Terpenoids are naturally occurring secondary metabolites that consist of isoprene units (i.e., 2-methyl-1,3-butadiene). Terpenoids became recognized because of their diverse pharmacological benefits, such as anti-cancer, anti-inflammatory, antioxidant, analgesic, antibacterial, antifungal, hepatoprotective, antiviral, and antiparasitic activities. But most of these compounds have limited lipophilicity, dissolution rate, aqueous solubility, and drug permeability, so they are not used effectively. The low bioavailability significantly interferes with the performance of terpenoids to cure diseases, and the absorption process of terpenoids also becomes disrupted; therefore, their bioavailability in the blood becomes insufficient to achieve optimal treatment activity. Thus, to overcome this limitation, some strategies are used, such as nanotechnology (nanoparticles, carrier complexation), cocrystal, and glycosylation. Thus, this review summarizes the chemistry of terpenoids, factors that limit the bioavailability of terpenoids, and strategies employed to date with their design principles and outcomes possibly increasing their bioactivity.

Background: Flavonoids are a class of polyphenolic bioactive compounds obtained from plants, which have a wide range of chemical structures and properties. More than 9000 distinct flavonoid molecules have been identified, and have been found to regulate numerous developmental processes and play key biological roles in living organism. Objective: This review aims to highlight the hepatoprotective potentiality of flavonoids and co-relate their pharmacological activity with their chemical structure. Methods: With advancement in the field of research related to phytochemicals, it is evident that flavonoids have versatile health benefits, viz., antioxidant property, free radical scavenging capacity, anticancer activity. The basic structures are C6—C3—C6 rings with various substitution patterns, resulting in a succession of subclass compounds, and the relationships between chemical structures and bioactivity have previously been investigated. Results: The hepatoprotective effects of bioactive flavonoids derived from plants have been widely linked to their antioxidant activity, antiinflammatory activity, effects on sterol regulatory element-binding proteins (SREBP), peroxisome proliferator-activated receptor gamma (PPARγ) receptors, and inflammatory mediator cytokines according to numerous studies. The C2-C3 double bond at the A ring, as well as the hydroxyl groups of C3′or C4′, and the carbonyl group at position C4,have been shown to augment their hepatoprotective activities; however, hydroxymethylation at C3′ and C4′ has been found to diminish the hepatoprotective activity. Conclusion: The impact of flavonoid moieties and the structure-activity relationship of flavonoids related to combating various hepatic disorders have been vividly discussed in this review paper.

The incidence of cancer is increasing worldwide, affecting a vast majority of the human population, therefore, new different anticancer agents are being developed now and their safety still needs to be evaluated. Among them, pyridine based drugs are contributing a lot, as they are one of the imperative pharmacophores occurring synthetically as well as naturally in heterocyclic compounds, having a wide-range of therapeutic applications in the area of drug discovery that offers many chances for further improvement in antitumor agents via acting onto numerous receptors of extreme prominence. Many pyridine derivatives are reported to inhibit enzymes, receptors and many other targets for controlling and curing the global health issue of cancer. Nowadays in combination with other moieties, researchers are focusing on the development of pyridine-based new derivatives for cancer treatment. Therefore, this review sheds light on the recent therapeutic expansion of pyridine together with its molecular docking, structure-activity-relationship, availability in the market, a summary of recently patented and published research works that shall jointly help the scientists to produce effective drugs with the desired pharmacological activity.

Background: Oxadiazole core displays various pharmacological properties among five membered nitrogen heterocyclic compounds, specially 1,3,4-oxadiazole containing molecules that have occupied a particular place in the field of synthetic medicinal chemistry as surrogates (bioisosteres) of carboxylic acids, carboxamides and esters. Moreover, they are having widespread kind of applications in numerous zones as polymers, as luminescence producing materials and as electron- transporting materials and corrosion inhibitors. Methods: This study contains comprehensive and extensive literature survey on chemical reactivity and biological properties associated with 1,3,4-oxadiazole containing compounds. Results: This review summarises 1,3,4-oxadiazole moiety in numerous compounds with reported pharmacological activity such as antiviral, analgesic and anti-inflammatory, antitumor, antioxidant, insecticidal and anti-parasitic, etc. Nevertheless, ring opening reactions of the 1,3,4-oxadiazole core have also made great attention, as they produce new analogues containing an aliphatic nitrogen atom and to other ring systems. Conclusion: In relation to the occurrence of oxadiazoles in biologically active molecules, 1,3,4- oxadiazole core emerges as a structural subunit of countless significance and usefulness for the development of new drug aspirants applicable to the treatment of many diseases. It concludes that 1,3,4-oxadiazole core compounds are more efficacious and less toxic medicinal agents with respect to new opinions in the search for rational strategies.

Cancer is the world’s second leading cause of death, accounting for nearly 10 million deaths and 19.3 million new cases in 2020. Curcumin analogs are gaining popularity as anticancer agents currently. We reported herein the isolation, molecular engineering, molecular docking, antiproliferative, and anti-epidermal growth factor receptor (anti-EGFR) activities of curcumin analogs. Three curcumin analogs were prepared and docked against the epidermal growth factor receptor (EGFR), revealing efficient binding. Antiproliferative activity against 60 NCI cancer cell lines was assessed using National Cancer Institute (NCI US) protocols. The compound 3b,c demonstrated promising antiproliferative activity in single dose (at 10 µM) as well as five dose (0.01, 0.10, 1.00, 10, and 100 µM). Compound 3c inhibited leukemia cancer panel better than other cancer panels with growth inhibition of 50% (GI₅₀) values ranging from 1.48 to 2.73 µM, and the most promising inhibition with GI₅₀ of 1.25 µM was observed against leukemia cell line SR, while the least inhibition was found against non-small lung cancer cell line NCI-H226 with GI₅₀ value of 7.29 µM. Compounds 3b,c demonstrated superior antiproliferative activity than curcumin and gefitinib. In molecular docking, compound 3c had the most significant interaction with four H-bonds and three π–π stacking, and compound 3c was found to moderately inhibit EGFR. The curcumin analogs discovered in this study have the potential to accelerate the anticancer drug discovery program.