Production of Effective Phyto-antimicrobials via Metabolic Engineering Strategies.

The emerging outbreak of infectious diseases poses a challenge and threatens human survival. The indiscriminate use and drying pipelines of antibiotic arsenals have led to the alarming rise of drug-resistant pathogens, projecting a serious concern. The rising antimicrobial resistance and redundancy of antibiotic discovery platforms (ADPs) have highlighted the growing concern to discover new antibiotics, necessitating exploring natural products as effective alternatives to counter drug resistance. Recently, plants have been extensively investigated in search of the "phytotherapeutics", attributed to their potential efficacy and tackling the majority of the drug-resistant mechanisms, including biofilms, efflux pumps, cell communication, and membrane proteins. However, major challenges in geographical fluctuations, low plant concentration, and over-harvestation of natural resources restrict availability and complete utilization of phyto-therapeutics as antimicrobials. Recent advances in scientific interventions have been instrumental in producing novel antimicrobials via metabolic engineering approaches in plant systems. The progress in plant genome editing, pathway reconstitution, and expression has defined new paradigms in the successful production of antimicrobials in the post-antibiotic era. The thematic review discusses the existing and emerging significance of phytotherapeutics in tackling antimicrobial resistance and employing metabolic engineering approaches. The prevailing scenario of antimicrobial resistance and the mechanisms, the traditional and modern drug-discovery approaches in addressing antimicrobial resistance, emphasizing advances in metabolic engineering approaches for antimicrobial production, and the plausible solutions for tackling drug-resistant pathogens, forms the key theme of the article.

Engineering Catharanthus roseus monoterpenoid indole alkaloid pathway in yeast.

Catharanthus roseus (Madagascar periwinkle), a medicinal plant possessing high pharmacological attributes, is widely recognized for the biosynthesis of anticancer monoterpenoid indole alkaloids (MIAs) - vinblastine and vincristine. The plant is known to biosynthesize more than 130 different bioactive MIAs, highly acclaimed in traditional and modern medicinal therapies. The MIA biosynthesis is strictly regulated at developmental and spatial-temporal stages and requires a well-defined cellular and sub-cellular compartmentation for completion of the entire MIAs biosynthesis. However, due to their cytotoxic nature, the production of vinblastine and vincristine occurs in low concentrations in planta and the absence of chemical synthesis alternatives projects a huge gap in demand and supply, leading to high market price. With research investigations spanning more than four decades, plant tissue culture and metabolic engineering (ME)-based studies were attempted to explore, understand, explain, improve and enhance the MIA biosynthesis using homologous and heterologous systems. Presently, metabolic engineering and synthetic biology are the two powerful tools that are contributing majorly in elucidating MIA biosynthesis. This review concentrates mainly on the efforts made through metabolic engineering of MIAs in heterologous microbial factories. KEY POINTS: • Yeast engineering provides alternative production source of phytomolecules • Yeast engineering also helps to discover missing plant pathway enzymes and genes.

Gymnema sylvestre for Diabetes: From Traditional Herb to Future's Therapeutic.

Diabetes has increased at an unprecedented rate and is fast emerging as a global threat worldwide. The focus on pharmacological studies pertaining to diabetes has seen a remarkable shift from conventional medicines to therapeutics employing bioactive phytomolecules from natural sources. The prospective effectiveness of natural products together with their low cost and minimal side effects has revolutionized the entire concept of drug discovery and management programs. One such beneficial herb is Gymnema sylvestre, possessing remarkable hypoglycemic properties and forms the platform of diabetes therapeutics in the traditional system of medication. The present article discusses the significance of G. sylvestre in diabetes management, the herbal-formulations from the herb together with its standardization and clinical trials on animal models, and why Peroxisome Proliferator Activated Receptor gamma (PPARγ) may serve as a prospective molecular target for Gymnemic acid analogs. Such studies would define the molecular basis of bioactive molecules which would aid in the development of natural product based therapeutics in the treatment of diabetes.

Phytochemical and pharmacological properties of Gymnema sylvestre: an important medicinal plant.

Gymnema sylvestre (Asclepiadaceae), popularly known as "gurmar" for its distinct property as sugar destroyer, is a reputed herb in the Ayurvedic system of medicine. The phytoconstituents responsible for sweet suppression activity includes triterpene saponins known as gymnemic acids, gymnemasaponins, and a polypeptide, gurmarin. The herb exhibits a broad range of therapeutic effects as an effective natural remedy for diabetes, besides being used for arthritis, diuretic, anemia, osteoporosis, hypercholesterolemia, cardiopathy, asthma, constipation, microbial infections, indigestion, and anti-inflammatory. G. sylvestre has good prospects in the treatment of diabetes as it shows positive effects on blood sugar homeostasis, controls sugar cravings, and promotes regeneration of pancreas. The herbal extract is used in dietary supplements since it reduces body weight, blood cholesterol, and triglyceride levels and holds great prospects in dietary as well as pharmacological applications. This review explores the transition of a traditional therapeutic to a modern contemporary medication with an overview of phytochemistry and pharmacological activities of the herb and its phytoconstituents.

Bioconversion of artemisinin to its nonperoxidic derivative deoxyartemisinin through suspension cultures of Withania somnifera Dunal.

Biotransformation of artemisinin was investigated with two different cell lines of suspension cultures of Withania somnifera. Both cell lines exhibited potential to transform artemisinin into its nonperoxidic analogue, deoxyartemisinin, by eliminating the peroxo bridge of artemisinin. The enzyme involved in the reaction is assumed to be artemisinin peroxidase, and its activity in extracts of W. somnifera leaves was detected. Thus, the non-native cell-free extract of W. somnifera and suspension culture-mediated bioconversion can be a promising tool for further manipulation of pharmaceutical compounds.