GC-MS profiling, biological activities and molecular docking of total sterol extracts from Pontederia crassipes (Lake Tana, Ethiopia)

Abstract

This research aimed to investigate, for the first time, the antioxidant, anti-aging, antidiabetic, and antibacterial activities of the total sterol extract from the aerial parts of Pontederia crassipes collected from Lake Tana, Ethiopia. The plant material was extracted using a specific extraction process to get the total sterol extract. Antioxidant activities were investigated using 1, 1-Diphenyl-2-picrylhydrazyl, 2, 2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid and iron chelation assays. Anti-aging and antidiabetic activities were explored using in vitro enzymatic spectrophotometric methods. The antimicrobial activity was assessed against Pseudomonas aeruginosa and its ability to impede bacterial biofilm production as well as swimming and swarming mobilities. As results stigmasterol and β-sitosterol wereidentified as major constituents of the total sterol extract by GC-MS analysis. The findings showed that the total sterol extract possessed antioxidant activities in all the bioassays and a promising antiaging effect with significant anti-tyrosinase, anti-collagenase, and anti-elastaseactivities. Moderate inhibitory effects on α-amylase and α-glucosidase activities were observed in the plant extract. Moreover, the total sterol extract induced a significant antibiofilm activity in P. aeruginosa at sub-inhibitory concentrations. Furthermore, the extract showed no sign of toxicity against human epidermal keratinocytes and human skin fibroblast cell lines. Molecular docking analyses confirmed that the major compounds identified by GC-MS exhibited more negative binding energies toward the target proteins, indicating stronger binding affinities. These in silico findings support the moderate antidiabetic and anti-aging activities observed experimentally, providing mechanistic insight into the inhibition of the corresponding enzymes. Overall, the results suggest that the aerial parts of P. crassipes are a sterol-rich source with potential applicability in skin-care formulations and possible health-promoting effects, including supportive roles in diabetes management, warranting further investigation.