Design, synthesis, and biological evaluation of new 12-substituted-14-deoxy-andrographolide derivatives as apoptosis inducers

Synthesis of novel pyrazole acetals of andrographolide and isoandrographolide as potent anticancer agents

Globally, cancer is the most prevalent chronic disease-related cause of death. Although there are many anticancer drugs, some of them have adverse effects. Due to their limited side effects, natural products are preferred over synthetic drugs. Andrographolide and its derivatives are known to be potent anticancer agents. In this context, sixteen novel 3,19-(NH-3-aryl-pyrazole) acetals of andrographolide and isoandrographolide (1a-1h, 2a-2g, 2i) from 3-aryl-1-H-pyrazole-4-carboxaldehydes (a-i) were synthesized. All the synthesized compounds were characterized using 1H NMR, 13C NMR, HRMS, FT-IR, and UV-vis spectroscopy. All the compounds were evaluated against a panel of 60 different human cancer cell lines for their anticancer potential at NCI, USA. Four compounds, having promising GI50s (50% growth inhibitory activity) on all 60-cell lines were selected for further in vitro studies. Out of these four compounds, compound 1g exhibited the best IC50 (3.08 μM) against the colon cancer cell line, HCT-116. Cell cycle analysis, annexin V-FITC/PI, and ROS assays revealed that the apoptosis of HCT-116 cells induced by compound 1g could be mainly attributed to the elevated levels of intracellular ROS. Further, the structure-activity relationship revealed that the pyrazole moiety of andrographolide plays a key role in their anticancer properties. These compounds were further examined for in silico ADMET and Lipinski characteristics to assess their potential as lead compounds.

Synthetic Modifications of Andrographolide Targeting New Potential Anticancer Drug Candidates: A Comprehensive Overview

This review collects the synthetic modifications performed on andrographolide, a natural molecule derived from Andrographis paniculata, for oncology applications. Various pharmacomodulations were carried out, and the products were tested on different cancer cell lines. The impact of these modifications was analyzed with the aim of mapping the positions essential for activity to facilitate future research in this field. However, this study makes it clear that, in addition to structural modifications of the molecule, which can result in varying degrees of effectiveness in targeting interactions, the lipophilic capacity of the structures obtained through hemisynthesis is of significant importance.

Andrographolide and its derivatives: Current achievements and future perspectives

Natural product andrographolide isolated from the plant Andrographis paniculata shows a plethora of biological activities, including anti-tumor, anti-bacterial, anti-inflammation, anti-virus, anti-fibrosis, anti-obesity, immunomodulatory and hypoglycemic activities. Based on extensive chemical structural modifications, a series of andrographolide derivatives with improved bioavailability and druggability has been developed. Moreover, greater understanding of their mechanisms of action at the molecular and cellular level has been thoroughly investigated. In this review, we give an outlook for the therapeutical potential of andrographolide and its derivatives in diverse diseases and highlighted the drug design, pharmacokinetic and mechanistic studies for the past ten years, together with a brief overview of the pharmacological effects. Notably, we focused to provide a critical enlightenment of the area of andrographolide and its derivatives with the intent of indicating the future perspectives, challenges and limitations. We believe that this review paper will benefit drug discovery where andrographolide was used as a template, shed light on the identification of drug targets for andrographolide and its analogs, as well as increase our knowledge for using them for therapeutic application, including the treatment for various forms of cancers.

Isolation of 4-hydroxy 3-methyl 2-butenyl 4-diphosphate reductase (ApHDR) gene of methyl erythritol diphosphate (MEP) pathway, in silico analysis and differential tissue specific ApHDR expression in Andrographis paniculata (Burm. f) Nees

The full length Andrographis paniculate 4-hydroxy 3-methyl 2-butenyl 4-diphosphate reductase (ApHDR) gene of MEP pathway was isolated for the first time. The ApHDR ORF with 1404 bp flanked by 100 bp 5'UTR and 235 bp 3'UTR encoding 467 amino acids (NCBI accession number: MK503970) and cloned in pET 102, transformed and expressed in E. coli BL21. The ApHDR protein physico-chemical properties, secondary and tertiary structure were analyzed. The Ramachandran plot showed 93.8% amino acids in the allowed regions, suggesting high reliability. The cluster of 16 ligands for binding site in ApHDR involved six amino acid residues having 5-8 ligands. The Fe-S cluster binding site was formed with three conserved residues of cysteine at positions C123, C214, C251 of ApHDR. The substrate HMBPP and inhibitors clomazone, paraquat, benzyl viologen's interactions with ApHDR were also assessed using docking. The affinity of Fe-S cluster binding to the cleft was found similar to HMBPP. The HPLC analysis of different type of tissue (plant parts) revealed highest andrographolide content in young leaves followed by mature leaves, stems and roots. The differential expression profile of ApHDR suggested a significant variation in the expression pattern among different tissues such as mature leaves, young leaves, stem and roots. A 16-fold higher expression of ApHDR was observed in the mature leaves of A. paniculata as compared to roots. The young leaves and stem showed 5.5 fold and fourfold higher expression than roots of A. paniculata. Our result generated new genomic information on ApHDR which may open up prospects of manipulation for enhanced diterpene lactone andrographolide production in A. paniculata.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s12298-021-00952-0.

Isolation, characterization and in silico analysis of 3-Hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR) gene from Andrographis paniculata (Burm. f) Nees

3-Hydroxy-3-methylglutaryl-coenzymeA reductase (HMGR), the first rate-limiting enzyme of Mevalonate (MVA) pathway was isolated from Andrographis paniculata (ApHMGR) and expressed in bacterial cells. Full length ApHMGR (1937 bp) was submitted to NCBI with accession number MG271748.1. The open reading frame (ORF) was flanked by a 31-bp 5'-UTR, 118-bp 3'-UTR and ApHMGR contained a 1787 bp ORF encoding protein of 595 amino acids. ApHMGR protein was approximately 64 kDa, with isoelectric point of 5.75. Isolated ApHMGR was cloned into pET102 vector and expressed in E. coli BL21 (DE 3) cells, and characterized by SDS-PAGE. HPLC analysis for andrographolide content in leaf, stem and root of A. paniculata revealed highest in leaf tissue. The expression patterns of ApHMGR in different plant tissues using qRT-PCR revealed high in root tissue correlating with HPLC data. Three dimensional (3D) structural model of ApHMGR displayed 90% of the amino acids in most favored regions of the Ramachandran plot with 93% overall quality factor. ApHMGR was highly conserved with plant specific N-terminal membrane domains and C-terminal catalytic regions. Phylogenetic analysis showed A. paniculata sharing common ancestor with Handroanthus impetiginosus. 3D model of ApHMGR was screened for the interaction with substrates NADPH, HMG CoA and inhibitor using Auto Dock Vina. In silico analysis revealed that full length ApHMGR had extensive similarities to other plant HMGRs. The present communication reports the isolation of full length HMGR from A. paniculata, its heterologous expression in bacterial cells and in silico structural and functional characterization providing valuable genomic information for future molecular interventions.