BackgroundCarica papaya is a well known medicinal plant used in the West and Asian countries to cope several diseases. Patients were advised to eat papaya fruit frequently during dengue fever epidemic in Pakistan by physicians. This study was conducted to establish Polyphenols, flavonoids and antioxidant potential profile of extracts of all major parts of the C. papaya with seven major solvents i.e. water, ethanol, methanol, n-butanol, dichloromethane, ethyl acetate, and n-hexane.ResultsTPC, TFC, antioxidant and antibacterial potential were determined using different aqueous and organic solvents in addition to the determination of trace element in leaves, pulp and peel of C. papaya. Total soluble phenolics and flavonoids were found in promising quantity (≈66 mg GAE/g) especially in case of methanol and ethanol extracts. Antioxidant activity using DPPH free radical scavenging assay indicated leaves, bark, roots and pulp extracts showed >75.0 % scavenging potential while leaves and pulp showed 84.9 and 80.9 % inhibition of peroxidation, respectively. Reducing power assay showed leaves, pulp and roots extracts active to reduce Fe3+ to Fe2+ ions. The antibacterial study showed pulp extract is the best to cope infectious action of bacteria.ConclusionThis study was conducted to test the medicinal profile of all parts of C. papaya by extracting secondary metabolites with organic and aqueous solvents. Ethanol and methanol both were found to be the best solvents of choice to extract natural products to get maximum medicinal benefits and could be used to medicinal formulation against different infectious diseases.Graphical abstractMedicinal evaluation of different parts of C. papaya.

Interdigital electrodes (IDE) coated with ion-imprinted polymers (IIP) as recognition materials have been tested for screening and ion quantification. For screening of receptors, three polymer systems based on styrene (Sty), N-vinylpyrrolidone (NVP), and Sty-co-NVP were examined to identify an efficient recognition system for mercury ions in an aqueous environment. Results showed that all these polymeric systems can detect analyte even in very low concentration, that is, 10 ppm. Ion-imprinted polystyrene system proved to be an ideal receptor for detecting mercury ions in solution with a detection limit of 2 ppm. The sensitivity of ion-imprinted copolymeric system was further enhanced by making its composite with graphene oxide, and estimated detection limit of composite system was around 1 ppm. Ion- imprinted Sty-co-NVP graphene composite-based sensor system exhibits 2 to 5 times higher sensor response towards templated analyte in comparison to other polymer-based sensor systems. Moreover, the composite-based sensor shows very low or negligible response to competing metal ions with similar or different oxidation states such as Zn, Mg, Na, and As metal ions.

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Molecularly imprinted polymers have been used for the creation of an electrochemical sensor for the detection of sucrose, which are modified by using functionalized graphene (fG). Using AIBN as the free radical initiator and sucrose as the template, imprinted polymers are synthesized. The monomer, 4,4′-diisocyanatodiphenylmethane (DPDI), has both proton donor groups (N-H or O-H) and lone-pair donor groups (C=O). By creating H-bonds with electron donor groups (C=O), the proton donor group in this polymer may interact with the sugar molecule serving as its template. The sensor signals have improved as a result of the interaction between the monomer and the template. Thermogravimetric and differential thermal analysis (TGA/DTA) curves, scanning electron microscopy (SEM), and FT-IR spectroscopy have been employed to characterize the fabricated receptors. The fabricated sensor has exhibited a limit of detection of 16 ppb for the target analyte that is highly sensitive, linear, reversible, regenerative, and selective. Moreover, the sensor’s stability, reproducibility, and reusability have been evaluated for six months, following the device’s manufacturing, and the results revealed similar responses with the percentage error of less than 1%. Most importantly, this sensor has demonstrated a quick response time, which is very sensitive, stable, and selective.