Biotechnology for propagation and secondary metabolite production in Bacopa monnieri

Bacopa monnieri (L.) Wettst. or water hyssop commonly known as Brahmi is a small, creeping, succulent herb from the Plantaginaceae family. It is popularly employed in Ayurvedic medicine as a nerve tonic to improve memory and cognition. Of late, this plant has been reported extensively for its pharmacologically active phyto-constituents. The main phytochemicals are brahmine, alkaloids, herpestine, and saponins. The saponins include bacoside A, bacoside B, and betulic acid. Investigation into the pharmacological effect of this plant has thrived lately, encouraging its neuroprotective and memory supporting capacity among others. Besides, it possesses many other therapeutic activities like antimicrobial, antioxidant, anti-inflammatory, gastroprotective properties, etc. Because of its multipurpose therapeutic potential, it is overexploited owing to the prioritization of natural remedies over conventional ones, which compels us to conserve them. B. monnieri is confronting the danger of extinction from its natural habitat as it is a major cultivated medico-botanical and seed propagation is restricted due to less seed availability and viability. The ever-increasing demand for the plant can be dealt with mass propagation through plant tissue culture strategy. Micropropagation utilizing axillary meristems as well as de novo organogenesis have been widely investigated in this plant which has also been explored for its conservation and production of different types of secondary metabolites. Diverse in vitro methods such as organogenesis, cell suspension, and callus cultures have been accounted for with the aim of production and/or enhancement of bacosides. Direct shoot-organogenesis was initiated in excised leaf and internodal explants without any exogenous plant growth regulator(s) (PGRs), and the induction rate was improved when exogenous cytokinins and other supplements were used. Moreover, biotechnological toolkits like Agrobacterium-mediated transformation and the use of mutagens have been reported. Besides, the molecular marker-based studies demonstrated the clonal fidelity among the natural and in vitro generated plantlets also elucidating the inherent diversity among the natural populations. Agrobacterium-mediated transformation system was mostly employed to optimize bacoside biosynthesis and heterologous expression of other genes. The present review aims at depicting the recent research outcomes of in vitro studies performed on B. monnieri which include root and shoot organogenesis, callus induction, somatic embryogenesis, production of secondary metabolites by in vitro propagation, acclimatization of the in vitro raised plantlets, genetic transformation, and molecular marker-based studies of clonal fidelity.

Automated summary

Bacopa monnieri, also known as water hyssop or Brahmi, is a small herb commonly used in Ayurvedic medicine for its memory-enhancing and cognition-improving effects. Recent research has focused on the pharmacologically active compounds in this plant, such as brahmine, alkaloids, herpestine, and saponins, including bacoside A, bacoside B, and betulic acid. Studies have shown its neuroprotective and memory-supporting properties, as well as other therapeutic activities like antimicrobial and antioxidant effects. However, overexploitation and habitat destruction have put this plant at risk of extinction, necessitating conservation efforts. In vitro studies have explored methods like organogenesis and cell suspension cultures to produce and enhance bacosides, as well as genetic transformation techniques. Molecular marker-based studies have also demonstrated clonal fidelity among natural and in vitro-generated plantlets. The review highlights the recent advancements in in vitro studies of B. monnieri, including root and shoot organogenesis, callus induction, secondary metabolite production, acclimatization of plantlets, genetic transformation, and clonal fidelity.