Anabolism and signaling pathways of phytomelatonin.

Phytomelatonin is a small multifunctional molecule found ubiquitously in plants, which plays an important role in plant growth, development, and biotic and abiotic stress responses. The classical biosynthetic and metabolic pathways of phytomelatonin have been elucidated, and uncovering alternative pathways has deepened our understanding of phytomelatonin synthesis. Phytomelatonin functions mainly via two pathways. In the direct pathway, phytomelatonin mediates the stress-induced reactive oxygen species burst through its strong antioxidant capacity. In the indirect pathway, phytomelatonin acts as a signal to activate signaling cascades and crosstalk with other plant hormones. The phytomelatonin receptor PMTR1/CAND2 was discovered in 2018, which enhanced our understanding of phytomelatonin function. This review summarizes the classical and potential pathways involved in phytomelatonin synthesis and metabolism. To elucidate the functions of phytomelatonin, we focus on the crosstalk between phytomelatonin and other phytohormones. We propose two models to explain how PMTR1 transmits the phytomelatonin signal through the G protein and MAPK cascade. This review will facilitate the identification of additional signaling molecules that function downstream of the phytomelatonin signaling pathway, thus improving our understanding of phytomelatonin signal transmission.

Analysis of arecoline in Semen Arecae decoction pieces by microchip capillary electrophoresis with contactless conductivity detection.

A new method for the determination of arecoline in Semen Arecae decoction pieces by microchip capillary electrophoresis with contactless conductivity detection (MCE-CCD) was proposed. The effects of various electrophoretic operating parameters on the analysis of arecoline were studied. Under the optimal conditions, arecoline was rapidly separated and detected in 1 min with good linearity over the concentration range of 20-1500 µM (r2=0.9991) and the detection limit of 5 µM (S/N=3). The method was used for the analysis of arecoline satisfactorily with a recovery of 96.8-104%.

[Determination of matrine in matrine injection by microfluidic chip with contactless conductivity detection].

OBJECTIVE: To establish a new method for the determination of matrine in matrine injection by microfluidic chip with contactless conductivity detection. METHODS: The electrophoretic parameters, such as the variety and concentration of buffer solution and additive, separation voltage and injection time, etc. were researched. RESULTS: In the optimal conditions, using 2 mmol/L HAc + 2 mmol/L NaAc (pH 4. 5) as buffer solution, with 0.20 mmol/L SDS as addition at the separation voltage of 2.00 kV and 10s injection, matrine was separated and detected within 2 min. The linear dependence of the concentration of matrine ranged from 10 to 300 microg/mL (r2 = 0.9992), with the detection limit of 1.0 microg/mL (S/N = 3), the RSD of 1.9% and the recoveries from 98.7% to 101%. CONCLUSION: The method is simple, rapid and well reproducible, and it can be used in the quality control of the product.