The survival of extreme water deficit stress by tolerant organisms requires a coordinated series of responses, including those at cellular, transcriptional, translational and metabolic levels. Small molecules play a pivotal role in creating the proper chemical environment for the preservation of cellular integrity and homeostasis during dehydration. This review surveys recent insights in the importance of primary and specialised metabolites in the response to drying of angiosperms with vegetative desiccation tolerance, i.e. the ability to survive near total loss of water. Important metabolites include sugars such as sucrose, trehalose and raffinose family of oligosaccharides, amino acids and organic acids, as well as antioxidants, representing a common core mechanism of desiccation tolerance. Additional metabolites are discussed in the context of species specificity and adaptation.

Osteoarthritis (OA) is a chronic inflammatory disorder of the joints caused by fluid and cartilage matrix component reduction. This disease results in symptoms of pain, deformity, and limitation of movement. In general, OA is treated with anti-inflammatory drugs and chondroprotection compounds, includes natural nutraceutical ingredients, which are expected to be effective and have minimal side effects. Arecaceae plants are widely spread worldwide, especially in tropical areas. The objective of this review is to collect information about the Arecaceae family as anti-OA agents, with the main study focusing on the primary and secondary metabolites of plants of the Arecaceae family, i.e., sugar palm (Arenga pinnata), nipa palm (Nypa fruticans), palmyra palm (Borassus flabellifer), date palm (Phoenix dactylifera), and betel nut (Areca catechu) have potential as anti-OA agents. The Arecaceae\'s metabolites that show anti-inflammatory and chondroprotective effects are galactomannan, fatty acids (linoleic and linolenic acids), flavonoids (quercetin, luteolin, isorhamnetin), phenolics (coumaric acid, ferulic acid), polyphenols (epicatechin), and steroids (stigmasterol, campesterol, spirostane). Based on the reports, the Arecaceae family plants become worthy of being explored and developed into natural anti-OA products, such as supplements or nutraceuticals.

Nanoparticles (NPs) are tiny substances that can exist in the soil with different forms at different concentrations. In general, they present enormous effects on the growth, physiology, and molecular responses in plants. Indeed, they can penetrate the roots, stem, and leaves via different ways like stomata, plasmodesmata, xylem, and phloem and through transporter proteins like aquaporins. Once entered the plants, NPs induce reactive oxygen species (ROS) formation, and the plants respond to ROS by stimulates the production of antioxidants and antioxidant enzymes as well as the production of various primary and secondary metabolites like flavonoids and phenolic compounds. In addition, NPs have significantly affected the distribution of mineral profiles in plants. NPs considerably affect plant growth and yield in a dose-dependent fashion. At higher concentrations, they induced potent cytotoxicity and genotoxicity and thus reduced the growth and development of plants in turn decrease the yield. NPs exert potent changes in the transcriptome and metabolome pattern of plants to counteract the ROS imposed by NPs. This review depicts the overview of transcriptomic and metabolomic responses of plants towards nanopollution.

The interest in developing microalgae for industrial use has been increasing because of concerns about the depletion of petroleum resources and securing sustainable energy sources. Microalgae have high biomass productivity and short culture periods. However, despite these advantages, various barriers need to be overcome for industrial applications. Microalgal cultivation has a high unit price, thus rendering industrial application difficult. It is indispensably necessary to co-produce their primary and secondary metabolites to compensate for these shortcomings. In this regard, this article reviews the following aspects, (1) co-production of primary and secondary metabolites in microalgae, (2) induction methods for the promotion of the biosynthesis of secondary metabolites, and (3) perspectives on the co-production and co-extraction of primary and secondary metabolites. This paper presents various approaches for producing useful metabolites from microalgae and suggests strategies that can be utilized for the co-production of primary and secondary metabolites.