Chemical Composition of the Essential Oils of Variegated Pink-Fleshed Lemon (Citrus x limon L. Burm. f.) and their Anti-Inflammatory and Antimicrobial Activities

Abstract

The volatile secondary metabolites of essential oils from fruit peel and leaves of variegated pink-fl eshed lemon (Citrus x limon) were investigated using GLC and GLC-MS (gas-liquid chromatography-mass spectroscopy). Altogether 141 compounds were identifi ed and quantifi ed, accounting for 99.59% and 96.33% of the total hydrodistilled peel and leaf oil, respectively. Limonene occurred in higher amounts in fruit peel (52.73%) than in leaf oil (29.13%). Neral (12.72%), neryl acetate (8.53%), ρ-menth-1-en-7-al (4.63%), β-pinene (6.35%), and nerol (4.42%) were the most abundant constituents in leaf oil, whereas γ-terpinene (9.88%), β-pinene (7.67%), geranial (4.44%), and neral (3.64%) dominated in the fruit peel oil. The antioxidant, anti-infl ammatory, antitrypanosomal, and antimicrobial activities of the fruit peel essential oil were evaluated. The oil had a low antioxidant activity with an IC 50 value of (26.66 ± 2.07) mg/ml as compared to the effi cient antioxidant ascorbic acid [IC 50 (16.32 ± 0.16) μg/ml]. The oil moderately inhibited soybean 5-lipoxygenase (5-LOX) with an IC 50 value of (32.05 ± 3.91) μg/ml and had moderate antitrypanosomal activity [IC 50 (60.90 ± 0.91) μg/ml]. In addition, moderate antimicrobial activities were detected against Gram-positive bacteria (Bacillus subtilis, Staphylococcus capitis, Micrococcus luteus), one Gram-negative bacterium (Pseudomonas fl uorescens), and yeasts (Saccharomyces cerevisiae, Candida parapsilosis).

Citrus limon (Lemon) Phenomenon—A Review of the Chemistry, Pharmacological Properties, Applications in the Modern Pharmaceutical, Food, and Cosmetics Industries, and Biotechnological Studies

“…The study found evidence that IL-6 markedly decreased during dietary supplementation with D-limonene [51]. Another study showed that the oil moderately inhibited soybean 5-lipoxygenase (5-LOX) with an IC 50 value of 32.05 µg/mL (Table 8) [52].…”

“…Moreover, under another study, C. limon essential oil showed antibacterial activity against Gram-positive bacteria (Bacillus subtilis (MIC 2 mg/mL), Staphylococcus capitis (MIC 4 mg/mL), Micrococcus luteus (MIC 4 mg/mL)), and Gram-negative (Pseudomonas fluorescens (MIC 4 mg/mL), Escherichia coli (100% inhibition)) ( Table 8) [52,53].…”

“…[8,48] Anti-inflammatory activity -Inhibition of NF-κB factor, nitric oxide (II) synthase (iNOS), induced cyclooxygenase (COX-2) (hesperidin, hesperitin); -Down-regulation of TLR-signaling pathway (limonin). [8,49,50,52] Antibacterial activity -Inhibiting activity against Gram-positive bacteria: Enterococcus faecalis, Bacillus subtilis; -Inhibiting activity against Gram-negative bacteria: Salmonella typhimurium, Shigella sonnei, Helicobacter pylori. [5,7] Antifungal activity -Inhibiting activity against Candida glabrata strains.…”

“…Currently, the essential oil from lemon, i.e., pure isolated linalol and citral, are used mainly as a flavouring and natural preservative due to their functional properties (antimicrobial, antifungal, etc.) [52,53]. In particular, they are often used to extend the short shelf-life of seafood products and in the production of some types of cheese because they significantly reduces populations of microorganisms, especially those from the family Enterobacteriaceae [41,76].…”

Evidence for the anti-inflammatory activity of Bupleurum marginatum (Apiaceae) extracts using in vitro and in vivo experiments supported by virtual screening

“…Nordihydroguaiaretic acid (NDGA) was used as a positive control (IC 50 = 0.24 lg/ ml). [26] In vivo assessment (Rat paw oedema assay)…”