Introgression of the heterologous nuclear DNAs and efficacious compositions from Swertia tetraptera Maxim. into Bupleurum scorzonerifolium Willd. via somatic hybridization

Therapeutic potential of plant iridoids in depression: a review

CONTEXT

Depression is a mental disorder characterized by low mood, reduced interest, impaired cognitive function, and vegetative symptoms such as sleep disturbances or poor appetite. Iridoids are the active constituents in several Chinese classical antidepressant formulae such as Yueju Pill, Zhi-Zi-Hou-Po Decoction, Zhi-Zi-Chi Decoction, and Baihe Dihuang Decoction. Parallel to their wide usages, iridoids are considered potential lead compounds for the treatment of neurological diseases.

OBJECTIVE

The review summarizes the therapeutic potential and molecular mechanisms of iridoids in the prevention or treatment of depression and contributes to identifying research gaps in iridoids as potential antidepressant medication.

METHODS

The following key phrases were sought in PubMed, Google Scholar, Web of Science, and China National Knowledge Internet (CNKI) without time limitation to search all relevant articles with in vivo or in vitro experimental studies as comprehensively as possible: ('iridoid' or 'seciridoid' or 'depression'). This review extracted the experimental data on the therapeutic potential and molecular mechanism of plant-derived iridoids for depression.

RESULTS

Plant iridoids (i.e., catalpol, geniposide, loganin), and secoiridoids (i.e., morroniside, gentiopicroside, oleuropein, swertiamarin), all showed significant improvement effects on depression.

DISCUSSION AND CONCLUSIONS

Iridoids exert antidepressant effects by elevating monoamine neurotransmitters, reducing pro-inflammatory factors, inhibiting hypothalamic-pituitary-adrenal (HPA) axis hyperactivity, increasing brain-derived neurotrophic factor (BDNF) and its receptors, and elevating intestinal microbial abundance. Further detailed studies on the pharmacokinetics, bioavailability, and key molecular targets of iridoids are also required in future research, ultimately to provide improvements to current antidepressant medications.

Biotechnological interventions and genetic diversity assessment in Swertia sp.: a myriad source of valuable secondary metabolites

The genus Swertia (Family: Gentianaceae) has cosmopolitan distribution which is present in almost all the continents except South America and Australia. Swertia genus has been renowned as one of the potent herbal drugs in the British, American, and Chinese Pharmacopeias as well as well-documented in the Indian traditional medicinal systems, viz. Ayurveda, Siddha, and Unani. Many species of this genus have therapeutic properties and have been used traditionally in the treatment of a number of health ailments viz. hepatitis, diabetes, inflammation, bacillary dysentery, cancer, malaria, fever etc. This genus is industrially important medicinal plant that has been used as a principal component in numerous marketed herbal/ polyherbal formulations. Medicinal usage of Swertia is endorsed to the miscellaneous compounds viz. xanthones, irridoids, seco-irridoids, and triterpenoids. A chain of systematic isolation of bio-active compounds and their diverse range of pharmacological effects during last 15-20 years proved this genus as industrially important plant. Due to the various practices of the Swertia species, annual demand is more than 100 tons per year for this important herb which is continuously increasing 10% annually. The market value rises 10% by the year as there is increased demand in national and international market resulted in adulteration of many Swertia spp. due to paucity of agricultural practices, exomorphological, phytochemical, and molecular characterization. Thus, efficient biotechnology methods are prerequisite for the mass production of authentic species, sustainable production of bio-active compounds and ex situ conservation. A chain of systematic biotechnological interventions in Swertia herb during last 20 years cover the assessment of genetic diversity, in vitro sustainable production of bio-active compounds and mass propagation of elite genotypes via direct and indirect organogenesis. This review attempts to present the comprehensive assessment on biotechnological process made in Swertia over the past few years. KEY POINTS: • Critical and updated assessment on biotechnological aspects of Swertia spp. • In vitro propagation and genetic diversity assessment in Swertia spp. • Biosynthesis and sustainable production of secondary metabolites in Swertia spp.

Progress in plant protoplast research

In this review we focus on recent progress in protoplast regeneration, symmetric and asymmetric hybridization and novel technology developments. Regeneration of new species and improved culture techniques opened new horizons for practical breeding in a number of crops. The importance of protoplast sources and embedding systems is discussed. The study of reactive oxygen species effects and DNA (de)condensation, along with thorough phytohormone monitoring, are in our opinion the most promising research topics in the further strive for rationalization of protoplast regeneration. Following, fusion and fragmentation progress is summarized. Genomic, transcriptomic and proteomic studies have led to better insights in fundamental processes such as cell wall formation, cell development and chromosome rearrangements in fusion products, whether or not obtained after irradiation. Advanced molecular screening methods of both genome and cytoplasmome facilitate efficient screening of both symmetric and asymmetric fusion products. We expect that emerging technologies as GISH, high resolution melting and next generation sequencing will pay major contributions to our insights of genome creation and stabilization, mainly after asymmetric hybridization. Finally, we demonstrate agricultural valorization of somatic hybridization through enumerating recent introgression of diverse traits in a number of commercial crops.