Comprehensive Review on Synthetic Approaches and Biological Activities of 1,3,4-Oxadiazole

Among the large variety of nitrogen and oxygen heterocycles, 1,3,4-oxadiazole, the scaffold, has attracted considerable attention owing to its ability to showing an extensive range of pharmacological actions. Therefore, significant efforts of organic chemists have been directed towards the construction of new drug candidates containing 1,3,4-oxadiazole subunits connected to a known pharmaceutical or a potential pharmacophore. This digest highlights recent publications on the various synthesis techniques of 1,3,4-oxadiazole and related compounds over the previous ten years (2011–2021). The purpose of this review is to learn about several ways for synthesizing oxadiazole. These heterocyclics are formed mainly by the cyclization reactions of various reactants under diverse circumstances. According to the literature investigations, they were given a high priority for their pharmacological significance, such as anticonvulsant, anticancer, antioxidant, anti-inflammatory, antibacterial, antidiabetic, etc.

FDA-Approved Oximes and Their Significance in Medicinal Chemistry

Despite the scientific advancements, organophosphate (OP) poisoning continues to be a major threat to humans, accounting for nearly one million poisoning cases every year leading to at least 20,000 deaths worldwide. Oximes represent the most important class in medicinal chemistry, renowned for their widespread applications as OP antidotes, drugs and intermediates for the synthesis of several pharmacological derivatives. Common oxime based reactivators or nerve antidotes include pralidoxime, obidoxime, HI-6, trimedoxime and methoxime, among which pralidoxime is the only FDA-approved drug. Cephalosporins are β-lactam based antibiotics and serve as widely acclaimed tools in fighting bacterial infections. Oxime based cephalosporins have emerged as an important class of drugs with improved efficacy and a broad spectrum of anti-microbial activity against Gram-positive and Gram-negative pathogens. Among the several oxime based derivatives, cefuroxime, ceftizoxime, cefpodoxime and cefmenoxime are the FDA approved oxime-based antibiotics. Given the pharmacological significance of oximes, in the present paper, we put together all the FDA-approved oximes and discuss their mechanism of action, pharmacokinetics and synthesis.

Phytochemical Analysis, Pharmacological Activities, Isolation and Characterization of Bioactive Compounds from the Roots of Sterculia urens Roxb.

The present study was intended to explore the pharmacological significance of the crude root extract of Sterculia urens Roxb. Further the bio-active compounds were isolated and characterized using chromatographic and spectroscopic techniques. Soxhlet extraction apparatus was utilized for isolation of the chemical constituents from the root using a series of solvents such as n-hexane, ethyl acetate, methanol and water. The pharmacological activities such as inhibition of DPPH radical, α-amylase enzyme activity, albumin denaturation along with antibacterial and thrombolytic activities. The isolation of purified bioactive constituents was carried using preparative HPLC technique and the purified compounds were characterized using spectroscopic techniques like NMR, IR and mass. Among the crude root extracts, methanolic extract shows high DPPH radical scavenging activity with IC50 concentration of 26.74 ± 0.08 μg/mL. The IC50 concentrations in α-amylase enzyme inhibition activity was 263.96 ± 0.90, 127.73 ± 1.23 and 223.54 ± 4.76 μg/mL, respectively for ethyl acetate, methanol and water extracts, respectively. The methanolic extract shows high albumin denaturation inhibition assay than other extracts with IC50 concentration as 137.09 ± 0.20 μg/mL, which is very close to standard ascorbic acid. The methanolic extract also shows high % clot lysis than other extracts and results were comparable with 100 μL of streptokinase standard. The preparative HPLC followed by spectral analysis confirm that two known alkaloids (Sterculinine I & II) and three known flavonoids (gossypetin, apigenin and 6-hydroxyluteolin) were purified and characterized from the root methanol of Sterculia urens Roxb. The purified and identified compounds were reported for the first time in Sterculia urens Roxb.

Ethnobotanical Study on Garcinia (Clusiaceae) in China

The genus Garcinia L. (Clusiaceae) is gaining increasing scientific attention worldwide owing to its ethnobotanical and pharmacological significance. In China, even though Garcinia plants have long been used for food, ethnomedicine, building materials, and other purposes, a comprehensive ethnobotanical study of the genus is notably limited. In the current study, the ethnobotanical importance of Garcinia plants has been extensively investigated through field surveys and literature reviews. Our studies revealed that Garcinia plants have been used in folk medicine since ancient times in China, including the Northern Song Dynasty, 960–1127 AD. Through their extensive interactions with genus, the Chinese people have gained various traditional knowledge, which is reflected in the following six aspects: food, traditional medicines, ornamental trees, construction and technology, cultural and spiritual significance, and miscellaneous uses. In particular, the four species: Garcinia hanburyi , G. paucinervis , G. xanthochymus , and G. oblongifolia , have cultural or spiritual values, among which G. paucinervis could be considered a cultural keystone species in the local communities, considering its crucial contribution to people’s cultures, spirits, and community identity. However, in general, some concerns originating from swift socio-economic changes have also been identified in the knowledge and Garcinia species. Strategies are needed to conserve traditional botanical knowledge, as well as plants.

The optimization of spray-drying process for the development of apricot powder using response surface methodology

PurposeApricots are not only nutritionally-rich but also possess pharmacological significance owing to their high antioxidant activity, and they are rich in vitamins, fibers, bioactive phytochemicals and minerals. Because of its immense organoleptic characteristics, apricot juice (AJ) is well accepted; however, it has a limited shelf-life, thereby demanding it to be converted into other shelf-stable form. One of the approaches is converting this juice into dehydrated powder. Amongst the various dehydration techniques available, spray drying is usually preferred; however, it involves the use of several independent variables, which need to be optimized, thus prompting to optimize the process to obtain spray dried apricot powder (SDAP) with improved quality.Design/methodology/approachThe spray-drying process of apricot juice was done using the response surface approach. The process variables included the inlet air temperature of 135–220°C, gum arabic concentration of 4–25%, feed flow rate of 124–730 mL/h, feed total soluble solids (TSS) of 10-30°Brix and atomization speed of 11,400–28,000 rpm. The dependent responses were powder yield, hygroscopicity, solubility, moisture content, carotenoids (CT), ascorbic acid (AA), radical scavenging activity (RSA), lightness, wettability, bulk density, particle density and porosity.FindingsAmongst all independent variables, inlet air temperature had most predominant impact on all the investigated responses. The optimum processing conditions for development of apricot powder with optimum quality were 190°C inlet air temperature, 18.99% gum arabic, 300.05 mL/h feed flow rate, 24°Brix feed TSS and 17433.41 rpm atomization speed. The experimental values were found to be in agreement with the predicted values, indicating the suitability of models in predicting optimizing responses of apricot powder. Flowability as Carr's index (CI) (22.36 ± 1.01%) suggests fair flow of powder. Glass transition temperature of powder was 57.85 ± 2.03°C, which is much higher than that of ambient, suggesting its better shelf stability.Originality/valueTo the best of author's knowledge, very limited or very few studies have been carried out on the spray-drying process for the manufacture of SDAP. The results of this investigation will open up new horizons in the field of food industry in the Union Territory of Jammu and Kashmir, India or elsewhere in the apricot-growing areas of India.

An update on the progress of microbial biotransformation of commercial monoterpenes

Monoterpenes, a class of isoprenoid compounds, are extensively used in flavor, fragrance, perfumery, and cosmetics. They display many astonishing bioactive properties of biological and pharmacological significance. All monoterpenes are derived from universal precursor geranyl diphosphate. The demand for new monoterpenoids has been increasing in flavor, fragrances, perfumery, and pharmaceuticals. Chemical methods, which are harmful for human and the environment, synthesize most of these products. Over the years, researchers have developed alternative methods for the production of newer monoterpenoids. Microbial biotransformation is one of them, which relied on microbes and their enzymes. It has produced many new desirable commercially important monoterpenoids. A growing number of reports reflect an ever-expanding scope of microbial biotransformation in food and aroma industries. Simultaneously, our knowledge of the enzymology of monoterpene biosynthetic pathways has been increasing, which facilitated the biotransformation of monoterpenes. In this article, we have covered the progress made on microbial biotransformation of commercial monoterpenes with a brief introduction to their biosynthesis. We have collected several reports from authentic web sources, including Google Scholar, Pubmed, Web of Science, and Scopus published in the past few years to extract information on the topic.

Pharmacological Significance of Hesperidin and Hesperetin, Two Citrus Flavonoids, as Promising Antiviral Compounds for Prophylaxis Against and Combating COVID-19

Hesperidin and hesperetin are flavonoids that are abundantly present as constituents of citrus fruits. These compounds have attracted attention as several computational methods, mostly docking studies, have shown that hesperidin may bind to multiple regions of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (spike protein, angiotensin-converting enzyme 2, and proteases). Hesperidin has a low binding energy, both with the SARS-CoV-2 “spike” protein responsible for internalization, and also with the “PLpro” and “Mpro” responsible for transforming the early proteins of the virus into the complex responsible for viral replication. This suggests that these flavonoids could act as prophylactic agents by blocking several mechanisms of viral infection and replication, and thus helping the host cell to resist viral attack.