Chemistry and Biology of Novel Meliaceae Limonoids

Nature has bestowed us with abundant bioactive/drug molecules for various uses in our everyday life. One such group of plant specialized molecules is limonoids, which are structurally characterized as 4,4,8-trimethyl-17-furanyl steroidal skeleton. Limonoids are well known for their various biological activities such as potent anti-feedent, anti-cancer, anti-inflammatory, insecticidal, anti-diabetic, anti-viral, anti-microbial etc. These tetranortriterpenes are highly oxygenated and structurally diversified molecules majorly found in Meliaceae and Rutaceae and less frequently in the Cneoraceae families in the plant kingdom. Many of these plants have been used in traditional medicine from ages. One of the well-known limonoid, azadirachtin A is highly valued and widely popular for its outstanding insecticidal properties. Till date, nearly 2500 limonoids with over 35 unique carbon frameworks have been observed. In recent times, these molecules have dig a great interest among researchers due to their myriad biological properties. With the advancement of analytical techniques, the limonoid research is aced to explore more different molecules from their sources. In our review we cover all the Meliaceous limonoids isolated during July 2010 to Dec 2020. We found over 1502 new limonoids, which are reported from various Meliaceae plants after Jun 2010. We have classified them based on their skeletal structure rearrangements and functional groups into various classes such as protolimonoids, Apoprotolionoid, Azadirone, Vilasinin, Cedrelone, Havanensin, Trichilin, Nimbin, Salannin, Azadirachtin, Nimbolidin, Nimbolinin, Obacunol, Evodulone, Trijugin, Cipadesin, Andirobin, Mexicanolide, Phragmalin, Khayanolide, Preieurianin, Aphanamixoid, Nor Limonoid and N-containing derivatives. Further we have discussed their biological activities in detail.