Ralstonia solanacearum is a phytopathogen causing bacterial wilt diseases of tomato and affecting its productivity, which leads to prominent economic losses annually. As an alternative to conventional pesticides, green synthesized nanoparticles are believed to possess strong antibacterial activities besides being cheap and ecofriendly. Here, we present the synthesis of silver nanoparticles (Sn-AgNPs) from medicinally important aqueous plant extracts of Salvia nubicola. Characterization of biologically synthesized nanoparticles was performed through UV-vis spectrophotometry, Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy (TEM), and thermogravimetric analysis. The antibacterial activity of the biosynthesized silver nanoparticles was tested against the phytopathogen R. solanacearum through in vitro experiments. Preliminary phytochemical analysis of the plant extracts revealed the presence of substantial amounts of flavonoids (57.08 mg GAE/g), phenolics (42.30 mg GAE/g), tannins, and terpenoids. The HPLC phenolic profile indicated the presence of 25 possible bioactive compounds. Results regarding green synthesized silver nanoparticles revealed the conformation of different functional groups through FTIR analysis, which could be responsible for the bioreduction and capping of Ag ions into silver NPs. TEM results revealed the spherical, crystalline shape of nanoparticles with the size in the range of 23-63 nm, which validates SEM results. Different concentrations of Sn-AgNPs (T1 (500 μg/mL) to T7 (78.1 μg/mL)) with a combination of plant extracts (PE-Sn-AgNPs) and plant extracts alone exhibited an efficient inhibition of R. solanacearum. These findings could be used as an effective alternative preparation against the bacterial wilt of tomato.

Stress is one of the important factors that directly or indirectly affects the plant architecture, biochemical pathways, and growth and development. Melatonin (MEL) is an important stress hormone; however, the exogenous addition of melatonin to culture media stimulates the defense mechanism and releases higher quantities of secondary metabolites. In this study, submerged adventitious root cultures (SARCs) of diabetically important Stevia rebaudiana were exposed to variable concentrations (0.5-5.0 mg/L) of MEL in combination with 0.5 mg/L naphthalene acetic acid (NAA) to investigate the biomass accumulation during growth kinetics with 07 days intervals for a period of 56 days. The effects of exogenous MEL on the biosynthesis of stevioside (Stev.), total phenolics content (TPC), total flavonoids content (TFC), total phenolics production (TPP), total flavonoids production (TFP), total polyphenolics content (TPPC), fresh and dry weight (FW & DW), and antioxidant potential were also studied. Most of the SARCs displayed lag, exponential, stationary, and decline phases with variable biomass accumulation. The maximum fresh (236.54 g/L) and dry biomass (28.64 g/L) was observed in SARCs exposed to 3.0 mg/L MEL and 0.5 mg/L NAA. The same combination of MEL and NAA also enhanced the accumulation of TPC (18.96 mg/g-DW), TFC (6.33 mg/g-DW), TPP (271.51 mg/L), TFP (90.64 mg/L), and TPPC (25.29 mg/g-DW). Similarly, the highest stevioside biosynthesis (91.45 mg/g-DW) and antioxidant potential (86.15%) were observed in SARCs exposed to 3.0 mg/L MEL and NAA. Moreover, a strong correlation was observed between the biomass and the contents of phenolics, flavonoids, antioxidants, and stevioside. These results suggest that MEL is one of multidimensional stress hormones that modulate the biosynthetic pathways to release higher quantities of metabolites of interest for various industrial applications.

Traditional medicine is cheaper and easily available to local people, to care for most frequent diseases in the Northern parts of Pakistan. Our study aimed at inventorying medicine from local plants, documenting their uses, and assessing their market value in 2015-2018 during spring, summer, and winter seasons. A total of 15 trips were made, 5 in each season. Semi-structured interviews with 165 inhabitant’s age range between 20-80 years were conducted, analyzed the data is analyzed using Relative frequency of citation(RFC), Use Value(UV), Fidelity Level(FL), Informants consensus factor(ICF), and Jaccard index(JI) to find the most frequent and well-known used species in the area. A total of 86 species belonging to 39 vascular plant families, 33 genera were documented as medicinally important. Family Asteraceae was observed as the dominant family among all the families with 10 species, the leaf was the most used parts and decoction 36% was the most preferred preparation type. Herb was the predominant life form (67%). The maximum UV (0.92) was demonstrated by J. adhatoda L. species, while A. sativum L. shows maximum RFC (0.58), the highest ICF value represented by diarrhea and dermatitis 0.92, and high FL value is recorded 100%. According to our collections, wild species were 45%, invasive species were 38% and cultivated 17% recorded, dicots species were recorded more 81%. Seven 7 medicinal species is being economically important and export to the local and international market of the world, whereas P. integrima L. species were the most exported species according to the local dealers. The investigated area is rural and the local people depend on the area's plants for their health needs, and other uses like a vegetable, fuelwood, fodder, etc. The current result of RFC, UV, ICF, FL, and JI shows that medicinal flora needs to be pharmacologically and phytochemically investigated to prove their efficacy. The documentation of medicinal knowledge is important to preserve this precious old knowledge before it is lost forever, due to technological and environmental changes in the world.

In recent years, the biological synthesis of silver nanoparticles has captured researchers’ attention due to their unique chemical, physical and biological properties. In this study, we report an efficient, nonhazardous, and eco-friendly method for the production of antibacterial silver/silver chloride nanoparticles utilizing the leaf extract of Stachys emodi. The synthesis of se-Ag/AgClNPs was confirmed using UV-visible spectroscopy, DPPH free radical scavenging activity, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD). An intense peak absorbance was observed at 437 nm from the UV-visible analysis. The Stachys emodi extract showed the highest DPPH scavenging activity (89.4%). FTIR analysis detected various bands that indicated the presence of important functional groups. The SEM morphological study revealed spherical-shaped nanoparticles having a size ranging from 20 to 70 nm. The XRD pattern showed the formation of a spherical crystal of NPs. The antibacterial activity performed against Erwinia carotovora showed the maximum inhibition by centrifuged silver nanoparticles alone (se-Ag/AgClNPs) and in combination with leaf extract (se-Ag/AgClNPs + LE) and leaf extract (LE) of 98%, 93%, and 62% respectively. These findings suggested that biosynthesized NPs can be used to control plant pathogens effectively.

Background: Rural people living in Madyan Valley, Swat, Pakistan, rely extensively on medicinal plants for treating respiratory chest infections, cough, cold, asthma and bronchitis. Therefore, the present aims to identify specific medicinal plants for the treatment of respiratory diseases and analysis of different types of preparation for relieving respiratory ailments. Methods: Accordingly, men and women were interviewed using medicinal herb data sheets, supplemented with a transect walk. Uses, modes of preparation, storage and collection habitats of individual plants used for treating respiratory disorders were identified and recorded. Medicinal plants’ natural habitat provided a platform to further explore the active medicinal properties unknown to the community. Medicinal plant data were quantitatively measured using measurement models such as relative frequency citation (RFC); use value (UV) and fidelity level (FL). Results: The study recorded fifty-one plant species belonging to 32 families used for relieving respiratory diseases. Lamiaceae was the largest family with six species followed by Asteraceae and Apiaceae. About 30% of women knew the active medicinal properties, compared to 53% of men. The elderly women who had a deeper knowledge of plant remedies dispensed the plants in infusions, decoctions, and syrups; however, the most common form of intake was sundried powder typically administered with water. Conclusions: Herbal treatments in Northern Pakistan are reliable, inexpensive alternatives for treating respiratory conditions. We recommend appropriate management and the promotion of the cultivation and conservation of medicinal plants. In addition, raising awareness of the importance of medicinal plants for respiratory conditions must be established. Keywords: Medicinal plants, herbal preparations, respiratory diseases, traditional medicine, Northern Pakistan