Nanoparticles and nanotechnology developments continue to advance the livelihood of humankind. However, health challenges due to microorganisms and cancerous cells continue to threaten many people’s lives globally. Therefore, new technological interventions are of great importance. The phytochemicals present in medicinal plants are suggested as biocompatible, cost-effective, and regenerative sources that can be utilized for the green synthesis of nanoparticles. Different plant extracts with various phytochemical constituents can form nanoparticles with specific shapes, sizes, and optical properties. This review focuses on advances in green nanotechnology and provides details on reliable synthetic routes toward medically and biocompatible relevant metallic nanoparticles. We cover a wide range of applications that use phytonanoparticles with an in-depth look at what makes these materials interesting. The study also provides details of the literature on the interventions made in phytonanotechnology for the production of plant-mediated synthesis and capped metallic nanoparticles and their applications in various industries. It was observed that a variety of plants have been well studied, and detailed findings have been reported; however, the study of Phyllanthus is still in its early stages, and more needs to be uncovered.

Background: Stigmasterol is an unsaturated phytosterol that belong to the class of tetracyclic steroids abundant in Rhoicissus tridentata. Stigmasterol is an important constituent since it has shown impressive pharmacological effects such as anti-osteoarthritis, anticancer, anti-diabetic, anti-inflammatory, antiparasitic, immunomodulatory, antifungal, antioxidant, antibacterial, and neuroprotective activities. Furthermore, due to the presence of π system and hydroxyl group, stigmasterol is readily derivatized through substitution and addition reactions, allowing for the synthesis of a wide variety of stigmasterol derivatives. Methods: Stigmasterol (1) isolated from Rhoicissus tridentata was used as starting material to yield eight bio-active derivatives (2–9) through acetylation, epoxidation, epoxide ring opening, oxidation, and dihydroxylation reactions. The structures of all the compounds were established using spectroscopic techniques, NMR, IR, MS, and melting points. The synthesized stigmasterol derivatives were screened for cytotoxicity against the hormone receptor-positive breast cancer (MCF-7), triple-negative breast cancer (HCC70), and non-tumorigenic mammary epithelial (MCF-12 A) cell lines using the resazurin assay. Results: Eight stigmasterol derivatives were successfully synthesized namely; Stigmasterol acetate (2), Stigmasta-5,22-dien-3,7-dione (3), 5,6-Epoxystigmast-22-en-3β-ol (4), 5,6-Epoxystigmasta-3β,22,23-triol (5), Stigmastane-3β,5,6,22,23-pentol (6), Stigmasta-5-en-3,7-dion-22,23-diol (7), Stigmasta-3,7-dion-5,6,22,23-ol (8) and Stigmast-5-ene-3β,22,23-triol (9). This is the first report of Stigmasta-5-en-3,7-dion-22,23-diol (7) and Stigmasta-3,7-dion-5,6,22,23-ol (8). The synthesized stigmasterol analogues showed improved cytotoxic activity overall compared to the stigmasterol (1), which was not toxic to the three cell lines tested (EC₅₀ ˃ 250 µM). In particular, 5,6-Epoxystigmast-22-en-3β-ol (4) and stigmast-5-ene-3β,22,23-triol (9) displayed improved cytotoxicity and selectivity against MCF-7 breast cancer cells (EC₅₀ values of 21.92 and 22.94 µM, respectively), while stigmastane-3β,5,6,22,23-pentol (6) showed improved cytotoxic activity against the HCC70 cell line (EC₅₀: 16.82 µM). Conclusion: Natural products from Rhoicissus tridentata and their derivatives exhibit a wide range of pharmacological activities, including anticancer activity. The results obtained from this study indicate that molecular modification of stigmasterol functional groups can generate structural analogues with improved anticancer activity. Stigmasterol derivatives have potential as candidates for novel anticancer drugs.

Species within the genus Rhoicissus (Vitaceae) are commonly used in South African traditional medicine. The current review discusses the occurrence, distribution, traditional uses, phytochemistry, and pharmacological properties of Rhoicissus species covering the period 1981–2020. The data reported were systematically collected, read, and analysed from scientific electronic databases including Scopus, Scifinder, Pubmed, and Google Scholar. Reported evidence indicates that species in this genus are used for the treatment of gastrointestinal complaints, sexually transmitted infections (STIs), and infertility, as well as to tone the uterus during pregnancy and to facilitate delivery. Pharmacological studies have further shown that members of the Rhoicissus genus display antidiabetic, uterotonic, ascaricidal, hepatoprotective, antioxidant, antimicrobial, anticancer, and anti-inflammatory properties. They are linked to the presence of bioactive compounds isolated from the genus. Hence, Rhoicissus species can potentially be an alternative therapeutic strategy to treat diseases and develop safer and more potent drugs to combat diseases. Plant species of this genus have valuable medicinal benefits due to their significant pharmacological potential. However, scientific investigation and information of the therapeutic potential of Rhoicissus remain limited as most of the species in the genus have not been fully exploited. Therefore, there is a need for further investigations to exploit the therapeutic potential of the genus Rhoicissus. Future studies should evaluate the phytochemical, pharmacological, and toxicological activities, as well as the mode of action, of Rhoicissus crude extracts and secondary compounds isolated from the species.

Fatalities caused by infectious diseases (i.e., diseases caused by parasite, bacteria, and viruses) have become reinstated as a major public health threat globally. Factors such as antimicrobial resistance and viral complications are the key contributors to the death numbers. As a result, new compounds with structural diversity classes are critical for controlling the virulence of pathogens that are multi-drug resistant. Derivatization of bio-active organic molecules with organometallic synthons is a promising strategy for modifying the inherent and enhanced properties of biomolecules. Due to their redox chemistry, bioactivity, and structural diversity, organometallic moieties make excellent candidates for lead structures in drug development. Furthermore, organometallic compounds open an array of potential in therapy that existing organic molecules lack, i.e., their ability to fulfill drug availability and resolve the frequent succumbing of organic molecules to drug resistance. Additionally, metal complexes have the potential towards metal-specific modes of action, preventing bacteria from developing resistance mechanisms. This review’s main contribution is to provide a thorough account of the biological efficacy (in vitro and in vitro) of metal-based complexes against infectious diseases. This resource can also be utilized in conjunction with corresponding journals on metal-based complexes investigated against infectious diseases.