Solvent polarity dictates the anti‐inflammatory potency and mechanism of two purslane ( Portulaca oleracea ) seed extracts

Abstract

This study aimed to assess the effect of solvent polarity on anti‐inflammatory potency and the underlying mechanisms of two purslane seed extracts. Methanol and dichloromethane extracts were prepared using Soxhlet extraction and chromatographically analyzed. Antioxidant activities were assessed by different assays, while the anti‐inflammatory potentials were assessed in RAW 264.7 macrophage cells. Methanol extraction yielded 15.5% water‐soluble extract while dichloromethane produced 3.74% fixed oil. Nineteen phenolic compounds were chromatographically identified in methanol extract compared with 16 in the fixed oil including omega fatty acids and phytosterols. Methanol extract showed significantly higher capacity in radical scavenging assays (p < .001), but the fixed oil showed higher total antioxidant capacity (p < .001). Both extracts demonstrated anti‐inflammatory potentials with different mechanisms, where the phenol‐rich methanol extract significantly reduced TNF‐α (p = .0371) and IL‐1β (p = .0029) production through an antioxidant‐mediated pathway, while the fixed oil inhibited COX1, COX2, and PGE2 gene expression through the upregulation of IL‐10. Practical applications Both purslane extracts presented herein demonstrated remarkable antioxidant/ anti‐inflammatory potentials that could be safely utilized as natural antioxidants and inflammation remedies or as functional food products, particularly that they showed no cytotoxic effects.

Portulaca oleracea L seed extracts counteract diabetic nephropathy through SDF-1/IL10/PPARγ–mediated tuning of keap1/Nrf2 and NF-κB transcription in Sprague Dawley rats

“…Still, the MO extract showed a rapid onset and longer duration of the antidiabetic effect, where it significantly alleviated the hyperglycemia, weight loss, and the rate of food/water intake within one week of treatment, unlike the MC fixed oil and the Losartan that exhibited their activity after 14 days. The superior antidiabetic activity of MO extract is probably related to a higher antioxidant capacity attributed to its protocatechuic acid-rich content [ 22 ]; a potent radical scavenger that was recently highlighted as Nrf2-inducer [ 37 ]. In a similar context, both extracts significantly improved the deregulated renal functions and restored the unbalanced redox system in diabetic kidneys.…”

“…However, each extract demonstrated a different pattern of renoprotection, where the MO extract– consistent with its anti-diabetic effect– showed a rapid onset of effect improving the early markers of renal nephropathy; however, for a short duration of action relative to the MC fixed oil that showed a better activity with a longer duration of action. These findings were not surprising given the potent anti-inflammatory activity of the ω-fatty acids-rich MC fixed oil that exhibited potent IL-10-mediated inhibition of PGE2 and COX2 transcription in RAW 264.7 macrophage cells [ 22 ].…”

“…Methanol (MO) extract and methylene chloride (MC) fixed oil were prepared from purslane seeds according to our previous report [ 22 ]. Purslane seeds were purchased from the local markets in Cairo-Egypt and were then authenticated by the senior botanist of El-Orman Garden (Giza, Egypt).…”

“…Besides the rich content of ω-3 fatty acids, purslane exhibits potent hypocholesterolemic and hypolipidemic activities owing to their high content of betalain pigments [ 18 , 21 ]. In our previous study, methanol (MO) and methylene chloride (MC) purslane seed extracts demonstrated remarkable antioxidant/anti-inflammatory potentials in vitro [ 22 ]. The chromatographic profiling revealed that protocatechuic acid (57.1%) represents the prominent phytoconstituent of MO extract, while ω-polysaturated fatty acids constituted ∼ 70% of the fixed oil (MC); prominently linoleic acid (43.2%) and palmitic acid (24.49%), with marginal fractions of phytosterols.…”

“…It was postulated that each extract undergoes a different anti-inflammatory mechanism that ultimately correlates with interrupting NF-κB transcription or phosphorylation/translocation. Specifically, the MO treatment of LPS-sensitized RAW 264.7 cells produced a significant inhibition of IL-1β and TNF-α production, which inferred a potential interception of NF-κB activation and subsequent nuclear translocation through neutralizing ROS trigger, whereas the fixed MC oil upregulated the levels of the anti-inflammatory cytokine IL-10, which intercepted the inflammatory cascade as indicated by the strong inverse correlation observed between IL-10 levels and the relative expression of PGE2 gene [ 22 ]. Herein, we aimed to assess these antioxidative/anti-inflammatory potentials in vivo in the context of type-1 diabetic nephropathy model, and to further explore the molecular mechanisms and signaling pathways underlying their anticipated renoprotective potentials.…”