Introduction

Herbal medicines have played a major role in disease prevention and cure. The World Health Organization (WHO) reported that nearly 80 percent of the world population, predominantly from the developing nations, consumes herbal medicines to meet their primary healthcare requirements. Medicinal plant cultivation through systemic methods were opted by scientists in order to yield medicinal plants of high quality. Medicinal and aromatic plants (MAPs) through biotechnological interventions have significantly improved the future of herbal medicines. Medicinal plants have yielded a plethora of drugs including: morphine, a narcotic from Papaver somniferum; reserpine, an antihypertensive drug from Rauvolfia serpentina; cocaine, an anesthetic and CNS stimulant from Erythroxylon coca to name a few.

Medicinal and Aromatic Plant Drugs

The MAPs undergo genetic transformation to yield hairy roots. These hairy roots are grown in bioreactors for the synthesis of secondary metabolites and for improved productivity. Other key applications of transformed root cultures include whole plant regeneration; biotransformation; artificial seeds production; high-quality metabolite production; and phytoremediation. Hairy root cultures have a plethora of advantages when compared to cell cultures. Hairy roots have played major roles in molecular farming, antibodies and fusion proteins production. The antimalarial drug Artemisnin and the anticholinergic drug Atropine are produced from hairy root cultures of Artemisia annua and Atropa belladonna respectively.

Bioinformatics in Drug Development

Biotechnology gave rise to new discipline called bioinformatics. Bioinformatics has had a huge impact on drug development. Bioinformatics approaches have paced up the process of drug discovery and have changed the way the drugs are designed. The rapid growth of bioinformatics has potentially improved allied technologies and automated DNA sequencers thereby improving gene sequences, gene expression, proteins, and protein expression. In the field of drug discovery, bioinformatics aims to:
(1) develop new models of proteins;
(2) develop various approaches to identify the function or structure of new proteins;
(3) examine protein relationship; and
(4) identify specific genes in stored DNA sequences.

Nanotechnology in Drug Development

The participation of nanotechnology in the production medicinal drugs has gained a reputation in recent times. Scientists have anticipated that nano and micro reactors will have a huge role to play in the discovery of medical drugs. These reactors are expected to produce high-quality and low- volume compounds such as nutritional compounds, fragrances, pharmaceuticals, dyes, and flavors to name a few. Pharmaceuticals that are produced by recombinant DNA technology (rDNA) and nanotechnology combined are likely to yield advanced medicinal compounds that aid in accurate disease diagnosis, nanobiosensors for culture conditions manipulation, and bionanostructures for functional molecule insertion.

The Advantages of the Four Host Types

Biochemical drugs are produced by four hosts namely: plant cell cultures; bacterial cells; mammalian cells; and yeast cells. Biochemical drugs produced from plant cell cultures are:

(1) secondary metabolites with the correct stereochemistry;
(2) multimeric proteins;
(3) homogenous;
(4) not oncogenes and do not produce endotoxin; and
(5) cells are separated from the culture medium with ease.

The advantages of producing biochemical drugs by bacterial cells include:
(1) short development time;
(2) product is secreted in the culture medium; and
(3) physiological and genetic characterization are profound.

Biochemical drugs from mammalian cells offer the biggest advantage in terms producing dominant drug proteins. Yeast cells produce biochemical drugs that are inducible promoters and are well-established in the industrial infrastructure. Apart from offering individual advantages, the four host types offer certain common advantages including:

(1) general safety;
(2) high protein accuracy ;
(3) high protein yield;
(4) easy scale-up and propagation;
(5) low cultivation costs;
(6) desired glycosylation activity; and
(7) post-transnational modification ability.

Additionally, in 2004, the Bill and Melinda Gates Foundation has granted $ 42 million funds toward synthetic biology approaches, aiming to make available the semi-synthetic artemisinin drug to the developing nations in Asian and African continent. This initiative was to emphasize the importance of biochemical compounds development.

Example- Drug Types

Noscapine is an antimicrotubule drug, a combination of codeine and noscapine, was discovered by French pharmacist Pierre-Jean Robiquet in 1817. The drug is an active cough suppressant and has now been employed to treat cancer cells. Perennial herbaceous plants such as mayapple and meadow saffron are used in the production of potent drugs podophyllotoxin and colchicine respectively.

The paradigm shift from traditional drug production methods to biotechnological methods has greatly improved the production of high-value chemical compounds that subsequently have improved the quality of life and disease prevention.

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