A comprehensive review of azadirachtin: physicochemical properties, bioactivities, production, and biosynthesis

Azadirachtin,a complex tetratriterpenoid limonin with potent insecticidal properties,is the most widely used biological pesticide worldwide.Its versatile pharmacological applications include the inhibition of tumor growth and anti-malarial,anti-bacterial,and anti-inflammatory properties.Azadirachtin plays a pivotal role in pest control and novel drug development.The primary source of azadirachtin is the neem tree(Azadirachta indica A.Juss),with an azadirachtin content ranging from 0.3%to 0.5%.Despite the market demand for botanical pesticides reaching approximately 100,000 tons per year,the annual neem production in China is only 1.14 tons.Although azadirachtin can be obtained through plant extraction or chemical synthesis,the quantity obtained does not meet the market demand in China.The sluggish pace of azadirachtin biosynthesis results from the limited availability of genetic information and the complexity of the synthetic pathway.Recent advancements in azadirachtin biosynthesis hold promise as an efficient collection method.In this study,we explored the physicochemical properties,biological activities,mechanisms of action,and acquisition methods of azadirachtin.We also delved into recent progress in azadirachtin biosynthesis and assessed potential future usage challenges.This study aims to establish a theoretical foundation for the scientific application and efficient synthesis of azadirachtin,offering valuable reference information to the industry.

Carbon Nanofibrous Sponge Made from Hydrothermally Generated Biochar and Electrospun Polymer Nanofibers

The objective of this study was to convert biochar,a byproduct generated from the hydrothermal process(in oxygen-limited environment)of biomass(e.g.,corn stover),into value-added product.In specific,three-dimensional(3D)biochar-containing precursor sponge,which was made by using electrospun polymer nanofibers as skeleton support,was fabricated via an innovative approach.The weight ratio of biochar to polymer(in the precursor sponge)was 2/1,and it appeared that the biochar weight ratio could be further increased.Upon heat treatments(i.e.,stabilization in air and carbonization in argon),the precursor sponge was converted into carbon nanofibrous sponge that had the porosity of~90 vol%,the BET surface area of~51.7 m^(2) g^(−1),and the carbon content of~95 wt%;and it was mechanically elastic/resilient.The electrochemical study indicated that,the carbon nanofibrous sponge could be utilized for making supercapacitor electrode with excellent rate capability and high kinetic performance.This study would not only demonstrate a high-value application of hydrothermally generated biochar,but also provide a facile while novel approach for the fabrication of carbon nanofibrous sponge which could be potentially used for various applications(particularly the energy storage application).