The genus Onosma belongs to the Boraginaceae family and contains over 230 species. The present review sheds light on the ethnopharmacology, phytoconstituents, bioactivity, and toxicology of the Onosma species from previous investigations. Furthermore, the paper also highlights the unresolved issues for the future investigations. The review included previous studies of the genus Onosma available from Google Scholar and Baidu Scholar, Science Direct, SciFinder, Wiley Online Library, and Web of Science. Until now, more than 200 chemical compounds have been detected from the genus Onosma, including naphthoquinone (33), flavonoids (30), hydrocarbon (23), phenolic (22), ester (17), alkaloids (20), aromatics (12), carboxylic acid (11), fatty acids (9), terpenoids (10), while the most important ones are rosmarinic, ferulic, protocatechuic, chlorogenic, caffeic, p-coumaric acids, and apigenin. The Onosma species are reported as traditional medicine for wound healing, heart disease, and kidney disorders, while the pharmacological investigations revealed that the extracts and the phytochemicals of Onosma species have different therapeutic properties including antioxidant, enzyme inhibitory, antitumor, hepatoprotective, antiviral, anti-inflammatory, and antimicrobial actions. The summarized knowledge in this review provides valuable ideas for the current and future drug discovery and a motivation for further investigation on the genus Onosma.

A new fluorescent probe L-Tryptophan was reported for the determination of folic acid (FA), based on its quenching effect of the fluorescence intensity of L-Tryptophan. The concentration of folic acid was proportional to the quenched fluorescence intensity of L-Tryptophan at an emission wavelength of 365 nm in Britton– Robinson (BR) buffer solution of pH 7. Optimized conditions of pH, time, order of addition of the reagent, potential interferences, concentrations of L-Tryptophan and buffer were investigated. Folic acid was determined in a linear range of 2.0 to 16.0 μg ml-1 with a correlation coefficient R2 0.9974. The limits of detection LOD and quantification LOQ values were 0.09 μg ml-1 and 0.27 μg ml-1, respectively. The standard deviation (RSD) values for five replicated measurements of 2, 8, 16 μg ml-1 folic acid were between 0.23 % and 1.07%. This method is efficient for routine analysis and quality control assay as it is relatively interferences free.

Centaurea virgata is broadly used as a traditional food and medicine across the globe for numerous health purposes. Although the species is reported to have antioxidant and anti‐inflammatory activities, literature data on its gastroprotective effects are scarce. Due to numerous shortcomings of conventional anti‐ulcer drugs, natural products gained renewed interest as a safer alternative. This study aimed to investigate the acute toxicity and gastroprotective effects of the aerial part extracts of Centaurea virgata (APCV) on ethanol‐induced gastric ulcers in Sprague–Dawley rats. Rats were divided into 5 groups: normal control, ulcer control (saline + EtOH), reference (lansoprazole + EtOH), APCV 100 mg/kg + EtOH, and APCV 200 mg/kg + EtOH. APCV 100 or 200 mg/kg, administered orally 1 h before the ethanol‐induced ulcer procedure delivery, increased the protective index % (26.82% and 31.40%, respectively). The histopathological results (using H&E and PAS) indicated preserved gastric defense barriers (restored mucus secretion and gastric pH) and tissue architecture as a result of APCV pretreatment. APCV intervention (100 and 200 mg/kg) increased superoxide dismutase by 24.33% and 62.14%; catalase by 59.07% and 90.37%; and upregulated IL‐10 by 24.40% and 79.52%, while significantly ( p < 0.01) lowering MDA by 25.97% and 38.77%, as well as significantly ( p < 0.001) downregulated IL‐6 by 14.67% and 33.08% and TNF‐α by 37.82% and 47.59%, respectively, compared to ulcer controls. It could also be noted that inhibited apoptosis (inhibited pro‐apoptotic Bax and increased HSP 70 appearances in gastric tissues) occurred in gastric tissues pretreated with APCV. Taken together, APCV exhibited a gastroprotective potential against gastric ulcers, which is attributed to its attenuation effects on oxidative stress, inflammatory, and apoptotic pathways.