Potential of natural products containing 3-acyl tetramic acid as antibacterial precursors / 药学学报

The natural products containing 3-acyl tetramic acid units have a large number of complex and diverse structures, showing a variety of biological activities such as antibacterial, antiviral, anti-tumor and so on, especially antibacterial activity which are regarded as a potential reservoir of new antibiotics. In this paper, the antibacterial activities of various natural products containing 3-acyl tetramic acids and the new research hotspots and directions are reviewed.

Phenolic Profile, Essential Oil Composition and Bioactivity of Lasia spinosa (L) Thwaites

Abstract Lasia spinosa (L.) Thwaites is a widely used ethnomedicinal plant in Bangladesh. In this study, we investigated phenolic contents, volatile compounds and fatty acids, and essential oil components of extracts prepared from aerial parts of the plant. The main volatile compounds were methyl ester of oleic acid, palmitic acid and stearic acid as determined by GC/MS. Phenolic contents of the extracts were determined qualitatively and quantitatively by HPLC/TOF-MS. Six phenolic compounds (syringic acid, morin, gentistic acid, 4-hydroxybenzoic acid, cinnamic acid, and apigenin) were found in the extracts. GC/MS analysis of steam distilled essential oil showed camphor, α-pinene and δ-3-carene as the main constituents. In DPPH radical scavenging assay, the highest free radical scavenging activity was observed for the methanol extract with an IC50 value of 0.48 ± 0.04 mg/mL, whereas, in metal chelating activity on ferrous ions (Fe2+) assay, the highest chelating activity was observed for hexane extract (IC50 = 0.55 ± 0.08 mg/mL). The extracts and essential oil were tested against five severe human pathogenic bacteria using disc diffusion assay and subsequent MIC values were also determined. All the extracts (except methanol extract) and the essential oil were found to possess potential antimicrobial activity with corresponding inhibition zone and minimum inhibitory concentration (MIC) ranging from 9-23 mm and 62.5-500 µg/mL. This study has been explored the plant Lasia spinosa can be seen as a potential source of biologically active compounds.

Design, synthesis and evaluation of genistein-polyamine conjugates as multi-functional anti-Alzheimer agents

A series of genistein-polyamine conjugates (4a-4h) were designed, synthesized and evaluated as multi-functional anti-Alzheimer agents. The results showed that these compounds had significant cholinesterases (ChEs) inhibitory activity. Compound 4b exhibited the strongest inhibition to acetylcholinesterase (AChE) with an IC50 value of 2.75 μmol/L, which was better than that of rivastigmine (5.60 μmol/L). Lineweaver-Burk plot and molecular modeling study showed that compound 4b targeted both the catalytic active site (CAS) and the peripheral anionic site (PAS) of AChE. Besides, compound 4b showed potent metal-chelating ability. In addition, it was found that 4a-4h did not affect HepG-2 cell viability at the concentration of 10 μmol/L.

Antioxidant potential of methanol Root extract of Mentha arvensis L from Kashmir Region.

The study was carried out to evaluate the phytochemical constituents and antioxidant potential of methanolic root extract of Mentha arvensis L. from Kashmir region. The antioxidant activity of methanol extract of Mentha arvensis L. was evaluated by using 1, 1-diphenyl, 2-picrylhydrazyl (DPPH) scavenging, reducing power, metal chelating, nitrous oxide scavenging and hydrogen peroxide scavenging assays. The total phenolic content and total flavonoid content was found to be 9.12 and 32.14 mg/g respectively. The percentage inhibition values of DPPH scavenging for methanol extract were found to be 35.83%. The percentage inhibition values of Nitrous oxide scavenging for extract were found to be 39.11%, the percentage inhibition values of H2O2 scavenging for extract were found to be 21.72%, the percentage inhibition values of metal chelating activity of methanol extract at the concentration of 500 μg/ml was found to be 79.31% and that for standard ascorbic acid was found to be 96% at same concentration and the reducing power of extract was found to be 0.75 at concentration of 0.25mg/ml. The results indicate that the methanolic root extract of Mentha arvensis L. has good antioxidant potential and it can be regarded as promising candidates for natural plant sources of antioxidants with high.

Effect of Traditional Sun-Drying on Phenolic Antioxidants of Averrhoa Bilimbi L.

Averrhoa bilimbi L. has various beneficial properties including antidiabetic and antioxidant activity. The effect of traditional sun drying on the stability of fresh A. bilimbi fruits was investigated by using different methanol/water extracts, and their total phenolic content (TPC) and total antioxidant capacity (TAC) compared. The TAC was evaluated using established in vitro models such as 1,1,diphenyl-2-picryl hydrazyl radical scavenging activity, 2,2´-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) scavenging assay, total reducing power, phosphomolybdenum assay and metal chelating activity. All the extracts of the dried fruit showed lower TPC compared to the fresh bilimbi extracts by 23-88%, TAC of which corresponded accordingly. The investigation revealed that A. bilimbi was a good source of antioxidants; however, the drying process of the fruit significantly affected the bioactive compounds.