Meselhy Ragab

Hydroxyl radical ( OH) scavenging capacity of aqueous dill (Anethum graveolens L.) shoot (ADSh) extract was assessed using electron paramagnetic resonance (EPR) spectroscopy. ADSh extract (at concentrations of 0.5 and 10 mg/ml) exerted high (OH) radical scavenging power. ADSh extract was further fractionated on Diaion HP-20 column to yield five fractions. EPR spin-trapping assay revealed fraction 4 (eluted with 75% aq. MeOH) to possess ( OH) radical scavenging capacity over a concentration range (0.01-10 mg/ml), whereas fraction 2 (eluted with 25% aq. MeOH) appeared to be pro-oxidant at concentration 0.01 mg/ml. UPLC-PDA-ESI-MS metabolite profiling of ADSh extract revealed 87 metabolites, of which 64 compounds were identified in fraction 4, the most active fraction. Furthermore, ADSh extract demonstrated a hepatoprotective effect against acetaminophen (APAP)-induced hepatotoxicity in rats. Pretreatment of rats with ADSh extract (200 mg/kg b.wt) markedly attenuated the increased in the serum hepatic enzyme levels. It also increased free glutathione level and total antioxidant capacity in the serum of treated rats. [Correction added on May 3, 2021, after first online publication: "rates" has been changed to "rats" in the previous sentence.] Additionally, levels of (TNF-α and IL-1β) were back to almost normal levels compared to the control group. The above findings suggest that ADSh extract has a protective effect against APAP-induced liver damage.

Phyllanthin and related lignans were found to be responsible, at least in part, for most of the activity of species. This observation encouraged the authors to develop methods for the preparation of an extract rich in phyllanthin and related lignans from the aerial parts of L. Direct extraction with solvents produced extracts with variable yields and contents of lignans. Lignans were identified by LC-ESI-MS analysis as phyllanthin (used as marker substance), hypophyllanthin, phylltetralin, nirtetralin, and niranthin. Extraction with boiling water produced 18.10 g% (/) extract with a trace amount of lignans (phyllanthin content of 0.33 ± 0.10 mg/g extract), while extraction with MeOH gave 3.6 g% / extract with a low phyllanthin content (3.1 mg/g extract), as determined by HPLC. However, Soxhlet extraction with hexane, CHCl, or acetone gave extracts with low yields (0.82, 1.12, and 3.40 g% /, respectively) and a higher phyllanthin contents (36.2 ± 2.6, 11.7 ± 1.68, and 11.7 ± 1.10 mg/g extract, respectively). Extraction quality and efficiency were optimized by adopting the following three different approaches: (1) Alkaline digestion of the plant material with 30% potassium hydroxide yielded 3.1 g% / of purified extract with high phyllanthin content (22.34 ± 0.13 mg/g); (2) microwave-assisted extraction using 80% MeOH gave an extract with a better yield (8.13 g% /) and phyllanthin content (21.2 ± 1.30 mg/g) (after filtration through a Diaion HP-20 column); and (3) treatment of the ground plant material at 50 °C with two hydrolytic enzymes, cellulase (9 U/g for 12 h) and then, protease (4 U/g up to 72 h) optimized the yield of extract (13.92 g% /) and phyllanthin content (25.9 mg/g extract and total lignans content of 85.87 mg/g extract). In conclusion, the nonconventional methods presented here are superior for optimizing the yield of extract and its lignan contents from the aerial parts of .