Biochemical characterization of recombinant mevalonate kinase from Bacopa monniera

Biotechnological production of bacosides from cell and organ cultures of Bacopa monnieri

Bacopa monnieri (L.) Wettst. (BM), also known as 'Brahmi' or 'Water Hyssop', has been utilized as a brain tonic, memory enhancer, sensory organ revitalizer, cardiotonic, anti-anxiety, antidepressant and anticonvulsant agent in the Indian system of medicine Ayurveda for centuries. BM is beneficial in the treatment of Parkinson's disease, Alzheimer's disease, epileptic seizures and schizophrenia in recent pharmacological research. Dammarane-type triterpenoid saponins containing jujubogenin and pseudojujubogenin as aglycones, also known as bacosides, are the principal chemical ingredients identified and described from BM. Bacosides have been shown to have anti-ageing, anticancer, anticonvulsant, antidepressant, anti-emetic, anti-inflammatory and antibacterial properties in a variety of pre-clinical and clinical studies. The pharmaceutical industry's raw material comes from wild sources; nevertheless, the concentration of bacosides varies in different regions of the plants, as well as seasonal and genotypic variation. Cell and tissue cultures are appealing alternatives for the long-term manufacture of bioactive chemicals, and attempts to produce bacosides using in vitro cultures have been made. This review discusses the biotechnological approaches used to produce bacosides, as well as the limitations and future potential. KEY POINTS: • Bacosides extracted from Bacopa monnieri are important pharmaceutical compounds. • The current review provides insight into biotechnological interventions for the production of bacosides using in vitro cultures. • Highlights the prospects improvement of bacoside production through metabolic engineering.

Low-Copy Genes in Terpenoid Metabolism: The Evolution and Expression of MVK and DXR Genes in Angiosperms

Terpenoids are a diverse class of metabolites that impact plant metabolism in response to environmental cues. They are synthesized either via a predominantly cytosolic (MVA) pathway or a plastidic pathway (MEP). In Arabidopsis, several enzymes from the MVA and MEP pathways are encoded by gene families, excluding MVK and DXR, which are single-copy genes. In this study, we assess the diversity, evolution and expression of DXR and MVK genes in selected angiosperms and Coffea arabica in particular. Evolutionary analysis revealed that DXR and MVK underwent purifying selection, but the selection effect for DXR was stronger than it was for MVK. Digital gene expression (DGE) profile analysis of six species revealed that expression levels of MVK in flowers and roots were high, whereas for DXR peak values were observed in leaves. In C. arabica, both genes were highly expressed in flowers, and CaDXR was upregulated in response to methyl jasmonate. C. arabica DGE data were validated by assessing gene expression in selected organs, and by plants treated with hexanoic acid (Hx) using RT-qPCR. MVK expression was upregulated in roots treated with Hx. CaDXR was downregulated in leaves by Hx treatment in a genotype-specific manner, indicating a differential response to priming.

Recent advances in steroidal saponins biosynthesis and in vitro production

Steroidal saponins exhibited numerous pharmacological activities due to the modification of their backbone by different cytochrome P450s (P450) and UDP glycosyltransferases (UGTs). Plant-derived steroidal saponins are not sufficient for utilizing them for commercial purpose so in vitro production of saponin by tissue culture, root culture, embryo culture, etc, is necessary for its large-scale production. Saponin glycosides are the important class of plant secondary metabolites, which consists of either steroidal or terpenoidal backbone. Due to the existence of a wide range of medicinal properties, saponin glycosides are pharmacologically very important. This review is focused on important medicinal properties of steroidal saponin, its occurrence, and biosynthesis. In addition to this, some recently identified plants containing steroidal saponins in different parts were summarized. The high throughput transcriptome sequencing approach elaborates our understanding related to the secondary metabolic pathway and its regulation even in the absence of adequate genomic information of non-model plants. The aim of this review is to encapsulate the information related to applications of steroidal saponin and its biosynthetic enzymes specially P450s and UGTs that are involved at later stage modifications of saponin backbone. Lastly, we discussed the in vitro production of steroidal saponin as the plant-based production of saponin is time-consuming and yield a limited amount of saponins. A large amount of plant material has been used to increase the production of steroidal saponin by employing in vitro culture technique, which has received a lot of attention in past two decades and provides a way to conserve medicinal plants as well as to escape them for being endangered.