Journal of Chemistry

Absorption​ of free radicals in the body cannot be done by antioxidant compounds originating from the human body, so exogenous antioxidants are required to help in their natural antioxidant action. Oxidative stress can be caused by an imbalance of free radical inhibitors and the accumulation of free radicals that enter cellular structures. Synthetic antioxidants found in external antioxidants are not the primary choice because they are harmful and carcinogenic. Therefore, using natural ingredients provides a necessary alternative to constructing novel natural antioxidants. Recent studies have highlighted critical analysis and evaluation that flavonoids are a unique class of secondary metabolites found in plants and used in communities as traditional therapeutics with proven bioactivity. This could support new discoveries based on various herbal medicines and in addition, the functional effectiveness of flavonoids as antioxidants against free radicals. In this review, there are several strengths in the discussion. First, the study takes a comprehensive approach by covering various aspects, including the properties and sources of free radicals, oxidative stress in relation to different diseases, antioxidant defense mechanisms, and the specific antioxidant mechanisms of flavonoids. Second, the focus on natural antioxidants, especially flavonoids, and also discussion about clinical applications and human studies, limitations, global perspectives, and future research directions of flavonoids compounds become references in the selection of natural medicines. But, several constraints should be considered when interpreting the findings of this review. First, the discussion about the mechanism of antioxidant compounds is only discussed in general and only takes one example of a compound (flavonoid) that has the potential as an antioxidant. Second, the lack of findings regarding the relationship between several diseases discussed with free radicals. Third, a limited number of studies investigated regarding clinical applications and human studies of some of the diseases discussed.

This study explores Daucus crinitus extracts (DCE) and zinc oxide nanoparticles (ZnO-NPs) synthesized using the extracts as corrosion inhibitors for carbon steel (CS) in HCl medium. The synthesized ZnO-NPs were characterized via UV-vis spectroscopy, exhibiting a peak at approximately 375 nm. The study employed weight loss (WL) and electrochemical measurements, alongside spectrophotometric evaluation of corrosion products. Surface morphology was assessed via scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS). Thermodynamic analysis revealed the physical adsorption of DCE on CS according to the Freundlich adsorption isotherm. Potentiodynamic polarization (PP) measurements indicated DCE as a mixed-type corrosion inhibitor. Electrochemical impedance spectroscopy (EIS) exhibited increased charge transfer resistance and reduced double-layer capacitance with inhibitory addition. The most effective inhibition was observed with butanol extract (BE) and improved more with its corresponding nanoparticles (BENPs), exhibiting inhibitory efficiencies of 80.20% and 91.20%, respectively, at 298 K with a concentration of 800 ppm. The evaluation of corrosion products using colorimetry revealed that the concentration of polyphenols decreased after the inhibitory process. Furthermore, the intensity of ferrous ions (Fe²⁺) decreased as the inhibitory concentration increased. In addition, SEM-EDS analysis confirmed the presence of ZnO-NPs, which enhanced the surface morphology and established a protective layer formed by the adsorbed inhibitors. The SEM-EDS analysis confirmed the presence of ZnO-NPs, the enhancement of surface morphology, and the establishment of a protective layer formed by the adsorbed inhibitors.

Aluminum can be found in water and vegetables in the form of the trivalent ion (Al³⁺), which can potentially contaminate food and water. Overconsumption of aluminum can lead to serious health problems in humans. Therefore, there is a need for an economical and simple procedure to detect the presence of aluminum. In this study, we synthesized a conjugate of Grewia asiatica extract with silver nanoparticles. The nanoparticle-stabilized fruit extract of Grewia asiatica was found to be an extremely selective sensor of Al³⁺ in tap water, DI water, industrial wastewater, and human blood plasma. We characterized the Grewia asiatica-conjugated silver nanoparticles (GA-AgNPs) using UV-visible, SEM, and AFM techniques and found that they were stable in an extensive pH range and different electrolyte concentrations up to 10 M NaCl. The GA-AgNPs were circular in shape with typical particle sizes of 65–97 nm. We inspected the photo physical properties of GA-AgNPs concerning metallic ions using UV-visible spectroscopy and found that they were highly selective for Al³⁺ ions, with no interfering ions detected in competitive experimentation. The absorption intensity of GA-AgNPs was directly related to Al³⁺ concentration over a wide range of concentrations (6.25–500 μM). Jobs plot experiment displayed 1 : 1 binding stoichiometry between GA-AgNPs, and Al³⁺. Additionally, GA-AgNPs were effectively utilized for the recognition of Al³⁺ in laboratory tap water, DI water, industrial wastewater, and human blood plasma.

Calotropis procera is a medicinal, traditional, and therapeutic plant in Pakistan. In this research study, the biological activities, for instance, anticancer, antileishmanial, antibacterial, antifungal, anti-inflammatory, and brine shrimp lethality assay and GC-MS are studied. MTT assay, antileishmanial bioassay, microplate Alamar Blue assay, agar tube dilution method, oxidative burst assay using chemiluminescence technique, B-hatching techniques, and triple quadrupole acquisition method MS parameters were the methods used for anticancer, antileishmanial, antibacterial, antifungal, anti-inflammatory, brine shrimp lethality assay, and gas chromatography-mass spectrometry. Whole plant methanol extract of Calotropis procera (WMECP) inhibited 69.1% of the growth of HeLa cell line with an IC₅₀ value of 3.1 ± 0.4 and whole plant n-hexane fraction of Calotropis procera (WHFCP) and whole plant and aqueous fraction of Calotropis procera (WAFCP) inhibited the growth by 70.2% and 65.2% with IC₅₀ values of 5.0 ± 0.3 and 17.1 ± 1.0. Whole plant methanol extract of Calotropis procera (WMECP) inhibited 70.1% of the growth of the PC3 cell line with an IC₅₀ value of 5.1 ± 0.3 and whole plant n-hexane fraction of Calotropis procera (WHFCP) and whole plant aqueous fraction of Calotropis procera (WAFCP) inhibited 61.6% and 59.7% with IC₅₀ values of 3.7 ± 0.5 and 16.4 ± 1.0. None of the extract and fractions of Calotropis procera showed anticancer activities against the 3T3 cell line. None of the extract and fractions of Calotropis procera showed antileishmanial, antibacterial, antifungal, and anti-inflammatory activities. Whole plant methanol extract of Calotropis procera (WMECP) exhibited lethality at the highest concentration while other fractions did not exhibit lethality. GC-MS studies revealed that the whole plant methanol extract of Calotropis procera (WMECP) consists of 11 compounds, whole plant n-hexane fraction of Calotropis procera (WHFCP) consists of 9 compounds, and whole plant aqueous fraction of Calotropis procera (WAFCP) consists of 7 compounds.

Hedychium flavum is an edible, medicinal, and aromatic plant widely cultivated for its essential oil. So far, little studies have been done on its phytoconstituents and bioactivities. Hence, the research aimed to determine the chemical constituents of leaf essential oil (L-EO) and stem essential oil (S-EO) of H. flavum and first estimate their antibacterial, antioxidant, cytotoxic, and enzyme inhibitory activities. According to gas chromatography-flame ionization detector/mass spectrometer (GC-FID/MS) assay, L-EO was mainly composed of β-pinene (33.4%), α-pinene (10.4%), humulene (6.8%), β-caryophyllene (6.0%), eucalyptol (6.0%), caryophyllene oxide (5.5%), endo-borneol (3.8%), humulene epoxide II (3.7%), and D-limonene (3.2%). The predominant components of S-EO were β-pinene (17.2%), eucalyptol (9.7%), nerolidol (7.8%), α-phellandrene (6.7%), α-pinene (5.8%), β-caryophyllene (5.4%), terpinen-4-ol (4.5%), D-limonene (4.4%), p-cymene (3.7%), endo-borneol (3.5%), and α-terpineol (3.5%). For the bioactivities, L-EO and S-EO showed strong antibacterial activity against Escherichia coli, Enterococcus faecalis, and Bacillus subtilis with the minimum inhibitory concentration (MIC) of 9.77–625.00 µg/mL and the minimum bactericidal concentration (MBC) of 9.77–1250.00 µg/mL. Both L-EO and S-EO exhibited moderate antioxidant activity in the DPPH (14.52 ± 0.93 mg/mL and 4.73 ± 0.15 mg/mL, respectively) and ABTS (4.05 ± 0.75 mg/mL and 2.38 ± 0.14 mg/mL, respectively) free radical scavenging capacity. S-EO showed selective cytotoxicity on human leukemic K562 cell line (IC₅₀ = 93.94 ± 0.91 µg/mL), which was nearly three times that of noncancer L929 cell line (IC₅₀ = 294.49 ± 9.40 µg/mL). In enzyme inhibitory properties, L-EO exerted a potent inhibition on α-glucosidase (IC₅₀ = 1.03 ± 0.02 mg/mL), and both essential oils had weak inhibition against cholinesterase and tyrosinase. Thus, H. flavum L-EO and S-EO possess antibacterial, antioxidant, cytotoxic, and enzyme inhibitory activities with potential for exploitation in the food, cosmetic, and pharmaceutical industries.

Pharmaceutical excipients are classified based on the function(s) in the processing and/or finished product. However, functionality evaluations, procedures, and related acceptance criteria for excipients tend to depend on the dosage form, and assessment is usually done on a case-by-case basis. This means that any useful and reliable evaluation of the overall functionality-related properties is only possible within the context of the specific formulation method. This study evaluated the physicochemical, functional, and related properties of purified gum obtained from the stem bark of the Cussonia arborea tree. The purified gum was acidic (pH 5.32–5.50) with percentage (%) moisture content and insoluble matter of 13.33 ± 0.33 and 0.47 ± 0.01, respectively. Moreover, it was soluble in all the aqueous-based solvents but insoluble in all the organic solvents. The total ash of the gum was higher than that of international standard gum Arabic. Micromeritic properties indicated the need for a flow aid to improve flowability. Six formulated batches of tablets containing 0.5–5%w/w of gum, respectively, were generally soft with none passing the USP standard of drug dissolution indicating poor tablet binding and drug-releasing properties. The disintegration action of CAPG was poor (only batches containing 0.5 and 1% CAPG passed) and was not comparable to that of the standard corn starch. The gum was therefore considered a poor disintegrant and binder in the formulation of conventional release tablets.