Investigation of phytochemical composition and enzyme inhibitory potential of Anagallis arvensis L

LC-MS/MS profiling of Tipuana tipu flower, HPLC-DAD quantification of its bioactive components, and interrelationships with antioxidant, and anti-inflammatory activity: in vitro and in silico approaches

BACKGROUND

Fabaceae plays a crucial role in African traditional medicine as a source of large number of important folk medication, agriculture and food plants. In a search of potential antioxidant and anti-inflammatory candidates derived from locally cultivated plants, the flowers of Tipuana tipu (Benth.) Lillo growing in Egypt were subjected to extensive biological and phytochemical studies. The impact of the extraction technique on the estimated biological activities was investigated.

METHODS

The flowers were extracted using different solvents (aqueous, methanol, water/methanol (1:1), methanol/methylene chloride (1:1), and methylene chloride). The different extracts were subjected to antioxidant (DPPH, ABTS, and FRAP) and anti-inflammatory (COX-2 and 5-LOX) assays. The methanol extract was assessed for its inhibitory activity against iNOS, NO production, and pro-inflammatory cytokines (NF-KB, TNF-R2, TNF-α, IL-1β, and IL-6) in LPS-activated RAW 264.7 macrophages. The composition-activity relationship of the active methanol extract was further investigated using a comprehensive LC-QTOF-MS/MS analysis. The major identified phenolic compounds were further quantified using HPLC-DAD technique. The affinity of representative compounds to iNOS, COX-2, and 5-LOX target active sites was investigated using molecular docking and molecular dynamics simulations.

RESULTS

The methanol extract exhibited the highest radical scavenging capacity and enzyme inhibitory activities against COX-2 and 5-LOX enzymes with IC50 values of 10.6 ± 0.4 and 14.4 ± 1.0 µg/mL, respectively. It also inhibited iNOS enzyme activity, suppressed NO production, and decreased the secretion of pro-inflammatory cytokines. In total, 62 compounds were identified in the extract including flavonoids, coumarins, organic, phenolic, and fatty acids. Among them 18 phenolic compounds were quantified by HPLC-DAD. The highest docking scores were achieved by kaempferol-3-glucoside and orientin. Additionally, molecular dynamics simulations supported the docking findings.

CONCLUSION

The flower could be considered a potentially valuable component in herbal medicines owing to its unique composition and promising bioactivities. These findings encourage increased propagation of T. tipu or even tissue culturing of its flowers for bioprospecting of novel anti-inflammatory drugs. Such applications could be adopted as future approaches that benefit the biomedical field.

Advances in chemical and biological characterization of triterpenoid saponins from Anagallis arvensis L. using UHPLC-MS/MS and cell-based assays

A fraction enriched in triterpenoid saponins (F4) from Anagallis arvensis L. was chemically characterized by UHPLC-ESI-QTOF-MS/MS and NMR analyses. The results proposed the presence of nine monodesmosidic saponins derived from oleanolic acid, including two reported for the first time for this species, 3: 3-O-{β-D-glucopyranosyl (1→4)-[β-D-xylopyranosyl (1→2)]-β-D-glucopyranosyl (1→4)-[β-D-glucopyranosyl (1→2)]-α-L-arabinopyranosyl}-13β, 28-epoxy- 22 acetyl- 28 methoxy-16α, 24-oleananediol and 4: 3-O-{β-D-glucopyranosyl (1→4)-β-D-glucopyranosyl (1→4)-[β-D-xylopyranosyl (1→2)]-β-D-glucopyranosyl (1→4)-[β-D-glucopyranosyl (1→2)]-α-L-arabinopyranosyl}-13β, 28-epoxy- 16α, 30-oleananediol. Furthermore, haemolytic activity was determined by dot-blot autography, and cytotoxicity on human lymphocyte cultures was analysed according to metabolic activity (MTT assay) and membrane integrity (Trypan blue exclusion test). F4 showed mild cytotoxicity (%V > 50% at 100 μg/mL) on human lymphocytes under conditions of activation or not by LPS; moreover, showed haemolytic activity between 50 and 500 μg. This work contributed to phytochemical knowledge of the triterpenoid saponins from A. arvensis, and its cytotoxic effects on normal human cells.