Phytochemical Analysis, Evaluation of Anti-Inflammatory and Antidiabetic Properties of Dombeya Burgessiae Leaves Complemented by an In Silico Study.

Dombeya is a genus within the family Malvaceace and some of its species used traditionally in Africa to treat rheumatism, diarrhea, and to manage ulcers, abdominal pains, and headaches. This research focused on the phytochemical composition and biological evaluation of Dombeya burgessiae. Phytochemical profile of the leaves extract was investigated by measuring total phenolic, total flavonoid and by LC/MS analysis. The biological evaluation reported the antioxidant, anti-inflammatory and antidiabetic activity of the extract. Total phenolic content of the extract was found to be 14.56 mg GAE/ g dry extract; the flavonoid content was 10.8 mg QE/ g dry extract. LC/MS analysis identified thirty compounds including 9 flavonoids, 7 flavonoid glycosides, 5 fatty acids, 4 phenolic acids and 2 coumarin in addition to malic acid, vascinol and eugenol. The biological evaluation of D. burgessiae reported its antioxidant, anti-inflammatory, and antidiabetic activities. The antioxidant activity was assessed using the DPPH method, and the extract showed an IC50 of 82.51 µg/mL compared to trolox with an IC50 of 59.31 µg/mL. The anti-inflammatory effects were evaluated in vitro by assessing the extract's ability to inhibit COX-1 and COX-2. The results indicated that the extract had an inhibitory effect against COX-2 with an IC50 of 7.659 ± 0.39 µg/mL. The anti-diabetic activity was evaluated through α-amylase inhibition, with the extract showing IC50 of 741 ± 30 µg/mL compared to acarbose with an IC50 of 389 ± 20 µg/mL. Molecular docking was performed on the detected compounds to evaluate their binding affinity in the active site of human pancreatic alpha-amylase (PDB ID: 1B2Y). Isorhamnetin 3-glucoside and kaempferol-3-O-rutinoside (nictoflorin) showed excellent binding affinity energies of -14.6104 kcal/mol and -13.9317 kcal/mol, respectively, surpassing the positive control acarbose, which had a binding score of -13.1275 kcal/mol. In conclusion, the results indicate that D. burgessiae plant is promising as an anti-inflammatory and antidiabetic agent, warranting further in-depth phytochemical and biological evaluation. The docking study suggests that flavonoids are promising antidiabetic candidates through α-amylase inhibition.