The use of metallic nanoparticles in engineering and biomedicine disciplines has gained considerable attention. Scientists are exploring new synthesis protocols of these substances considering their small size and lucrative antimicrobial potential. Among the most economical techniques of synthesis of metallic nanoparticles via chemical routes, which includes the use of chemicals as metal reducing agents, is considered to generate nanoparticles possessing toxicity and biological risk. This limitation of chemically synthesized nanoparticles has engendered the exploration for the ecofriendly synthesis process. Biological or green synthesis approaches have emerged as an effective solution to address the limitations of conventionally synthesized nanoparticles. Nanoparticles synthesized via biological entities obtained from plant extracts exhibit superior effect in comparison to chemical methods. Recently, conifer extracts have been found to be effective in synthesizing metallic nanoparticles through a highly regulated process. The current review highlights the importance of conifers and its extracts in synthesis of metallic nanoparticles. It also discusses the different applications of the conifer extract mediated metallic nanoparticles.

Carissa, a genus of the Apocynaceae family, consists of evergreen species, such as shrubs as well as small trees that are native to Asia, Africa, and Oceania’s subtropical and tropical regions. Most of the Carissa species are traditionally used to treat various diseases, such as chest pain, headaches, gonorrhoea, rheumatism, syphilis, oedema, rabies, stomach pain, hepatitis, cardiac diseases, and asthma. The pharmacological studies on Carissa species revealed its antioxidant, antimicrobial, anticancer, cardioprotective, antipyretic, analgesic, wound healing, anticonvulsant, antiarthritic, adaptogenic, anti-inflammatory, and antidiabetic activities, thus validating its use in indigenous medicine systems. The review article summarised the comprehensive literature available, including morphology, indigenous uses, bioactive composition, nutraceutical, and pharmacological activities of Carissa species. A total of 155 research papers were cited in this review article. The Carissa fruits are rich in dietary fibre, lipids, proteins, carbohydrates, vitamin C, and macro- and micro-elements. A total of 121 compounds (35 polyphenols (flavonoids and phenolic acids), 30 lignans, 41 terpenoids, 7 steroids, 2 coumarins, and 6 cardiac glycosides) have been extracted from C. spinarum, C. carandas, and C. macrocarpa. Among all chemical constituents, lupeol, carissol, naringin, carisssone, scopoletin, carissaeduloside A, D, J, carandinol, sarhamnoloside, carissanol, olivil, carinol, 3β-hydroxyolean-11-en-28,13β-oilde, ursolic acid, and carissone are the key bioactive constituents responsible for pharmacological activities of genus Carissa. The gathered ethnopharmacological information in the review will help to understand the therapeutic relevance of Carissa as well as paving a way for further exploration in the discovery of novel plant-based drugs.

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Rubus ellipticus fruits aqueous extract derived ZnO-nanoparticles (NPs) were synthesized through a green synthesis method. The structural, optical, and morphological properties of ZnO-NPs were investigated using XRD, FTIR, UV-vis spectrophotometer, XPS, FESEM, and TEM. The Rietveld refinement confirmed the phase purity of ZnO-NPs with hexagonal wurtzite crystalline structure and p-63-mc space group with an average crystallite size of 20 nm. XPS revealed the presence of an oxygen chemisorbed species on the surface of ZnO-NPs. In addition, the nanoparticles exhibited significant in vitro antioxidant activity due to the attachment of the hydroxyl group of the phenols on the surface of the nanoparticles. Among all microbial strains, nanoparticles’ maximum antibacterial and antifungal activity in terms of MIC was observed against Bacillus subtilis (31.2 µg/mL) and Rosellinia necatrix (15.62 µg/mL), respectively. The anticancer activity revealed 52.41% of A549 cells death (IC50: 158.1 ± 1.14 µg/mL) at 200 μg/mL concentration of nanoparticles, whereas photocatalytic activity showed about 17.5% degradation of the methylene blue within 60 min, with a final dye degradation efficiency of 72.7%. All these results suggest the medicinal potential of the synthesized ZnO-NPs and therefore can be recommended for use in wastewater treatment and medicinal purposes by pharmacological industries.

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