. A ratio of 15 mg/mL of biomass to alkaline solution and an alkaline solution concentration of 1% w/w were determined to be the optimal conditions. Both heating temperature and treatment time were associated with positive effects on lipid recovery, up to a certain level. The maximum extraction yield (77.37% of total lipid) was obtained by heating at 150 °C for 30 min. Additionally, microwaves were employed to the extraction system and could further reduce the reaction time. Our study could be expanded to other types of microalgal biomass and will aid in establishing a protocol for organic solvent-free lipid extraction directly from wet biomass.

The purpose of this study was to isolate an active constituent from the essential oil of Eugenia caryophyllata leaves and to evaluate its insecticidal activity against the nymph and adults of Pochazia shantungensis. According to some chromatographic methods and spectroscopic analyses, the active constituent of E. caryophyllata leaves was identified as eugenol. Based on the LC50 values of eugenol and its structural analogues against the nymph and adults of P. shantungensis, isoeugenol (LC50, 83.29 and 91.03 mg/L) exhibited the highest insecticidal activity, followed by methyl isoeugenol (105.61 and 114.48 mg/L), eugenol (124.44 and 143.24 mg/L), methyl eugenol (126.31 and 143.84 mg/L), and acetyl eugenol (165.11 and 170.06 mg/L). Insecticidal activity against P. shantungensis was dependent on the presence of a functional group in 4-ally-2-methoxyphenol. In conclusion, E. caryophyllata oil and eugenol analogues might be suitable alternative synthetic insecticides.

Insecticidal and acaricidal responses of Cinnamomum cassia oils made by organic solvent (OS), steam distillation (SD), and supercritical fluid (SF) and their components were examined in two bioassays (contact and fumigant bioassays) against Plodia interpunctella, Sitophilus oryzae, S. zeamais, Tyrophagus putrescentiae, and Sitotroga cerealella adults. Using the contact or fumigant bioassay against T. putrescentiae adults, OS oil exhibited the strongest toxicities (50% lethal dose [LD50], 2.60 μg/cm2 and 1.34 μg/cm3), followed by SF and SD oils. Furthermore, using two bioassays, SD oil against S. oryzae and S. zeamais adults exhibited the strongest toxicities (LD50, 102.25 μg/cm2 and 68.62 μg/cm3, 102.03 μg/cm2 and 57.59 μg/cm3), followed by SF and OS oils. Using the fumigant bioassay against S. cerealella and P. interpunctella adults, OS oil exhibited the strongest toxicities (LD50, 1.17 μg/cm3 and 0.79 μg/cm3) followed by SF and SD oils. Cinnamaldehyde, cinnamyl acetate, and coumarin against T. putrescentiae adults showed no significant differences in the contact bioassay, but in the fumigant bioassay, cinnamaldehyde exhibited the highest toxicity (LD50, 0.91 μg/cm3) followed by cinnamyl acetate and coumarin. Against S. oryzae, S. zeamais, S. cerealella, and P. interpunctella adults, cinnamaldehyde using two bioassays exhibited the most potent toxicities (LD50, 108.81 μg/cm2 and 77.80 μg/cm3, 104.72 μg/cm2 and 36.48 μg/cm3, 0.57 μg/cm2 and 2.29 μg/cm3), followed by coumarin and cinnamyl acetate in order. The results showed that cinnamaldehyde and the C. cassia oils could be effective values in the management of stored product pests.

Angiotensin-converting enzyme (ACE) is an important therapeutic target in the regulation of high blood pressure. This study was conducted to investigate the alterations in blood pressure associated with ACE inhibition activity of the polyphenols (1–10), including 3-O-feruloylquinic acid (1), lutonarin (2), saponarin (3), isoorientin (4), orientin (5), isovitexin (6), isoorientin-7-O-[6-sinapoyl]-glucoside (7), isoorientin-7-O-[6-feruloyl]-glucoside (8), isovitexin-7-O-[6-sinapoyl]-glucoside (9), and isovitexin-7-O-[6-feruloyl]-glucoside (10), isolated from barley seedlings (BS). All the isolated polyphenols exhibited comparable IC50 values of ACE inhibition activity (7.3–43.8 µM) with quercetin (25.2 ± 0.2 µM) as a positive control, and their inhibition kinetic models were identified as noncompetitive inhibition. Especially, compound 4 was revealed to be an outstanding ACE inhibitor (IC50 = 7.3 ± 0.1 µM, Ki = 6.6 ± 0.1 µM). Based on the compound structure–activity relationships, the free hydroxyl groups of flavone-moieties and glucose connections at the A ring of the flavone moieties were important factors for inhibition of ACE. The alcohol extract of BS also demonstrated potent ACE inhibition activity (66.5% ± 2.2% at 5000 µg mL−1). The polyphenols from BS had strong inhibitory activity on ACE and this study results suggest that BS can be used as an effective blood pressure regulator through ACE inhibition.

Artemisia species have significant commercial, medical, and economic value and are widely used in the traditional medicine and pharmaceutical industries. Artemisinin, a powerful antimalarial agent, is an important pharmaceutical metabolite that primarily accumulates within the glandular trichomes (GTs) on the leaf surface of Artemisia plants. Trichomes arising from the elongation of epidermal cells can be classified into GTs and non-glandular trichomes (NGTs) based on their morphology. GTs and NGTs are present in Artemisia species, and the relationship between GTs and artemisinin has been extensively studied; however, the correlation between NGTs and artemisinin remains relatively unexplored. In this study, we inferred artemisinin derivatives and trichome characteristics based on the type of species, developmental stage, and leaf age and conducted correlation analyses to investigate the factors influencing artemisinin content across different Artemisia species. Artemisinin and its derivatives exhibited variations in distribution based on species and leaf age, with a decreasing trend observed across most species as the developmental stage progressed. Noticeable differences among Artemisia species were observed in leaf shape, morphology, and trichome distribution. Although the observed data did not evidently differentiate between species, developmental stage, and leaf age groups, principal component analysis revealed that artemisinin was positively associated with the NGTs density, indicating a correlation coefficient of 0.56 (p < 0.0001). Therefore, the number of NGTs may affect the artemisinin content in different Artemisia species.

Mycotoxins are secondary metabolites produced by various fungi and are known to have a significant negative impact on human and animal health. When feedstuffs are contaminated with mycotoxins, their toxicities may be caused a variety of diseases. In this study, the residual mycotoxins in feedstuffs were analyzed using LC–MS/MS incorporated with QuEChERS extraction. Analytical method validation was performed for LOD, LOQ, linearity, and recoveries with consideration of matrix effects prior to the residual analysis. They were all reached to the accepted range of validation level. Using 39 feedstuff samples (5 g) for mycotoxin analysis, nine samples were contaminated by four major mycotoxins such as fumonisin B1 (FB1), deoxynivalenol, fumonisin B2, and zearalenone. Among them, FB1 was detected at the highest concentration as 18.0943 mg/kg. The total sum of fumonisins in 39 samples did not exceed the maximum residual level (MRL) criterion set by Korean Food and Drug Administration. Altogether, intensive management of mycotoxins in Korean feedstuffs should be implemented with proper and routine monitoring, even their residual concentrations are not exceeded over the MRL levels because of high frequent detection found in this study.