Anti-oxidant, anti-estrogenic and anti-inflammatory activities of the UHPLC fingerprinted Acacia seyal Delile (Mimosaceae) extracts: possible anticancer modes of action

Ethnopharmacological relevance: According to a report published in 2025, Cameroon has the highest breast cancer mortality rate in Africa, with 91,300 deaths recorded in 2022 out of 198,300 new cases. Referring to the use of Acacia seyal Delile in Cameroonian traditional system to treat inflammatory conditions and cancer, we demonstrated that its hydro-ethanolic stem barks extract has anti-breast cancer potential in vitro and in vivo.Aim of the study: To evaluate the modes of action (anti-oxidant, anti-inflammatory and anti-estrogenic activities) of fractions (polyphenols, polysaccharides and residue) from Acacia seyal Delile. Materials and methods: Once the polyphenol-rich (ASpo), polysaccharides (ASsu) and residue (ASres) fractions were obtained, their total phenolic, and UPLC-HR-LC-MS fingerprints were determined and compared to those of the crude extract. Their in vitro anti-oxidant (DPPH, ABTS and total anti-oxidant capacity), anti-inflammatory (egg albumin denaturation and human erythrocyte membrane stabilization) and estrogenic/anti-estrogenic (MCF-7 cell proliferation/E-screen) activities were determined. Having demonstrated the best activities, the ASpo fraction was then evaluated for its in vivo anti-oxidant effect using the D-Galactose-induced oxidative stress rat model, anti-inflammatory activity via the carrageenan induced-inflammation rat model and estrogenic/anti-estrogenic activity through the 3-day uterotrophic assay in rats. Results: The Acacia seyal Delile polyphenol-rich fraction (ASpo) showed a higher total phenol content (6292.53 ± 282.03 μg Eq ascorbic acid/mg dry extract) with its UHPLC chromatograms presenting many peaks putatively detected in the range of flavonoids. It was the most potent fraction with potent anti-oxidative activities (EC₅₀ of 0.05 mg/mL, 100 % free radical scavenging after 15 min in DPPH). It contents 2.9 mg Eq trolox/g dry matter of antiradical ingredients and 2803.92 ± 9.61 μg Eq ascorbic acid/g dry matter in ATBS and TAC, respectively. ASpo at 4 mg/mL had a highest percentage of membrane stabilization (97.9 %) and protected the egg albumin against denaturation induced by the heat with IC₅₀ of 70.2 μg/mL. ASpo exhibited in vitro estrogenic and anti-estrogenic effect in MCF-7 cells in dose-dependent fashion. In vivo, ASpo exhibited a significant and dose-dependent reduction of the MDA levels, increase the GSH levels and SOD activity with a maximum effect (p < 0.001) observed at 150 mg/kg BW. However, at a dose of 75 mg/kg, ASpo had a similar effect to that induced by the crude extract (ASEH) at a dose of 150 mg/kg BW. The ASpo exhibited a dose-dependent protection against hepatotoxicity and nephrotoxicity induced by the D-Galactose in rats, as well as a dose-dependent and time-dependent inhibition of carrageenan-induced acute inflammation in the rat hind paws. It induced no estrogenic effect in vivo but a significant anti-estrogenic effect, which was abrogated when co-treated with an anti-estrogen, suggesting that its effects are mediated through estrogen receptors. Conclusion: Out of the three fraction of Acacia seyal Delile, the polyphenol-rich fraction (ASpo) have inherited the anti-oxidant, anti-inflammatory and anti-estrogenic potential of the crude extract, and appears to be a promising candidate in the fight against breast cancer.