Natural Deep Eutectic Solvents for the Extraction of Spilanthol from Acmella oleracea (L.) R.K.Jansen

With a growing focus on green chemistry, the extraction of natural products with natural deep eutectic solvents (NADES), which are eutectic mixtures of hydrogen bond donors and acceptors, has become an ever-expanding field of research. However, the use of NADES for the extraction of spilanthol from Acmella oleracea (L.) R.K.Jansen has not yet been investigated. Therefore, in this study, 20 choline chloride-based NADES, and for comparison, ethanol, were used as green extraction agents for spilanthol from Acmella oleracea flower heads. The effects of time, water addition, and temperature on NADES extractions were investigated and analysed by HPLC-DAD quantification. Additionally, UHPLC-DAD-ESI-MSn results for dichloromethane extracts, as well as the isolation of spilanthol and other main constituents as reference compounds, are reported. The best green extraction results were achieved by choline chloride (ChCl) with 1,2-propanediol (P, 1:2 molar ratio, +20% water) at 244.58 µg/mL, comparable to yields with ethanol (245.93 µg/mL). Methylurea (MeU, 1:2, +20% water) also showed promising results as a hydrogen bond donor in combination with choline chloride (208.12 µg/mL). In further experiments with NADES ChCl/P (1:2) and ChCl/MeU (1:2), extraction time had the least effect on spilanthol extraction with NADES, while yield decreased with water addition over 20% and increased with extraction temperature up to 80 °C. NADES are promising extraction agents for the extraction of spilanthol, and these findings could lead to applicable extracts for medicinal purposes, due to their non-toxic constituents.

Pharmacological Characteristics of the Hydroethanolic Extract of Acmella oleracea (L) R. K. Jansen Flowers: ADME/Tox In Silico and In Vivo Antihypertensive and Chronic Toxicity Evaluation

Acmella oleracea (L.) R. K. Jansen, popularly known as jambu in Northern Brazil, is widely used in folk medicine and local cuisine. Its consumption in different ways reinforces the need for safety assessments. In this study, the major compounds found in the hydroethanolic extract of A. oleracea flowers (EHFAO) were characterized by ultra-performance liquid mass spectrometry (UHPLC-ESI-QTOF-MS/MS). The effects of oral administration of 100/mg/kg of EHFAO extract over 60 days in male spontaneously hypertensive (SHR) and Wistar (WR) rats and the in silico ADME/Tox predictions, lipophilicity, and water solubility were accomplished for the compounds identified. Spilanthol was detected as the foremost major compound at a concentration of 97.7%, followed by 1.53% scopoletin and 0.77% d-limonene. The treatment with EHFAO did not alter the animals´ weight over the studied period. Moderate alterations were observed solely in the hepatic enzymes AST (WR = 97 UI/L and SHR = 150 UI/L ∗ p < 0.05) and ALT (WR = 55 UI/L and SHR = 95 UI/L ∗ p < 0.05), while no relevant histopathological alterations were found. The in-silico study confirmed the in vivo findings, as the identified compounds were considered highly bioactive orally, due to their drug similarity profiles, adequate lipid solubility, bioavailability, and pharmacokinetics. Therefore, the chronic treatment with EHFAO was found safe at the concentration of 100/mg/kg, with no interference in the blood pressure levels neither appreciable toxic effects.

Jambu Flower Extract (Acmella oleracea) Increases the Antioxidant Potential of Beer with a Reduced Alcohol Content

Craft beers with different sensory perceptions have received the attention of more demanding consumers. In this sense, the application of plant extracts as brewing adjuncts is being increasingly studied. Allied with these perspectives is the consumption of lower alcoholic beverages, which also represents the desire for a market niche that has been growing gradually. The present work aimed to produce craft lager beer with the addition of plant extract and reduced alcohol content by partial replacement of malt with malt bagasse. The physical-chemical analyzes of the beer produced showed that it was possible to reduce the alcohol content by 40.5% compared to the control sample. In addition, an extract of Acmella oleracea (Jambu) obtained by supercritical extraction was added to increase the beer's antioxidant capacity. The ABTS, DPPH, and ORAC methods evaluated the antioxidant capacity. These assays were performed again after six months of storage. The quantification and identification of the significant substance in the extract (spilanthol) were performed using Gas Chromatography (GC-FID), Thin Layer Chromatography (TLC), and Attenuated Total Reflectance Infrared Spectroscopy (FTIR-ATR). The results showed significant increases in antioxidant activity compared to the sample without extract. This positive aspect opens a perspective for using jambu flower extract as a prominent antioxidant adjunct in beer.

Insecticidal efficacy of the essential oil of jambú (Acmella oleracea (L.) R.K. Jansen) cultivated in central Italy against filariasis mosquito vectors, houseflies and moth pests

ETHNOPHARMACOLOGICAL RELEVANCE

Acmella oleracea (L.) R.K. Jansen (Compositae), well-known as jambú, is a medicinal herb of pungent taste, native to Brazil but cultivated in different parts of the world due to its aromatic and pharmacological properties. In folk medicine, the plant has been used against parasites and to combat insects and mites. No data are available on the insecticidal activity of jambú essential oil.

AIM OF THE STUDY

To test the jambú essential oil obtained from A. oleracea cultivated in central Italy against the filariasis vector, Culex quinquefasciatus, the Egyptian cotton worm, Spodoptera littoralis, and the housefly, Musca domestica.

MATERIALS AND METHODS

The chemical composition of the essential oil was achieved by GC-FID and GC-MS analyses. Acute toxicity experiments were conducted on larvae of the filariasis vector C. quinquefasciatus and S. littoralis and adults of M. domestica to determine the LC₅₀(LD₅₀) and LC₉₀(LD₉₀) values of the oil, along with the positive control, α-cypermethrin.

RESULTS

(E)-caryophyllene (20.8%), β-pinene (17.3%), myrcene (17.1%) and caryophyllene oxide (10.0%) were the major volatile constituents. Interestingly, the oil contained little amounts (3.9%) of the insecticidal spilanthol. Jambú essential oil exerted relevant effects on C. quinquefasciatus (LC₅₀ = 42.2 mg L^-1, LC₉₀ = 73.6 mg L^-1) and S. littoralis 3rd instar larvae (LD₅₀ = 68.1 µg larva^-1, LD₉₀ = 132.1 µg larva^-1). High acute toxicity was also detected testing the jambú oil against adult females of M. domestica, achieving a LD₅₀ value of 44.3 µg adult^-1 and a LD₉₀ value of 87.5 µg adult^-1.

CONCLUSIONS

Taken together our data support the traditional use of jambú as an insecticidal agent and represent the scientific basis for the industrial exploitation of the essential oil in the fabrication of green insecticides.