Meroterpenoids are secondary metabolites formed due to mixed biosynthetic pathways which are produced in part from a terpenoid co-substrate. These mixed biosynthetically hybrid compounds are widely produced by bacteria, algae, plants, and animals. Notably amazing chemical diversity is generated among meroterpenoids via a combination of terpenoid scaffolds with polyketides, alkaloids, phenols, and amino acids. This review deals with the isolation, chemical diversity, and biological effects of 452 new meroterpenoids reported from natural sources from January 2016 to December 2020. Most of the meroterpenoids possess antimicrobial, cytotoxic, antioxidant, anti-inflammatory, antiviral, enzyme inhibitory, and immunosupressive effects.

Psidium guajava L. (guava) is a small tree known for its fruit flavor that is cultivated almost around the globe in tropical areas. Its fruit is amazingly rich in antioxidants, vitamin C, potassium, and dietary fiber. In different parts of the world, this plant holds a special place with respect to fruit and nutritional items. Pharmacological research has shown that this plant has more potential than just a fruit source; it also has beneficial effects against a variety of chronic diseases due to its rich nutritional and phytochemical profile. The primary goal of this document is to provide an updated overview of Psidium guajava L. and its bioactive secondary metabolites, as well as their availability for further study, with a focus on the health benefits and potential industrial applications. There have been several studies conducted on Psidium guajava L. in relation to its use in the pharmaceutical industry. However, its clinical efficacy and applications are still debatable. Therefore, in this review a detailed study with respect to phytochemistry of the plant through modern instruments such as GC and LC-MS has been discussed. The biological activities of secondary metabolites isolated from this plant have been extensively discussed. In order to perform long-term clinical trials to learn more about their effectiveness as drugs and applications for various health benefits, a structure activity relationship has been established. Based on the literature, it is concluded that this plant has a wide variety of biopharmaceutical applications. As a whole, this article calls for long-term clinical trials to obtain a greater understanding of how it can be used to treat different diseases.

A wide range of natural products important for the engineering and drug design of pharmaceuticals comprise largely of nitrogen-based heterocycles. Fungal natural products have proven to be a rich source of the industrially-important molecules, many of which are promising drug leads. Although, natural products containing a phthalimidine core tends not to be given distant classification, but compounds containing these structures exhibit antimicrobial, anthelmintic, antimalarial and insecticidal activities, and are among the potential target for discovering new drug candidates. Intriguingly, these are primarily isolated from fungal sources and to a very lesser extent from plants or bacteria. This review surveys fungal-derived phthalimidine metabolites published until the end of 2022, isolated from both terrestrial and aquatic or marine sources with emphasis on their unique chemistry, bioactivities, biogenesis and taxonomic classification. Their unique chemistry and diverse bioactivities (including antiviral, antiproliferative, antioxidant and antimicrobial) provide a chemical library with high medicinal potential, representing a treasure trove for synthetic chemists. Graphical Abstract

In this study, we harnessed the properties of desert plants to synthesize silver nanoparticles to explore potential antimicrobial solutions. Chrozophora plicata and Heliotropium curassavicum extracts were used as green reducing agents to transform silver ions into nanoparticles. Our findings revealed novel properties of C. plicata, which have not been reported before. Surface plasmon resonance peak at 453.6 and 431 nm for C. plicata and H. curassavicum, respectively, via ultraviolet (UV) spectral analysis evidenced the successful fabrication of silver nanoparticles with particle sizes ranging from 4.3–8 and 3.1–6.97 nm respectively, which was validated by field emission scanning electron microscopy (FE-SEM). X-ray diffraction analysis revealed that the crystal structure of these nanoparticles had a face-centered cubic geometry. Fourier transform infrared spectrometry of the plant extract showed strong signals corresponding to carbohydrates, proteins, and phenolics. Antibacterial assays of the silver nanoparticles from C. plicata displayed zones of inhibition at 5 and 4 mm against Staphylococcus aureus and Escherichia coli, respectively. Meanwhile, the silver nanoparticles from H. curassavicum exhibited zones of inhibition against both pathogens at 10 and 7 mm, respectively. The test samples were substantial inhibitors of S. aureus and E. coli biofilm formation since these displayed IC₅₀ values in the range of 8.88–10.57 mg/mL, which is as potent as the reference ciprofloxacin. Consequently, the silver nanoparticles derived from these desert plants can be potential drug candidates for treating respiratory and digestive tract infections alone or in combination with existing antibiotics.