*Article* **Enantiomeric Composition, Antioxidant Capacity and Anticholinesterase Activity of Essential Oil from Leaves of Chirimoya (***Annona cherimola* **Mill.)**

**Eduardo Valarezo \*, Jeannette Ludeña, Estefanía Echeverria-Coronel, Luis Cartuche, Miguel Angel Meneses, James Calva and Vladimir Morocho**

> Departamento de Química, Universidad Técnica Particular de Loja, Loja 110150, Ecuador; isah4a@hotmail.com (J.L.); beecheverria@utpl.edu.ec (E.E.-C.); lecartuche@utpl.edu.ec (L.C.); mameneses@utpl.edu.ec (M.A.M.); jwcalva@utpl.edu.ec (J.C.); svmorocho@utpl.edu.ec (V.M.)

**\*** Correspondence: bevalarezo@utpl.edu.ec; Tel.: +593-7-3701444

**Abstract:** *Annona cherimola* Mill. is a native species of Ecuador cultivated worldwide for the flavor and properties of its fruit. In this study, hydrodistillation was used to isolate essential oil (EO) of fresh *Annona cherimola* leaves collected in Ecuadorian Sierra. The EO chemical composition was determined using a non-polar and a polar chromatographic column and enantiomeric distribution with an enantioselective column. The qualitative analysis was carried out by gas chromatography coupled to a mass spectrometer and quantitative analysis using gas chromatography equipped with a flame ionization detector. The antibacterial potency was assessed against seven Gram-negative bacteria and one Gram-positive bacterium. ABTS and DPPH assays were used to evaluate the radical scavenging properties of the EO. Spectrophotometric method was used to measure acetylcholinesterase inhibitory activity. GC-MS analysis allowed us to identify more than 99% of the EO chemical composition. Out of the fifty-three compounds identified, the main were germacrene D (28.77 ± 3.80%), sabinene (3, 9.05 ± 1.69%), β-pinene (4, 7.93 ± 0.685), (E)-caryophyllene (10.52 ± 1.64%) and bicyclogermacrene (11.12 ± 1.39%). Enantioselective analysis showed the existence of four pairs of enantiomers, the (−)-β-Pinene (1S, 5S) was found pure (100%). Chirimoya essential oil exhibited a strong antioxidant activity and a very strong anticholinesterase potential with an IC50 value of 41.51 ± 1.02 μg/mL. Additionally, EO presented a moderate activity against *Campylobacter jejuni* and *Klebsiella pneumoniae* with a MIC value of 500 μg/mL.

**Keywords:** essential oil; *Annona cherimola*; chemical composition; enantioselective analysis; antibacterial activity; antioxidant activity; anticholinesterase activity; germacrene D; *Campylobacter jejuni*
