Synthetic heterocyclic compounds have incredible potential against different diseases; pyridines, phenolic compounds and the derivatives of azo moiety have shown excellent antimicrobial, antiviral, antidiabetic, anti-melanogenic, anti-ulcer, anticancer, anti-mycobacterial, anti-inflammatory, DNA binding and chemosensing activities. In the present review, the above-mentioned activities of the nitrogen-containing heterocyclic compounds (pyridines), hydroxyl (phenols) and azo derivatives are discussed with reference to the minimum inhibitory concentration and structure–activity relationship, which clearly indicate that the presence of nitrogen in the phenyl ring; in addition, the hydroxyl substituent and the incorporation of a diazo group is crucial for the improved efficacies of the compounds in probing different diseases. The comparison was made with the reported drugs and new synthetic derivatives that showed recent therapeutic perspectives made in the last five years.

The plant Caralluma edulis is traditionally used against diabetes and inflammatory conditions in Pakistan. This study was designed to provide scientific validation of the traditional use of Caralluma edulis. Phytochemicals were extracted from the plant by different solvents (distilled water, methanol, ethanol, and acetone) using the Soxhlet’s extraction method. Bioactive compounds were detected by gas chromatography–mass spectrometry (GC-MS). The in vitro anti-inflammatory activities (albumin denaturation, membrane stabilization, and proteinase inhibition) and antioxidant capacity (DPPH scavenging activity, FRAP reducing activity) of different extracts from Caralluma edulis were assessed. The antidiabetic potential of Caralluma edulis plant extracts was determined in acute and subacute diabetic rabbit models. Oxidative stress and enzymatic antioxidant status were also estimated in MDA, CAT, and SOD levels. Results showed that the methanol extract yielded the highest contents of phenolics, flavonoids, alkaloids, and terpenoids. The in vitro anti-inflammatory activity and antioxidant potential of the methanol extract were the highest among the tested solvents. The tested extracts did not show any remarkable antidiabetic activity in the acute diabetic model. However, all tested extracts demonstrated antidiabetic potential in the subacute diabetic model. No adverse effect was observed at the tested dose (200 mg/kg) of Caralluma edulis extracts in experimental animals. It is concluded that methanol is the key solvent for extracting bioactive compounds from Caralluma edulis. The plant can be used against inflammatory disorders and may prove a potential candidate for drug development. Long-term use of Caralluma edulis at the tested dose (200 mg/kg) showed antidiabetic properties in the animal model.

In this review, specific therapeutic and medicinal advantages including antiviral, antibacterial, antifungal and antitumor, strategies for drug designing, structure-activity relationship, advances in the syntheses of azo and hippuric acid derivatives of more than 50 compounds have been discussed since 2009-2018. It is found that phenyl-diazenyl azo derivatives and pyridinyl substituted hippuric acid derivatives showed promising antiretroviral potential. The incorporation of azo functionality to the respective quinolones and coumarin moieties and the insertion of thiocarbazone to hippuric acid displayed immense antibacterial activities. While, azo and hippuric acid derivatives of triazole and phenyl species gave maximum fungicidal as well as cytotoxic activities.

Designing and developing small organic molecules for use as urease inhibitors is challenging due to the need for ecosystem sustainability and the requirement to prevent health risks related to the human stomach and urinary tract. Moreover, imaging analysis is widely utilized for tracking infections in intracellular and in vivo systems, which requires drug molecules with emissive potential, specifically in the low-energy region. This study comprises the synthesis of a Schiff base ligand and its selected transition metals to evaluate their UV/fluorescence properties, inhibitory activity against urease, and molecular docking. Screening of the symmetrical cage-like ligand and its metal complexes with various eco-friendly transition metals revealed significant urease inhibition potential. The IC₅₀ value of the ligand for urease inhibition was 21.80 ± 1.88 µM, comparable to that of thiourea. Notably, upon coordination with transition metals, the ligand–nickel and ligand–copper complexes exhibited even greater potency than the reference compound, with IC₅₀ values of 11.8 ± 1.14 and 9.31 ± 1.31 µM, respectively. The ligand–cobalt complex exhibited an enzyme inhibitory potential comparable with thiourea, while the zinc and iron complexes demonstrated the least activity, which might be due to weaker interactions with the investigated protein. Meanwhile, all the metal complexes demonstrated a pronounced optical response, which could be utilized for fluorescence-guided targeted drug delivery applications in the future. Molecular docking analysis and IC₅₀ values from in vitro urease inhibition screening showed a trend of increasing activity from compounds 7d to 7c to 7b. Enzyme kinetics studies using the Lineweaver–Burk plot indicated mixed-type inhibition against 7c and non-competitive inhibition against 7d.