Thymus serpyllum L., a well-known aromatic plant of the Himalayan region is often used in pharmaceutical, cosmetic, flavoring and fragrance industries because of its phenolic and non-phenolic constituents. The amount of these compounds varies with the origin, the climatic conditions and the developmental stage of harvesting time of the plant. Under different environmental conditions, plant specimen of the same species respond differently through production and accumulation of the primary and secondary metabolites. In the present work, T. serpyllum L. was collected from its natural habitat and grown at different agro-climatic zones, i.e., Auli (higher Himalayas; 2744 m asl), Pithoragarh (lower Himalayas; 1524 m asl) and Haldwani (foothill areas; 412 m asl). The essential oil from fresh aerial parts of cultivated plants at full blooming stage was obtained using Clevenger apparatus and analyzed by GC-FID and GC-MS. The amount of thymol was also quantified by HPTLC. The data were statistically analyzed using MS Excel and SPSS 16.0. The percentage yield of the essential oils varied from 0.20 to 0.84%. Thymol was the major compound found in all the three cultivations, being the highest for Haldwani (84.63%) followed by Auli (50.80%) and Pithoragarh (41.15%) cultivations. Camphor was the second major compound, only identified in Pithoragarh (36.34%) region. Alpha-thujene, p-cymene, alpha-terpineol, (E)-caryophyllene, beta-bisabolene, alpha-pinene and carvacrol were also identified in significant amounts. HPTLC quantification suggested the similar pattern of thymol percentage as obtained from GC-FID. The study revealed that there was a significant difference in the terpenoid constituents of the plant grown at different agro-climatic zones. Thymus serpyllum grown at lower altitude area (warm climatic zone) can be a potential source of thymol along with high essential oil yield.

Carbon-based 0D materials have shown tremendous potential in the development of biomedical applications of the next generation. The astounding results are primarily motivated by their distinctive nanoarchitecture and unique properties. Integrating these properties of 0D carbon nanomaterials into various polymer systems has orchestrated exceptional potential for their use in the development of sustainable and cutting-edge biomedical applications such as biosensors, bioimaging, biomimetic implants and many more. Specifically, carbon dots (CDs) have gained much attention in the development of biomedical devices due to their optoelectronic properties and scope of band manipulation upon surface revamping. The role of CDs in reinforcing various polymeric systems has been reviewed along with discussing unifying concepts of their mechanistic aspects. The study also discussed CDs optical properties via the quantum confinement effect and band gap transition which is further useful in various biomedical application studies. Graphical Abstract

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Graphene-based materials have undergone substantial investigation in recent years owing to their wide array of physicochemical characteristics. Employment of these materials in the current state, where infectious illnesses caused by microbes have severely damaged human life, has found widespread application in combating fatal infectious diseases. These materials interact with the physicochemical characteristics of the microbial cell and alter or damage them. The current review is dedicated to molecular mechanisms underlying the antimicrobial property of graphene-based materials. Various physical and chemical mechanisms leading to cell membrane stress, mechanical wrapping, photo-thermal ablation as well as oxidative stress exerting antimicrobial effect have also been thoroughly discussed. Furthermore, an overview of the interactions of these materials with membrane lipids, proteins, and nucleic acids has been provided. A thorough understanding of discussed mechanisms and interactions is essential to develop extremely effective antimicrobial nanomaterial for application as an antimicrobial agent. Graphical abstract