Chemical analysis and bioactivity evaluation of Citrus limon leaves volatile oil from Palestine: investigating phytochemical, anti-inflammatory, antimicrobial, and cytotoxic properties

Introduction

Scientists consider repurposing discarded waste into valuable resources for the pharmaceutical, cosmetic, and food flavoring manufacturing industries a challenge to generate new revenue streams, lower production costs, and reduce waste. Therefore, the current study aimed to identify Citrus limon leaf volatile oil (VO) constituents from Palestine and assess its in vitro antimicrobial, anti-inflammatory, and cytotoxic properties.

Methods

The components of the VO were analyzed using Gas Chromatography/Mass Spectrometry (GC/MS). The antimicrobial activity of VO was assessed using a microdilution technique. The cyclooxygenases (COX-1 and COX-2) assay was utilized to assess the anti-inflammatory effect. An aqueous one solution cell proliferation (MTS) assay was employed to determine the cytotoxic effect of the VO.

Results

Thirty-six molecules were identified in the oil, and geranial, neral, and limonene are the most abundant molecules, comprising 31.06%, 23.98%, and 14.32%, respectively. The antimicrobial results showed that the VO has notable inhibition against Proteus vulgaris, Methicillin-resistant Staphylococcus aureus, and Candida albicans. The COX IC₅₀ calculations revealed that it has high potency against COX-2 IC₅₀ = 9.32 ± 0.88 µg/ml. The most potent cytotoxic effect of C. limon VO was noticed against MCF-7, with an IC₅₀ dose of 162.90 ± 1.85 mg/ml.

Conclusion

The GC-MS analyses revealed that geranial, neral, and limonene are the predominant compounds in the VO of C. limon leaves from Palestine. The biological test results demonstrated that the VO has potential inhibitory actions against some cancer cells, bacterial and fungal species, and COX-2 enzyme, suggesting it may be a viable choice for treating or preventing microbial infections, cancer, and inflammatory illnesses.